The Multi-Site PFAS Health Study

Associations of a Prenatal Serum Per- and Polyfluoroalkyl Substance Mixture with the Cord Serum Metabolome in the HOME Study

Study Purpose: While numerous statistical methods have been developed to quantify the potential effects of chemical mixtures, few studies have evaluated the impact of PFAS mixtures on the fetal metabolome. Understanding the impact of PFAS exposures on the fetal metabolome is important because PFAS can cross the placenta, and the fetus may be more sensitive to environmental exposures compared to later life stages. To address these research gaps, this study evaluated the impact of a mixture of PFAS [PFOS, PFOA, PFHxS, and perfluorononanoic acid (PFNA)] concentrations on the fetal metabolome.

Prenatal Exposure to PFAS, Associations with Preterm Birth and Modification by Maternal Estrogen Levels: The Maoming Birth Study

Study Purpose: Assessing modification of PFAS-preterm birth associations by the different estrogen types may shed light on the reproductive toxicity of PFAS exposure and inform public health strategies for maternal and child health. In this context, we examined associations between maternal PFAS exposure and preterm birth in 879 Chinese women and then further explored if these associations were modified by
estrogen profile.

Study Conclusion: Our findings suggest that estrogen modified the association between maternal PFAS exposure and preterm birth. Further studies on maternal PFAS exposure and preterm birth, taking interaction effects of cord estrogens into account, are warranted.

Prenatal and Early Postnatal Exposure to Persistent Organic Pollutants (POPs): What Is the Correlation between Dioxins and Long-Chain Per- and Polyfluorinated Alkyl Substances (PFAS)?

Study Purpose: The study purpose is to investigate the potential correlation between prenatal and early postnatal exposure to persistent organic pollutants (POPs), specifically dioxins and long-chain per- and polyfluorinated alkyl substances (PFAS), and their impact on male reproductive health in adulthood. The study also aims to highlight the need for cautious interpretation of epidemiological data and the consideration of other lifestyle factors that may influence male reproductive health.

Study Conclusion: The study concludes that there is a moderate correlation between dioxin I-TEq and the four PFAS in maternal blood drawn 11 months after delivery. The study suggests that the observed correlations of plasma levels of dioxins and PFAS make simple association analyses of biological parameters and single compound groups difficult with respect to generating hypotheses of causal relationships, if not all compound groups can be analyzed in parallel. The study also highlights the need for cautious interpretation of epidemiological data with respect to causality, given the complex issue of co-exposure of different possible agents in a mixture with different doses, different possible windows of exposure, and the long latency time between exposure and possible effects.

Environmental exposure to per- and perfluoroalkyl substances in early pregnancy and newborn anogenital distance: A prospective cohort study

Study Purpose: The primary aim of this study was to investigate the potential associations between maternal exposure to PFAS during pregnancy and AGD in newborns.

Study Conclusion: This prospective cohort study has yielded additional evidence supporting the notion that PFAS exposure has the potential to influence AGD in both boys and girls. 

Prenatal exposure to per- and polyfluoroalkyl substances and DNA methylation in the placenta: A prospective cohort study

Study Purpose: Epidemiological studies regarding the relationship between per- and polyfluoroalkyl substances (PFAS) and DNA methylation were limited. We investigated the associations of maternal PFAS concentrations with placental DNA
methylation and examined the mediating role of methylation changes between PFAS and infant development.

Study Conclusion: Prenatal exposure to PFAS may contribute to alterations in the DNA methylation profile of the placental genome, most notably in angiogenesis and neurological development. Among the five candidate genes(i.e., CHST7, FGF13, IRS4, PHOX2A, and PLXDC1), placental DNA methylation of CHST7, IRS4, and PLXDC1 was associated with PFAS exposure. Additionally, decreased methylation of PLXDC1 may mediatethe association between PFOA exposure and increased risk of developmental delay in infants.

Prenatal per- and polyfluoroalkyl substances (PFAS) exposure in relation to preterm birth subtypes and size-for-gestational age in the LIFECODES cohort 2006-2008

Study Purpose: Many studies have linked prenatal PFAS exposure with increased risk of preterm birth and small for gestational age. This study examines associations of PFAS with subtypes of preterm birth, birthweight, and size for gestational age.

Study Conclusion: The effects of prenatal exposure to single and multiple types of PFAS on preterm birth and large for gestational age depend on the sex of the offspring. 

Fetal Glucocorticoid Mediates the Association between Prenatal Per- and Polyfluoroalkyl Substance Exposure and Neonatal Growth Index: Evidence from a Birth Cohort Study

Study Purpose: Glucocorticoid plays a role in the growth and organ development of the fetus. However, the effect of glucocorticoid on the association between PFAS exposure and fetal growth is unknown. This study measurements cortisol (active glucocorticoid in humans) and PFAS in maternal serum. The effects of newborn cortisol levels on the relationship between maternal PFAS and the neonatal growth index were estimated. 

Study Conclusion: These findings suggest that fetal glucocorticoid can affect the relationship between prenatal PFAS exposure and neonatal growth index. Higher maternal PFAS was also associated with greater fetal cortisol.

Associations between maternal exposure to perfluoroalkylated substances (PFASs) and infant birth weight: a meta-analysis

Study Purpose: The objective of this study was to evaluate associations between maternal exposure to PFAS and infant birth weight.

Study Conclusion: These findings suggest an adverse relationship between maternal exposure to PFAS during pregnancy and infant birth weight, and this relationship appears to vary by the type of PFAS and the geographical region. 

Association between prenatal exposure to perfluoroalkyl substance mixtures and intrauterine growth restriction risk: A large, nested case-control study in Guangxi, China

Study Purpose: Intrauterine growth restriction (IUGR) is an abnormal fetal growth pattern that can affect neonatal development. IUGR may be affected by prenatal exposure to environmental pollutants, but research linking PFAS exposure to IUGR is limited, with inconsistent results. This study aims to investigate the association between PFAS exposure and IUGR.

Study Conclusion: This study observed a relationship between increasing maternal exposure to PFHpA, PFDoA, and PFHxS with the risk of IUGR. Further study is needed to better understand the mechanisms behind this relationship.

Newborn metabolomic signatures of maternal per- and polyfluoroalkyl substance exposure and reduced length of gestation

Study Purpose: This study assessed the relationship between prenatal PFAS exposure and gestational age at birth and other birth outcomes among African Americans in Atlanta, GA.

Study Conclusion: Increases in maternal PFAS levels were associated with early term birth and medically indicated early birth prior to full-term. Newborn blood samples revealed disruptions in biological pathways that may be related to the PFAS and gestational at birth findings. 

Association between perfluoroalkyl and polyfluoroalkyl substances exposure and fetal overgrowth: A prospective birth cohort study conducted in China

Study Purpose: Prenatal exposure to PFAS has been associated with gestational diabetes and increased body fatness, but data on fetal overgrowth outcomes, including macrosomia and large for gestational age (LGA) is lacking. This study explores the relationship between maternal PFAS exposure and macrosomia and large for gestational age.

Study Conclusion: This study suggests that associations between PFAS and fetal overgrowth depend on the level of exposure. When the level of PFDA exceeded a threshold, it was associated with greater risks of developing macrosomia and LGA. When PFOA levels reached a threshold, it was associated with a higher risk of macrosomia. 

Prenatal exposure to per- and polyfluoroalkyl substances and pregnancy outcome in Austria

Study Purpose: PFAS may harm reproductive health. This study investigates possible associations between prenatal PFAS exposure and adverse pregnancy outcomes. 

Study Conclusion: This study found that exposure to PFOA, PFOS, PFHxS, and PFNA has decreased from 2010/2012 to 2017/2019. Further studies are needed to assess the relationship between prenatal PFAS exposure and pregnancy outcomes, in particular to confirm findings in this study of elevated PFDA levels contributing to increased risk of small for gestational age.

Association of Early Pregnancy Perfluoroalkyl and Polyfluoroalkyl Substance Exposure With Birth Outcomes

Study Purpose: PFAS have been linked to adverse birth outcomes. Previous research has shown that higher folate levels are associated with lower blood PFAS concentrations. This study examines whether prenatal folate levels modify the relationship between pregnancy PFAS concentrations, birth weight, and gestational age.

Study Conclusion: In this study, higher early pregnancy PFAS concentrations were associated with lower birth weight and gestational age, and higher risk of low birth weight only among mothers whose early pregnancy dietary folate intake or plasma folate levels were low (below the 25th percentiles). Findings suggest that mothers with the lowest folate status were more susceptible to PFAS-related adverse birth outcomes. These findings should be confirmed in future studies.

Metals and per- and polyfluoroalkyl substances mixtures and birth outcomes in the New Hampshire Birth Cohort Study: Beyond single-class mixture approaches

Study Purpose: This study aims to investigate the joint and individual impacts of PFAS, toxic metals, and essential elements on birth outcomes in a group of mothers and children.

Study Conclusion: This study identified a positive relationship between prenatal manganese (Mn) and head circumference at birth among male infants. Our findings suggest that, within the range of concentrations represented in our population, higher maternal Mn in pregnancy may contribute to a larger infant head circumference at birth. These findings need to be further investigated.

Pregnancy-related hemodynamic biomarkers in relation to trimester-specific maternal per - and polyfluoroalkyl substances exposures and adverse birth outcomes

Study Purpose: The distribution of PFAS in maternal and fetal tissues might be affected by pregnancy-related cardiovascular changes that occur. During pregnancy, blood volume increases and kidney function changes. These changes are thought to affect associations between PFAS exposure measures in late pregnancy with gestational length and fetal growth. This study analyzes two pregnancy-related cardiovascular markers, creatinine and estimated glomerular filtration rate (a marker of kidney function), as factors affecting trimester-specific relationships between maternal PFAS concentrations and adverse birth outcomes.

Study Conclusion: The results presented here demonstrate that the associations between prenatal PFAS exposure and adverse birth outcomes are modestly influenced by trimester of pregnancy, but are not strongly influenced by pregnancy-related cardiovascular changes. 

Unveiling Distribution of Per- and Polyfluoroalkyl Substances in Matched Placenta-Serum Tetrads: Novel Implications for Birth Outcome Mediated by Placental Vascular Disruption

Study Purpose: The placenta is needed for fetal development and can be a source of exposure to PFAS chemicals for the fetus. In this study, fetal-side placenta, maternal-side placenta, cord blood, and maternal blood samples were collected and PFAS levels measured to understand the distribution of PFAS in the placenta. 

Study Conclusion: This study explored comprehensive PFAS distribution profiles in placental-serum tetrads and revealed adverse placental vascular effects of PFASs.

Mediation effects of DNA methylation and hydroxymethylation on birth outcomes after prenatal per- and polyfluoroalkyl substances (PFAS) exposure in the Michigan mother-infant Pairs cohort

Study Purpose: PFAS may impact development of the genome, but current human evidence is limited to assessments of total DNA methylation, or DNA changes. This study assessed the associations between first trimester PFAS exposures with newborn DNA methylation. Then, the study evaluates associations between PFAS exposure and birth outcomes and whether DNA methylation impacts this association. 

Study Conclusion: This study demonstrates the role of specific types of DNA methylation on the relationship between PFAS exposure and birth outcomes. These results suggest that 5-mC and 5-hmC DNA methylation may be more sensitive to the developmental impacts of PFAS than total DNA methylation.

Mediating effect of endocrine hormones on association between per- and polyfluoroalkyl substances exposure and birth size: Findings from sheyang mini birth cohort study

Study Purpose: Prenatal exposure to PFAS has been reported to affect fetal growth, but current results have been inconsistent and the mechanism remains unclear. This study aims to evaluate the associations of prenatal exposure to single and/or multiple PFAS with birth size and to investigate whether thyroid hormones and reproductive hormones impact these associations.

Study Conclusion: Prenatal PFAS mixture exposure, especially PFNA, was associated with larger birth size. Neonatal thyroid stimulating hormone (TSH) levels partially affected this relationship.

Prenatal exposure to persistent and non-persistent chemical mixtures and associations with adverse birth outcomes in the Atlanta African American Maternal-Child Cohort

Study Purpose: African Americans experience higher rates of preterm birth and fetal growth restriction relative to other pregnant populations. Different exposure prenatally to environmental chemicals may partially explain these health disparities, as African Americans are disproportionately exposed to environmental hazards. This study examines the individual and mixture effects of PFAS and other environmental chemicals on gestational age at birth and birthweight for gestational age within a study of pregnant African Americans.

Study Conclusion: These findings suggest that prenatal exposure to multiple classes of environmental chemicals is associated with reduced gestational age and birthweight in African Americans.

Serum Concentrations of Selected Poly- and Perfluoroalkyl Substances (PFASs) in Pregnant Women and Associations with Birth Outcomes. A Cross-Sectional Study from Southern Malawi

Study Purpose: Exposure to PFAS has been associated with adverse pregnancy outcomes. The aim of this study was to examine factors associated with different serum PFAS concentrations in late pregnancy and their relationship with birth outcomes in Malawi.

Study Conclusion: Area of residence was the predictor for high concentrations of PFASs detected in serum of women from urban settings. Maternal serum PFAS concentrations were associated with some but not all birth outcomes. PFAS concentrations assessed in the present study, except PFHxS, are lower as compared to other parts of the world. Follow-up studies are needed to evaluate the association between the source of drinking water and maternal serum PFAS concentrations. 

Prenatal exposure to persistent organic pollutants and changes in infant growth and childhood growth trajectories

Study Purpose: This study investigates associations between prenatal exposure to persistent organic pollutants, including PFAS, and growth during infancy and childhood.

Study Conclusion: This study provides some support for the effect of prenatal PCB-153 on elevated infant growth. Prenatal p,p’-DDE may be associated with reduced infant growth. No persistent effects of prenatal POP exposures across childhood were observed. Larger prospective studies with repeated measures and advanced multi-pollutant approaches are warranted to validate these results and inform policy recommendations.

Systematic review and meta-analysis of birthweight and PFNA exposures

Study Purpose: This paper reviews published literature on the association between PFNA exposure and birthweight and assessed the potential risk of bias and sensitivity in the included studies. As part of this effort, the study assesses statistical similarities between the studies, evaluates the potential for publication bias, and uses meta-analyses to highlight any differences. 

Study Conclusion: Overall, we detected a sizeable deficit in mean birthweight per each unit increase of PFNA that was seen across numerous analyses and showed little evidence of either publication bias or between-study heterogeneity. Importantly, this is the first PFAS meta-analysis to report birthweight deficits that do not appear to be fully explained by sample timing considerations and pregnancy hemodynamics. 

Reduced Birth Weight and Exposure to Per- and Polyfluoroalkyl Substances: A Review of Possible Underlying Mechanisms Using the AOP-HelpFinder

Study Purpose: Prenatal exposure to PFAS may impair fetal growth. This study used the Adverse Outcome Pathway (AOP)-helpFinder tool to search PubMed for studies published until March 2021 that examined PFAS exposure in relation to birth weight, oxidative stress, hormones/hormone receptors, or growth signaling pathways. 

Study Conclusion: Overall, data suggest thyroid-damaging effects of PFAS affecting thyroid hormones, thyroid hormone gene expression, and histology that are associated in animal studies with decreased body and organ weight. The effects of PFAS on the complex relationships between oxidative stress, endocrine system function, adipogenesis, and fetal growth should be further explored.

Detected prenatal perfluorooctanoic acid (PFOA) exposure is associated with decreased fetal head biometric parameters in participants experiencing higher perceived stress during pregnancy in the MADRES cohort

Study Purpose: PFAS are known to cross the placenta during pregnancy. This study examines the influence of maternal PFAS levels on in utero fetal growth trajectories and assessed whether maternal stress modified these associations.

Study Conclusion: Maternal serum PFOA concentrations were associated with lower fetal head circumference and biparietal diameter growth trajectories across pregnancy and these associations were stronger among participants reporting higher levels of perceived stress.

High maternal glucose exacerbates the association between prenatal per- and polyfluoroalkyl substance exposure and reduced birth weight

Study Purpose: PFAS exposure has been associated with reduced birth weight. However, the association may be complicated by glucose status due to PFAS impact on fetal growth and placental transport. The objective of this study was to examine whether maternal glucose status modifies the association between prenatal PFAS exposure and birth weight z-score.

Study Conclusion: High maternal glucose level may increase the risk of reduced birth weight z-score related to prenatal PFAS exposure. Moreover, exploring these estimated effects with different FPG cutoffs may contribute to providing intervention strategies for pregnant women with high PFAS exposure.

Perfluoroalkyl Mixture Exposure in Relation to Fetal Growth: Potential Roles of Maternal Characteristics and Associations with Birth Outcomes

Study Purpose: PFAS exposure is suggested to interfere with fetal growth. However, limited investigations considered the roles of parity and delivery on PFAS distributions and the joint effects of PFAS mixtures on birth outcomes.

Study Conclusion: Maternal age, BMI, parity, and delivery mode were considered as influencing factors of PFAS burden. Multivariate linear regression suggested that prenatal exposure to PFOA, PFOS, and PFNS significantly reduced neonatal birth weight. PFHpA and PFHpS exposure were associated with increased respiration scores. PFOA and PFNS were identified as risk factors to preterm birth. 

Gestational exposure to perfluoroalkyl substances is associated with placental DNA methylation and birth size

Study Purpose: DNA methylation is one potential mechanism for the effects of gestational exposure to PFAS on fetal growth. This study investigated pregnant women who participated in a study in Northern China and determined the concentrations of PFAS and the methylation of two genes related to fetal growth and one marker for methylation in placental tissue.

Study Conclusion: This study measured 11 PFASs and DNA methylation of two typical genes related to fetal growth (IGF2 and NR3C1) and one surrogate marker for global genome (LINE-1) in the placenta of Chinese pregnant women. The data indicated that intrauterine PFASs exposure affected placental DNA methylation and reduced fetal growth and these effects showed some sex-specific differences. In view of relatively small sample size, more studies are needed to interrogate these findings.

Per- and polyfluoroalkyl substances and psychosocial stressors have a joint effect on adverse pregnancy outcomes in the Atlanta African American Maternal-Child cohort

Study Purpose: African Americans experience high rates of adverse pregnancy outcomes relative to white Americans. Differences in in utero exposure to environmental chemicals and psychosocial stressors may explain some of these disparities, as exposures to PFAS and experiences of discrimination have been linked to adverse birth outcomes. This study examines the joint effects of PFAS and psychosocial stress on birth outcomes in African Americans.

Study Conclusion: This study found that a simultaneous increase in in utero PFAS exposure and psychosocial stressors was associated with reduced birthweight for gestational age.

Preconception exposure to perfluoroalkyl and polyfluoroalkyl substances and couple fecundity: A couple-based exploration

Study Purpose: This study aimed to assess the effects of PFAS on time to pregnancy and infertility, with a focus on the effects of PFAS exposure from either partner.

Study Conclusion: In this study population, exposure to 6:2 diPAP and PFHpA (two emerging PFAS replacement) in women was associated with reduced couple fecundity, which was shown as prolonged time to pregnancy and increased risk of infertility. Certain PFAS protected couple fecundity in men, suggesting that PFAS may exert different effects in men and women related to couple fecundity.

Association between prenatal exposure to perfluoroalkyl substances and anogenital distance in female neonates

Study Purpose: Anogenital distance (AGD) is a marker of intrauterine androgen exposure and an indicator of genital development. An animal study reported that female rats exposed to PFOA or PFOS during 1-5 days following birth exhibited longer AGD, while studies in humans have been inconsistent. This study aimed to examine the effects of prenatal exposure to PFAS on the AGD in female neonates.

Study Conclusion: High maternal concentrations of PFAS were associated with increased AGD in female neonates, indicating that PFAS may impair reproductive development in female offspring in early life.

Associations of prenatal exposure to perfluoroalkyl substances with preterm birth: A family-based birth cohort study

Study Purpose: Studies have investigated associations between maternal exposure to PFAS and preterm birth, but the impact of paternal and overall family exposure to PFAS mixtures on preterm birth remains unknown. To address this knowledge gap, a total of 355 preterm births and 481 controls were selected for a family-based birth cohort study in a coastal area of China, between 2016 and 2018. 

Study Conclusion: These results suggest that higher family-level PFNA and PFDA exposure was associated with greater preterm birth risk, although the results for individual paternal, maternal and neonatal PFAS exposures were contradictory. These findings highlight a need to study further family PFAS concentrations and seafood consumption when assessing reproductive toxicity.

Gestational per- and polyfluoroalkyl substances exposure and infant body mass index trajectory in the New Hampshire Birth Cohort Study

Study Purpose: Mothers participating in the New Hampshire Birth Cohort Study (NHBCS) provided a plasma sample during pregnancy to measure concentrations of seven PFAS, and infant weight and length were measured in infants between birth and 12 months.

Study Conclusion: This study observed sex-specific associations of prenatal PFAS during pregnancy with growth patterns during infancy. Greater BMI growth during the first year was observed among girls to mothers with higher pregnancy concentrations of PFOS.

Effect of perfluoroalkyl exposure in pregnancy and infancy on intrauterine and childhood growth and anthropometry. Sub study from COPSAC2010 birth cohort

Study Purpose: PFOS and PFOA have a range of suspected negative health effects. It is hypothesized that exposure during prenatal and early postnatal life may have effects on intrauterine and childhood growth. This study investigates effects of PFOS and PFOS in pregnancy and infancy on intrauterine and childhood growth and anthropometry.

Study Conclusion: Higher PFOS and PFOA plasma concentrations during pregnancy had detrimental effects on fetal growth. The effects on childhood growth were not similar as PFOA increased child height, opposite of PFOS in models. Sex specific growth effects were affected by an altered lactosyl-ceramide metabolism, which may be a possible effect of PFOS exposure.

Association of single and multiple perfluoroalkyl substances exposure with preterm birth: Results from a Chinese birth cohort study

Study Purpose: PFAS are persistent organic pollutants that may lead to adverse birth outcomes, such as preterm birth (PTB). However, previous studies have reported inconsistent results on the association between PFASs and PTB, and lack of the epidemiological evidence regarding the effect of PFASs mixture on PTB. This study aimed to explore association of individual and multiple exposure to PFASs with PTB.

Study Conclusion: Overall, this study provided evidence of the effect of PFAS on preterm birth and found that prenatal exposure to PFAS mixtures was associated with higher risk of preterm birth, in which PFHpA, PFOS, and PFBS were the main contributors. 

Prenatal PFAS and psychosocial stress exposures in relation to fetal growth in two pregnancy cohorts: Applying environmental mixture methods to chemical and non-chemical stressors

Study Purpose: Prenatal exposure to individual PFAS and psychosocial stressors have been associated with reductions in fetal growth. Studies suggest cumulative or joint effects of chemical and non-chemical stressors on fetal growth. However, few studies have examined PFAS and non-chemical stressors together as a mixture, which better reflects real life exposure patterns. We examined joint associations between PFAS, perceived stress, and depression, and fetal growth using two approaches developed for exposure mixtures.

Study Conclusion: The study found that PFAS, perceived stress, and depression in combination were modestly associated with less fetal growth, which supports prior studies indicating that chemical and non-chemical stressors are jointly associated with adverse health outcomes.

Association Between Exposure to Per- and Polyfluoroalkyl Substances and Birth Outcomes: A Systematic Review and Meta-Analysis

Study Purpose: Emerging evidence suggests that PFAS affect birth outcomes, but the evidence is inconsistent. Therefore, this study aimed to systematically review the epidemiological evidence on PFAS exposure and birth outcomes.

Study Conclusion: This study showed that PFAS exposure was significantly associated with increased risks of various adverse birth outcomes and that different birth outcome indicators had different degrees of sensitivity to PFAS.  More studies are needed to confirm these results.

Associations between prenatal exposure to perfluoroalkyl substances, hypomethylation of MEST imprinted gene and birth outcomes

Study Purpose: PFAS exposure has been linked to adverse birth outcomes, but the underlying mechanism is not understood. DNA methylation changes in the MEST gene may be a mechanism of the prenatal exposure effects of PFASs on fetal growth. The aim of the study was to investigate the prenatal PFAS exposure effects on DNA methylation changes in MEST genes involved in fetal growth.

Study Conclusion: In conclusion, our results suggest that prenatal PFAS exposure, especially PFOS, is associated with lower methylation levels at MEST promoter region, which not only leverages the role of imprinted gene in ensuring the integrity of fetal growth but also provides a potential mechanism for evaluating the prenatal exposure effect.

High in Utero Exposure to Perfluoroalkyl Substances from Drinking Water and Birth Weight: A Cohort Study among Infants in Ronneby, Sweden

Study Purpose: In utero PFAS exposure can influence birth weight, but little is known about the effects at very high levels. This study aimed to examine the association between in utero PFAS exposure and birth weight. 

Study Conclusion: This study shows that high exposure to PFAS may influence birth weight in a sex-specific way, though this is likely a minor influence.

Concentrations of per- and polyfluoroalkyl substances (PFAS) in human placental tissues and associations with birth outcomes

Study Purpose: Previous studies have observed associations between maternal serum PFAS concentrations and adverse pregnancy and birth outcomes such as lower birth weight or pre-eclampsia; however, few studies have explored these associations with birth outcomes and placental tissue PFAS concentrations. The goal of this study was to measure placental PFAS concentrations and examine associations with birth outcomes. 

Study Conclusion: The present study shows that several PFAS are frequently detected in the placenta, and our observed associations with birth outcomes indicate potential concern for adverse health effects on infants exposed to the highest levels of PFAS exposure. In this study, PFAS placental exposure was associated with sex-specific birth outcomes. They found that the highest exposure of placental PFOS was associated with lower birth weight for gestational age in infant males and higher birth weight in female infants.

Relationships between maternal perfluoroalkyl substance levels, polymorphisms of receptor genes, and adverse birth outcomes in the Hokkaido birth cohort study, Japan

Study Purpose: The goal of this study was to look at the association between PFOA and PFOS in third trimester women's blood samples, maternal genotypes, and birth outcomes in their children.

Study Conclusion: PFOS levels during pregnancy were associated with decreased birth weight, chest circumference, and birth Ponderal index (a measure of thinness at birth) and that those associations were different according to the maternal genotype LXRB. Further studies may help identify more vulnerable or preventive genetic groups.

Per- and polyfluoroalkyl substance (PFAS) exposure, maternal metabolomic perturbation, and fetal growth in African American women: A meet-in-the-middle approach

Study Purpose: Prenatal exposures to PFAS have been linked to reduced fetal growth. This study aims to investigate biological pathways and biomarkers underlying the association between serum PFAS and fetal growth using high-resolution metabolomics in a cohort of pregnant African American women in the Atlanta area, Georgia.

Study Conclusion: In this cohort of pregnant African American women, higher serum concentrations of PFOA and PFNA were associated with reduced fetal growth. Perturbations of biological pathways involved in amino acid, lipid and fatty acid, bile acid, and androgenic hormone metabolism were associated with PFAS exposures and reduced fetal growth, and uric acid was shown to be a potential intermediate biomarker. Our results provide opportunities for future studies to develop early detection and intervention for PFAS-induced fetal growth restriction.

Associations between exposure to perfluoroalkyl substances and birth outcomes: A meta-analysis

Study Purpose: This study reviews the published literature on the effects of prenatal PFAS exposure on birth outcomes, specifically premature birth, low birth weight, small for gestational age, and miscarriage.

Study Conclusion: In this study, we observed significant associations between PFOS and premature birth, PFOA and miscarriage, and PFOS and low birth weight. Study region, sampling time, and sample were potential sources of differences between the studies included in this paper. 

Association of maternal exposure to perfluoroalkyl and polyfluoroalkyl substances with infant growth from birth to 12 months: A prospective cohort study

Study Purpose: Although maternal PFASs have been associated with adverse birth outcomes, much less is known about their impact on infant growth during early infancy. This study investigates the association between maternal PFASs exposure and infant growth during the first 12 months of life.

Study Conclusion: In this study, there were negative associations found for maternal PFHpA exposure and infant length and PFBS exposure and weight and BMI. Maternal PFDoA exposure was positively associated with weight and BMI. The adverse association of maternal PFHpA exposure and infant length was more pronounced in males.

Early pregnancy loss: Do Per- and polyfluoroalkyl substances matter?

Study Purpose: PFAS can transfer across the blood-follicle barrier. However, it is unknown whether PFAS can affect human fertility. This study aims to analyze the associations of women's exposure to PFAs with pregnancy loss, the relevant processes of fertilization, zygote implantation, and embryo development.

Study Conclusion: Overall, this study concluded that most PFAS were not associated with early pregnancy loss at the current average exposure levels. As for the PFDA, there may exist susceptibility among different populations.

Association between maternal exposure to perfluoroalkyl and polyfluoroalkyl substances and risks of adverse pregnancy outcomes: A systematic review and meta-analysis

Study Purpose: This reviews and analyzes previous studies on the relationship of maternal PFAS exposure and adverse pregnancy outcomes.

Study Conclusion: It was found that maternal exposure to PFOS could be positively associated with preterm birth, while no statistically significant association have been found between PFASs exposure and miscarriage and stillbirth. Epidemiological evidence to date are insufficient to draw definitive conclusions on potential toxicities of PFASs with stronger statistical power.

Prenatal exposure to mixtures of persistent endocrine disrupting chemicals and postnatal body size in British girls

Study Purpose: This study investigates the association of prenatal exposure to endocrine disrupting chemicals such as PFAS, PCBs, and OCPS as mixtures with postnatal body size in female offspring.

Study Conclusion: This study found an inverse association between prenatal exposure to PFAS, PCBs, and OCPs and longitudinal postnatal body size through age 19 months.

Associations of paternal and maternal per- and polyfluoroalkyl substances exposure with cord serum reproductive hormones, placental steroidogenic enzyme and birth weight

Study Purpose: Maternal PFAS exposure has been associated with placental function and fetal growth. In this study, they evaluate the associations of maternal or paternal PFAS levels with placental function and fetal growth measures.

Study Conclusion: Several maternal PFAS were associated with fetal steroid hormones and placental enzymes. Despite a correlation of PFAS level within the couples, no association was found for paternal PFAS exposure on these outcomes. The findings suggest the intrauterine PFAS exposure effect on fetal endocrine hormones and growth is unlikely to be confounded by exposure sources or familial factors shared within the couples.

The relationship between maternal perfluoroalkylated substances exposure and low birth weight of offspring: a systematic review and meta-analysis

Study Purpose: This article reviews past studies to assess the association between maternal PFAS exposure and low birth weight in offspring.

Study Conclusion: The present meta-analysis showed a significant positive association between maternal prenatal PFOS exposure and LBW of offspring, but no association between maternal PFOA exposure and LBW of offspring. Meanwhile, we observed regional factors might influence the occurrence of LBW

Per- and polyfluoroalkyl substances exposure during pregnancy and adverse pregnancy and birth outcomes: A systematic review and meta-analysis

Study Purpose: Exposure to PFAS during pregnancy has been suggested to be associated with adverse pregnancy and birth outcomes; however, the findings have been inconsistent. This study provides an overview of these associations.

Study Conclusion: Our findings indicated that PFOS, PFOA and PFNA exposure during pregnancy might be associated with increased preterm birth risk and that PFAS exposure might be associated with the risk of miscarriage and preeclampsia. Due to the limited evidence obtained for most associations, additional studies are required to confirm these findings.

Effects of gestational exposures to chemical mixtures on birth weight using Bayesian factor analysis in the Health Outcome and Measures of Environment (HOME) Study

Study Purpose: This study looks at the effects of gestational exposures to chemical mixtures (including PFAS) on infant birth weight.

Study Conclusion: This study used three different statistical approaches to examine the association between birth weight and prenatal exposures to seven types of environmental chemical mixtures. They found that PCBs and PFASs displayed strong associations with reduced birth weight.

Exploring associations between prenatal exposure to multiple endocrine disruptors and birth weight with exposure continuum mapping

Study Purpose: This study examines how prenatal exposure to environmental mixtures influence birth weight or other adverse outcomes

Study Conclusion: Findings from our study revealed a wide range of prenatal exposure scenarios and found that combinations exhibiting higher levels of PBDEs were associated with lower birth weight and combinations with higher levels of PCBs and PFAS were associated with increased birth weight. Our ECM approach provides a promising framework for supporting studies of other exposure mixtures.

Prenatal exposure to mixtures of persistent endocrine-disrupting chemicals and birth size in a population-based cohort of British girls

Study Purpose: This study investigates the association of prenatal exposure to mixtures of PFASs, PCBs, and pesticides with birth size among female offspring in the United Kingdom.

Study Conclusion: These results are consistent with the hypothesis that prenatal exposure to mixtures of endocrine-disrupting chemicals may affect birth size.

PFAS concentration during pregnancy in relation to cardiometabolic health and birth outcomes

Study Purpose: To examine the relationship between PFAS concentration during pregnancy in relation to cardiometabolic health and birth outcomes.

Study Conclusion: This study observed a positive association between PFAS exposure and serum-lipid concentrations. No association was observed between PFAS exposure and birth weight. PFNA was associated with preterm birth.

Associations between prenatal maternal exposure to per- and polyfluoroalkyl substances (PFAS) and polybrominated diphenyl ethers (PBDEs) and birth outcomes among pregnant women in San Francisco

Study Purpose: To observe the associations between prenatal maternal exposure PFAS and PBDEs, and birth outcomes among pregnant women in San Francisco.

Study Conclusion: Most PFAS were not associated with adverse birth outcomes.

Persistent organic pollutants exposure in newborn dried blood spots and infant weight status: A case-control study of low-income Hispanic mother-infant pairs

Study Purpose: This study looks at the associations between PFAS and other pollutant exposure and birth weight and overweight status at 18 months old.

Study Conclusion: Some PFASs were associated with lower birth weight. No associations with infant overweight status at 18 months were observed.

Per- and polyfluoroalkyl substances in drinking water and birthweight in the US: A county-level study

Study Purpose: This study used public data to examine potential associations between PFAS in drinking water and birthweight at county levels.

Study Conclusion: Associations between PFAS and birthweight varied by the PFAS chemical in this study. Conclusions should be interpretation due to limitations of the 2 public datasets used.

Exposure to per- and polyfluorinated alkyl substances in pregnant Brazilian women and its association with fetal growth

Study Purpose: In this study, concentrations of PFAS were determined in the second trimester of pregnancy in Brazilian women.

Study Conclusion: To the best of our knowledge, this is the first study to assess whole blood concentrations of PFASs in pregnant Brazilian women. The results suggest ubiquitous exposure to PFOS and PFOA in pregnant women from Ribeirao Preto, an industrialized region in Brazil. PFOS and PFOA concentrations in pregnant women were positively associated with IUGR (p < 0.05). Further studies are needed to evaluate long-term effects of prenatal exposure of PFASs on developmental outcomes in children.

Associations of Exposure to Perfluoroalkyl Substances With Thyroid Hormone Concentrations and Birth Size

Study Purpose: To determine the associations between maternal serum-PFAS concentrations and birth weight, birth length, and head circumference.

Study Conclusion: In this study, several PFASs were negatively associated with birth size and increased thyroid hormone levels; however, this did not explain lower birth weight among children exposed to PFAS.

Exposure to PFAS and small for gestational age newborns: A birth records study in Veneto Region (Italy)

Study Purpose: To examine the association between PFAS exposure and the risk of small for gestational age in a PFAS contaminated area.

Study Conclusion: The findings suggest that living in a contaminated area by PFAS may have an effect on fetal growth. Individual data on exposure is needed to confirm the direct association.   

Prenatal exposure to 11 perfluoroalkyl substances and fetal growth: A large-scale, prospective birth cohort study

Study Purpose: To investigate whether prenatal maternal exposure to 11 PFAS is associated with fetal growth.

Study Conclusion: The study results suggest that prenatal, maternal exposure to PFAS with longer carbon chains may have effect on fetal growth.

Maternal serum levels of perfluoroalkyl substances in early pregnancy and offspring birth weight

Study Purpose: To examine associations between first-trimester exposure to PFAS and birth weight and examine differences between boys and girls.

Study Conclusion: This study observed associations between prenatal exposure for five different PFASs and birth weight, with more pronounced associations in girls than in boys.

Prenatal exposure to per- and polyfluoroalkyl substances and infant growth and adiposity: the Healthy Start Study

Study Purpose: To test the hypothesis that faster growth in early infancy may be associated with maternal PFAS concentrations.

Study Conclusion: Although maternal PFAS concentrations are inversely associated with infant weight and adiposity at birth, rapid gain may occur in infancy, particularly in fat mass.      

First-trimester maternal concentrations of polyfluoroalkyl substances and fetal growth throughout pregnancy

Study Purpose: To determine the association between first-trimester maternal concentrations of PFAS and fetal growth.

Study Conclusion: Study results did not suggest an overall association between prenatal PFASs and fetal growth.

Maternal serum concentrations of perfluoroalkyl substances and birth size in British boys

Study Purpose: To determine the association of prenatal maternal serum concentrations and birth size in boys.

Study Conclusion: Prenatal exposure to high levels of PFOS may be associated with reduced birth size in male infants.

Cumulative exposure to environmental pollutants during early pregnancy and reduced fetal growth: the Project Viva cohort

Study Purpose: To examine interactions between early pregnancy exposure to cigarette smoke, traffic pollution, and PFAS on birth weight for gestational age.

Study Conclusion: Prenatal exposure to PFOS was associated with lower fetal growth.

Prenatal Exposure to Perfluoroalkyl Substances: Infant Birth Weight and Early Life Growth

Study Purpose: To determine if prenatal PFAS exposure was associated with birth weight, body composition and growth until 2 years of age.

Study Conclusion: The study observed inverse associations between prenatal serum PFAS concentrations and anthropometry until age 2 years. Prenatal serum PFAS concentrations were not associated with growth rate in the first 2 years of life.

Gestational exposure to endocrine disrupting chemicals in relation to infant birth weight: a Bayesian analysis of the HOME Study

Study Purpose: To examine the association of gestational exposure to endocrine disrupting chemicals, including PFAS.

Study Conclusion: Gestational exposure to PFAS had small associations with birth weight.          

Prenatal exposure to perfluoroalkyl substances and birth outcomes in a Spanish birth cohort

Study Purpose: To estimate associations between prenatal PFAS exposure and birth outcomes, and the influence of kidney factors, in a birth cohort.

Study Conclusion: PFAS showed little association with birth outcomes. Higher PFHxS, PFOA, and PFNA were associated with reduced birth weight. The association between PFOS and low birth weight seems to be sex-specific.

Maternal Concentrations of Perfluoroalkyl Substances and Fetal Markers of Metabolic Function and Birth Weight

Study Purpose: To examine associations between first-trimester maternal plasma PFAS concentrations and birth weight.

Study Conclusion: All associations between maternal PFAS concentrations and cord blood adipocytokine concentrations were small.

Other

Mixtures of persistent organic pollutants are found in vital organs of late gestation human fetuses

Study Purpose: This study measured persistent organic pollutants, such as PFAS, in maternal serum, placenta, and fetal tissues in 20 pregnancies that ended in stillbirth.

Study Conclusion: This study quantified many POPs in fetal tissues. All studied chemicals were detected in fetal adipose tissue even in places when the chemical was not detected in the maternal serum and placenta.

A case-cohort study of perinatal exposure to potential endocrine disrupters and the risk of cryptorchidism in the Norwegian HUMIS study

Study Purpose: Exposure to PFAS and other endocrine-disrupting chemicals (EDCs) during the critical period of testicular descent may increase the risk of cryptorchidism and male fertility. The objective of this study was to investigate 27 potential EDCs in breast milk and the risk of cryptorchidism.

Study Conclusion: Perinatal exposure to PCB-74, PCB-114, PCB-194, and B-HCH were associated with increased odds of congenital cryptorchidism.

Exposure to endocrine disrupting chemicals (EDCs) and cardiometabolic indices during pregnancy: The HOME Study

Study Purpose: Toxicology studies have identified pregnancy as a time sensitive to endocrine disrupting chemicals (EDCs), such as PFAS, and cardiometabolic indices in women. No study has examined this in humans.

Study Conclusion: Overall, there were positive associations between PBDEs with glucose and cholesterol levels during pregnancy, while negative associations were found between some phthalates and cholesterol. No relationship was noted for BPA or PFAS with cardiometabolic indices during pregnancy across both models.

Associations of single and multiple per- and polyfluoroalkyl substance (PFAS) exposure with vitamin D biomarkers in African American women during pregnancy

Study Purpose: Vitamin D has been linked to various physiological function in pregnant women and their fetuses. This study aims to evaluate the associations of PFAs levels with vitamin D levels during pregnancy in a cohort of African American women in Atlanta.

Study Conclusion: This study suggests that exposure to PFAs might disturb vitamin D metabolism among pregnant African American women and that some of these effects might be changed by the sex of the fetus. More studies are needed to confirm these findings.

Association between maternal exposure to perfluoroalkyl and polyfluoroalkyl substances and risks of adverse pregnancy outcomes: A systematic review and meta-analysis

Study Purpose: This reviews and analyzes previous studies on the relationship of maternal PFAS exposure and adverse pregnancy outcomes.

Study Conclusion: It was found that maternal exposure to PFOS could be positively associated with preterm birth, while no statistically significant association have been found between PFASs exposure and miscarriage and stillbirth. Epidemiological evidence to date are insufficient to draw definitive conclusions on potential toxicities of PFASs with stronger statistical power.

Associations of single and multiple per- and polyfluoroalkyl substance (PFAS) exposure with vitamin D biomarkers in African American women during pregnancy

Study Purpose: Vitamin D has been linked to various physiological function in pregnant women and their fetuses. This study aims to evaluate the associations of PFAs levels with vitamin D levels during pregnancy in a cohort of African American women in Atlanta.

Study Conclusion: This study suggests that exposure to PFAs might disturb vitamin D metabolism among pregnant African American women and that some of these effects might be changed by the sex of the fetus. More studies are needed to confirm these findings.

Maternal exposure to perfluoroalkyl chemicals and anogenital distance in the offspring: a Faroese cohort study

Study Purpose: Exposure to PFASs has in some studies been associated with reduced anogenital distance in newborns, an indicator of prenatal anti-androgenic exposure. The aim of this study was to investigate the association between maternal PFAS exposure and offspring anogenital distance in a population with wide ranges of PFAS exposures.

Study Conclusion: In conclusion, we found that maternal PFAS exposure was significantly associated with a longer AGDs in boys. No significant associations were found among girls, suggesting sex-dimorphic effects of PFASs. Whether the observed association with longer ASD and PFAS influences the reproductive health of males is unknown and needs to be investigated further.

Prenatal exposures to mixtures of endocrine disrupting chemicals and children's weight trajectory up to age 5.5 in the SELMA study

Study Purpose: This study evaluates the effect of prenatal exposure to mixtures of endocrine disrupting chemical (such as PFASs) mixtures on birthweight and childhood weight trajectories.

Study Conclusion: Prenatal exposure to EDC mixtures was associated with lower birthweight and altered infant weight gain trajectories.

Exposure to perfluoroalkyl substances in early pregnancy and risk of sporadic first trimester miscarriage

Study Purpose: The aim of this study was to investigate whether PFASs in early pregnancy are associated with unexplained, sporadic first trimester miscarriage.

Study Conclusion: There was an association between PFOA and miscarriage in this study. The study can only represent early placentation and clinical pregnancy loss during the second half of the first trimester.

Perfluorooctanoic acid (PFOA) or perfluorooctane sulfonate (PFOS) and DNA methylation in newborn dried blood spots in the Upstate KIDS cohort

Study Purpose: PFOA and PFOS may alter prenatal development, through modifying DNA. Prior studies on this subject have had few subjects and inconsistent results. This study examines relationships between PFOA and PFOS with DNA changes among nearly 600 infants.

Study Conclusion: There was limited evidence of an association between high concentrations of PFOA/PFOS and DNA changes in newborns in this study. Future studies are needed in populations with higher concentrations of PFOA/PFOS.

Prenatal Exposure to Per- and Polyfluoroalkyl Substances, Umbilical Cord Blood DNA Methylation, and Cardio-Metabolic Indicators in Newborns: The Healthy Start Study

Study Purpose: This study looks at the associations between prenatal PFAS exposure and changes in DNA in umbilical cord blood.

Study Conclusion: DNA changes in umbilical cord blood were associated with maternal PFAS concentrations during pregnancy, which could affect offspring growth, metabolism, and immune function.

Per- and polyfluoroalkyl substance mixtures and gestational weight gain among mothers in the Health Outcomes and Measures of the Environment study

Study Purpose: This study looks at associations between PFAS exposure and gestational weight gain.

Study Conclusion: Although there were consistent small increases in gestational weight gain with increasing PFOA, PFOS, and PFNA serum concentrations in this cohort, the associations were imprecise. Additional investigation of the association of PFAS with GWG in other cohorts would be informative and could consider pre-pregnancy BMI as a potential modifier.

Perfluoroalkyl substances exposure in early pregnancy and preterm birth in singleton pregnancies: a prospective cohort study

Study Purpose: To investigate the associations between prenatal PFAS exposure and preterm birth among singleton live births.

Per- and Poly-fluoroalkyl Substances and Bile Acid Profiles in
Pregnant Women

Study Purpose: Alterations in bile acid (BA) profiles are closely associated with adverse outcomes in pregnant women and their offspring and may be one potential pathway underlying the related metabolic effects of per- and poly-fluoroalkyl substances (PFAS) exposure.

Study Conclusion: Our findings provide the first epidemiological evidence for the associations of a PFAS mixture with BA profiles in pregnant women and may provide explanatory insights into the biological pathways underlying the related metabolic effects of PFAS exposure.

Perfluoroalkyl and polyfluoroalkyl substances and hypertensive disorders of pregnancy: A systematic review and meta-analysis

Study Purpose: Hypertensive disorders of pregnancy (HDP), including gestational hypertension and preeclampsia, may be partially attributed to environmental toxins. This study reviews the evidence of associations between PFAS and HDP.

Study Conclusion: This study provides low to moderate certainty evidence of associations between PFOA, PFOS, and PFHxS exposure and the risk of pre-eclampsia. The certainty of evidence for an association between PFOS and HDP was considered low. 

In utero exposure to per-/polyfluoroalkyl substances (PFASs): Preeclampsia in pregnancy and low birth weight for neonates

Study Purpose: PFAS have been linked to preeclampsia with inconsistent findings. However, information regarding the joint effects of PFAS mixtures on preeclampsia as well as their associations with low birth weight (LBW) and small for gestational age (SGA) is not well studied. The present study included 82 women with preeclampsia and 169 healthy participants from China.

Study Conclusion: Several PFAS were associated with higher odds of preeclampsia, while some others showed a reverse trend. Overall, the analysis suggested that combined PFAS exposure increased the risks for the development of preeclampsia. We observed that PFOA and PFUnDA were significantly associated with increased odds of early-onset preeclampsia, while it was not the case in late-onset. Whether early-onset preeclampsia is particularly at higher risks for PFASs exposure and might induce adverse fetal outcomes deserved in-depth exploration. With regard to neonatal development, negative associations were observed between birth weight and PFNA, PFUnDA, PFOS and 6:2Cl-PFESA exposure. Higher risks of low birth weight and small for gestational age were associated with preeclampsia and PFOA exposure. 

Exposure to endocrine-disrupting chemicals and risk of gestational hypertension and preeclampsia: A systematic review and meta-analysis

Study Purpose: Prenatal exposure to PFAs has been linked to gestational hypertension and preeclampsia, though some results have been conflicting. This paper reviews the findings of studies on these relationships.

Study Conclusion: Since most of these associations have limited evidence, more research is needed to confirm these findings.

Associations of perfluoroalkyl and polyfluoroalkyl substances with gestational hypertension and blood pressure during pregnancy: A cohort study

Study Purpose: This study aimed to evaluate effects of PFAS on gestational hypertension (GH) and blood pressure measures throughout pregnancy.

Study Conclusion: This study found that high concentrations of PFAS in early pregnancy were associated with decreased risk of gestational hypertension and reduced longitudinal blood pressure measures in the third trimester, which may reflect the effect of PFAS at relatively high exposure levels. This may vary by the sex of the baby.

Early-pregnancy plasma per- and polyfluoroalkyl substance (PFAS) concentrations and hypertensive disorders of pregnancy in the Project Viva cohort

Study Purpose: Hypertensive disorders of pregnancy (HDP) affect up to 10% of pregnancies in the United States and are associated with substantial maternal and neonatal morbidity and mortality. Per- and polyfluoroalkyl substances (PFAS) are associated with adverse cardiometabolic outcomes during pregnancy, but associations between PFAS and HDP are inconsistent and joint effects of PFAS mixtures have not been evaluated.

Study Conclusion: These findings suggest that exposure to certain PFAS may increase the odds of gestational hypertension during pregnancy.

Per- and polyfluoroalkyl substances in drinking water and hypertensive disorders of pregnancy in the United States during 2013-2015

Study Purpose: This study investigates the associations between PFAS and hypertensive disorders of pregnancy.

Study Conclusion: There was a weak positive association between the PFAS mixture and hypertensive disorders of pregnancy, although there are limitations as this was public data.

Endocrine-Disrupting Chemical Exposures in Pregnancy: a Sensitive Window for Later-Life Cardiometabolic Health in Women

Study Purpose: Pregnancy can be seen as a "stress test" with complications predicting later-life cardiovascular disease risk. Here, we review the growing epidemiological literature evaluating environmental endocrine-disrupting chemical (EDC) exposure in pregnancy in relation to two important cardiovascular disease risk factors, hypertensive disorders of pregnancy and maternal obesity.

Study Conclusion: Although numerous studies evaluated pregnancy outcomes, few evaluated the postpartum period or assessed chemical mixtures. Overall, there is a need to better understand whether pregnancy exposure to these chemicals could contribute to adverse cardiometabolic health outcomes in women, particularly given that cardiovascular disease is the leading cause of death in women.

Maternal Levels of Perfluoroalkyl Substances (PFAS) during Early Pregnancy in Relation to Preeclampsia Subtypes and Biomarkers of Preeclampsia Risk

Study Purpose: This study examines the associations between PFAS, any preeclampsia diagnosis, and early- and late-onset preeclampsia. In addition, they estimate associations between PFAS and biomarkers that provide an estimate of pro- and anti- angiogenic activity within the placenta.

Study Conclusion: Maternal PFAS concentrations were associated with higher odds of late-onset preeclampsia. Differences in preeclampsia should be considered in future studies because populations may have different distributions of disease subtypes.

Exposure to perfluoroalkyl substances in early pregnancy and the risk of hypertensive disorders of pregnancy: A nested case-control study in Guangxi, China

Study Purpose: Previous studies have examined the associations between exposure to PFAS and the risk of hypertensive disorders of pregnancy. However, these studies have had some limitations. This study again addresses this association.

Study Conclusion: This study found that combined exposure to nine PFAS had a positive effect on the development of hypertensive disorders of pregnancy (HDP). PFOS and PFBS were positively associated with HDP risk, while PFHxS and PFHpA were negatively associated with the HDP risk in women in Guangxi, China.

Considering Environmental Exposures to Per- and Polyfluoroalkyl Substances (PFAS) as Risk Factors for Hypertensive Disorders of Pregnancy

Study Purpose: This reviews the literature on associations between PFAS and hypertensive disorders of pregnancy and recommends next steps for research and prevention.

Study Conclusion: Positive associations between 6 PFASs--PFOA, PFOS, PFHxS, PFHpA, PFBS, and PFNA-- and risk for HDP have been reported in some studies, though these associations have not been seen in other studies.

Exposure to perfluoroalkyl substances and blood pressure in pregnancy among 1436 women from the Odense Child Cohort

Study Purpose: This study investigates the association between PFAS exposure in early pregnancy and maternal blood pressure throughout pregnancy, gestational hypertension, and preeclampsia.

Study Conclusion: The strength of the relationship between PFAS exposure blood pressure may appear small. However, at a population level this may slightly shift the distribution of blood pressure towards an increased incidence of gestational hypertension. If blood pressure increases in pregnancy, it may have a long-term impact on health not only of the pregnant woman but also of her offspring.

Exposure to toxic metals and per- and polyfluoroalkyl substances (PFAS) and the risk of preeclampsia and preterm birth in the United States: A review

Study Purpose: This article reviews past studies to provide an overview on environmental contaminants (such as PFAS) and the development of preeclampsia and preterm birth among U.S. women.

Study Conclusion: There are inconsistent findings on the relationship between PFASs and preeclampsia and preterm birth.

Per- and Polyfluoroalkyl Substances in Early Pregnancy and Risk for Preeclampsia: A Case-Control Study in Southern Sweden

Study Purpose: To investigate the association between serum concentrations of PFAS in early pregnancy and the risk of developing preeclampsia.

Study Conclusion: This study provides limited support for the association between PFAS and preeclampsia in a population with relatively low exposure levels.

Study Conclusion: There were no associations between maternal PFAS levels in early pregnancy and infant length, preterm birth, or spontaneous or indicated preterm birth.

Association of perfluoroalkyl substances with gestational hypertension and preeclampsia in the MIREC study

Study Purpose: To examine the relationship between background levels of PFOA, PFOS, and PFHxS and the development of gestational hypertension or preeclampsia in a Canadian pregnancy cohort.

Study Conclusion: Higher levels of PFHxS were associated with the development of preeclampsia, but not gestational hypertension. Both PFOA and PFOS were not associated with either outcome.

Perfluoroalkyl substances in early pregnancy and risk of hypertensive disorders of pregnancy: A prospective cohort study

Study Purpose: This study looks at associations between PFAS exposure and hypertensive disorders of pregnancy.

Study Conclusion: Maternal levels of PFASs in early pregnancy were not associated with gestational hypertension, preeclampsia, or hypertensive disorders of pregnancy.

Early pregnancy serum levels of perfluoroalkyl substances and risk of preeclampsia in Swedish women

Study Purpose: To investigate the association between early pregnancy serum levels of PFAS and preeclampsia.

Study Conclusion: Increasing serum levels of PFOS and PFNA during early pregnancy were associated with a clinically relevant risk of preeclampsia, adjusting for established confounders.

Prenatal exposure to perfluoroalkyl and polyfluoroalkyl substances and the risk of hypertensive disorders of pregnancy

Study Purpose: PFAS have been reported to disrupt the endocrine system and reproductive system, but information on the association between PFAS and preeclampsia is not consistent. This study looks at the association between prenatal PFAS exposure and hypertensive disorders of pregnancy.

Study Conclusion: Prenatal exposure to PFBS was associated with elevated risk of preeclampsia and hypertensive disorders of pregnancy.

PFAS exposure exert negative effects on oocyte
yield, fertilization and high-quality embryo in women
undergoing IVF

Study Purpose: As part of standard Assisted Reproductive Technology (ART) procedures, both the treatment results and collected samples present valuable prospects for exploring the connection between PFAS levels and In Vitro Fertilization (IVF) results, which may provide insights into the potential impact of PFAS on female
reproductive health. Previous studies primarily examined individual PFAS and did not
investigate the possible combined impact of PFAS mixtures on human reproductive capabilities. To address these gaps in existing research, this study aimed to assess the links between plasma levels of individual PFAS and PFAS mixtures in women undergoing IVF-ET and how these exposures might affect female reproductive health. 

Study Conclusion: Blood samples were collected over the first three days of a woman's menstrual cycle to analyze the foundational hormone profiles, which comprised follicular-stimulating-hormone (FSH), luteal hormone (LH), and estradiol (E2).

Environmental Exposure to Emerging Alternatives of Per- and Polyfluoroalkyl Substances and Polycystic Ovarian Syndrome in Women Diagnosed with Infertility: A Mixture Analysis

Study Purpose: PFAS have been previously linked to polycystic ovarian syndrome (PCOS), but this has only been assessed in a few PFAS. This study aimed to explore this association with a variety of PFAS, including emerging alternatives, as well as PFAS mixtures. 

Study Conclusion: In this study population, exposure to PFAS mixtures was associated with elevated odds of PCOS, with 6:2 Cl-PFESA, HFPO-DA, uppercase sigma 3,4,5 lowercase m-uppercase p f o sΣ3,4,5m-PFOS, and PFDoA being the major contributors, especially in overweight or obese women.

Perfluoroalkyl Acids in Follicular Fluid and Embryo Quality during IVF: A Prospective IVF Cohort in China

Study Purpose: There are few human studies that have demonstrated a link between exposure to PFAS and decreased fertility. This study assessed the associations between preconception plasma PFAS concentrations and fertility outcomes in women.

Study Conclusion: Higher PFAS exposure may be associated with decreased fertility in women. The mechanisms behind this relationship need further study.

Perfluoroalkyl Acids in Follicular Fluid and Embryo Quality during IVF: A Prospective IVF Cohort in China

Study Purpose: PFAS have been measured in follicular fluid from women undergoing IVF, although associations between follicular fluid PFAS levels and IVF outcomes have been inconsistent. This study investigated the association between follicular fluid PFAS levels and embryo quality in women undergoing IVF.

Study Conclusion: Higher PFAS levels in follicular fluid were associated with poorer embryo quality during IVF. Branched PFOS isomers may have a stronger effect than linear PFOS isomers. More studies are needed to confirm these findings and to directly estimate the effects on pregnancy and live-birth outcomes. 

The effects of perfluoroalkyl and polyfluoroalkyl substances on female fertility: A systematic review and meta-analysis

Study Purpose: The reproductive toxicity of PFAS has been shown in animal experiments, however, the association between PFAS and female fertility remains contradictory in population studies. This review evaluates the effects of PFAS on female fertility based on population evidence.

Study Conclusion: Based on the evidence provided by the current study, increased levels of PFAS exposure are associated with reduced fertility in women, this was characterized by a reduction in fecundability odds and an increase in odds for infertility. This finding could partially explain the decline in female fertility and provide insight into risk assessment when manufacturing products containing PFAS.

Association between chemical mixtures and female fertility in women undergoing assisted reproduction in Sweden and Estonia

Study Purpose: Women of reproductive age are exposed to chemicals such as phthalates, parabens, and PFAS, which may affect fertility. The objective of this study was to investigate associations between potential endocrine disrupting chemicals (EDCs), including PFAS, and female fertility in two cohorts of women attending fertility clinics.

Study Conclusion: This study provided evidence supporting the presence of and an inverse association between DEHP metabolites and female fertility and identifying chemicals such as methylparaben, and possibly PFUnDA and PFOA, that can be involved in the biological processes causing female infertility via disruption of ovarian function.

Mixtures of persistent organic pollutants and ovarian function in women undergoing IVF

Study Purpose: This study investigates whether internal levels of persistent organic pollutants (POPs)--such as PFAS--in serum and follicular fluid affect ovarian function of women undergoing IVF.

Study Conclusion: Globally, associations between POP and the markers of ovarian function or responsiveness were lacking. Nonetheless, the stratification analysis suggested that current smoking could be a risk modifier, and extension of the study to a larger population sample size is needed.

Associations between internal concentrations of fluorinated and organochlorinated chemicals in women and in vitro fertilization outcomes: A multi-pollutant study

Study Purpose: The impact of persistent pollutants on reproductive health is poorly understood. This study aims to characterize the internal levels of PCBs, OCPs, and PFAS in women undergoing IVF and evaluate their association with IVF outcomes.

Study Conclusion: The results showed that mixtures of low concentrations of PCBs, OCPs, and PFAS are widespread among women. Most pollutants were not associated with IVF outcomes, like live birth rate. Further study is needed.

Per- and polyfluoroalkyl substances (PFAS) exposure in women seeking in vitro fertilization-embryo transfer treatment (IVF-ET) in China: Blood-follicular transfer and associations with IVF-ET outcomes

Study Purpose: Follicular fluid is a critical environment for the development of oocytes, so investigation of environmental contaminants in follicular fluid may facilitate a better understanding of the influence of environmental exposure on reproductive health. In this study, they aim to investigate PFAS exposure in women receiving in vitro fertilization-embryo transfer (IVF-ET) treatment, determine the blood-follicle transfer efficiencies (BFTE) of PFAS, and explore potential associations between PFAS exposure and selected IVF-ET outcomes.

Study Conclusion: In the present study, we measured a suite of PFAS chemicals in paired blood and follicular fluid collected from women receiving the IVF-ET treatments through a prospective cohort study. Our results reveal the frequent detection of several legacy and emerging PFAS in the study population, suggesting broad exposure. A number of PFAS exhibited high potency to cross the blood-follicle barrier, and the BFTE may be partially affected by their physicochemical properties such as Kow, although other influencing factors could also exist. Although our data did not find any significant association between blood or follicular fluid concentrations of PFAS and selected IVF-ET outcomes, our study raises the need of better characterization of follicular exposure to environmental chemicals and potential influence on reproductive health.

Follicular fluid and blood levels of persistent organic pollutants and reproductive outcomes among women undergoing assisted reproductive technologies

Study Purpose: Persistent organic pollutants (POPs), such as PFAS, are chemicals resistant to degradation. This study measured POP levels in women who were seeking fertility treatment.

Study Conclusion: These results suggest that age plays a role in the chemical transfer from blood to follicular fluid and that exposure to POPs is associated with fertility treatment outcomes.

Associations between human internal chemical exposure to Persistent Organic Pollutants (POPs) and In Vitro Fertilization (IVF) outcomes: Systematic review and evidence map of human epidemiological evidence

Study Purpose: The aim of this study was to review the evidence on associations between internal levels of persistent organic pollutants, such as PFAs, and IVF outcomes among women.

Study Conclusion: The review showed that many types of persistent pollutants (POPs) are in follicular fluid and serum of women attending IVF treatments. Globally, there were inconsistent findings across studies for specific exposure-outcome dyads, suggesting that adverse effects of POPs on IVF outcomes cannot be ruled out. These results suggest that POPs may impair embryo quality and pregnancy rates.

Perfluoroalkyl Chemicals and Male Reproductive Health: Do PFOA and PFOS Increase Risk for Male Infertility?

Study Purpose: This review looks at previous studies on PFOS/PFOA effects on male reproductive health.

Study Conclusion: Human and rodent studies suggest that increased PFAS exposure could be associated with changes in some enzymes, including gonadal or serum testosterone, testicular receptors for gonadotropin, growth hormone, and IGF-1 and semen parameters.

Endocrine disrupting chemicals: Impacts on human fertility and fecundity during the peri-conception period

Study Purpose: The goals of this study include:

1. Identify and review evidence regarding the effects of endocrine-disrupting chemicals on adult male and female fertility, reproductive hormone concentrations, gamete and embryo characteristics, as well as the time to pregnancy
2. To investigate whether individuals or couples diagnosed as sub-fertile have higher endocrine-disrupting chemical levels
3. To highlight where little or no data exists that prevents associations from being identified.

Study Conclusion: Currently, the findings from human studies do not support a consistent effect of PFAS on male fertility. No association is evident from animal studies. For women, nearly all measured fertility results had conflicting findings. Few animal studies have been conducted regarding female fertility and PFAS exposure.

Persistent organic pollutants and couple fecundability: a systematic review

Study Purpose: To summarize the strength of evidence for associations of four common groups of persistent organic pollutants and a couple's probability to conceive. To identify gaps and limitations in the literature in order to inform policy decisions and future research.

Study Conclusion: This review found no support for associations between female exposure to pesticides or male exposure to any persistent organic pollutant's groups and time to pregnancy.

Parental plasma concentrations of perfluoroalkyl substances and In Vitro fertilization outcomes

Study Purpose: This study looks at whether maternal or paternal PFAS levels have effects on in vitro fertilization (IVF) outcomes.

Study Conclusion: These results suggest that PFAS may have reproductive effects on both men and women, and that exposure to PFAS may negatively affect IVF outcomes.

Per- and poly-fluoroalkyl substances (PFASs) in follicular fluid from women experiencing infertility in Australia

Study Purpose: This study investigates if associations exist between PFAS concentrations, age, and fertilization rate. This study also investigates the associations between PFAS concentrations and infertility.

Study Conclusion: PFASs were detected in follicular fluid of Australian women who had been treated at an IVF clinic. This study found that PFAS in follicular fluids was linked to an increased risk of some infertility factors. Increased age was associated with decreased fertilization rate. There was no relationship between PFAS and fertilization rate.   

Perfluoroalkyl substances and endometriosis-related infertility in Chinese women

Study Purpose: To examine the association between PFASs and endometriosis-related infertility.

Study Conclusion: Exposure to PFBS may increase the risk of female infertility due to endometriosis.

Perfluoroalkyl and polyfluoroalkyl substances and measures of human fertility: a systematic review

Study Purpose: To review current evidence on the association between exposure to PFASs and measures of human fertility.

Study Conclusion: For PFOS and PFOA, the literature indicates an association with female fertility in women who have had children.

Early menarche and other endocrine disrupting effects of per- and polyfluoroalkyl substances (PFAS) in adolescents from Northern Norway. The Fit Futures study

Study Purpose: The aim of this study was to investigate associations of various PFAS with thyroid, parathyroid, steroid and sex hormones, as well as with menstrual function and pubertal development in teenagers recruited from the general population of Northern Norway.

Study Conclusion: Serum concentrations of several PFAS were associated with parathyroid and steroid hormones in both sexes, and with thyroid hormones in boys, as well as with early menarche in girls and higher PDS in boys.

Environmental exposure to legacy and emerging per- and polyfluoroalkyl substances and endometriosis in women of childbearing age

Study Purpose: In the present study, we investigated (i) whether single PFAS exposure was associated with endometriosis; (ii) whether PFAS mixture has a
joint effect on endometriosis; and (iii) which PFAS was the dominant contributor. 

Study Conclusion: Our study suggests that PFAS exposure is associated with an
increased odds of endometriosis. The branched isomer of PFOS, i.e., 1mPFOS, is the dominant contributor, suggesting that emerging PFAS (isomers, precursors and alternatives) warrants further research. Considering the wide-ranging PFAS exposure in women of childbearing age, our findings may have significant public health implications. More studies are needed to confirm or refute our results and to elucidate the underlying mechanisms. 

Trimester-specific hemodynamics of per- and polyfluoroalkyl substances and its relation to lipid profile in pregnant women

Study Purpose: PFAS can be detected in the blood of pregnant women, but the effects of pregnancy on blood volume may affect PFAS measurements by trimester. Additionally, little is known on specific windows during pregnancy where PFAS may interrupt cholesterol metabolism. In this study, PFAS and cholesterol measures were obtained in pregnant women.

Study Conclusion: PFAS levels showed a decline in maternal blood samples during pregnancy, except for PFTrDA. 

Associations of Pregnancy Per- and Polyfluoroalkyl Substance Concentrations and Uterine Fibroid Changes across Pregnancy: NICHD Fetal Growth Studies - Singletons Cohort

Study Purpose: Fibroids often undergo changes during pregnancy. Because PFAS disrupt hormonal signaling, they may affect fibroid growth. This study assesses associations between PFAS and fibroid changes in pregnancy.

Study Conclusion: In this study, prenatal levels of certain PFAS were associated with both first-trimester total fibroid volume and total fibroid volume trajectory across pregnancy. Because PFAS were not associated with the number of fibroids, PFAS may primarily influence volume change in fibroids rather than contributing to fibroid formation.

An exposure to endocrine active persistent pollutants and endometriosis - a review of current epidemiological studies

Study Purpose: Widespread exposure to persistent organic pollutants (POPs) can disrupt natural endocrine functions and contribute to reproductive diseases such as endometriosis. This review focuses on the relationship between several POPs, including PFAS, and risk of endometriosis.

Study Conclusion: In conclusion, the results of the reviewed studies suggest that exposure to POPs may be associated with the occurrence of endometriosis. The consistent results were found in the case of all described organochlorine pesticides (OCPs), lead, and PCBs. The results of the studies on mercury, cadmium, copper, chromium, zinc, PCB-52, PCB-101, PCB-118, PCB-138, PCB-156, PCB-180, 2,3,7,8— TCDD, OCDF, PBB-77, PBB-101, PBB-153, PBB-180, PBDE-47, PBDE-183, PFOA, PFNA, PFBS, and PFOS exposure are inconclusive. Due to conflicting results, further study is needed to confirm these findings.

Association between Perfluoroalkyl and Polyfluoroalkyl Substances and Women's Infertility, NHANES 2013-2016

Study Purpose: The role of PFAS in infertility is poorly understood. This study included 788 women to explore the association between PFAS exposure and self-reported infertility.

Study Conclusion: This study found that associations with PFAS and women's infertility varied according to types of PFAS and age. There was a non-linear association between PFAS and women's infertility. Mixed PFAS exposure might influence infertility negatively as revealed in the BKMR model. Our study indicated that further profound studies are needed to address the impact of low-dose PFAS exposure on women’s infertility.

Endocrine disrupting chemicals impact on ovarian aging: Evidence from epidemiological and experimental evidence

Study Purpose: It is important to summarize the impacts of endocrine disrupting chemicals (EDCs), such as PFAS, on ovarian aging. This review focuses on the impacts of 10 environmental contaminants on the progression of ovarian aging during adult exposure, including epidemiological data in humans and experimental models in rodents, with their clinical phenotypes and underlying mechanisms.

Study Conclusion: Most epidemiological evidence demonstrated that both persistent (PFASs and PCBs) and non-persistent EDCs (phthalates) exposure could increase the overall risk of ovarian aging, leading to DOR (diminished ovarian reserve), fertility or fecundity decline, menstrual cycle irregularity and an earlier age at menopause, due to the accelerated follicles loss and endocrine disorder.

Perfluoroalkyl Substances and Incident Natural Menopause in Midlife Women: The Mediating Role of Sex Hormones

Study Purpose: PFAS exposure has been associated with earlier natural menopause; however, the underlying mechanisms are not well understood, or how the relationship is affected by sex hormones. This study investigates the relationship between PFAS and menopause and how the relationship may be affected by sex hormones.

Study Conclusion: In conclusion, this study is the first to investigate and quantify the degree to which FSH is an explanatory factor for the shortened time to natural menopause in midlife women with higher exposure to PFAS. Although mediation analysis still does not concretely establish a causal pathway, our findings provide evidence that PFAS exposure may accelerate ovarian aging through endocrinologic mechanisms associated with changing serum concentrations of FSH. Any potential mechanism underlying the relationships between PFAS exposure and natural menopause is likely to involve an interplay of hormones, beyond the action of single hormone levels. Future replication of our findings should consider other hormones such as luteinizing hormone in the analysis.

Per- and Poly-fluoroalkyl Substances (PFAS) and Female Reproductive Outcomes: PFAS Elimination, Endocrine-Mediated Effects, and Disease

Study Purpose: This paper summarizes the role of PFAS in female reproductive tract dysfunction and disease. Since these chemicals can affect reproductive tissue, this is also discussed.

Study Conclusion: Given the global decline in female fertility and the ability of PFAS to negatively impact female reproductive health, further studies are needed to examine effects on women.

Perfluoroalkyl substances (PFAS) in drinking water and risk for polycystic ovarian syndrome, uterine leiomyoma, and endometriosis: A Swedish cohort study

Study Purpose: PFAS may interfere with the female reproductive system. The aim of this study is to investigate possible associations between PFAS exposure and PCOS, uterine leiomyoma, and endometriosis.

Study Conclusion: Exposure to high levels of PFAS in drinking water was associated with increased risk of PCOS and possibly uterine leiomyoma, but not endometriosis. The findings for PCOS are consistent with prior studies reporting positive associations between PCOS and PFAS exposure at background levels.

Association between maternal exposure to perfluoroalkyl and polyfluoroalkyl substances and risks of adverse pregnancy outcomes: A systematic review and meta-analysis

Study Purpose: This reviews and analyzes previous studies on the relationship of maternal PFAS exposure and adverse pregnancy outcomes.

Study Conclusion: It was found that maternal exposure to PFOS could be positively associated with preterm birth, while no statistically significant association have been found between PFASs exposure and miscarriage and stillbirth. Epidemiological evidence to date are insufficient to draw definitive conclusions on potential toxicities of PFASs with stronger statistical power.

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) and their effects on the ovary

Study Purpose: To review the available literature for correlations between PFAS exposure and ovarian function.

Study Conclusion: The published literature supports associations between PFAS exposure and adverse reproductive outcomes; however, the evidence remains insufficient to infer a causal relationship between PFAS exposure and ovarian disorders.

Quantitative bias analysis of a reported association between perfluoroalkyl substances (PFAS) and endometriosis: The influence of oral contraceptive use

Study Purpose: To evaluate the influence of oral birth control use on the association between PFAS and endometriosis.

Study Conclusion: Study results suggest that the influence of oral contraceptive use on the association between PFAS levels and endometriosis is relatively small.

Endocrine-disrupting chemicals and uterine fibroids

Study Purpose: A useful summary of the known literature showing associations between environmental exposure to endocrine disrupting chemicals and uterine fibroids.

Study Conclusion: Delineating the effects of EDC exposure and the underlying mechanisms by which they, or other environmental exposures, promote MSC progression to UFs, including the role of epigenetic alterations and acquisition of mutations in genes such as MED12, will be key to the development of new interventions to prevent and treat this important disease of women.

Perfluoroalkyl substances and endometriosis in US women in NHANES 2003-2006

Study Purpose: To examine the relationship between PFAS and endometriosis.       

Study Conclusion: These findings suggest that PFOA, PFNA, and PFOS may be of interest in future studies with improved endometriosis diagnostic criteria and prospectively measured exposure.

PFOS Impairs Mitochondrial Biogenesis and Dynamics and Reduces Oxygen Consumption in Human Trophoblasts

Study Purpose: This study aimed to examine the role of mitochondrial dynamics and biogenesis in trophoblasts exposed to PFOS. We hypothesized that PFOS disrupts the expression of genes associated with biogenesis and dynamics, leading to mitochondrial dysfunction.

Study Conclusion: Findings indicate that exposure to PFOS may impair the bioenergetic capacity of trophoblasts by reducing OCR associated with basal and ATP-linked respiration. Additionally, PFOS exposure downregulates the expression of genes involved in mitochondrial fission, fusion, and biogenesis in trophoblasts.

Evaluating the Effect of Gestational Exposure to Perfluorohexane Sulfonate on Placental Development in Mice Combining Alternative Splicing and Gene Expression Analyses.

Study Purpose: Perfluorohexane sulfonate (PFHxS) is a frequently detected per- and polyfluoroalkyl substance in most populations, including in individuals who are pregnant, a period critical for early life development. Despite epidemiological evidence of exposure, developmental toxicity, particularly at realistic human exposures, remains understudied. The objectives of the current study were to investigate exposure of mice to human-relevant doses (0.03 and 0:3lg=kg=day ) of PFHxS, orders of magnitude lower thanPFOS (2:5mg=kg=day, a dose which decreased placenta size and fetal weight)orPFOA(5mg=kg=day, a dose which impaired follicle development in mice), and its toxic effect on fetal development as well as the potential toxicological mechanisms underlying placenta impairment in mice.

Study Conclusion: The findings from this study suggest that exposure to human relevant very low dose PFHxS during pregnancy in mice caused IUGR. Via downregulating of placental amino acid transporters, impairing placental amino acid transportation, resulting in impairment of placental development.

Low transplacental transfer of PFASs in the small-for-gestational-age (SGA) new-borns: Evidence from a Chinese birth cohort

Study Purpose: In this study, 30 PFAS were measured in pregnant mothers and in cord serum from 195 births to understand transfer of PFAS from mom to offspring.

Study Conclusion: These results show that there were differences in transfer of PFAS across the placenta between small for gestational age and appropriate for gestational age offspring, with small for gestational age groups having PFAS not transferred as much across the placenta as the appropriate for gestational age group.

The transplacental transfer efficiency of per- and polyfluoroalkyl substances (PFAS): a first meta-analysis

Study Purpose: The aim of this study was to provide a review of literature on PFAS transfer rates across the human placental barrier by means of a meta-analysis based on systematic review.

Study Conclusion: The results of this study showed that PFAS with sulfonyl groups are transferred less efficiently than those containing carboxyl groups. Less well studied PFAS such as PFHxA, 6:2 FTS, and PFBA are highly efficiently transported across the placental barrier, suggesting that PFAS with a more complex structure may also enter the fetal circulation. The potential consequences for fetal health need to be further investigated, as these compounds are increasingly used, but their mode of action is poorly understood.

Placental Transfer and Composition of Perfluoroalkyl Substances (PFASs): A Korean Birth Panel of Parent-Infant Triads

Study Purpose: In this study, they measured PFAS concentrations in maternal, paternal, and umbilical cord serum collected from 62 pregnant women and their matched biological fathers. Placental transfer rates of PFAS were calculated.

Study Conclusion: The results of this study showed different concentrations and types of PFAS among maternal, paternal, and cord serum. Placental transfer rates of PFAS differed by compound, and several factors such as gestational age were associated with placental transfer.

The occurrence of PFAS in human placenta and their binding abilities to human serum albumin and organic anion transporter 4

Study Purpose: To better understand the occurrence of PFAS in the placenta and how PFAS might transfer from the placenta.

Study Conclusion: The placental transfer of PFAS is related to the length of the PFAS. More research is needed to understand the occurrence of PFAS in the placenta and the transfer mechanisms of PFAS.

Organophosphate Flame Retardants, Highly Fluorinated Chemicals, and Biomarkers of Placental Development and Disease during Mid-Gestation

Study Purpose: This study measured 12 PFASs and flame retardants in healthy pregnant women in the middle of the pregnancy and examined signs of placental development and disease.

Study Conclusion: This study found potential associations of PFAS and flame retardant exposure with signs related to placenta-related pregnancy complications. Associations with blood pressure and lipid concentrations need further research.

Early life exposure to per- and polyfluoroalkyl substances (PFAS) and latent health outcomes: A review including the placenta as a target tissue and possible driver of peri- and postnatal effects

Study Purpose: To review early life exposure to PFAS and potential latent health outcomes.

Study Conclusion: The effects of PFAS on humans differs based on the compound. Early life PFAS exposure may disrupt placental growth and function, increasing susceptibility for later life chronic conditions, which could worsen from lifelong PFAS exposure.

Perfluoroalkyl Substances (PFAS) and Their Effects on the Placenta, Pregnancy, and Child Development: a Potential Mechanistic Role for Placental Peroxisome Proliferator-Activated Receptors (PPARs)

Study Purpose: To review the current literature on PFAS and their effects on the placenta, pregnancy outcomes, and child health.

Study Conclusion: This review summarizes how PFAS, critical environmental contaminants, may contribute to diseases of pregnancy as well as early and later child health. 

The association between prenatal per-and polyfluoroalkyl substance levels and Kawasaki disease among children of up to 4 years of age: A prospective birth cohort of the Japan Environment and Children’s study

Study Purpose: A systematic review and meta-analysis was conducted by pooling current evidence to investigate the potential association between PFAS exposure and reproductive hormones to promote human reproductive health.

Study Conclusion: Exposure to PFAS was associated with reproductive hormones in the meta-analysis. Researchers found statistically significant results in the association of PFHxS with E2 levels in female, PFOA and PFOS with TT levels in male. Children were more susceptible to PFAS exposure than adults. Even subtle changes in reproductive hormone levels can have serious implications for human health.

Association between exposure to per- and perfluoroalkyl substances (PFAS) and reproductive hormones in human: A systematic review and meta-analysis

Study Purpose: A systematic review and meta-analysis was conducted by pooling current evidence to investigate the potential association between PFAS exposure and reproductive hormones to promote human reproductive health.

Study Conclusion: Exposure to PFAS was associated with reproductive hormones in the meta-analysis. Researchers found statistically significant results in the association of PFHxS with E2 levels in female, PFOA and PFOS with TT levels in male. Children were more susceptible to PFAS exposure than adults. Even subtle changes in reproductive hormone levels can have serious implications for human health.

Exposure to Perfluoroalkyl Substances and Associations with Pubertal Onset and Serum Reproductive Hormones in a Longitudinal Study of Young Girls in Greater Cincinnati(GC) and the San Francisco Bay Area(SFBA)

Study Purpose: The primary objective of this study was to examine the longitudinal relationship between PFAS serum concentrations measured in young girls to determine whether PFAS exposure is associated with the age at three pubertal milestones: thelarche, pubarche, and menarche. To identify subclinical outcomes of the PFAS exposures, we also examined the relationship between serum reproductive hormone concentrations around the time of thelarche with PFAS exposure.

Study Conclusion: PFAS may delay pubertal onset through the intervening effects on BMI and reproductive hormones. The decreases in DHEAS and uppercase e begin subscript 1 end subscriptE1 associated with PFOA represent biological biomarkers of effect consistent with the delay in onset of puberty.

Levels of PFAS concentrations in the placenta and pregnancy complications

Study Purpose: This study aimed to evaluate the potential impacts of PFAS in the placenta.

Study Conclusion: PFOA concentrations in the placenta appeared to be associated with adverse perinatal outcomes, consistent with findings for PFAS concentrations in blood.

Association of exposure to per- and polyfluoroalkyl substances with hemoglobin and hematocrit during pregnancy

Study Purpose: PFAS are common environmental contaminants that have been linked to adverse birth outcomes. However, the association between maternal exposure to PFAS and hemoglobin (Hb) and hematocrit (HCT) remains unclear. The aim of this study was to explore the relationship between PFAS exposure with Hb and HCT during pregnancy.

Study Conclusion: Maternal PFAS exposure was associated with increased serum Hb and HCT. Maternal iron supplementation may affect this relationship.

Association between per- and polyfluoroalkyl substances and semen quality

Study Purpose: Some studies have suggested that PFAS exposure may be associated with semen quality in the general population, but results have not been consistent. To identify a more precise relationship, a meta-analysis was performed.

Study Conclusion: In this study, we discovered that exposure to PFNA and PFOA was negatively associated with sperm progressive motility. Further animal studies should be performed to uncover the causality and elucidate underlying mechanisms. 

Association of serum per- and polyfluoroalkyl substances and gestational anemia during different trimesters in Zhuang ethnic pregnancy women of Guangxi, China

Study Purpose: Gestational anemia is a complication of pregnancy, and a low level of hemoglobin (Hb) has been linked to adverse pregnancy outcomes. Previous studies reported that PFAS were more strongly associated with Hb than red blood cells, indicating that Hb is more susceptible to the effects of PFAS. This study explores the affects of PFAS on anemia in pregnant women.

Study Conclusion: These findings suggest that maternal exposure to PFAS is associated with gestational anemia. Diverse PFAS play roles in increasing and decreasing the risk of gestational anemia in different trimesters. PFDoA was positively associated with gestational anemia in the first trimester, while PFBS was negatively associated with gestational anemia in the second trimester. Further research is needed to understanding these associations.

Maternal Exposure to Per- and Polyfluoroalkyl Substances (PFAS) and Male Reproductive Function in Young Adulthood: Combined Exposure to Seven PFAS

Study Purpose: This study examined associations between maternal plasma PFAS levels during early pregnancy and male offspring reproductive function in adulthood.

Study Conclusion: In a sample of young men, we observed that as maternal PFAS concentrations increased, semen quality in their offspring decreased. 

Associations of per- and polyfluoroalkyl substances (PFAS) and their mixture with oxidative stress biomarkers during pregnancy

Study Purpose: Oxidative stress from excessive reactive oxygen species (ROS) is a hypothesized contributor to preterm birth. PFAS is reported to generate ROS in laboratory settings, and is linked to adverse birth outcomes. However, the relationship between PFAS and oxidative stress has not been examined in the context of human pregnancy. The objective of this study is to investigate the associations between prenatal PFAS exposure and oxidative stress biomarkers in pregnant people.

Study Conclusion: This study is the first to investigate the relationship between PFAS exposure and markers of oxidative stress during pregnancy. They found that PFOS was associated with elevated levels of oxidative stress, which is consistent with findings in animals. Future studies are needed to understand how this may affect fetal development.

Association of maternal perfluoroalkyl substance exposure with postpartum haemorrhage in Guangxi, China

Study Purpose: Postpartum haemorrhage (PPH) is the leading cause of maternal death worldwide, and it may be caused by environmental endocrine disruptors. Prenatal exposure to PFAS has been linked to pregnancy disorders and adverse birth outcomes, but no data are available on the relationship between PFAS exposure during pregnancy and postpartum haemorrhage. This study aimed to explore associations of maternal PFAS exposure with postpartum haemorrhage risk and total blood loss.

Study Conclusion: The concentrations of PFHxS were positively associated with PPH, and the concentrations of PFDoA were negatively correlated with PPH. Exposure to a mixture of nine PFASs was positively correlated with the PPH risk, and PFHxS exposure exerted the most significant effect on the PPH risk. 

Disparities in chemical exposures among pregnant women and neonates by socioeconomic and demographic characteristics: A nontargeted approach

Study Purpose: This study aims to identify sociodemographic differences in exposures that can inform contributions to health inequities.

Study Conclusion: Chemical exposures differed between delivery hospitals likely due to underlying social conditions faced by populations served. Differential exposures to 2,4-dichlorophenol or 2,5-dichlorophenol may contribute to disparities in adverse outcomes.

Longitudinal Changes in Maternal Serum Concentrations of Per- and Polyfluoroalkyl Substances from Pregnancy to Two Years Postpartum

Study Purpose: Exposure to PFAS during pregnancy and lactation is of increasing public health concern, but little is known about longitudinal changes in maternal PFAS concentrations from pregnancy to years postpartum. PFAS were quantified in California mothers during the first, second, and third trimesters of pregnancy and at 3,6, and 24 months after delivery over 2009-2017.

Study Conclusion: From this study, we observed decreases in serum concentrations of n-PFOS, Sm-PFOS, n-PFOA, and PFNA during pregnancy, Sm-PFOS, PFHxS, n-PFOA, and PFNA during early postpartum, and n-PFOS, Sm-PFOS, and PFNA during late postpartum. Throughout the whole study period, later child’s birth year was associated with decreased concentrations of n-PFOS, Sm-PFOS, PFHxS, n-PFOA, and PFNA which appear to reflect regulations and manufacturing changes for these compounds. Longer breastfeeding duration was associated with decreased n-PFOA and PFNA concentrations during late postpartum. Maternal serum PFAS concentration changes from pregnancy to two years postpartum may improve understanding of pregnancy and lactational transfers. Furthermore, our findings might be useful for reconstructing reliable pregnancy or early life PFAS exposure for case-control or cross-sectional epidemiologic studies with only postpartum PFAS serum concentrations.

Association of emerging and legacy per- and polyfluoroalkyl substances with unexplained recurrent spontaneous abortion

Study Purpose: It remains unknown whether exposure to PFAS has any impact on the risk of unexplained recurrent spontaneous abortion (URSA). We conducted a case-control study with 464 URSA cases who had at least 2 unexplained miscarriages and 440 normal controls who had at least one normal livebirth.

Study Conclusion: These findings suggest that exposure to PFAS alternatives may be related to elevated odds of unexplained recurrent spontaneous abortion. More studies are needed to confirm these findings.

Environmental Exposure to 6:2 Polyfluoroalkyl Phosphate Diester and Impaired Testicular Function in Men

Study Purpose: 6:2 diPAP has been demonstrated to disrupt reproductive endocrine functions using experimental studies. However, evidence from humans is not available yet. This study aims to assess the relationship between 6:2 diPAP exposure and the testicular function among adult men.

Study Conclusion: This study suggests that exposure to 6:2 diPAP may inhibit androgen synthesis and impair Leydig cell function in adult men.

Environmental exposure to legacy poly/perfluoroalkyl substances, emerging alternatives and isomers and semen quality in men: A mixture analysis

Study Purpose: This study explores the associations of PFAS with semen quality.

Study Conclusion: In the study, we found that two emerging PFAS replacements (i.e.,6:2 Cl-PFESA and PFBS) and PFHxS exposure were associated with reduced semen concentration, total sperm count and motility in men. Meanwhile, significant positive associations between PFHpS and sperm count and concentration were also observed. But there were no consistent associations between PFAS mixture, branched isomers and semen quality.

Per- and polyfluoroalkyl substances (PFAS) and male reproductive function in young adulthood; a cross-sectional study

Study Purpose: This study aims to examine biomarkers of reproductive function in young adult males according to current environmental exposure to single and combined PFAS.

Study Conclusion: We examined exposure to a range of common PFAS in relation to biomarkers of male reproductive function and found an association with higher levels of FSH (follicle-stimulating hormone) among young men from the general population in Denmark. Further studies on especially combined exposure to PFAS are needed to expand our understanding of potential endocrine disruption from both legacy and emerging compounds in relation to male reproductive function.

Quantitation of linear and branched perfluoroalkane sulfonic acids (PFSAs) in women and infants during pregnancy and lactation

Study Purpose: This paper reviews the literature on the effects of PFAS exposure, with a  specific focus on male reproduction.

Study Conclusion: Increasing awareness of the potential health implications of PFAS and realization of the extent of environmental contamination has led to a rising demand for research into definitive health risks and effective remediation strategies. Animal models have been widely employed to investigate in vitro and in vivo consequences of PFAS exposure, as well as the toxicology of these chemicals. Such studies complement a growing body of evidence from human epidemiological studies. However, the literature abounds with conflicting evidence, and as such, it remains challenging to draw accurate conclusions regarding the causality of PFAS related health issues. This situation is exacerbated by the repeated demonstration that outcomes differ depending on factors such as the specific PFAS chemical(s) (of which there are over 4,700), stage of development (i.e., during fetal development or in later life) and duration of exposure, level and mix of contamination, route of exposure, and interaction with other environmental contaminants and toxicants, all of which are influenced by geographical location. These factors present significant difficulties for researchers in planning, executing, and interpreting studies, and thus hinder our ability to directly compare PFAS exposure studies. While standardization therefore remains an essential priority for future research, the identification of appropriate cellular model(s) with which to directly investigate and unlock the interaction of PFAS with the male reproductive system would also be advantageous. In addition, agreement is needed regarding endpoint measures, in which subtle changes, such as decreases in fertility or metabolic sequelae, may be used as early markers of PFAS-mediated health effects, rather than more extreme factors such as tumors. In this regard, the male reproductive system offers notable advantages as a sensitive marker of human disease and may ultimately provide a unique opportunity for assessing the emerging threat to human health posed by PFAS exposure. Indeed, this model draws on a growing body of evidence of a strong association between a male’s general health and reproductive potential, with infertility being strongly correlated with future health concerns such as testicular cancer, ischemic heart disease and diabetes.

A Review of Per- and Polyfluorinated Alkyl Substance Impairment of Reproduction

Study Purpose: In this article, they review studies describing PFAS exposure and reproductive effects in animals and humans. The aim was to compare environmental occurrence and effects of the most prominent long-chain PFAS compounds and their short-chain replacements.

Study Conclusion: The chemical properties of PFAS are valuable for manufacturing and consumer convenience; however, these same properties make them resistant to degradation and persistent in the environment, wildlife, and humans. Generally, longer carbon chains in PFAS correlate with higher toxicity, however, differential reproductive effects are observed in vitro and in vivo. Short-chain PFAS tend to bioaccumulate less, but are more persistent in surface water. While surface water data show individual short-chain PFAS presence to be in the low ng/L range, sum total concentrations of PFAS are orders of magnitude higher. Some studies indicate that reproductive effects of PFAS seen in laboratory models and human cell lines are at concentrations greater than what will be realized in the environment. Most studies do not consider mixture toxicity; epidemiological studies inherently address mixture toxicity. Epidemiological studies indicate that environmentally-relevant PFAS concentrations are associated with reproductive effects. Indeed, even though most ecological and epidemiological studies quantify a few PFAS, these studies are effectively assessing the impact of many more PFAS. The majority of evidence for reproductive effects is linked to long-chain PFAS exposure. Long-chain PFAS is on the decline worldwide but will remain an exposure issue. Short-chain PFAS exposure is on the rise. Even though some specific short-chain PFAS have been studied, data on reproductive effects of short-chain PFAS are considerably less than for long-chain. In addition, there are many short-chain PFAS byproducts from manufacturing that have yet to be identified.

Quantitation of linear and branched perfluoroalkane sulfonic acids (PFSAs) in women and infants during pregnancy and lactation

Study Purpose: PFAS are associated with negative health effects and exposure during fetal life and infancy are of concern. The objective of this study was to investigate types of PFAS in never-pregnant, pregnant, and postpartum women and infants. 

Study Conclusion: The linear relations between PFSA concentrations in infants aged six months and mothers in pregnancy week 18 confirm that pregnancy and lactation are major excretion routes for PFSA, but accumulate in the infant. The observed great variability in PFSA burden among mothers and infants, as well as the reduced maternal transfer of branched PFHxS isoforms and increased transfer of branched PFOS isoforms compared to the respective linear isoforms to the infant, might impact adverse health effects associated with PFSA exposure, but this should be confirmed in future studies.

Overview of the Mechanisms of Action of Selected Bisphenols and Perfluoroalkyl Chemicals on the Male Reproductive Axes

Study Purpose: This study provides an overview of mechanisms of action common to PFAS and bisphenols on male fertility.

Study Conclusion: The negative impact of endocrine disrupting chemicals (EDCs) (such as PFAS) on fertility has been demonstrated. However, there are differences between laboratory experiments and human studies. We are exposed to many different EDCs and not all mixtures can be evaluated. The results of this review provided indication that persistent and non-persistent EDCs are associated with formation of ROS, disruption of BTB, disturbance of testosterone production, and interference with estrogenic and antiandrogenic signaling at environmentally relevant concentrations.

Mixtures of persistent organic pollutants are found in vital organs of late gestation human fetuses

Study Purpose: This study measured persistent organic pollutants, such as PFAS, in maternal serum, placenta, and fetal tissues in 20 pregnancies that ended in stillbirth.

Study Conclusion: This study quantified many POPs in fetal tissues. All studied chemical projects were detected in fetal adipose tissue even in places when the chemical was not detected in the maternal serum and placenta.

A case-cohort study of perinatal exposure to potential endocrine disrupters and the risk of cryptorchidism in the Norwegian HUMIS study

Study Purpose: Exposure to PFAS and other endocrine-disrupting chemicals (EDCs) during the critical period of testicular descent may increase the risk of cryptorchidism and male fertility. The objective of this study was to investigate 27 potential EDCs in breast milk and the risk of cryptorchidism.

Study Conclusion: Perinatal exposure to PCB-74, PCB-114, PCB-194, and B-HCH were associated with increased odds of congenital cryptorchidism.

Exposure to endocrine disrupting chemicals (EDCs) and cardiometabolic indices during pregnancy: The HOME Study

Study Purpose: Toxicology studies have identified pregnancy as a time sensitive to endocrine disrupting chemicals (EDCs), such as PFAS, and cardiometabolic indices in women. No study has examined this in humans.

Study Conclusion: Overall, there were positive associations between PBDEs with glucose and cholesterol levels during pregnancy, while negative associations were found between some phthalates and cholesterol. No relationship was noted for BPA or PFAS with cardiometabolic indices during pregnancy across both models.

Associations of single and multiple per- and polyfluoroalkyl substance (PFAS) exposure with vitamin D biomarkers in African American women during pregnancy

Study Purpose: Vitamin D has been linked to various physiological function in pregnant women and their fetuses. This study aims to evaluate the associations of PFAs levels with vitamin D levels during pregnancy in a cohort of African American women in Atlanta.

Study Conclusion: This study suggests that exposure to PFAs might disturb vitamin D metabolism among pregnant African American women and that some of these effects might be changed by the sex of the fetus. More studies are needed to confirm these findings.

Association between maternal exposure to perfluoroalkyl and polyfluoroalkyl substances and risks of adverse pregnancy outcomes: A systematic review and meta-analysis

Study Purpose: This reviews and analyzes previous studies on the relationship of maternal PFAS exposure and adverse pregnancy outcomes.

Study Conclusion: It was found that maternal exposure to PFOS could be positively associated with preterm birth, while no statistically significant association have been found between PFASs exposure and miscarriage and stillbirth. Epidemiological evidence to date are insufficient to draw definitive conclusions on potential toxicities of PFASs with stronger statistical power.

Associations of single and multiple per- and polyfluoroalkyl substance (PFAS) exposure with vitamin D biomarkers in African American women during pregnancy

Study Purpose: Vitamin D has been linked to various physiological function in pregnant women and their fetuses. This study aims to evaluate the associations of PFAs levels with vitamin D levels during pregnancy in a cohort of African American women in Atlanta.

Study Conclusion: This study suggests that exposure to PFAs might disturb vitamin D metabolism among pregnant African American women and that some of these effects might be changed by the sex of the fetus. More studies are needed to confirm these findings.

Maternal exposure to perfluoroalkyl chemicals and anogenital distance in the offspring: a Faroese cohort study

Study Purpose: Exposure to PFASs has in some studies been associated with reduced anogenital distance in newborns, an indicator of prenatal anti-androgenic exposure. The aim of this study was to investigate the association between maternal PFAS exposure and offspring anogenital distance in a population with wide ranges of PFAS exposures.

Study Conclusion: In conclusion, we found that maternal PFAS exposure was significantly associated with a longer AGDs in boys. No significant associations were found among girls, suggesting sex-dimorphic effects of PFASs. Whether the observed association with longer ASD and PFAS influences the reproductive health of males is unknown and needs to be investigated further.

Prenatal exposures to mixtures of endocrine disrupting chemicals and children's weight trajectory up to age 5.5 in the SELMA study

Study Purpose: This study evaluates the effect of prenatal exposure to mixtures of endocrine disrupting chemical (such as PFASs) mixtures on birthweight and childhood weight trajectories.

Study Conclusion: Prenatal exposure to EDC mixtures was associated with lower birthweight and altered infant weight gain trajectories.

Exposure to perfluoroalkyl substances in early pregnancy and risk of sporadic first trimester miscarriage

Study Purpose: The aim of this study was to investigate whether PFASs in early pregnancy are associated with unexplained, sporadic first trimester miscarriage.

Study Conclusion: There was an association between PFOA and miscarriage in this study. The study can only represent early placentation and clinical pregnancy loss during the second half of the first trimester.

Perfluorooctanoic acid (PFOA) or perfluorooctane sulfonate (PFOS) and DNA methylation in newborn dried blood spots in the Upstate KIDS cohort

Study Purpose: PFOA and PFOS may alter prenatal development, through modifying DNA. Prior studies on this subject have had few subjects and inconsistent results. This study examines relationships between PFOA and PFOS with DNA changes among nearly 600 infants.

Study Conclusion: There was limited evidence of an association between high concentrations of PFOA/PFOS and DNA changes in newborns in this study. Future studies are needed in populations with higher concentrations of PFOA/PFOS.

Prenatal Exposure to Per- and Polyfluoroalkyl Substances, Umbilical Cord Blood DNA Methylation, and Cardio-Metabolic Indicators in Newborns: The Healthy Start Study

Study Purpose: This study looks at the associations between prenatal PFAS exposure and changes in DNA in umbilical cord blood.

Study Conclusion: DNA changes in umbilical cord blood were associated with maternal PFAS concentrations during pregnancy, which could affect offspring growth, metabolism, and immune function.

Per- and polyfluoroalkyl substance mixtures and gestational weight gain among mothers in the Health Outcomes and Measures of the Environment study

Study Purpose: This study looks at associations between PFAS exposure and gestational weight gain.

Study Conclusion: Although there were consistent small increases in gestational weight gain with increasing PFOA, PFOS, and PFNA serum concentrations in this cohort, the associations were imprecise. Additional investigation of the association of PFAS with GWG in other cohorts would be informative and could consider pre-pregnancy BMI as a potential modifier.

Perfluoroalkyl substances exposure in early pregnancy and preterm birth in singleton pregnancies: a prospective cohort study

Study Purpose: To investigate the associations between prenatal PFAS exposure and preterm birth among singleton live births.

The Association of Perfluoroalkyl Substance Exposure and a
Serum Liver Function Marker in Korean Adults

Study Purpose: PFAS and liver disease. In addition, regulations on PFAS in Korea are delayed compared to developed countries, such as Europe and the United States, and public interest is insufficient compared to others. Therefore, we would like to investigate the exposure of Koreans to PFAS in the blood and examine the relationship between these substances and markers
of liver function (AST, ALT, and GGT).

Study Conclusion: We found that serum PFAS concentrations were positively correlated with some liver function markers, such as AST, ALT, and GGT. However, this result differs according to sex, obesity, and type of PFAS. In the case of women, the results were generally more sensitive to exposure to most PFAS than men. In addition, the non-obese group generally showed more sensitive results to exposure to most PFAS. Long-term, well-designed longitudinal
studies and continuous follow-up are needed.

Association of per- and polyfluoroalkyl substances with hepatic steatosis
and metabolic dysfunction-associated fatty liver disease among patients
with acute coronary syndrome

Study Purpose: This study will help us provide a reasonable opportunity to hypothesize mechanisms behind comorbidity of hepatic steatosis among ACS patients and provide evidence for tertiary prevention of ACS.

Study Conclusion: In conclusion, we demonstrated that plasma PFOS, PFHxS and total PFAS concentrations were associated with higher hepatic steatosis index
and risk of MAFLD among ACS patients. Mixture analysis observed significant positive association between PFAS mixtures and HSI. Moreover, overall results of PFAS congeners and mixture analysis highlighted the crucial role of PFOS on hepatic steatosis among ACS patients.

Dietary exposure to per- and polyfluoroalkyl substances: Potential health 
impacts on human liver

Study Purpose: This study summarized the source and fate of PFAS, and reviewed the occurrence of PFAS in food system (natural and processed food).
Subsequently, the characteristics of human dietary exposure PFAS (population characteristics, distribution trend, absorption and distribution) were mentioned.

Study Conclusion: Per- and polyfluoroalkyl substances (PFAS), dubbed “forever chemicals”, are environmental pollutant which could penetrate into the food system, increasing the risk of human dietary exposure. More importantly, epidemiological studies have shown that PFAS levels in human serum are closely related to dietary habits, and PFAS exposure may worsen the development of liver disease. 

Close association of PFASs exposure with hepatic fibrosis than steatosis: evidences from NHANES 2017-2018

Study Purpose: This study was performed to evaluate whether exposed to PFAS impacts the occurrence of nonalcoholic fatty liver disease (NAFLD).

Study Conclusion: This study suggests that PFAS exposure did not significantly change the risk of developing non-alcoholic fatty liver disease. PFAS exposure however appears to be more closely associated with hepatic fibrosis.

Associations between per- and polyfluoroalkyl substances, liver function, and daily alcohol consumption in a sample of U.S. adults

Study Purpose: This study aimed to evaluate the association of PFAS with liver function and evaluate whether alcohol intake affects this relationship. 

Study Conclusion: Like other studies, this study found increasing levels of PFOA, PFHxS, and PFNA to be associated with higher levels of ALT. A weak association between increased levels of some PFAS and total bilirubin was also observed.

Firefighters and the liver: Exposure to PFAS and PAHs in relation to liver function and serum lipids (CELSPAC-FIREexpo study)

Study Purpose: Firefighters can be exposed to PFAS, and exposure is suspected to affect liver function and lipid levels. This study investigates the relationship between PFAS exposure and liver function and lipid levels in firefighters.

Study Conclusion: This study observed a mixture of PFAS to increase bilirubin and alter serum lipids. 

Sex-specific effect of perfluoroalkyl substances exposure on liver and thyroid function biomarkers: A mixture approach

Study Purpose: This study investigates the effects of PFAS on liver and thyroid function and differences between sexes.

Study Conclusion: This study observed positive associations between exposure to single PFAS and groups of PFASs and the liver biomarkers ALT and GGT levels in adults, though these associations were only in significant in males.

Perfluoroalkyl substance (PFAS) exposure and risk of nonalcoholic fatty liver disease in the elderly: results from NHANES 2003-2014

Study Purpose: This study aimed to investigate the association between PFAS exposure and the risk of nonalcoholic fatty liver disease (NAFLD) in the elderly.

Study Conclusion: This study showed an association between PFOA/PFNA exposure and NAFLD. The associations were stronger for participants with higher socioeconomic status or inactive lifestyles. 

The association between endocrine disrupting chemicals and MAFLD: Evidence from NHANES survey

Study Purpose: Previous study on the association of endocrine-disrupting chemicals (EDCs), such as PFAS, with metabolic dysfunction-associated fatty liver disease (MAFLD) are very limited. This study analyzed the association of EDCs exposure with MAFLD among American adults.

Study Conclusion: This research suggests that exposure to EDCs (including heavy metals and PFAS) may be linked to MAFLD. Females, participants with hepatitis, and people over the age of 65 are most vulnerable to be effected by EDCs on MAFLD. 

Association between maternal exposure to per- and polyfluoroalkyl substances and serum markers of liver function during pregnancy in China: A mixture-based approach

Study Purpose: Previous studies have shown that PFAS may have toxic effects in the livers of animals. However, evidence in humans is limited, especially in pregnant women. This study aimed to assess the association of PFAS exposure with markers of liver function in pregnant women.

Study Conclusion: In summary, PFBS exposure was associated with increased maternal serum GGT levels and PFHxS exposure was associated with increased maternal serum TBIL and IBIL levels. In contrast, PFHpA exposure was associated with decreased serum TBIL levels. The association of PFUnA with liver enzymes was complex. A mixture of nine PFAS was significantly positively associated with GGT levels in pregnant women, with PFBS identified as the main contributor.

Association of per- and polyfluoroalkyl substance exposure with fatty liver disease risk in US adults

Study Purpose: This study evaluates the association between PFAS levels and fatty liver disease risk in adults.

Study Conclusion: Higher serum PFAS was moderately associated with fatty liver disease risk and worse liver function in the general population and among those with risk factors such as heavy alcohol intake, obesity, or high fat diets, PFAS increase the risk. These data suggest PFAS exposure and lifestyle risk factors together may increase effects on liver steatosis. 

Exposure to serum perfluoroalkyl substances and biomarkers of liver function: The Korean national environmental health survey 2015-2017

Study Purpose: Exposure to PFAS may increase the risk of liver disease by disrupting cholesterol and lipid metabolism, leading to higher liver-enzyme levels. This study examines the association between exposure to both individual and combined PFAS chemicals and liver-function markers and assesses whether this relationship varies by sex and obesity status.

Study Conclusion: Exposure to individual and combined PFAS chemicals is associated with higher liver enzymes in Korean adults.

Association between perfluoroalkyl substances exposure and the prevalence of nonalcoholic fatty liver disease in the different sexes: a study from the National Health and Nutrition Examination Survey 2005-2018

Study Purpose: There is evidence that PFAS may be toxic to the liver, and there may be differences in this association between sexes. This study aims to explore the association between exposure to PFOA, PFOS, PFHxS, and PFNA and the risk of nonalcoholic fatty liver disease in adults 20 years or older in the US.

Study Conclusion: This study found that PFAS were associated with non-alcoholic fatty liver disease. The associations were different between sexes, even in premenopausal women and postmenopausal women. The association between PFAS exposure and non-alcohol fatty liver disease in women was positive, particularly for PFOA and PFNA. 

Human Evidence of Perfluorooctanoic Acid (PFOA) Exposure on Hepatic Disease: A Systematic Review and Meta-Analysis

Study Purpose: Although many studies have reported an association between PFOA exposure and the risk of developing liver diseases, it is still in debate because studies have shown conflicting results. Therefore, this study reviews literature on the relationship between PFOA exposure and hepatic diseases. 

Study Conclusion: Since the number of studies in this analysis was not large enough to conclude that PFOA exposure is associated with the development of liver diseases, more studies are needed to confirm long-term effects.

Individual and mixture associations of perfluoroalkyl substances on liver function biomarkers in the Canadian Health Measures Survey

Study Purpose: PFAS can disrupt liver metabolism and may be associated with liver function biomarkers. This study examined individual and mixture associations of PFAS on liver function biomarkers in a sample of Canadian adults. They explored how these relationships may change by sex and body mass index (BMI), as well as by physical activity level.

Study Conclusion: Higher plasma concentrations of PFOA, PFOS, PFHxS, and PFNA were associated with higher serum concentrations of liver function biomarkers. The results suggest that higher levels of physical activity appear to protect against the liver toxicity of PFOA. 

Association of Prenatal Exposure to Endocrine-Disrupting Chemicals With Liver Injury in Children

Study Purpose: Prenatal exposure to endocrine disrupting chemicals (EDCs), such as PFAS, may increase the risk for liver injury in children; however, human evidence is scarce. The association between prenatal EDC exposure and hepatocellular apoptosis in children have has not been studied previously

Study Conclusion: This study provides evidence that prenatal exposure to EDCs are associated with higher risk for liver injury and CK-18 levels and constitute a potential risk factor for pediatric nonalcoholic fatty liver disease.

Exposure to per- and Polyfluoroalkyl Substances and Markers of Liver Injury: A Systematic Review and Meta-Analysis

Study Purpose: Experiments have indicated that exposure to certain pollutants is associated with liver damage. The objective of this study was to review literature evaluating PFAS exposure and evidence of liver injury from rodent and epidemiological studies. 

Study Conclusion: There is consistent evidence for PFAS being toxic to the liver in rodent studies, and this is supported by associations of PFAS and markers of liver function in observational human studies.

Per- and perfluoroalkyl substances alternatives, mixtures and liver function in adults: A community-based population study in China

Study Purpose: Evidence from animal studies has shown that PFAS alternatives and mixtures may exert toxic liver effects in animals. However, we have very little evidence in humans. 

Study Conclusion: In conclusion, our study found adverse associations of PFAS alternatives and mixtures with liver function in a Chinese adult general population. Our findings add epidemiological evidence for the potential subclinical hepatotoxicity of PFAS. More studies are needed to confirm our findings and address potential toxicological mechanisms.

Exposure to environmental contaminants is associated with altered hepatic lipid metabolism in non-alcoholic fatty liver disease

Study Purpose: This study tests the hypothesis that exposure to environmental contaminants contributes to the initiation and pathology of non-alcoholic fatty liver disease (NAFLD).

Study Conclusion: Females may be more sensitive to the harmful impacts of PFAS. Lipid-related changes following PFAS exposure may be secondary to the interplay between PFAS and bile acid metabolism.

Prenatal Exposure to Perfluoroalkyl Substances Associated with Increased Susceptibility to Liver Injury in Children

Study Purpose: Non-alcoholic fatty liver disease (NAFLD) is increasing among children. It is important to find risk factors for liver injury that can be addresses through prevention methods.

Study Conclusion: The study observed that higher exposure to PFAS during pregnancy was associated with higher liver enzyme levels in children.

Per- and Polyfluoroalkyl Substances and Obesity, Type 2 Diabetes and Non-alcoholic Fatty Liver Disease: A Review of Epidemiologic Findings

Study Purpose: This study reviews evidence for associations between PFASs and the development of obesity, diabetes, and non-alcoholic fatty liver disease/non-alcoholic steatohepatitis.

Study Conclusion: There is evidence that supports the association between PFASs and the onset or development of metabolic diseases, including obesity, diabetes, and non-alcoholic fatty liver disease. However, there are inconsistent results in many cases.

Perfluoroalkyl substances and severity of nonalcoholic fatty liver in Children: An untargeted metabolomics approach

Study Purpose: There have been studies looking at the correlation between PFAS exposure and fatty liver disease in adults and rodents, but there are few studies looking at this correlation in children.

Study Conclusion: PFAS exposure was associated with increased risk of nonalcoholic steatohepatitis (NASH) and fibrosis in children diagnosed with non-alcoholic fatty liver disease (NAFLD).

Sex differences in the association between perfluoroalkyl acids and liver function in US adolescents: Analyses of NHANES 2013-2016

Study Purpose: This study was designed to determine whether or not there is association between exposure to PFASs and signs of liver function in adolescents, and whether or not this varies between sexes.

Study Conclusion: This study was found to have sex differences in the association between PFAS levels and signs of liver function.

Selective Associations of Recent Low Concentrations of Perfluoroalkyl Substances with Liver Function Biomarkers: NHANES 2011 to 2014 Data on US Adults Aged ≥20 Years

Study Purpose: This study looks at the association between PFAS levels and liver function signs.

Study Conclusion: Lower levels of PFOA, PFHxS, and PFNA are associated with higher liver functions, but this association is only seen in obese patients.

Liver function biomarkers disorder is associated with exposure to perfluoroalkyl acids in adults: Isomers of C8 Health Project in China

Study Purpose: This study looks at the association between PFAS levels and liver function signs.

Study Conclusion: These results support previous studies showing association between PFAS exposure and liver function biomarkers.

Environmental perfluoroalkyl acid exposures are associated with liver disease characterized by apoptosis and altered serum adipocytokines

Study Purpose: This study looks at the association between environmental PFASs and signs of liver disease.

Study Conclusion: These findings support previous findings that PFASs may cause liver injury.

Changes in markers of liver function in relation to changes in perfluoroalkyl substances - A longitudinal study

Study Purpose: This study looks at the association of PFAS levels and signs of liver function.

Study Conclusion: These findings suggest a relationship between low-dose PFAS exposure and altered liver function.

Plasma levels of per- and polyfluoroalkyl substances (PFAS) and cardiovascular disease – Results from two independent population-based cohorts and a meta-analysis

Study Purpose:  The primary aim of the present study was to investigate incident CVD risk (a combined CVD end-point consisting of myocardial infarction, 
ischemic stroke, or heart failure) in relation to moderately elevated 
levels of PFAS in two population-based cohorts of middle-aged and 
elderly women and men (The Epihealth study and PIVUS study, Uppsala, 
Sweden). In the PIVUS study we also performed a supportive analysis of 
associations between levels of six PFAS and subclinical markers of CVD. 
Meta-analysis was performed together with data from previously 
published studies investigating associations between PFAS levels and 
incident CVD. 

Study Conclusion: This longitudinal study using data from two population-based cohort studies in Sweden did not indicate any increased risk of incident CVD for moderately elevated PFAS levels. A meta-analysis of five independent cohort studies rather indicated a modest inverse association between PFOA levels and incident CVD, further supporting that increasing PFAS levels are not linked to an increased risk of CVD.

Perfluoroalkyl substances in umbilical cord blood and blood pressure in offspring: a prospective cohort

Study Purpose: To investigate the potential association between PFAS levels in umbilical cord blood and BP of the offspring at 4 years of age in a prospective cohort study.

Study Conclusion: Our findings suggested that umbilical blood PFAS exposure was negatively associated with BP in offspring at 4 years of age, including SBP, DBP, and MAP.

Prenatal and Childhood Per- and Polyfluoroalkyl Substance (PFAS) Exposures and Blood Pressure Trajectories From Birth to Late Adolescence in a Prospective US Prebirth Cohort

Study Purpose: This study investigates associations with prenatal PFAS exposure and blood pressure in children.

Study Conclusion: There were associations between prenatal and childhood PFAS exposure with blood pressure at specific time points between birth and late teenage years, but it was not consistent over time.

Association between per- and polyfluoroalkyl substances and risk of hypertension: a systematic review and meta-analysis

Study Purpose: Evidence suggests exposure to PFAS may increase risk of hypertension, but findings are inconsistent. This study summarizes the relationship between FPAS and hypertension.

Study Conclusion: This study evaluated the link between PFAS exposure and hypertension, finding that higher levels of PFOS, PFOA, and PFHxS were correlated with increased risk of hypertension. 

The relationship between perfluoroalkyl substances and hypertension: A systematic review and meta-analysis

Study Purpose: Hypertension is an important risk factor for cardiovascular diseases. This study evaluates the body of evidence from past studies on the correlation between PFAS exposure and hypertension.

Study Conclusion: This study observed that PFAS exposure is a risk factor for hypertension, but that there are differences in this relationship between men and women. Males exposed to PFNA, PFOA, and PFOS appeared to have a higher risk of hypertension compared to females. Further study is needed to understand the underlying mechanism causing this relationship.

The role of exposure to per- and polyfluoroalkyl substances in racial/ethnic disparities in hypertension: Results from the study of Women's health across the nation

Study Purpose: Racial/ethnic disparities in hypertension are a pressing public health problem. The contribution of environmental pollutants such as PFAS have not been explores, even though certain PFAS have been thought to be higher in Black populations and have been associated with hypertension. This study examines the extent to which racial/ethnic disparities in hypertension are explained by racial/ethnic differences in serum PFAS levels.

Study Conclusion: These findings suggest differences in PFAS exposure may be an unrecognized modifiable risk factor that partially accounts for racial/ethnic disparities in timing of hypertension onset among midlife women.

Per- and Polyfluoroalkyl Substances and Incident Hypertension in Multi-Racial/Ethnic Women: The Study of Women's Health Across the Nation

Study Purpose: PFAS may disrupt blood pressure controls; however, human evidence to support this hypothesis is lacking. This study examines the association between serum PFAS and risk of developing hypertension.

Study Conclusion: Several PFAS showed positive associations with hypertension. These findings suggest that PFAS may contribute to women's cardiovascular disease risk.

Associations of serum PFOA and PFOS levels with incident hypertension risk and change of blood pressure levels

Study Purpose: This study aimed to evaluate the associations of PFOA and PFOS levels with hypertension risk and change of blood pressure levels over 5 years.

Study Conclusion: In conclusion, the present study found a negative association of serum PFOS levels with the incident hypertension risk and the magnitude of systolic blood pressure rise. Further researches are warranted to verify our findings and to explore the potential mechanisms behind this association.

Exposure to toxic metals and per- and polyfluoroalkyl substances (PFAS) and the risk of preeclampsia and preterm birth in the United States: A review

Study Purpose: This article reviews past studies to provide an overview on environmental contaminants (such as PFAS) and the development of preeclampsia and preterm birth among U.S. women.

Study Conclusion: There are inconsistent findings on the relationship between PFASs and preeclampsia and preterm birth.

Per- and Polyfluoroalkyl Substance and Cardio Metabolic Markers in Firefighters

Study Purpose: This study aims to evaluate if PFAS are associated with cardio metabolic markers.

Study Conclusion: PFHxS levels were elevated in firefighters compared to the general population. PFAS levels were not associated with increased cardiometabolic risk measures in this population of firefighters.

Perfluoroalkyl substances are associated with elevated blood pressure and hypertension in highly exposed young adults

Study Purpose: Residents in a large area of North-Eastern Italy were exposed to PFAS via drinking water. Studies on the association between PFAS and blood pressure levels have found inconsistent results. This study looks at the association between PFAS levels and blood pressure and hypertension.

Study Conclusion: These results suggest that PFAS levels are associated with increased blood pressure in highly exposed adults.

Serum levels of per- and polyfluoroalkyl substances alternatives and blood pressure by sex status: Isomers of C8 health project in China

Study Purpose: This study looks at the associations between PFAS levels and blood pressure.

Study Conclusion: In this study, levels of PFASs are associated with higher blood pressure. Women appeared to be more susceptible than men.           

Association between perfluoroalkyl acids and the prevalence of hypertension among US adults

Study Purpose: This study looks at the association of PFAS levels with hypertension and blood pressure in adults

Study Conclusion: PFOA and PFHxS were related with higher risk of hypertension at lower levels and higher levels.

Association between perfluoroalkyl substance concentrations and blood pressure in adolescents

Study Purpose: This study looks at the associations between PFAS levels and hypertension in adolescents.        

Study Conclusion: These results provide evidence that PFOS level increases are associated with increases in diastolic blood pressure.

Gender-specific associations between serum isomers of perfluoroalkyl substances and blood pressure among Chinese: Isomers of C8 Health Project in China

Study Purpose: This study looks at the relationship between a variety of PFAS types and blood pressure.

Study Conclusion: PFASs were associated with elevated blood pressure.

Association of per‑ and polyfuoroalkyl substance exposure with metabolic syndrome and its components in adults and adolescents

Study Purpose: The aim was to explore the potential mechanisms through which PFAS might infuence MetS and to lay the groundwork for future research.

Study Conclusion: Our study found that PFAS was associated with a lower prevalence of MetS in both adults and adolescents, offering new insights into the relationship between PFAS and metabolic health. Interestingly, however, we observed conflicting findings across the components of MetS.

Prenatal exposures to mixtures of endocrine disrupting chemicals and sex-specific associations with children's BMI and overweight at 5.5 years of age in the SELMA study

Study Purpose: Prenatal exposure to endocrine disrupting chemicals (EDCs) such as PFAS may disrupt human metabolism. Prenatal exposure to EDCs such as PFAS have been inconsistently associated with BMI and obesity in children. This study investigated if prenatal exposure to many EDCs was associated with children's BMI and overweight at 5 years of age.

Study Conclusion: Prenatal exposure to EDCs in this study was associated with BMI and overweight in 5 year old children, with differences between boys and girl. The levels of EDCs were associated with lower BMI and lower risk of overweight among girls. 

Prenatal and childhood exposure to per-/polyfluoroalkyl substances (PFASs) and its associations with childhood overweight and/or obesity: a systematic review with meta-analyses

Study Purpose: This work reviews past studies to summarize the associations between prenatal or childhood exposure to PFASs and childhood overweight/obesity.

Study Conclusion: There is evidence to suggest possible associations between prenatal PFAS exposure and childhood BMI, and stronger evidence that suggests childhood exposure to PFAS is associated with lower childhood BMI.

Per- and polyfluoroalkyl substances, gestational weight gain, postpartum weight retention and body composition in the UPSIDE cohort

Study Purpose: This study investigates PFAS exposure and associations with gestational weight gain and postpartum body mass index.

Study Conclusion: PFAS, particularly PFOA and PFHxS, were associated with altered patterns of gestational weight gain and postpartum BMI.

Associations of Gestational Perfluoroalkyl Substances Exposure with Early Childhood BMI z-Scores and Risk of Overweight/Obesity: Results from the ECHO Cohorts

Study Purpose: Gestational PFAS exposure may be associated with increased body fatness and increased risk of obesity among children and adolescents. However, studies in humans have had inconsistent findings. This study estimates the associations of pregnancy PFAS concentrations with child body mass index and risk of overweight/obesity in the U.S.

Study Conclusion: Gestational exposure to higher levels of PFAS were associated with slightly higher child BMIs and risk of overweight or obesity.

Weight loss relapse associated with exposure to perfluoroalkylate substances

Study Purpose: The purpose of this study was to test the hypothesis that PFAS exposures are associated with body weight increases.

Study Conclusion: In this study of Europeans with obesity, elevated plasma PFAS concentrations predicted increased weight gain after an initial weight loss, no matter the diet group that the participants were assigned to. The results suggest that PFOA and PFHxS may cause weight gain among people with obesity in weight loss programs.

Nutritional Modulation of Associations between Prenatal Exposure to Persistent Organic Pollutants and Childhood Obesity: A Prospective Cohort Study

Study Purpose: Prenatal exposure to environmental chemicals such as PFAS may contribute to the development of childhood obesity and metabolic disorders. However, it is not known whether maternal nutrition status during pregnancy affects this relationship. This study aimed to assess the associations between prenatal levels of environmental chemicals and maternal nutritional status on childhood obesity.

Study Conclusion: These results support that maternal nutritional status may affect the relationship between prenatal exposure to environmental chemicals such as PFAS and childhood overweight/obesity.

Maternal per- and poly-fluoroalkyl substances exposure and child adiposity measures: A birth cohort study

Study Purpose: Maternal exposure to PFAS during pregnancy may affect physical development of offspring. This study evaluates associations between maternal PFAS exposure and offspring body fatness during the first two years of life.

Study Conclusion: In this study, they found that maternal PFAS exposure may increase body fatness in young children. This relationship may vary by specific PFAS chemical.

In utero exposure to perfluoroalkyl substances and early childhood BMI trajectories: A mediation analysis with neonatal metabolic profiles

Study Purpose: In utero PFAS exposure has been associated with childhood body weight, but the mechanisms are not well understood. This study investigates the potential mediating role of neonatal metabolites in the relationship between prenatal PFAS exposure and childhood body weight trajectories in the first four years of life.

Study Conclusion: Prenatal exposure to PFAS was associated with a persistent increase in BMI trajectory in early childhood. This relationship may be partially affected by acylcartinine C8, a fatty acid, suggesting a role of perturbed fatty acid metabolism in the pathway between PFAS and BMI.

Cross-sectional associations between exposure to per- and polyfluoroalkyl substances and body mass index among European teenagers in the HBM4EU aligned studies

Study Purpose: PFAS are widespread that may impact youth body mass index (BMI). This study investigated associations between PFAS and BMI in teenagers across nine European countries.

Study Conclusion: There was evidence of negative cross-sectional associations with age- and sex- standardized BMI for 5 of the 10 PFAS compounds in teenagers from nine studies across Europe. This indicates that these exposures may impact pathways relevant to metabolism in teenagers. Our results furthermore suggest opposite associations for PFOS, PFOA and PFNA versus PFHxS on BMI z-scores in teenagers. Although effect estimates were only minor, this could still be relevant for population health considering that such a large part of the population is exposed to these compounds. Further research is needed.

Prenatal exposure to per- and polyfluoroalkyl substances and childhood adiposity at 7 years of age

Study Purpose: An increasing number of studies have reported that prenatal PFAS exposure may increase childhood adiposity. However, limited data is available in China and the overall effects of PFAS mixtures remain unclear. The goal of this study was to examine the association of prenatal exposure to individual PFAS and PFAS mixtures with childhood adiposity at 7 years of age.

Study Conclusion: This study suggests potential sex-specific associations of prenatal exposure to individual PFAS and their mixture with childhood adiposity, with the observed relationship being negative for boys but positive for girls.

Serum levels of perfluoroalkyl substances (PFAS) and body composition - A cross-sectional study in a middle-aged population

Study Purpose: It has been suggested that PFAS are endocrine disruptors with a potential to influence fat mass.

Study Conclusion: PFOS and PFHxS levels did not show any consistent associations with body composition, but PFOA, PFNA, and PFDA were inversely related to multiple measures reflecting the amount of fat, but in women only.

Prenatal exposure to persistent organic pollutants and childhood obesity: A systematic review and meta-analysis of human studies

Study Purpose: This paper presents a review of existing literature on the association between prenatal exposure to persistent organic pollutants (POPs), such as PFAS, and childhood obesity.

Study Conclusion: The current evidence from epidemiological studies suggests that prenatal exposures to DDE and HCB are associated with greater body fatness in childhood. There was insufficient evidence to conclude that prenatal exposure to other POPs, including PFAS, are associated with obesity in children. 

Umbilical cord serum concentrations of perfluorooctane sulfonate, perfluorooctanoic acid, and the body mass index changes from birth to 5 1/2 years of age

Study Purpose: This study investigates whether umbilical cord blood concentrations of PFOS and PFOA are associated with children's risk trajectory for obesity.

Study Conclusion: These findings demonstrate that the effect of prenatal exposure to PFAS is a possible risk for obesity through an increase in BMI, especially for girls.

Temporal trends of concentrations of per- and polyfluoroalkyl substances among adults with overweight and obesity in the United States: Results from the Diabetes Prevention Program and NHANES

Study Purpose: This study aims to determine trends and rate of change of plasma PFAs concentrations in overweight or obese U.S. adults and evaluate if this changes by sex, race/ethnicity, or age.

Study Conclusion: They observed a decreasing trend in plasma PFOS in overweight/obese participants over time. Male and Black participants showed higher PFOS and PFNA than female and white participants.

Associations between exposure to perfluoroalkyl substances and body fat evaluated by DXA and MRI in 109 adolescent boys

Study Purpose: Exposure to PFASs has been associated with changes in BMI and adiposity, but evidence is inconsistent between studies. This study investigates the associations between PFAS exposure and body fat in a cross-sectional study of healthy boys.

Study Conclusion: Overall, we found no consistent associations between PFAS exposure and body fat. This could be due to our cross-sectional study design. Furthermore, we assessed PFAS exposure in adolescence and not in utero, which is considered a more vulnerable time window of exposure.

Perfluoroalkyl and polyfluoroalkyl substances and body size and composition trajectories in midlife women: the study of women's health across the nation 1999-2018

Study Purpose: This study examined associations of serum PFAS concentrations with trajectories of weight, waist circumference, fat mass, and proportion of fat in midlife women.

Study Conclusion: Certain PFAS were positively associated with greater body size and body fat, and higher rates of change over time. PFAS may be a contributing factor to obesity risk.

Plasma Concentrations of Per- and Polyfluoroalkyl Substances and Body Composition from Mid-childhood to Early Adolescence

Study Purpose: This study evaluates the associations of PFAS levels in childhood with body changes through early adolescence.

Study Conclusion: In a large prospective U.S. cohort, children with higher plasma concentrations of PFAS had less accrual of lean mass from mid-childhood to early adolescence. While children with higher plasma concentrations of some PFAS (i.e., PFOS and PFHxS) had less accrual of fat mass, particularly subcutaneous fat mass, children with higher concentrations of other PFAS (i.e., PFDA and PFNA) had greater accrual of visceral fat mass. Thus, early life exposure to some but not all PFAS may be associated with adverse changes in body composition.

Exposure to perfluoroalkyl substances (PFAS) and dyslipidemia, hypertension and obesity in adolescents. The Fit Futures study

Study Purpose: The prevalence of obesity, hypertension, and dyslipidemia has been increasing in children and teenagers across the world. Exposure to environmental pollutants may contribute to this. The aim of this study was to look at the associations between PFASs and dyslipidemia, hypertension, and obesity in a sample of adolescents

Study Conclusion: This study showed a possible link between several PFASs and dyslipidemia, hypertension, and obesity in this adolescent sample.

The Confounder-Mediator Dilemma: Should We Control for Obesity to Estimate the Effect of Perfluoroalkyl Substances on Health Outcomes?

Study Purpose: This article describes possible biases that can be introduced by adjusting for obesity in PFAS studies.

Study Conclusion: This article highlights the complexity of seemingly simple adjustment or stratification analyses, and the need for careful consideration of the confounding and/or mediating role of obesity in PFAS studies.

Exposure to Per- and Polyfluoroalkyl Substances and Adiposity at Age 12 Years: Evaluating Periods of Susceptibility

Study Purpose: PFAS exposure may increase body fatness and obesity risk in children. This study estimates associations of PFAS concentrations with adolescent risk of overweight/obesity.

Study Conclusion: There were positive associations between gestational PFOA and PFHxS levels with stomach fat levels and the risk of obesity in adolescents, while no pattern was seen for postnatal PFAS concentrations.

Gestational perfluoroalkyl substance exposure and body mass index trajectories over the first 12 years of life

Study Purpose: Gestational exposure to PFAS is associated with increased risk of obesity and cardiometabolic disease. This study explores that association.

Study Conclusion: These results suggest that gestational PFOA exposure may be associated with BMIs related to adult obesity and cardiometabolic disease, while PFOS and PFHxS exposure is associated with lower BMI in the first 12 years of life.

PFAS exposure and overweight/obesity among children in a nationally representative sample

Study Purpose: PFASs are associated with cardiovascular disease, but their relationship with obesity, a risk factor for cardiovascular disease, is not known. This study explores the relationship between PFAS and overweight/obesity and abdominal obesity in children.

Study Conclusion: Findings show that there may be an associated between elevated PFOA and overweight/obesity among children.

Prenatal Exposures to Perfluoroalkyl Acids and Associations with Markers of Adiposity and Plasma Lipids in Infancy: An Odense Child Cohort Study

Study Purpose: Maternal PFAS concentrations have been associated with offspring obesity and dyslipidemia (abnormal levels of cholesterol and other lipids) in childhood and adulthood, but this association has not been studied in infancy. This study looks as the associations between maternal PFAS concentrations and signs of obesity and lipid metabolism in infancy.

Study Conclusion: Prenatal PFAS levels were associated with greater signs of obesity and higher total cholesterol in infancy.

Per- and Polyfluoroalkyl Substances and Obesity, Type 2 Diabetes and Non-alcoholic Fatty Liver Disease: A Review of Epidemiologic Findings

Study Purpose: This study reviews evidence for associations between PFASs and the development of obesity, diabetes, and non-alcoholic fatty liver disease/non-alcoholic steatohepatitis.

Study Conclusion: There is evidence that supports the association between PFASs and the onset or development of metabolic diseases, including obesity, diabetes, and non-alcoholic fatty liver disease. However, there are inconsistent results in many cases.

Isomers of perfluoroalkyl substances and overweight status among Chinese by sex status: Isomers of C8 Health Project in China

Study Purpose: Studies on the associations of PFASs with overweight/obesity have mixed results. This study examines the relationship between BMI, waist circumference, and overweight and PFASs.

Study Conclusion: This study suggests that PFASs are associated with overweight or increased waist circumference, and these associations are stronger in women. PFOA had the strongest association.

Decreased plasma levels of perfluoroalkylated substances one year after bariatric surgery

Study Purpose: This study determines the levels of PFASs before and after bariatric surgery, and to assess whether weight loss and protein levels could influence one another.

Study Conclusion: Bariatric surgery did not influence the changes of PFAS levels before and after the operation.

Prenatal exposure to persistent organic pollutants and child overweight/obesity at 5-year follow-up: a prospective cohort study

Study Purpose: Prenatal exposure to some pollutants, such as PFASs, may influence offspring weight gain. This study looks at the relationship between prenatal exposure to PFASs and child overweight/obesity.

Study Conclusion: Increasing PFAS levels were associated with greater risk of child overweight/obesity at 5 years.

Perfluoroalkyl Substances during Pregnancy and Offspring Weight and Adiposity at Birth: Examining Mediation by Maternal Fasting Glucose in the Healthy Start Study

Study Purpose: Prenatal PFAS exposure has been associated with lower birth weight; however, impacts on body weight in later life is not well known. This study looks at the associations between maternal PFAS concentrations and offspring weight and percent body fat at birth, as well as to estimate associations between PFAS concentrations and maternal blood glucose and lipid levels.

Study Conclusion: Prenatal exposure to some PFASs was associated with lower birthweight and percent body fat at birth.

Prenatal Exposure to Perfluoroalkyl Substances and Body Fatness in Girls

Study Purpose: This study looks at the association between exposure to PFAS during pregnancy and female children's percent body fat at age 9.

Study Conclusion: Prenatal exposure to PFOA and PFOS was associated with girls' percent body fat.

Early-life exposures to persistent organic pollutants in relation to overweight in preschool children

Study Purpose: Some pollutants, such as PFASs, are suspected to be related to causing obesity. This study looks at the associations of maternal and child levels of PFASs with the risk of childhood overweight.

Study Conclusion: In this study, there were associations between maternal PFOS and PFOA levels and overweight risk in preschool children.

Prenatal Exposure to Perfluoroalkyl Substances and Adiposity in Early and Mid-Childhood

Study Purpose: This study looks at the associations of prenatal exposure to PFASs with obesity in early and mid-childhood.

Study Conclusion: Prenatal exposure to PFASs was associated with small increases in weight measurements in mid-childhood, but only among girls.

Per- and Polyfluoroalkyl Substances (PFAS) and Lipid Trajectories in Women 45-56 Years of Age: The Study of Women's Health Across the Nation

Study Purpose: This study looks at associations between serum PFAS levels and levels of blood total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides in middle-aged women undergoing menopause.

Study Conclusion: This study showed that PFAS concentrations were associated with less-favorable cholesterol levels, particularly total and LDL cholesterol. This suggests that PFAS exposure may be a risk factor for cholesterol disorders.

Associations between Per- and Polyfluoroalkyl Substances Exposures and Blood Lipid Levels among Adults-A Meta-Analysis

Study Purpose: This study aims to summarize associations between PFAS and blood lipid levels in adults.

Study Conclusion: These results suggest that plasma PFAS levels are associated with cholesterol in small HDL, IDL, and all LDL subfractions, as well as apolipoproteins and composite fatty acid and phospholipid profiles but to a lesser extent with triglycerides in lipoproteins. 

Associations of perfluoroalkyl substances (PFAS) with lipid and lipoprotein profiles

Study Purpose: Recent studies suggest that PFAS are involved in cholesterol metabolism, but the mechanisms underlying the associations are poorly understood. This study aims to evaluate associations of plasma PFAS with lipids in adults.

Study Conclusion: These results suggest that plasma PFAS levels are associated with cholesterol in small HDL, IDL, and all LDL subfractions, as well as apolipoproteins and composite fatty acid and phospholipid profiles but to a lesser extent with triglycerides in lipoproteins. 

Occurrence of legacy and alternative per- and polyfluoroalkyl substances in serum from high exposure population and their disrupting effects on serum lipids and thyroid function

Study Purpose: High exposure to PFAS has been reported in chemical production areas in China, but human studies on exposure risk is still limited. In this study, 26 PFAS chemicals were measured in the blood of adults living in a famous chemical production area in northern China. The effects of this PFAS exposure on lipid levels and thyroid function were explored. 

Study Conclusion: In this study, concentrations of PFAS were detected in serum samples of 161 adults. A high level of PFOA was observed in serum samples, which contributed 72 % of the total PFAS concentrations. The serum PFOA of all participants was higher than the US EPA derived reference dose for increased total cholesterol, and higher serum PFOA was associated with increased total cholesterol and LDL in serum. No significant association was observed between PFAS and thyroid stimulating hormone (TSH) levels or any other autoimmunity markers. Compared to effects of individual PFAS, co-exposure of long-chain PFAS including n-PFOA, PFNA, PFDA, and PFOS showed effects on free T4, while the mixture of serum PFBA and 6:2Cl-PFESA showed a influence on total and free T3 levels. It revealed that both legacy and alternative PFAS could interrupt thyroid function, but the effects and related mechanisms may be different. 

Plasma concentrations of per- and polyfluoroalkyl substances are associated with perturbations in lipid and amino acid metabolism

Study Purpose: Little is known about how PFAS impact underlying biology that leads to adverse health effects. The metabolome represents the end results of cellular processes and has been used in the past to understand changes in the body that lead to disease. This study investigates whether exposure to PFAS was associated with the metabolome. 

Study Conclusion: This study represents an investigation into the metabolomic profiles of mothers and children in response to PFAS exposure. Our results indicated disrupted metabolism of both lipids and amino acids, and specifically showed Sphingomyelins, Lysophospholipid, Long Chain Polyunsaturated Fatty Acid (n3 and n6), Fatty Acid- Dicarboxylate, and Urea cycle metabolism as particular pathways of interest that may play a large role in adverse health effects related to PFAS exposures. These findings may vary by age and sex. 

Metabolome-wide association study of four groups of persistent organic pollutants and abnormal blood lipids

Study Purpose: Research has shown that persistent organic pollutants, such as PFAS, are associated with a higher risk of abnormal blood lipid levels in humans, which this study aims to investigate.

Study Conclusion: This study found that blood PFAS levels were associated with total cholesterol and LDL levels and that certain factors may affect these associations. The PPARγ mechanism likely plays a role in the relationships between PFHxS, PFNA, PFOS, and abnormal cholesterol metabolism.

Serum per- and polyfluoroalkyl substances and abnormal lipid metabolism: A nationally representative cross-sectional study

Study Purpose: The associations of legacy PFAS with lipid metabolism are controversial, and there is little information about the impact of emerging PFAS on lipid metabolism. This study aimed to explore the associations of legacy and emerging PFAS with lipid profiles and dyslipidemia in Chinese adults.

Study Conclusion: This study showed that lipid levels and dyslipidemia may be associationed with PFAS exposure in the Chinese population, with PFHpS, PFUnDA, PFNA, and PFOS having the strongest associations. 6:2 Cl-PFESA also had a positive association with lipid profiles, but the effect was smaller than that of PFOS, which may be related to the different durations of exposure to legacy and emerging PFAS. The dose–response relationship between PFAS and lipid profiles was nonlinear. More studies should be conducted in the future to verify these findings and investigate the potential biological mechanisms.

Effect of lifestyle-based lipid lowering interventions on the relationship between circulating levels of per-and polyfluoroalkyl substances and serum cholesterol

Study Purpose: Exposure to certain PFAS has been shown to be positively associated with total and/or LDL cholesterol. Examining this association in cholesterol-lowering interventions may provide additional evidence linking PFAS to cardiovascular risk. This study examines the relationship of 6 PFAS with cholesterol in a 6-month lifestyle-based intervention.

Study Conclusion: The levels of PFAS observed, except for PFOS, were comparable to national levels. This cohort had clinically significant cholesterol levels at baseline, and the cohort shows similarities to the average US adult. The results indicate that lipid-lowering through lifestyle modification may impact levels of PFAS in the body.

Perfluoroalkyl Substance Serum Concentrations and Cholesterol Absorption-Inhibiting Medication Ezetimibe

Study Purpose: PFAS have been associated with multiple health effects, including higher serum cholesterol and LDL cholesterol. This study investigates potential population differences in serum PFAS attributable to exetimibe, a medication that inhibits cholesterol absorption. 

Study Conclusion: Ezetimibe does not appear to affect serum PFAS concentrations. We sought but did not find direct evidence that ezetimibe could inhibit PFAS uptake nor inferential evidence that inter-individual differences in sterol absorption could provide a confounding factor explanation for the association of serum total- and LDL-cholesterol with serum PFAS.

Is the cholesterol-perfluoroalkyl substance association confounded by dietary fiber intake?: a Bayesian analysis of NHANES data with adjustment for measurement error in fiber intake

Study Purpose: Concentrations of total cholesterol and other lipid measures have been associated with PFAS in humans, even among those with only background-level exposure to PFAS. Fiber is known to decrease cholesterol and recent reports showed that PFAS and fiber intake may be inversely associated. This study investigates the notion that confounding by dietary fiber may account for some of the association between cholesterol and PFAS.

Study Conclusion: The results indicated that the association of serum cholesterol with PFAS was not substantially confounded by fiber intake.

Associations of PFAS-related plasma metabolites with cholesterol and triglyceride concentrations

Study Purpose: To better understand the PFAS-induced effects on lipid pathways, this study investigated associations between PFAS exposure and cholesterol and triglyceride concentrations.

Study Conclusion: In conclusion, this study did not find evidence for associations of PFAS with total cholesterol. Instead, they found that PFAS exposure was associated with triglyceride levels.

Associations between Mixture of Perfluoroalkyl Substances and Lipid Profile in a Highly Exposed Adult Community in the Veneto Region

Study Purpose: Residents of the Veneto region in Northern Italy were exposed to drinking water contaminated by PFAS for decades. While exposure to PFAS has been consistently associated with elevated serum lipids, combined exposures to multiple PFASs have been poorly investigated. Utilizing different statistical approaches, we examine the association between chemical mixtures and lipid parameters.

Study Conclusion: In this study, we found that PFAS exposure, especially PFOS and PFNA, is associated with lipid levels in this population. The mixture of PFOA, PFOS, PFHxS, and PFNA with higher concentrations in blood samples was associated with higher total cholesterol, HDL cholesterol, and LDL cholesterol.

Drinking Water-Associated PFAS and Fluoroethers and Lipid Outcomes in the GenX Exposure Study

Study Purpose: Residents of Wilmington, NC were exposed to drinking water contaminated by PFAS from 1980 to 2017. This study measured the association between serum PFAS levels and cholesterol outcomes.

Study Conclusion: PFNA and PFOS were associated with higher levels of total and non-HDL cholesterol, with associations larger in magnitude among older adults. Fluoroethers appeared to be associated with HDL but non-HDL lipid measures.

Perfluoroalkyl substances and lipid concentrations in the blood: A systematic review of epidemiological studies

Study Purpose: This review assesses PFAS associations with LDL and HDL cholesterols, total cholesterol, and total triglyceride concentrations.

Study Conclusion: There was evidence of associations between the concentrations of some PFAS-lipid pairs in humans. 

Lipoprotein profiles associated with exposure to poly- and perfluoroalkyl substances (PFASs) in the EuroMix human biomonitoring study

Study Purpose: Exposure to PFAS is associated with increased blood cholesterol. Although elevated cholesterol is a well-established risk factor for cardiovascular diseases, it is not clear whether PFAS affect this risk. Lipoproteins may provide an insight to physiological implications of PFAS exposure. This study explores the association between PFAS concentrations and lipoproteins.

Study Conclusion: Background PFAS serum concentrations were associated with altered lipoprotein profiles in a generally healthy population. The strongest associations identified were between long-chained PFCAs and increased cholesterol in large and medium sized HDL-particles in women. The change in cholesterol distribution among the LDL-particles appeared more complex, but the most significant increases were found among the LDL1-LDL3 fraction and in particular among the PFCAs. A general reduction in large VLDL particle number and lipid content was suggested. This study suggests that PFAS serum concentrations are associated with both lipoprotein particle distributions and particle content at background PFAS exposure levels.

Perfluoroalkyl substance mixtures and cardio-metabolic outcomes in highly exposed male workers in the Veneto Region: A mixture-based approach

Study Purpose: PFAS have been consistently associated with cardio-metabolic traits. Occupational exposures to multiple PFAS with health outcomes have been poorly investigated. The aim of the present study was to examine these associations among former workers involved in PFAS production.

Study Conclusion: The results showed a clear association between serum PFAS levels and markers of cardiovascular risk and support the importance of clinical surveillance of cardiovascular risk factors in population with a high exposure to PFAS, especially in the occupational setting.

The association between blood PFAS concentrations and clinical biochemical measures of organ function and metabolism in participants of the Canadian Health Measures Survey (CHMS)

Study Purpose: This study tests the association between human blood levels of PFAS and measures of organ and metabolic function among a nationally representative sample of 6768 participants in Canada.

Study Conclusion: At the concentrations found in a large sample of the Canadian population, we found that selected PFAS were associated with biochemical markers of liver, kidney and thyroid function, and lipid, calcium and glucose metabolism. We also found associations between several PFAS and GGT, a marker of all-cause mortality. The observed associations on average were generally small and need to be interpreted with caution, but they may possibly be important at a population level and in population subgroups, who may have higher than average exposure. More research is needed.

Changes in plasma levels of per- and polyfluoroalkyl substances (PFAS) are associated with changes in plasma lipids - A longitudinal study over 10 years

Study Purpose: Associations between PFAS and increased blood lipids have been reported primarily from cross-sectional studies. The aim of this study was to investigate associations between multiple PFAS and blood lipids.

Study Conclusion: In this study with three measurements over 10 years of both plasma PFAS and lipids, increasing levels of PFAS were associated with changes in plasma lipids.

The effects of Cl-PFESAs exposure on blood lipids – A community-based large population study in Guangzhou

Study Purpose: In this study, they investigate the association between CI-PFESAs, a PFAS alternative in China, and blood lipid profiles in community residents.

Study Conclusion: This study found a positive association between Cl-PFESAs and total cholesterol, triglycerides, and LDL cholesterol, as well as a negative association between Cl-PFESAs and dyslipidemia. An exposure-response relationship was suggested between PFAS alternatives and lipids.

Why is elevation of serum cholesterol associated with exposure to perfluoroalkyl substances (PFAS) in humans? A workshop report on potential mechanisms

Study Purpose: There may be an association between PFAS exposure and elevated cholesterol. A workshop was held in 2019 to discuss possible mechanisms behind this. In this report, they summarize data, discussion among attendees, and recommendations for further research.

Study Conclusion: The mechanisms behind the association of serum cholesterol with exposure to PFAS have not been determined.

Lipid responses to environmental perfluoroalkyl substance exposure in a Taiwanese Child cohort

Study Purpose: The purpose of this study was to assess changes in lipids in children after exposure to PFASs and suggest potential health effects.

Study Conclusion: This study found that some PFASs were associate with lipid changes. The PFOS level was most correlated with lipid alterations. The results of these lipid alterations suggest possible effects on hepatic lipid metabolism, metabolic disorders, and PFAS interactions in the body.

Early-life associations between per- and polyfluoroalkyl substances and serum lipids in a longitudinal birth cohort

Study Purpose: Exposures to PFASs may affect metabolic outcomes, including lipid concentrations in blood. This study estimates associations between PFAS and lipid concentrations at birth and at several points in childhood.

Study Conclusion: These findings suggest that childhood PFAS exposures may be associated with elevated serum lipid concentrations. This is a public health concern because a detrimental lipid profile in childhood is a risk factor for later development of hyperlipidemia and cardiovascular disease.

Systemic PFOS and PFOA exposure and disturbed lipid homeostasis in humans: what do we know and what not?

Study Purpose: This review presents the main issues on regulation of lipids by PFOS and PFOA, emphasizing underlying mechanisms in the body.

Study Conclusion: There is a difference between the mechanisms in lipid regulation in mice versus humans, which may be due to doses of PFASs.

Perfluoroalkyl substances (PFASs) and mercury in never-pregnant women of fertile age: association with fish consumption and unfavorable lipid profile

Study Purpose: This study examines concentrations of PFASs and lifestyle factors that may contribute to higher levels of pollutants in women of fertile age who have never been pregnant.

Study Conclusion: The majority of the women in this study had a mixture of seven different PFASs and mercury detected in their blood. PFAS concentrations were higher in older women and associated with fish intake.

The association between perfluoroalkyl substances and lipid profile in exposed pregnant women in the Veneto region, Italy

Study Purpose: Residents of northeastern Italy were exposed for decades to high concentrations of PFASs via drinking water. Elevated lipid levels during pregnancy can have long-lasting effects on pregnant women and the developing fetus. This study looks at the association between PFASs and lipid levels in highly exposed pregnant women.

Study Conclusion: These results suggest that the associations between PFAS concentrations and lipid levels in pregnant women may differ by trimester of pregnancy. In the first trimester, patterns are like those in non-pregnant women, while they differ in late pregnancy.

Serum perfluoroalkyl substances in relation to lipid metabolism in Chinese pregnant women

Study Purpose: Exposure to PFASs could affect lipid levels, but studies on these effects in pregnant women are limited. This study looks at the association between PFASs and lipid levels in pregnant women.

Study Conclusion: Exposure to PFASs may influence lipid levels in pregnant women.

Associations between perfluoroalkyl substances and lipid profile in a highly exposed young adult population in the Veneto Region

Study Purpose: Residents of a large area of North-Eastern Italy were exposed for decades to drinking water contaminated by PFAS. This study looks at the association between PFAS levels and lipid levels and how the amount of PFAS changes this association in this heavily exposed population.

Study Conclusion: The largest jumps in cholesterol levels occurred at the lower ranges of PFAS concentrations.

Prenatal exposure to perfluoroalkyl substances and cord plasma lipid concentrations

Study Purpose: The effects of PFAS exposure on lipid levels in newborns is unknown. This study looks at the health effects of prenatal exposure to PFAS on umbilical cord lipid levels.

Study Conclusion: These findings suggest that prenatal exposure to PFAS may disrupt lipid levels and metabolism in newborns.

Serum albumin mediates the effect of multiple per- and polyfluoroalkyl substances on serum lipid levels

Study Purpose: Previous studies looking at the association between PFAS exposure and lipid levels have mainly focused on individual PFASs; the influence of multiple PFAS exposure on lipids is not clear. This study looks at the combined effects of multiple PFASs on lipid levels.

Study Conclusion: PFAS exposure was associated with lipid levels.

Associations between perfluoroalkyl substances and serum lipids in a Swedish adult population with contaminated drinking water

Study Purpose: Exposure to PFAS have been shown to affect lipid levels in past studies. This study looks at the association between lipid levels and PFAS, and if these associations with PFAS remained in a comparison based on residency in areas with differing exposure to PFAS.

Study Conclusion: This study provides more evidence of an association between PFAS and lipid levels, especially for PFHxS.

The Association Between Perfluoroalkyl Substances and Lipids in Cord Blood

Study Purpose: PFAS were suspected to have been released during the collapse of the World Trade Center on 9/11. Evidence suggests that PFAS may alter lipid levels. This study looks at the association between umbilical cord PFAS levels and lipids in a group prenatally exposed to the WTC disaster.

Study Conclusion: These findings support an association between exposure to PFAS and altered lipid levels.

Roles of gender and obesity in defining correlations between perfluoroalkyl substances and lipid/lipoproteins

Study Purpose: This study looks at the relationship between PFASs and total cholesterol, LDL, HDL, and triglycerides and how gender and obesity change these relationships.

Study Conclusion: PFAS affected lipids such as LDL and total cholesterol more in obese individuals.

Associations between lipid/lipoprotein levels and perfluoroalkyl substances among US children aged 6-11 years

Study Purpose: Levels of lipids have been associated with exposure to PFASs. This study looks at the associations between PFASs and lipid levels in children aged 6-11 years.

Study Conclusion: PFOS and PFNA was related with total cholesterol levels in children and PFASs may be related to non-HDL cholesterol in children.

Liver and cardiometabolic markers and conditions in a cross-sectional study of three Australian communities living with environmental per- and polyfluoroalkyl substances contamination

Study Purpose: PFAS have been associated with higher cholesterol and liver function markers in some studies, but evidence has been inconclusive. This study assesses associations of single and combined PFAS chemicals with cardiometabolic markers in Australian communities with PFAS-contaminated water from firefighting activities.

Study Conclusion: This study is one of few that has assessed associations blood PFAS levels with multiple markers of cardiometabolic health in multiple communities. Findings for total cholesterol were consistent with previous studies.

Metabolic Signatures of Youth Exposure to Mixtures of Per- and Polyfluoroalkyl Substances: A Multi-Cohort Study

Study Purpose: Exposure to PFAS has been associated with an increased risk of cardiometabolic diseases. This study examines associations of PFAS mixtures with alterations in metabolic pathways in adolescents and young adults.

Study Conclusion: Exposure to PFAS is associated with alterations in amino acid and lipid metabolism in adolescents and young adults.

Associations between Per- and Polyfluoroalkyl Substances (PFAS) and Cardiometabolic Biomarkers in Adults of Czechia: The Kardiovize Study

Study Purpose: Even though there is evidence of decreasing trends of PFAS in Czechia, there are still major sources of PFAS pollution. Regarding the still-inconsistent results of the relationship between cardiometabolic health and PFAS, the present study sought to determine the association between PFAS levels and the presence of cardiometabolic biomarkers, including blood pressure, cholesterol, and other factors in a Czech population.

Study Conclusion: In conclusion, PFAS exposure in this population was lower than in other areas of the world. The results indicated that even with lower PFAS levels, it was possible to detect associations with cardiometabolic biomarkers, with results generally consistent with the literature. 

Associations of perfluoroalkyl substances with adipocytokines in umbilical cord serum: A mixtures approach

Study Purpose: PFAS may interfere with the secretion of adipokines and affect fetal metabolic function and intrauterine development. However, human data is limited. This study examines the associations of single and multiple PFAS exposures in utero with adipocytokine concentrations in umbilical cord serum.

Study Conclusion: PFAS levels were significantly associated with adipokines in cord serum, suggesting that intrauterine mixture of PFAS exposure may be related to decreased fetal leptin level but increased fetal adiponectin level and the associations may be sex-specific.

Characterization of Potential Adverse Outcome Pathways Related to Metabolic Outcomes and Exposure to Per- and Polyfluoroalkyl Substances Using Artificial Intelligence

Study Purpose: A new artificial intelligence tool was used to rapidly and systematically explore all published information to identify existing associations between PFAS and metabolic health outcomes.

Study Conclusion: The strength of the study lies in the identification and selection of complex and generalized information data on PFAS related to metabolic outcomes in a time-efficient manner due to the AOP-helpFinder tool. We were able to show that when considering PFAS as stressors in the AOP framework the potential interrelationships of different events and pathways can be revealed. That seems relevant for the further development of AOPs and AOP networks and should be further explored. Furthermore, we managed to provide an overview of the available data in the published scientific literature, which will help scientists obtain an easier understanding of potential linkages between MIE, KE, and AO in the case of metabolic outcomes initiated by PFAS exposure. This overview shows where information is lacking and points out where further research would be beneficial to support AOP development and hazard assessment.

Do perfluoroalkyl substances aggravate the occurrence of obesity-associated glucolipid metabolic disease?

Study Purpose: This article summarizes the literature on PFAS and obesity-related glucolipid metabolic disease, as well as experimental evidence.

Study Conclusion: Cross-sectional studies have reported that PFAS exposure increases the risk of GLMD, although this type of study cannot conclude causation. The occurrence of GLMD is also closely connected with obesity. However, there are few studies on this topic and more are needed.

Do perfluoroalkyl substances aggravate the occurrence of obesity-associated glucolipid metabolic disease?

Study Purpose: This article summarizes the literature on PFAS and obesity-related glucolipid metabolic disease, as well as experimental evidence.

Study Conclusion: Cross-sectional studies have reported that PFAS exposure increases the risk of GLMD, although this type of study cannot conclude causation. The occurrence of GLMD is also closely connected with obesity. However, there are few studies on this topic and more are needed.

Perfluorooctane sulfonate alternatives and metabolic syndrome in adults: New evidence from the Isomers of C8 Health Project in China

Study Purpose: Cl-PFESAs are alternatives to PFOS, a widely used PFAS. Despite evidence in the laboratory of metabolic toxicity, no study has explored associations of Cl-PFESAs with metabolic syndrome in a human population. To help address this gap, this study measured 32 PFAS, including Cl-PFESAs, in serum from 1228 adults participating in the cross-sectional Isomers of C8 Health Project in China.

Study Conclusion: These results suggest that exposure to Cl-PFESAs was associated with metabolic syndrome, though additional studies are needed to more definitively address potential health concerns of these PFOS alternatives.

To which extent are per-and poly-fluorinated substances associated to metabolic syndrome?

Study Purpose: This study assesses current literature investigating the association between exposure to PFAS and metabolic syndrome.

Study Conclusion: Based on this analysis, the current small body of evidence does not support an association between PFAS and metabolic syndrome. However, due to the small number of studies and differences between studies, results should be interpreted with caution. More studies are needed.

Prenatal exposure to persistent organic pollutants as a risk factor of offspring metabolic syndrome development during childhood

Study Purpose: This review looks at the role of prenatal exposure to persistent pollutants in offspring who develop metabolic syndrome in childhood, the latest research on metabolic syndrome, epidemiological and experimental findings on metabolic syndrome, and modes of action of persistent pollutants.

Study Conclusion: Even though the studies in this review had many strengths, one major weakness was the usage of different combinations of MetS criteria to measure the outcomes. These findings elucidate the urgent need to solidify the pediatric MetS definition. An accurate definition will permit scientists to measure the MetS as a health outcome properly and allow clinicians to diagnose pediatric MetS and provide individualized treatment appropriately.

Associations of Perfluoroalkyl Substances with Prevalence of Metabolic Syndrome in Highly Exposed Young Adult Community Residents-A Cross-Sectional Study in Veneto Region, Italy

Study Purpose: This study investigates the associations between PFAS serum levels and the prevalence of metabolic syndrome among highly exposed young adults in north-eastern Italy stemming from PFAS water contamination.

Study Conclusion: These results did not support a consistent association between PFAS and metabolic syndrome.

Association between exposure to perfluoroalkyl substances and metabolic syndrome and related outcomes among older residents living near a Science Park in Taiwan

Study Purpose: The largest Science Park in Taiwan discharges wastewater containing PFASs into the Keya River, and a high concentration of PFASs have been found in this river and its aquatic life. This study looked at residents living near the river and evaluated the association of PFASs with metabolic syndrome and lipid levels.

Study Conclusion: These results showed that there were no associations between PFASs and metabolic syndrome. PFAS levels were associated with lipid levels. Certain PFASs were associated with increased uric acid levels, especially in males.

Estimated exposure to perfluoroalkyl substances during infancy and serum-adipokine concentrations in later childhood

Study Purpose: The aim of the study was to evaluate the possible association of childhood adipokine concentrations with PFAS concentrations during infancy. Adipokines are molecules produced by  fat tissue that play roles in the bodies metabolism.

Study Conclusion: Increasing PFAS levels were associated with lower resistin concentrations at age 9 years. Resistin is a protein with links to both insulin resistance and inflammation. Additionally, there was some evidence of an association between increasing PFAS levels and increasing adiponectin levels. Adiponectin is a protein hormone involved in regulating glucose levels and breaking down fatty acids in the body.

Physical activity modifies the relation between gestational perfluorooctanoic acid exposure and adolescent cardiometabolic risk

Study Purpose: Exposure to PFAS may increase cardiometabolic risk. This study evaluates whether adolescent lifestyle factors modified associations between gestational PFAS exposure and cardiometabolic risk using a prospective cohort study.

Study Conclusion: Childhood physical activity modified the association between PFOA exposure with children's cardiometabolic risk, indicating that lifestyle changes may lessen the adverse effects of PFOA exposure.

Global DNA methylation mediates the association between serum perfluorooctane sulfonate and carotid intima-media thickness in young and middle-aged Taiwanese populations

Study Purpose: Previous reports have shown PFAS exposure may contribute to cardiovascular diseases (CVD). Recent studies have also identified a role for DNA methylation in the development of CVD. PFAS has also been shown to affect DNA methylation. This study investigates the association between PFOS and mean carotid intima-media thickness (CIMT), a marker of arteriosclerosis, and how this association may be affected by DNA methylation.

Study Conclusion: These results showed that PFOS exposure has direct associations on arteriosclerosis and indirect associations on arteriosclerosis through DNA methylation. The results suggest that DNA methylation might regulate the relationship between PFOS and arteriosclerosis in the study subjects. Additional works are required to understand the causal inference between PFOS, DNA methylation, and arteriosclerosis.

Prenatal and postnatal exposure to PFAS and cardiometabolic factors and inflammation status in children from six European cohorts

Study Purpose: In this study, they test the hypothesis that early life exposure to PFAS is associated with poor metabolic health in children. They studied the association between prenatal and postnatal PFAS mixture exposure and cardiometabolic health in children, and the role of inflammatory proteins.

Study Conclusion: This study supports the hypothesis that prenatal, rather than postnatal, PFAS exposure might contribute to unfavorable lipid profiles and adiposity in childhood.

Exposure to legacy and novel perfluoroalkyl substance disturbs the metabolic homeostasis in pregnant women and fetuses: A metabolome-wide association study

Study Purpose: This study evaluates the associations between metabolites in maternal and infant cord serum and exposure to several PFASs.

Study Conclusion: This study identified metabolites and pathways in pregnant women and fetuses associated with exposure to several PFASs.

Associations of Perfluoroalkyl substances with blood lipids and Apolipoproteins in lipoprotein subspecies: the POUNDS-lost study

Study Purpose: This study looks at the association between PFAS levels and lipoprotein (transports fats and lipids in blood) and apolipoprotein levels (transport fat and cholesterol in body).

Study Conclusion: These findings suggest that PFAS levels are associated with blood lipids and polyproteins, which may elevate cardiovascular risk.

Associations between repeated measure of plasma perfluoroalkyl substances and cardiometabolic risk factors

Study Purpose: PFASs may increase metabolic risks, but there are not many studies on the topic. This study looks at the associations between PFASs and total cholesterol, triglycerides, and hypertension.

Study Conclusion: This study found rising PFAS levels associated with lower triglyceride levels. There was no clear link between cholesterol or hypertension and PFASs.

Perfluoroalkyl substances and changes in body weight and resting metabolic rate in response to weight-loss diets: A prospective study

Study Purpose: Whether PFASs may interfere with body weight regulation is mostly unknown. This study looks at the associations of PFAS exposure with changes in body weight and resting metabolic rate in diet-induced weight-loss setting.

Study Conclusion: In this diet-induced weight-loss setting among overweight and obese individuals, higher levels of PFAS were associated with greater weight regain, especially in women.

Perfluoroalkyl substances, bone density, and cardio-metabolic risk factors in obese 8–12-year-old children: A pilot study

Study Purpose: PFASs have been associated with negative bone and metabolic changes in adults; however, these associations are understudied in children. This study looks at the relationships of PFASs with bone health in children.

Study Conclusion: PFAS exposure in obese children may play a role in adverse skeletal and cardiovascular risk profiles.

Serum perfluoroalkyl substances and cardiometabolic consequences in adolescents exposed to the World Trade Center disaster and a matched comparison group

Study Purpose: Children who lived or attended school near the World Trade Center disaster site were exposed to many substances, including PFASs. This study looks at the relationship of PFAS levels with lipid levels and weight.

Study Conclusion: There is a potential high risk of atherosclerosis (plaque buildup) and cardiovascular diseases in these children as a result of PFAS exposure.

Associations between endocrine disruptor contamination and thyroid hormone homeostasis in Belgian type 1 diabetic children

Study Purpose: Some populations may be susceptible to thyroid disruption, like diabetics due to the relation between thyroid function and the control of carbohydrate homeostasis by the pancreas. The aim of this study was to investigate the associations between the exposure to PFAS and other environmental pollutants and thyroid hormone levels in children with type 1 diabetes.

Study Conclusion: These results showed that this small group of children with type 1 diabetes were potentially susceptible to thyroid disruptions by some pollutants. For these children, both di-(2-ethylhexyl) phthalate metabolites would potentially hamper the glucose homeostasis. Further study is needed to confirm these findings.

Prenatal exposure to perfluoroalkyl substances modulates neonatal serum phospholipids, increasing risk of type 1 diabetes

Study Purpose: This study examines the effects during pregnancy on markers of type 1 diabetes risk in children.

Study Conclusion: Findings suggest that PFAS exposure during pregnancy contributes to the risk and development of type 1 diabetes in offspring.

Cardiometabolic health and per and polyfluoroalkyl substances in an 
Inuit population 

Study Purpose: Our study aimed to expand on this previous study to include a wider range of PFAAs congeners, add to the literature pertaining to the effects of PFAAs mixtures and cardiometabolic health, and specifically examine the effect of an 
Arctic-specific PFAAs mixture. 

Study Conclusion: The study provides further evidence of increase of circulating lipids with increased exposure to PFAAs. The increased risk of prediabetes points to the influence of PFAAs on potential clinical outcomes. International regulation of PFAAs is essential to curb PFAAs exposure and related health effects in Arctic communities.  

Associations between per- and polyfluoroalkyl substances (PFAS) and diabetes in two population-based cohort studies from Sweden

Study Purpose: PFAS have been suggested to contribute to the development of metabolic diseases such as obesity, diabetes, and non-alcoholic fatty liver disease. However, evidence in human studies is inconclusive. The aim of this study was to evaluate the relationship between PFAS exposure and diabetes and fasting glucose.

Study Conclusion: Increasing PFOA concentrations were found to be associated with decreased diabetes diagnoses and lower plasma glucose levels in women only. 

Exposure to high levels of PFAS through drinking water is associated with increased risk of type 2 diabetes-findings from a register-based study in Ronneby, Sweden

Study Purpose: Human studies linking type 2 diabetes and exposure to PFAS are limited and have had conflicting results. This study aimed to investigate the risk of type two diabetes among adults who had been exposed to PFAS from highly contaminated drinking water for decades.

Study Conclusion: This study suggests an increased risk of type two diabetes after long-term high PFAS exposure through drinking water. In particular, a higher risk of early onset diabetes was found, indicating increased susceptibility to PFAS-related health effects at younger ages.

Exposure to per- and polyfluoroalkyl substances and glycemic control in older US adults with type 2 diabetes mellitus

Study Purpose: PFAS have been associated with impaired glucose control. This study aimed to examine associations between PFAS levels and poor glycemic control (PGC) in US adults aged 65 and older with type 2 diabetes.

Study Conclusion: In US adults aged 65 and older with type two diabetes, poor glycemic control is more likely to be observed in those with high serum levels of PFNA and PFHxS (independent of sex) and PFDeA (in men), after controlling for confounders.

Exposure to per- and polyfluoroalkyl substances (PFAS) and type 2 diabetes risk

Study Purpose: This study aimed to review the evidence on the associations of PFAS with diabetes.

Study Conclusion: These findings suggest that PFAS exposure may increase the risk of type 2 diabetes, and that PFOA may exert non-monotonic dose-response effects on type 2 diabetes. 

Exposure to per- and polyfluoroalkyl substances (PFAS) and type 2 diabetes risk

Study Purpose: This review summarizes the current state of the literature linking PFAS to type 2 diabetes and discusses important future directions including the use of more complex mixtures-based statistical analyses.

Study Conclusion: Overall, while studies have long been shown to demonstrate the major impact of genetic and lifestyle factors on the development and progression of T2D, emerging studies examined in this review have begun to investigate the impact of exposure to PFAS on glucose and insulin homeostasis as well as T2D incidence. In general, there seems to be strong evidence supporting a link between PFAS exposure and increased glucose levels and insulin resistance in individuals with multiple risk factors for diabetes, while PFAS exposures found in national surveys do not demonstrate consistent positive associations. In most cases however, these associations have been shown to vary depending on the specific PFAS examined and the gender of the subject.

The association of PFAS exposure with T2D incidence remains convoluted. It is possible these studies have produced such varied results due to an inverse U-shaped association between PFAS exposure and T2D incidence, as a couple studies have demonstrated. Continued investigations into the relationships between PFAS exposure and T2D need to be done in order to better understand the impacts of environmental pollutants on diabetes progression and prevalence.

Per- and polyfluoroalkyl substances and incident diabetes in midlife women: the Study of Women's Health Across the Nation (SWAN)

Study Purpose: It has been suggested that there are diabetogenic effects of PFAS. However, there is limited evidence in longer-term studies. This paper examines the association between serum PFAS concentrations and incident diabetes in the Study of Women's Health Across the Nation Multi-Pollutant Study (SWAN-MPS).

Study Conclusion: This study suggests that PFAS may increase diabetes risk in midlife women. Reduced exposure to these ‘forever and everywhere chemicals’ may be an important preventative approach to lowering population-wide diabetes risk.

Exposure to novel and legacy per- and polyfluoroalkyl substances (PFASs) and associations with type 2 diabetes: A case-control study in East China

Study Purpose: This study evaluates the effects of PFAS exposure on type 2 diabetes by estimating the associations of PFAS levels in humans with the risk of type 2 diabetes.

Study Conclusion: In conclusions, the correlations between PFASs and glycemic markers and lipid levels indicate that PFAS exposure could be a factor in type 2 diabetes development.

Serum concentrations of per-/polyfluoroalkyl substances and risk of type 2 diabetes: A case-control study

Study Purpose: In this study, type 2 diabetics and individuals comparable but without type 2 diabetes were compared to explore associations between serum PFASs and type 2 diabetes risk.

Study Conclusion: Our findings suggested that there are associations between exposure to PFASs and risk of T2DM. Further mechanism research is worthy to be conducted to elucidate the mode of action of different PFASs on T2DM at different exposure levels.

Per- and polyfluoroalkyl substances and calcifications of the coronary and aortic arteries in adults with prediabetes: Results from the diabetes prevention program outcomes study

Study Purpose: PFAS are endocrine disrupting chemicals that have been associated with cardiovascular risk factors including elevated body weight and hypercholesterolemia. This study investigates the contribution of PFAS to the development of arterial calcification in prediabetics.

Study Conclusion: In this study, prediabetic adults with higher levels of some PFASs had higher risk of coronary and thoracic aorta calcification. PFAS exposure may be a risk factor for adverse cardiovascular health among high-risk populations.

Per- and polyfluoroalkyl substance plasma concentrations and metabolomic markers of type 2 diabetes in the Diabetes Prevention Program trial

Study Purpose: PFASs have been linked to type 2 diabetes in previous studies. In this study, they test whether PFAS concentrations were associated with metabolites shown to predict type 2 diabetes in a trial of individuals at high risk of type 2 diabetes.

Study Conclusion: PFAS concentrations were associated with metabolites linked to type 2 diabetes. Further research is needed.

Plasma metabolites associated with exposure to perfluoroalkyl substances and risk of type 2 diabetes: A nested case-control study

Study Purpose: This study examines if PFAS metabolite patterns were associated with risk of developing type 2 diabetes.

Study Conclusion: PFAS could be associated with two groups of lipids with unknown relations to type 2 diabetes development, which could explain conflicting associations found between PFAS and type 2 diabetes risk.

Pre- and post-diagnostic blood profiles of perfluoroalkyl acids in type 2 diabetes mellitus cases and controls

Study Purpose: To explore associations between pre- and post-diagnostic PFAA blood profiles and T2DM and assess factors associated with longitudinal changes in PFAAs in T2DM cases and controls.

Study Conclusion: The study did not find evidence of association between PFAS and type 2 diabetes. Changes in PFAS concentrations over time were not influenced by development of type 2 diabetes.

Impact of the co-occurrence of obesity with diabetes, anemia, hypertension, and albuminuria on concentrations of selected perfluoroalkyl acids

Study Purpose: This study evaluates the occurrence of obesity with diabetes, anemia, albuminuria, and hypertension on concentrations of PFAS.

Study Conclusion: Obesity is associated with lower concentrations of PFAS. As compared to those who have no diseases, anemia, albuminuria, and diabetes were associated with lower concentrations of PFAS and hypertension was associated with higher concentrations of PFAS.

Per- and Polyfluoroalkyl Substances and Obesity, Type 2 Diabetes and Non-alcoholic Fatty Liver Disease: A Review of Epidemiologic Findings

Study Purpose: This study reviews evidence for associations between PFASs and the development of obesity, diabetes, and non-alcoholic fatty liver disease/non-alcoholic steatohepatitis.

Study Conclusion: There is evidence that supports the association between PFASs and the onset or development of metabolic diseases, including obesity, diabetes, and non-alcoholic fatty liver disease. However, there are inconsistent results in many cases.

Associations of Perfluoroalkyl and Polyfluoroalkyl Substances with Incident Diabetes and Microvascular Disease          

Study Purpose: This study looks at which PFASs are associated diabetes and microvascular disease. This study also tests whether a lifestyle intervention can change this association and decrease concentrations.

Study Conclusion: Some PFASs were associated with diabetes and microvascular disease. Exercise and diet may reduce the association between PFASs and diabetes.

Perfluoroalkyl substances and risk of type II diabetes: A prospective nested case-control study

Study Purpose: This study looks at the association between PFAS levels and type 2 diabetes risk.

Study Conclusion: In participants without type 2 diabetes, long-term PFAS exposure was associated with lower insulin resistance.

Plasma Concentrations of Perfluoroalkyl Substances and Risk of Type 2 Diabetes: A Prospective Investigation among U.S. Women

Study Purpose: This study aimed to examine the associations between PFAS exposures and development type 2 diabetes.

Study Conclusion: Background exposures to PFASs in the later 1990s were associated with higher type 2 diabetes risk during following years.

PFOA is associated with diabetes and metabolic alteration in US men: National Health and Nutrition Examination Survey 2003-2012

Study Purpose: This study looks at the relationship between PFAS and diabetes prevalence.

Study Conclusion: These results provide evidence that levels of PFOA may be associated with diabetes in men and with total cholesterol in adults.

Perfluoroalkyl substances and beta cell deficient diabetes

Study Purpose: PFAS are shown to preserve pancreatic islet cells (related to insulin production). This study looks at the relationship between PFAS levels and diabetes--type 1 and type 2.

Study Conclusion: PFAS levels were negatively associated with diabetes. The inverse relationship was strongest for type 1 diabetes.

PFAS concentrations in early and mid‑pregnancy and risk of gestational
diabetes mellitus in a nested case‑control study within the ethnically and racially diverse PETALS cohort

Study Purpose: We hypothesize that participants with higher levels of PFAS concentrations during gestation will have greater risk of GDM

Study Conclusion: This prospective nested case–control study observed
that higher serum levels of PFDA, PFNA, and PFOA during early and mid-pregnancy were consistently associated with higher GDM risk in an ethnically diverse
population.

Gestational hypertension, preeclampsia, and gestational diabetes mellitus
after high exposure to perfluoroalkyl substances from drinking water in
Ronneby, Sweden

Study Purpose: This study investigated the associations between high PFAS exposure,modelled as residential history during the five-year period before
childbirth, and GH, PE, and GDM in a large register-based cohort.

Study Conclusion: We found no evidence of an increased risk of GHP or GDM in a large register-based study of a population with high exposure and large contrasts
of primarily PFOS and PFHxS. As more PFAS hotspots are continuously discovered, the study adds important knowledge to public health management.

Environmental pollutants exposure and gestational diabetes mellitus: Evidence from epidemiological and experimental studies

Study Purpose: Long-term exposure to environmental pollutants has been shown to contribute to the development of gestational diabetes, but the conclusions remain controversial. This study reviews findings from past studies between environmental pollutants and gestational diabetes.

Study Conclusion: These results suggest that exposure to the environmental pollutants PAE, PFAS, PCB, and PBDE was associated with higher risk of gestational diabetes. 

Exposure to per- and polyfluoroalkyl substances in early pregnancy, risk of gestational diabetes mellitus, potential pathways, and influencing factors in pregnant women: A nested case-control study

Study Purpose: Although previous studies have reported an association between maternal PFAS levels and gestational diabetes risk, results have been inconsistent. Few studies have evaluated the combined effects of emerging and legacy PFAS on glucose homeostasis while humans are always exposed to multiple PFAS simultaneously. This study evaluates this relationship and evaluates potential pathways by which PFAS exposure induces gestational diabetes. Additionally, the study assesses whether thyroid and liver function affect this relationship.

Study Conclusion: This study found that maternal PFAS exposure in early pregnancy was associated with increased risk of gestational diabetes and changes in glucose homeostasis, with PFOA, 6:2 Cl-PFESA, and PFNA being the major contributors. The effects of PFAS exposure on gestational diabetes incidence were more pronounced in underweight and normal weight subjects.

Human serum poly- and perfluoroalkyl substance concentrations and their associations with gestational diabetes mellitus

Study Purpose: PFAS have the potential to impair glucose metabolism in pregnant women. However, the effects of PFAS exposure on the risk of gestational diabetes remains inconsistent. In this study, a case-control study involving 135 patients with gestational diabetes and 69 controls was conducted in Hangzhou, China.

Study Conclusion: These results suggested that higher PFAS exposure was associated with gestational diabetes incidence in pregnant women.

Human serum poly- and perfluoroalkyl substance concentrations and their associations with gestational diabetes mellitus

Study Purpose: PFAS have the potential to impair glucose metabolism in pregnant women. However, the effects of PFAS exposure on the risk of gestational diabetes remains inconsistent. In this study, a case-control study involving 135 patients with gestational diabetes and 69 controls was conducted in Hangzhou, China.

Study Conclusion: These results suggested that higher PFAS exposure was associated with gestational diabetes incidence in pregnant women.

Exposure to per- and polyfluoroalkyl substances as a risk factor for gestational diabetes mellitus through interference with glucose homeostasis

Study Purpose: PFAS are hypothesized to trigger gestational diabetes through modulation of glucose metabolism. However, studies investigating links between joint PFAS to gestational diabetes are limited and have had mixed findings. This study investigates women with gestational diabetes and healthy controls.

Study Conclusion: PFOA, PFOS, PFUnDA, PFDoA and 6:2Cl-PFESA were associated with a disturbance of glucose homeostasis in pregnancy and an increased risk of gestational diabetes mellitus (GDM), while 4:2FTS, 6:2FTS, PFHxS, and ADONA exhibited inverse associations on GDM.

Endocrine-disrupting chemicals and the risk of gestational diabetes mellitus: a systematic review and meta-analysis

Study Purpose: To conduct a comprehensive systematic review and meta-analysis to estimate the relationship between endocrine-disrupting chemicals (EDCs), including PCBs, PBDEs, PAEs, and PFAS exposure and risk of gestational diabetes mellitus (GDM).

Study Conclusion: The results support that exposure to certain EDCs, including PCBs, PBDEs, PAEs, and PFAS, increase the risk of GDM. Further studies are needed to verify the potential relationship and biological mechanisms.

Association between per- and polyfluoroalkyl substances and risk of gestational diabetes mellitus

Study Purpose: PFAS exposure might contribute to the incidence of gestational diabetes. This study aims to perform an analysis to identify the association between PFAS and the risk of gestational diabetes (GDM).

Study Conclusion: This study conducted an analysis of existing literature to investigate the association between PFAS exposure and GDM and found that PFOA levels were associated with a higher risk of GDM. Further studies are needed to better understand this relationship and a potential mechanism.

A pathway level analysis of PFAS exposure and risk of gestational diabetes mellitus

Study Purpose: This study summarizes the literature that supports a pathway between PFAS exposure and development of gestational diabetes.

Study Conclusion: Epidemiology studies have shown that PFAS were positively associated with the thyroid hormone TSH and negatively associated with the thyroid hormones T3 and T4. PFASs were generally associated with glucose and insulin levels in pregnancy. This study proposes that dysregulation of thyroid function and glucose metabolism may be a missing component in the accurate estimation of PFAS on the risk of GDM.

Environmental exposure to perfluoroalkyl substances in early pregnancy, maternal glucose homeostasis and the risk of gestational diabetes: A prospective cohort study

Study Purpose: This study investigates the association between PFAS exposure and glucose homeostasis in pregnancy.

Study Conclusion: Exposure to PFAS may affect glucose homeostasis in pregnancy and increase the risk of gestational diabetes, especially in normal weight women.

Persistent organic pollutants and maternal glycemic outcomes in a diverse pregnancy cohort of overweight women

Study Purpose: This study looks at the associations between exposure to persistent organic pollutants (such as PFASs) and prenatal fasting glucose levels, insulin, and insulin resistance during pregnancy in overweight women.

Study Conclusion: Rising PFAS levels were associated with lower fasting glucose levels in overweight women in this study. However, this was a small study and more research is needed on this topic.

Concentrations of perfluoroalkyl and polyfluoroalkyl substances and blood glucose in pregnant women

Study Purpose: Evidence on the association between exposure to PFASs and blood glucose concentrations in pregnant women is inconsistent. This study looks at the association between PFAS exposure and the concentrations of fasting glucose levels and one hour plasma glucose levels after a oral glucose tolerance test in pregnant women.

Study Conclusion: PFAS exposure was associated with increased risk of high 1-hour plasma glucose levels among pregnant women, but there was no association for fasting glucose levels.

Structure-based investigation on the association between perfluoroalkyl acids exposure and both gestational diabetes mellitus and glucose homeostasis in pregnant women

Study Purpose: This study looks at the association between PFAS and gestational diabetes and glucose levels in pregnant women.

Study Conclusion: This study showed an association between certain PFASs and both gestation diabetes risk and reduced blood glucose regulation in pregnant women.

Perfluoroalkyl substances and glycemic status in pregnant Danish women: The Odense Child Cohort

Study Purpose: This study looks at associations between PFASs and blood glucose levels in pregnant women based on their risk of gestational diabetes.

Study Conclusion: PFHxS and PFNA concentrations were associated with impaired glucose levels in vulnerable pregnant women and exposure to PFAS might increase the risk of developing gestational diabetes.

Association of serum levels of perfluoroalkyl substances with gestational diabetes mellitus and postpartum blood glucose

Study Purpose: This study looks at the association between PFAS exposure with risk of gestational diabetes and postpartum blood glucose levels.

Study Conclusion: Results suggest negative effects of maternal exposure to certain PFAS compounds on blood glucose levels.

Perfluoroalkyl substances, glucose homeostasis, and gestational diabetes mellitus in Chinese pregnant women: A repeat measurement-based prospective study

Study Purpose: This study aims to explore the associations of exposure to PFASs with glucose levels and gestational diabetes.

Study Conclusion: Findings show that exposure to PFASs might have influences on glucose homeostasis and gestational diabetes.

Exposure to organophosphorus and organochlorine pesticides, perfluoroalkyl substances, and polychlorinated biphenyls in pregnancy and the association with impaired glucose tolerance and gestational diabetes mellitus: The MIREC Study

Study Purpose: Studies have reported increases in rates of gestational diabetes over recent decades. Environmental chemicals may increase the risk of diabetes by impacting glucose metabolism. This study looks at the associations between pesticides, PFASs, and PCBs measured in early pregnancy and impaired glucose tolerance and gestational diabetes.

Study Conclusion: There were no associations found between PFASs and gestational diabetes or impaired glucose tolerance during pregnancy.

Concentrations and association between exposure to mixed perfluoroalkyl and polyfluoroalkyl substances and glycometabolism among adolescents

Study Purpose: The aim of this study was to examine the relationship between PFAS and metabolism of sugars among US teenagers.

Study Conclusion: This study did not observe evidence to suggest adverse effects of PFAS exposure on glucose metabolism in American teenagers. In this study, higher PFAS levels were associated with lower insulin resistance. Given these findings are contrary to past studies, conclusions should be treated with caution.

Associations between both legacy and alternative per- and polyfluoroalkyl substances and glucose-homeostasis: The Isomers of C8 health project in China

Study Purpose: This study investigates associations of PFAS alternatives and PFOA and PFOS with glucose-homeostasis markers and explore associations of 13 PFAS with the outcomes.

Study Conclusion: Legacy and alternative PFASs were associated with glucose-homeostasis markers. 6:2 Cl-PFESA was the primary contributor. Sex-specific associations were also identified.

Exposure to Perfluoroalkyl Substances and Glucose Homeostasis in Youth

Study Purpose: Exposure to PFAS may increase the risk of type 2 diabetes. This study examines associations between PFAS exposure and glucose metabolism in youth.

Study Conclusion: Youth exposure to PFHxS was associated with dysregulated glucose metabolism in females, which may be due to changes in beta-cell function. These associations appeared during puberty and were most pronounced post-puberty.

Exposure to Perfluoroalkyl Substances and Glucose Homeostasis in Youth

Study Purpose: Exposure to PFAS may increase the risk of type 2 diabetes. This study examines associations between PFAS exposure and glucose metabolism in youth.

Study Conclusion: Youth exposure to PFHxS was associated with dysregulated glucose metabolism in females, which may be due to changes in beta-cell function. These associations appeared during puberty and were most pronounced postpuberty.

Life-course exposure to perfluoroalkyl substances in relation to markers of glucose homeostasis in early adulthood

Study Purpose: This study investigates associations of PFAS exposure with glucose homeostasis in adulthood.

Study Conclusion: In this study, PFAS exposure was associated with decreased insulin sensitivity and increased pancreatic beta-cell function in young adults.

Dysregulated lipid and fatty acid metabolism link perfluoroalkyl substances exposure and impaired glucose metabolism in young adults

Study Purpose: This study looks at the association between PFAS exposure and altered metabolic pathways that are linked to increased cardiometabolic risk in young adults.

Study Conclusion: Certain mechanisms of PFAS on the body could reduce glucose metabolism in young adults.

Perfluoroalkyl substances, metabolomic profiling, and alterations in glucose homeostasis among overweight and obese Hispanic children: A proof-of-concept analysis

Study Purpose: This study looks at the associations between PFASs and glucose levels in high-risk overweight and obese Hispanic children.

Study Conclusion: This study found that higher PFAS exposure was associated with changes in glucose levels in Hispanic youth.

Longitudinal Associations of Exposure to Perfluoroalkylated Substances in Childhood and Adolescence and Indicators of Adiposity and Glucose Metabolism 6 and 12 Years Later: The European Youth Heart Study

Study Purpose: This study looks at the long-term relationship between exposure to PFAS during childhood and teenage years on indicators of body fatness and glucose metabolism in teenage years and young adulthood.

Study Conclusion: This study found evidence that childhood exposure to PFOS and PFOA was associated with greater body fatness at 15 and 21 years of age and signs of impaired glucose metabolism at 15 years of age, respectively.

Associations between prenatal exposure to per- and polyfluoroalkyl substances and wheezing and asthma symptoms in 4-year-old children: The Japan Environment and Children's Study

Study Purpose: Analyzed data from 17,856 mother-child pairs examined in the Japan Environment and Children's Study (JECS) to investigate the associations between prenatal PFAS exposure and wheezing and asthma symptoms among 4-year-old children.

Study Conclusion: This study found no clear associations between prenatal PFAS exposure and the prevalence of wheezing and asthma among children at the age of 4 years.

Prenatal exposure to poly- and perfluoroalkyl substances and the incidence of asthma in early childhood

Study Purpose: These studies illustrate the need to further characterize how PFAS
exposure may disrupt immune function in children.

Study Conclusion: In this cohort, we did not observe an association between individual PFAS concentrations or the mixture of PFAS in maternal serum during
pregnancy, and the incidence of asthma in early childhood. Additional well-powered longitudinal studies will be needed to fully characterize the immunomodulating effects of prenatal PFAS exposure on child health.

Exposures to perfluoroalkyl substances and asthma phenotypes in childhood: an investigation of the COPSAC2010 cohort

Study Purpose: Exposure to PFAS may affect immune development and increase risk of asthma, but the underlying mechanisms and specific types of asthma affected by exposure are not understood.

Study Conclusion: Prenatal exposure to PFOS and PFOA, but not childhood exposure, increased the risk of low prevalent non-atopic asthma, while there was no effect on atopic asthma, lung function, or atopic dermatitis.

Associations between serum per- and polyfluoroalkyl substances and asthma morbidity in the National Health and Nutrition Examination Survey (2003-18)

Study Purpose: PFAS exposure has been associated with impairment of immune responses. This study evaluates the relationship between PFAS levels and asthma attacks in a nationally representative sample of individuals.

Study Conclusion: This study found higher levels of PFOA and PFDA were associated with higher odds of asthma attacks in the last year. Further study is needed to understand why this occurs.

Perfluoroalkyl substance exposure is associated with asthma and innate immune cell count in US adolescents stratified by sex

Study Purpose: Exposure to PFAS may be harmful; however, previous studies have been inconsistent on the potential for PFAS to influence immunosuppression. This study explored the relationship between PFAS exposure and risks of asthma, wheezing, and immunosuppression in 12-19 year olds using national data.

Study Conclusion: In this study, medium-high levels of PFHxS were associated with wheezing in boys. Among asthmatics, PFAS exposure might not increase the risk of asthma exacerbation. They also found a week association between increasing levels of PFOA and PFNA levels and basophil count, indicating that basophils may be important in the immune response to PFAS exposure in asthmatics. 

PFAS (per- and polyfluoroalkyl substances) and asthma in young children: NHANES 2013-2014

Study Purpose: PFAS may affect the immune system to increase the risk of allergic and respiratory disease. However, there are substantial gaps in the knowledge about the relationship between PFAS and outcomes such as asthma in children. This study examines the associations between PFAS exposure and childhood asthma.

Study Conclusion: There was weak association with increased asthma prevalence in US children.

Association between prenatal exposure to perfluoroalkyl substances and asthma in 5-year-old children in the Odense Child Cohort

Study Purpose: PFAS has been associated with immune suppression and may contribute to the development of asthma. This study investigates the association between prenatal exposure to PFAS and asthma in 5-year-old children.

Study Conclusion: There was no association between prenatal exposure to PFAS and doctor-diagnosed asthma or wheeze.

Association between prenatal exposure to perfluoroalkyl substances and asthma-related diseases in preschool children

Study Purpose: The studies on PFAS and asthma in children have had inconsistent results. This study aimed to evaluate whether and to what extent prenatal PFAS exposure is associated with childhood asthma.

Study Conclusion: This study found no associations were found between prenatal exposure to PFAS and asthma in preschool children.

Maternal levels of perfluoroalkyl substances (PFASs) during pregnancy and childhood allergy and asthma related outcomes and infections in the Norwegian Mother and Child (MoBa) cohort

Study Purpose: PFAS have been inconsistently associated with asthma and allergic diseases and increased number of infections in early childhood. This study examines the association of PFAS measured in pregnancy with childhood asthma, allergies, and common infectious diseases up to age 7 years.

Study Conclusion: Maternal PFAS levels during pregnancy showed little association with asthma or allergy related outcomes. Findings from this study suggest PFAS affects the immune system, especially with airway infections, such as bronchitis and pneumonia.

Association of polyfluoroalkyl substances and allergy in U.S. adolescents: Results from NHANES 2005-2006

Study Purpose: This study aims to investigate the association between PFAS and allergy in US adolescents.

Study Conclusion: This study shows that PFAS are associated with increased incidence of current allergic symptoms in US adolescents. More studies are needed to support these findings.

Perfluoroalkyl substances are linked to incident chronic spontaneous urticaria: A nested case-control study

Study Purpose: This study aims to investigate the association of serum PFASs with incidence chronic spontaneous urticaria (CSU), or hives, in adults.

Study Conclusion: This study found an association of serum PFAS with incidence CSU and identified PFBA and PFHpA as two potentially effective compounds and proposed a possible mediation effect of IL-4.

Exposure to perfluoroalkyl substances and allergic outcomes in children: A systematic review and meta-analysis

Study Purpose: PFAS may contribute to the development of allergies in children, but evidence is inconclusive. This study compares the evidence from many studies on the topic.

Study Conclusion: This review suggests that PFAS exposure could potentially be associated with eczema, atopic dermatitis, and allergic rhinitis during childhood, but not with childhood asthma or wheeze.   

Effect of prenatal exposure to per- and polyfluoroalkyl substances on childhood allergies and common infectious diseases in children up to age 7 years: The Hokkaido study on environment and children's health

Study Purpose: Studies have reported prenatal exposure to PFAS decreased the risk of allergies, while increasing the risk of infectious diseases at ages 2 and 4 years. However, it is unclear whether the effects of PFAS on allergies and infectious diseases continue until a reliable age of diagnosing allergies. This study investigates the effects of PFAS exposure and the prevalence of allergies and infectious diseases in children up to age 7.

Study Conclusion: Prenatal exposure to PFOS, PFNA, PFUnDA, PFDoDA, and PFTrDA were associated with reduced risks of wheeze, eczema, and rhino-conjunctivitis, and with increased risks of pneumonia and respiratory syncytial virus (RSV) infection. This inverse association between allergic symptoms and increased risks of infectious diseases is thought to be due to the immunosuppressive effects of PFAS.

Serum perfluoroalkyl substances (PFAS) and risk of asthma and various allergies in adolescents. The Tromsø study Fit Futures in Northern Norway

Study Purpose: This study investigates possible associations between asthma and other allergies with exposure to PFASs.

Study Conclusion: There are several associations between PFASs and asthma, as well as between PFOS and nickel allergy.   

Effects of prenatal exposure to perfluoroalkyl acids on prevalence of allergic diseases among 4-year-old children

Study Purpose: This study examines whether prenatal PFAS exposure is associated with allergies in 4-year-olds.

Study Conclusion: Prenatal exposure to PFDoDA and PFTrDA may suppress the immune system leading to allergic diseases in 4-year-old children.

Prenatal perfluorooctanoic acid exposure is associated with early onset atopic dermatitis in 5-year-old children

Study Purpose: To investigate the association between prenatal PFAS exposure and earlier onset of atopic dermatitis in children in a 5 year study.

Study Conclusion: Findings suggest that children with higher prenatal PFOA exposure may have a higher risk of developing atopic dermatitis earlier.

Prenatal perfluorooctanoic acid exposure and glutathione s-transferase T1/M1 genotypes and their association with atopic dermatitis at 2 years of age

Study Purpose: This study investigates the association between gene and environmental interactions and childhood atopic dermatitis.

Study Conclusion: In-utero PFOA exposure and the GSTT1/M1 null genotype were associated with atopic dermatitis. There could be genetic susceptibility to atopic dermatitis development.

Prenatal exposure to perfluoroalkyl and polyfluoroalkyl substances and childhood atopic dermatitis: a prospective birth cohort study

Study Purpose: PFASs have been reported to suppress immune function. However, previous studies on prenatal exposure to PFASs and allergic disorders in offspring did not have consistent results. This study examines the association between prenatal exposure to PFASs and childhood atopic dermatitis in children up to 2 years of age.

Study Conclusion: Prenatal exposure to PFOS, PFDA, PFDoA, and PFHxS increased the risk of atopic dermatitis in female children over the first two years of life.

Emerging and legacy PFAS and cytokine homeostasis in women of childbearing age

Study Purpose: This study aimed to evaluate the associations between legacy and emerging PFAS and cytokine profiles, and identify potential characteristics to disruption of cytokine homeostasis.

Study Conclusion: In conclusion, our study suggests that both legacy PFAS and emerging alternatives may affect the homeostasis of cytokines in humans.

Early-life exposure to perfluoroalkyl substances in relation to serum adipokines in a longitudinal birth cohort

Study Purpose: PFAS exposure has been linked to metabolic health outcomes like obesity, and changes in adipokines may be one of the underlying mechanisms behind these changes.

Study Conclusion: Serum PFHxS at birth was associated with increased leptin receptor at  birth, and childhood PFAS were associated with decreased leptin and resisting and increased leptin receptor at age 9. Given the associations of PFAS exposure with adipokine levels and metabolic functions, future studies should include assessment of adipokines when examining PFAS-associated metabolic alterations.

Exposure to perfluoroalkylated substances (PFAS) in relation to fitness, physical activity, and adipokine levels in childhood: The European youth heart study

Study Purpose: PFAS can alter metabolism by disrupting cell pathways, where adipokines play a role. Adiponectin and leptin are influenced by and have influence on energy storage and how you use energy. PFAS and adipokines could be mediated by fitness and fat mass.

Study Conclusion: Results may indicate favorable leptin levels with increasing PFAS, although the results could be due to factors related to socioeconomics.

Early Life Exposures to Perfluoroalkyl Substances in Relation to Adipokine Hormone Levels at Birth and During Childhood

Study Purpose: This study examines the associations between PFAS exposures and concentrations of adipokine hormones from birth to adolescence.

Study Conclusion: These findings suggest adipokine hormone dysregulation in early life could be due to PFAS exposure.

Environmental perfluoroalkyl acid exposures are associated with liver disease characterized by apoptosis and altered serum adipocytokines

Study Purpose: This study tests the hypothesis that PFAS are associated with disruptions in the liver in humans and decreased pro-inflammatory cytokines.

Study Conclusion:  PFAS were associated with increased evidence of liver cell death and decreased tumor necrosis factor (TNF) levels. This supports that PFAS may cause liver injury.

Prenatal exposure to perfluoroalkyl substances and adipocytokines: the HOME Study

Study Purpose: Gestational PFAS exposure has been associated with decreased birthweight. This study investigates if PFAS exposure is associated with fetal metabolic markers (leptin and adiponectin).

Study Conclusion: Despite previous studies reporting associations with reduced birthweight, gestational PFAS levels were no associated with infant adipocytokine levels.    

Association of prenatal exposure to perfluoroalkyl substances with cord blood adipokines and birth size: The Hokkaido Study on environment and children's health

Study Purpose: There is a possible association between prenatal PFAS exposure and neonatal adipokines and birth size, but there are not many studies on this topic. This study looks at the associations of prenatal PFAS exposure with adipokines and birth size.

Study Conclusion: Results suggest that prenatal PFAS exposure could alter adiponectin levels in infants and decrease birth size.

Associations of serum perfluoroalkyl acid levels with T-helper cell-specific cytokines in children: By gender and asthma status

Study Purpose: Experiments have suggested that PFAS may alter immune function and could increase allergic inflammation. This study looks at the association between PFAS levels and signs of immune function and to determine if gender changes this.

Study Conclusion: Increased serum PFAS levels may alter the immune system, which could contribute to the development of asthma that may impact males greater than females.

Prenatal Exposure to Poly- and Perfluoroalkyl Substances (2009–2014) and Vaccine Antibody Titers of Measles, Mumps, Rubella, and Varicella in Children Four to Eight Years Old from the Healthy Start Cohort

Study Purpose: To estimate prenatal exposures to certain poly- and perfluoroalkyl substances (PFAS) and  their association with reduced humoral responses to some childhood immunizations.

Study Conclusion: Some prenatal PFAS were associated with lower antibody titers among fully immunized children. The potential for immunotoxic effects of PFAS requires further investigation in a larger study, because exposure is ubiquitous globally.

Early-life exposure to perfluoroalkyl substances and serum antibody concentrations towards common childhood vaccines in 18-month-old children in the Odense Child Cohort

Study Purpose: The aim of this study was to investigate the association between exposure to PFAS assessed during pregnancy and at age 18-months with vaccine-specific IgG Ab concentrations towards diphtheria, tetanus, measles, mumps and rubella measured at age 18 months.

Study Conclusion: This large population-based birth cohort study investigated associations between prenatal PFAS exposure assessed in maternal blood samples collected during first trimester pregnancy and child PFAS exposure assessed at 18 months of age with serum IgG levels towards diphtheria, tetanus, measles, mumps and rubella assessed at age 18 months.

Association between serum per- and polyfluoroalkyl substances concentrations and common cold among children and adolescents in the United States

Study Purpose: PFAS have immunosuppressive effects in animal studies. Few human studies have investigated PFAS exposure and immune-related outcomes like the common cold, especially during childhood when the immune system is developing.

Study Conclusion: Among US children, serum concentrations of PFAS mixtures, especially PFHxS and PFNA, were associated with higher odds of common cold. Among adolescents, PFOS was associated with increased common cold in the last month. 

Associations of exposure to perfluoroalkyl substances individually and in mixtures with persistent infections: Recent findings from NHANES 1999-2016

Study Purpose: Certain viruses and parasites can cause persistent infections. Some studies indicate PFASs may suppress the immune system. This study tests whether PFAS exposures might increase susceptibility to persistent infections.

Study Conclusion: These results suggest PFAS exposure may increase susceptibility to persistent infections, particularly among adolescents.

Exposure to perfluoroalkyl substances during fetal life and hospitalization for infectious disease in childhood: A study among 1,503 children from the Odense Child Cohort

Study Purpose: This study investigates the association between maternal levels of PFASs during pregnancy and the child's rate of hospitalization due to common infectious diseases between birth and 4 years of age.

Study Conclusion: These results agree with prior studies, where maternal levels of PFOS and PFOA were associated with the number of days those children experienced fever, suggesting that PFOS and PFOA may affect the prevalence of infectious diseases even in low-exposed populations.

Association between prenatal exposure to perfluoroalkyl substances and respiratory tract infections in preschool children

Study Purpose: PFAS is considered to negatively affect immune function; however, the effects of PFAS exposure on respiratory tract infections (RTIs) in children is unclear.

Study Conclusion: Children with higher prenatal PFBS were more vulnerable to respiratory tract infections in early life, which may be due to suppression of IgG production.

Association between prenatal exposure to perfluorinated compounds and symptoms of infections at age 1-4 years among 359 children in the Odense Child Cohort

Study Purpose: To see if higher prenatal PFAS exposure might affect the number of infections in early childhood.

Study Conclusion: The study observed a positive association between prenatal exposure to PFOS and PFOA and the prevalence of fever, which may be a sensitive marker of infection.

Inflammation and cardiometabolic diseases induced by persistent organic pollutants and nutritional interventions: Effects of multi-organ interactions

Study Purpose: This review highlights inflammatory disease mechanisms related to POPs (PCBs, PFASs, and PBDEs) exposure, and discusses the potential nutritional intervention approaches, with a focus on multi-organ systems interactions, thus,
providing a scientific basis for the design of precision nutritional intervention
strategies to prevent toxicity from environmental insults.

Study Conclusion: The toxicity of POPs is linked to the multi-organ interplays involving the liver, gut, brain, vascular, and immune system, which lead to
inflammation and cardiometabolic diseases. Consumption of food rich in
anti-inflammatory phytochemicals, dietary fibers, and vitamins may be
a feasible way to counteract POP toxicity by acting on multi-organ interactions
and preventing inflammatory diseases.

Association between a Mixture of Per- and Polyfluoroalkyl Substances (PFAS) and Inflammatory Biomarkers in the Atlanta African American Maternal-Child Cohort

Study Purpose: This study looks at associations between a PFAS mixture and inflammatory markers during pregnancy.

Study Conclusion: Serum PFAS levels were associated with inflammatory responses during pregnancy. 

Prenatal exposure to perfluoroalkyl substances and inflammatory biomarker concentrations

Study Purpose: This study looks at associations between first trimester PFAS levels and third trimester levels of inflammatory markers.

Study Conclusion: PFOA, PFOS, and PFHxS, individually and as a mixture, were positively associated with proinflammatory biomarkers during pregnancy.

In utero exposure to poly- and perfluoroalkyl substances and children respiratory health in the three first years of life

Study Purpose: Studies have suggested impaired lung development and inflammatory responses following exposure to some PFAS; therefore, this study aimed to evaluate the relationship between prenatal exposure to PFAS and child respiratory health.

Study Conclusion: This study did not observe evidence to suggest prenatal PFAS exposure negatively impacts respiratory health at an early age.

Association of perfluoroalkyl and polyfluoroalkyl substances with sex hormones in children and adolescents 6-19 Years of age

Study Purpose: PFAS have been suggested to disrupt sex hormones during critical windows in childhood and adolescence, but evidence in humans is limited. This study explores the associations of total testosterone, estradiol, and sex hormone binding globulin (SHBG) in children and adolescents with PFAS in participants aged 6-19 years.

Study Conclusion: This study found levels of PFAS and mixtures of PFAS were associated with decreased levels of total testosterone in children aged 6-11 and female adolescents aged 12-19. PFAS mixtures were associated with elevated levels of sex hormone binding globulin in boys aged 6-11. Results by sex-puberty status showed a similar pattern.

Impact of PFAS exposure on prevalence of immune-mediated diseases in adults in the Czech Republic

Study Purpose: PFAS may be toxic to the immune system. Human exposure to PFAS has been associated with various immune-related diseases. This study aimed to investigate the association between PFAS exposure and immune-related diseases such as allergies, eczema, and autoimmune diseases in Czech adults.

Study Conclusion: These results suggest that PFAS affect the immune system and found that PFOA, PFOS, and PFUnDA appear to be the main drivers of outcomes in PFAS mixtures. 

Consideration of pathways for immunotoxicity of per- and polyfluoroalkyl substances (PFAS)

Study Purpose: The aim of this review is to explore PFAS-associated immune-related effects. This includes relevant mechanisms that may cause the observed effects on the immune system.

Study Conclusion: Both human and animal studies show that there is evidence that PFAS, not just PFOA and PFOS, affect multiple aspects of the immune system. Timing of PFAS exposure is important, because the developing immune system is especially vulnerable, resulting in a higher risk of adverse immune effects later in life.

Red Blood Cell Folate Modifies the Association between Serum Per- and Polyfluoroalkyl Substances and Antibody Concentrations in U.S. Adolescents

Study Purpose: PFAS exposure has been associated with reduced antibody levels. High red blood cell folate was previously associated with lower serum PFAS concentrations in adolescents. This study included 819 adolescents aged 12-19 years who had detectable rubella and measles antibody levels in serum from the NHANES 2003-2004 and 2009-2010 cycles.

Study Conclusion: In conclusion, this U.S. representative study found inverse associations between serum concentrations of PFOS and PFHxS and the total PFAS mixture in relation to rubella antibodies and between serum concentrations of PFOA and the total PFAS mixture in relation to mumps antibodies only in adolescents with lower red blood cell folate levels, while not among adolescents with higher folate levels. These findings suggest that folate could potentially counteract the immune-altering effects of PFAS exposure. 

A systematic evidence map of chronic inflammation and immunosuppression related to per- and polyfluoroalkyl substance (PFAS) exposure

Study Purpose: The ability to induce chronic inflammation and immunosuppresion are key characteristics of carcinogens and important forms of immunotoxicity. The National Toxicology Program (NTP) evaluated the immunotoxicity of two per- and polyfluoroalkyl substances (PFASs), PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonate), in 2016. However, the potential pro-inflammatory and immunosuppressive effects of other PFASs remain largely uncharacterized.

Study Conclusion: While a growing body of evidence validates PFASs’ ability to induce immunosuppressive outcomes in human/animal in vivo and in vitro/ex vivo studies, the data to champion the inflammatory abilities of PFASs have been inconsistent and contradictory. Using our improved search terms, transparent study screening processes, and visualization by systematic evidence maps, we retrieved, identified, and extracted data from qualified studies to garner more evidence to 1) support conclusions by Temkin et al. (2020) that PFAS exposure causes immunosuppression; 2) provide additional evidence that PFAS exposure may cause chronic inflammation; and 3) use biomarker-based evidence to propose potential underlying mechanisms as to how PFASs induce both chronic inflammation and immunosuppression. Applying the new literature search strategy in combination with further research investigating the immunotoxicity of PFASs is warranted to more fully characterize how PFASs, both common and lesser known, may impact the immune system and affect human health, including cancer.

Association between serum concentrations of perfluoroalkyl substances and global DNA methylation levels in peripheral blood leukocytes of Japanese women: A cross-sectional study

Study Purpose: Global DNA methylation levels in blood leukocytes can be a marker for cancer risk; however, levels can be changed by various factors such as environmental pollutants. 

Study Conclusion: Our results indicate that exposure to PFASs may increase global DNA methylation levels in peripheral blood leukocytes of Japanese women. 

Exposure to perfluoroalkyl substances and neonatal immunoglobulin profiles in the upstate KIDS study (2008-2010)

Study Purpose: Infant exposure to PFAS compounds is associated with immune disruption. This study examined associations between neonatal concentrations of PFOA and PFOS and immunoglobulin (Ig) isotope profiles in a prospective cohort of infants. 

Study Conclusion: In neonates, higher PFOA levels were associated with higher IgA, IgM, IgG2, and lower levels of IgE in models using newborn dried bloodspot samples. Once corrected for multiple comparisons, PFOS did not show significant association with Ig isotype profiles, though the associations were consistent in direction with those for PFOA. When PFOS and PFOA were examined as mixture, we found small but significant effects of the mixture on the outcome isotypes, consistent with single-pollutant PFAS models: with significant PFAS mixture effects for IgA, IgM, IgG2, and IgE. While the clinical relevance of these findings is yet to be established, the results suggest that the effects of PFAS exposure on immunity are measurable even in newborns. 

Perfluoroalkyl substances exposure and immunity, allergic response, infection, and asthma in children: review of epidemiologic studies

Study Purpose: Increased exposure to PFAS potentially affects infant and child health through immunosuppression. This review assessed the effects of PFAS fetal, infant, and childhood exposures upon the development of immune function during early life.

Study Conclusion: This review summarizes more recent findings on PFAS effects on infant childhood immune health. Evidence of immunosuppression, diminished vaccine efficacy, and increased risk of infections, allergies, asthma, and atopic dermatitis were described following in utero, infant, and early childhood PFAS exposure. Further study is needed to understand the mechanisms behind this.

Perfluoroalkyl substances and immune cell counts in adults from the Mid-Ohio Valley (USA)

Study Purpose: This study looked at the association between 4 PFASs and circulating levels of several types of immune cells

Study Conclusion: These results suggest an association between PFHxS and, less consistently, for PFOA and PFOS, and total lymphocytes. The increase in lymphocyte count appeared to be evenly distributed across lymphocyte subsets since associations with their percentages were not significant.

Perfluoroalkyl substances, airways infections, allergy and asthma related health outcomes - implications of gender, exposure period and study design
Study Purpose: Exposure to PFAS is inconsistently associated with asthma, allergic diseases, and airways infection in early childhood. This study aimed to investigate the effect of childhood exposure to PFAS on asthma and allergy related outcomes and on airway infections before and during puberty.
Study Conclusion: There is evidence of associations between PFAS and atopic dermatitis and lower respiratory tract infections. There is no clear pattern in associations.    

Plasma perfluoroalkyls are associated with decreased levels of proteomic inflammatory markers in a cross-sectional study of an elderly population

Study Population: PFAS are associated with altered immune responses in children, but effects in elderly are unknown.

Study Conclusion: Findings suggest that PFAS are related to decreased levels of several proteomic markers of inflammation in the elderly.          

Alternatives of perfluoroalkyl acids and hepatitis B virus surface antibody in adults: Isomers of C8 Health Project in China

Study Purpose: The immunosuppressive effects of PFAS alternatives are unknown. This study investigates the relationship of serum PFAS and PFAS alternatives with the hepatitis B virus antibodies in adults.

Study Conclusion: Exposure to PFAS alternatives are associated with lower Hepatitis B virus antibodies in adults. This relationship seems to be stronger in 6:2 PFESA than PFOS.

Prenatal exposure to perfluoroalkyl substances, immune-related outcomes, and lung function in children from a Spanish birth cohort study

Study Purpose: Prenatal exposure to PFASs has been associated with impaired immune and respiratory health during childhood but the evidence is inconsistent. This study looked at the association between prenatal PFASs exposure and immune and respiratory health, including lung function, up to age 7.

Study Conclusion: This study suggests that different PFAS may affect the developing immune and respiratory systems differently. Prenatal exposure to PFNA and PFOS could be associated with a reduced risk of respiratory and immune issues, in particular asthma and eczema. However, exposure to PFOA may be associated with reduced lung function in young children.

Exposure to per- and polyfluoroalkyl substances leads to immunotoxicity: Epidemiological and toxicological evidence

Study Purpose: A review of epidemiological and toxicological studies.

Study Conclusion: The results of epidemiological studies, supported by findings from toxicological studies, provide strong evidence that humans exposed to PFOA and PFOS are at risk for immunosuppression. Results suggest that exposure to per- and polyfluoroalkyl substances leads to immunotoxicity.

Serum perfluoroalkyl substances and lung function in adolescents exposed to the World Trade Center disaster

Study Purpose: The effects of childhood exposure to PFAS on lung function are still mostly unknown. Previous research indicates that children living or going to school near the World Trade Center disaster were exposed to high levels of PFASs. To explore the effects of PFAS exposure on lung function, PFASs were measured in children from the World Trade Center Health Registry and matched to a control group, not exposed.

Study Conclusion: PFAS were not associated with lung function or asthma in this study.

A critical review of perfluorooctanoate and perfluorooctanesulfonate exposure and immunological health conditions in humans

Study Purpose: This article reviews previous studies on the association between exposure to PFOS and PFOA and immune-related health conditions.

Study Conclusion: The available information is not consistent, and a conclusion cannot be made on exposure to PFOA and PFOS and immune-related health conditions.

Prepandemic personal concentrations of per- and polyfluoroalkyl substances (PFAS) and other pollutants: Specific and combined effects on the incidence of COVID-19 disease and SARS-CoV-2 infection

Study Purpose: This study investigates the effects of PFAS and other environmental contaminants on the development of COVID-19.

Study Conclusion: The PFAS measured were not associated with SARS-CoV-2 seropositivity or COVID-19 disease.

High Exposure to Perfluoroalkyl Substances and Antibody Responses to SARS-CoV-2 mRNA Vaccine-an Observational Study in Adults from Ronneby, Sweden

Study Purpose: This study looks at associations between PFAS and antibody responses in adults 5 weeks and 6 months after two-doses of COVID vaccines.

Study Conclusion: This study did not find an association between PFAS exposure and levels of serum antibodies against COVID 5 weeks or 6 months after immunization. There may be differences by sex that need to be studied further in the future.

Immune response to COVID-19 vaccination in a population with a history of elevated exposure to per- and polyfluoroalkyl substances (PFAS) through drinking water

Study Purpose: Exposure to PFAS has been linked to lower vaccine-induced antibody concentrations in children, while data from adults is limited. Characteristics of PFAS exposure and age at vaccination may affect these relationships. This study used the administration of COVID-19 vaccines to test the hypothesis that prior exposure to PFAS affects antibody response to vaccines in adults and teens.

Study Conclusion: Many factors contribute to variability in individual response to immunizations, including age, medications, and underlying health conditions. This study does not support the hypothesis that higher serum PFAS concentrations reduce antibody response to vaccines against COVID-19. Future studies are needed to clarify the impact of age of vaccination (early life vs. adulthood vaccination), period of PFAS exposure (gestational/early life vs. later in life) and timeframe of when the effects of PFAS might manifest in antibody response to vaccination (months vs. years following vaccination).

Cross-sectional associations of maternal PFAS exposure on SARS-CoV-2 IgG antibody levels during pregnancy

Study Purpose: Given that pregnancy itself represents an altered state of immunity, PFAS exposure-related immunotoxicity is an important factor to consider in a COVID infection during pregnancy as it may further affect immune responses. This study investigated the relationship between maternal plasma PFAS concentrations and COVID antibody levels in a NYC-based pregnancy cohort.

Study Conclusion: This pilot study is the first to demonstrate that maternal PFAS exposure may negatively impact maternal COVID antibody titers following COVID infection during pregnancy. This study adds to the weight-of-evidence that PFAS, including the short-chain “emerging” congeners, are immunotoxic. Further study is needed.

Antibody response to COVID-19 vaccines among workers with a wide range of exposure to per- and polyfluoroalkyl substances

Study Purpose: This study examines COVID-19 antibody responses to vaccines and PFAS serum concentrations among employees and retirees from two 3M facilities, one of which historically manufactured PFOS, PFOA, and PFHxS.

Study Conclusion: In our study data, the fully adjusted coefficients relating concentration of vaccine-induced antibodies to COVID-19 and IQR difference in serum concentration of PFOS, PFOA, PFHxS, and PFNA were inverse but small with confidence intervals that included zero. Our analysis showed that the coefficient for the four PFAS examined in detail was considerably affected by adjustment for antigenic stimulus group.

Influence of Perfluoroalkyl Substances on Occurrence of Coronavirus Disease 2019

Study Purpose: Studies have indicated that exposure to PFAS influences immunosuppression and diminishes vaccine response. The relationship between PFAS blood levels and COVID-19 occurrence by age needs further investigation. This study identifies blood PFAS exposure levels by age category.

Study Conclusion: Elderly populations in the US bear the greatest burden of hospitalization and death from COVID-19. It is not clear what percent of that morbidity and mortality is due to prior lifetime PFAS exposure. Due to historic exposure to PFAS, elderly populations in some locations may bear the brunt of lifetime exposure. Lifetime PFAS exposure could be one contributing factor to increased COVID-19 vulnerability among an elderly population.

Ongoing efforts to continue to reduce PFAS exposures nationally may not directly affect a group that previously had significant lifetime PFAS exposure. It is therefore important to better understand the nature of the relationship between PFAS exposure and COVID-19 infection through ongoing biomonitoring and environmental assessment studies. 

Susceptibility to COVID-19 after High Exposure to Perfluoroalkyl Substances from Contaminated Drinking Water: An Ecological Study from Ronneby, Sweden

Study Purpose: There is concern that environmental contaminants, such as PFAS, may play a role in the clinical course of COVID-19. The objective of this was to determine if exposure to highly PFAS-contaminated water was associated with an increased incidence of COVID-19 in Ronneby, Sweden, during the first year of the pandemic.

Study Conclusion: The results suggest a potential link between high PFAS exposure and susceptibility to COVID-19 that warrant further research.

Association between urinary per- and poly-fluoroalkyl substances and COVID-19 susceptibility

Study Purpose: This study examines the association between PFAS exposure and COVID-19 susceptibility as well as investigates metabolic dysregulation associated with PFAS exposure in COVID-19 patients.

Study Conclusion: Elevated exposure to PFASs was associated with increased risk of COVID-19 infection. PFAS-associated metabolites were shown to be involved in mitochondrial function and immune activity.

Exposure to Perfluoroalkyl Substances and Mortality for COVID-19: A Spatial Ecological Analysis in the Veneto Region (Italy)

Study Purpose: This study evaluates if in the Veneto region of Italy, where residents were exposed to PFAS contaminated water for decades, there was higher mortality for COVID-19.

Study Conclusion: There was a higher mortality risk for COVID-19 in the population heavily exposed to PFAS compared to other parts of Italy. This may be explained by immunosuppresion, bioaccumulation in lung tissue, or pre-existing disease related to PFAS.

Severity of COVID-19 at elevated exposure to perfluorinated alkylates

Study Purpose: This study looks at the association between PFAS exposure and COVID-19 severity.

Study Conclusion: This study found that elevated PFBA levels were associated with an increased risk of more severe COVID-19; however, this study is not yet published.     

Drinking water pollutants may affect the immune system: concerns regarding COVID-19 health effects

Study Purpose: This study explores major contaminants in drinking water that are known to be immunotoxic, exploring sources and drinking water routes and emphasizing the known mechanisms of action that could likely compromise immune response in humans, particularly regarding people exposed to COVID-19.

Study Conclusion: Based on this literature review, metals, plastic components, plasticizers, and PFASs may have the potential to exacerbate COVID-19 respiratory symptoms; however, epidemiological studies are still required to confirm these effects between the pollutants and the virus.

Endocrine disruption of vitamin D activity by perfluoro-octanoic acid (PFOA)

Study Purpose: Vitamin D levels have been associated with COVID-19 outcomes. This study is not directly associated with COVID, however, this study looks at evidence supporting the interference of PFOA on vitamin D.

Study Conclusion: These results provide evidence of disruption on Vitamin D activity by PFOA through competition and inhibiting vitamin D-responsive genes in cells.

Serum per- and polyfluoroalkyl substance concentrations and longitudinal change in post-infection and pot-vaccination SARS-COV-2 antibodies 

Study Purpose: In this analysis, we explore the association between PFAS and SARSCoV-2 infection immune response and PFAS and COVID-19 vaccination
immune response in a cohort of first responders and frontline essential
workers in the United States, a priority population in which to assess
PFAS risk as these occupations are at increased risk of both PFAS
exposure and COVID-19.

Study Conclusion:  From this research, we found a potential relationship between serum PFAS concentration and antibody response following a SARS-CoV-2
infection but found no evidence of a relationship following completion
of a primary COVID-19 vaccination series.

Systematic review and meta-analysis of epidemiologic data on vaccine response in relation to exposure to five principal perfluoroalkyl substances

Study Purpose: Human studies of PFAS and antibody response to vaccines have suggested an adverse association, but results have been inconsistent. The goal of this review was to determine the degree to which PFAS levels impact antibody concentrations following vaccination.

Study Conclusion: Human studies on immunosuppression and five better-studied PFAS chemical suggest an association, with support across multiple vaccine antibodies. Data on Diphtheria, Rubella, and Tetanus were more supportive of an association than for other antibodies, and support was greater for associations with PFOA, PFOS, and PFHxS, than for PFNA or PFDA.

Effects of exposure to per- and polyfluoroalkyl substances on vaccine antibodies: A systematic review and meta-analysis based on epidemiological studies

Study Purpose: This study aims to summarize literature on the relationship between PFAS exposure and vaccine antibody levels based on epidemiology and identify the difficulties and challenges in relevant research of PFAS exposure and vaccine antibodies to guide future research.

Study Conclusion: This review suggests that PFAS can have adverse health effects on children by hindering the production of vaccine antibodies.  There are some consistent and negative associations between children exposure to certain PFAS and tetanus antibody level. The association of the other four vaccines (measles, rubella, mumps, and influenza) with PFAS remains uncertain, because very few studies are available. Further studies are needed to validate the possible associations.

Serum vaccine antibody concentrations in adults exposed to per- and polyfluoroalkyl substances: A birth cohort in the Faroe Islands

Study Purpose: This study evaluates the associations between exposure to PFASs and serum antibody concentrations in adults vaccinated at 28 years old.

Study Conclusion: The present study longitudinally-investigated potential immunotoxic effects of PFASs in adults as assessed via any changes in PFAS-associated deficient vaccine responses. Overall, limited evidence was shown for associations between PFAS exposures and decreased antibody concentrations. Potential inverse trends of recent PFAS exposure with lower de novo vaccine responses to hepatitis type A and B at ages 28 years were noted; these mandate further investigation. Lastly, sex-specific associations with vaccine responses were observed for prenatal and early-life exposures to PFASs.

Serum Perfluoroalkyl Substances, Vaccine Responses, and Morbidity in a Cohort of Guinea-Bissau Children

Study Purpose: This study looks at the association between infant PFAS exposure and antibody responses to measles vaccines.

Study Conclusion: These findings support that PFAS exposure decreases vaccine antibodies to measles before and after vaccination.

Internal exposure to perfuoroalkyl substances (PFASs) and biological markers in 101 healthy 1‑year‑old children: associations between levels of perfuorooctanoic acid (PFOA) and vaccine response

Study Purpose: This study looks at the association between vaccine-specific antibodies and PFAS exposure in children.

Study Conclusion: These findings support that PFAS exposure decreases vaccine antibodies, but only PFOA showed these effects in this study.

Rubella immunity and serum perfluoroalkyl substances: Sex and analytic strategy

Study Purpose: PFASs have been associated with decreased immunity to childhood tetanus and diphtheria immunizations. This study examines whether PFAS levels are associated with reduced immunity to rubella immunization.

Study Conclusion: There was an association between reduced rubella immunity and PFOA in men but not women.

Estimated exposures to perfluorinated compounds in infancy predict attenuated vaccine antibody concentrations at age 5-years

Study Purpose: This study looks at the association between vaccine-specific antibodies and PFAS exposure in children.

Study Conclusion: These findings support the idea that the developing immune system is vulnerable to PFAS during infancy. This vulnerability appears to be greatest during the first 6 months after birth, where PFAS exposures are affected by breastfeeding.

Serum Vaccine Antibody Concentrations in Adolescents Exposed to Perfluorinated Compounds

Study Purpose: PFAS exposure is associated with lower antibody levels against certain childhood vaccines at 7 years old. This study looks at this association at 13 years old.

Study Conclusion: Findings from this study are similar to previous findings, that antibody levels to vaccinations decrease at higher PFAS exposure levels.

Association between perfluoroalkyl substance exposure and asthma and allergic disease in children as modified by MMR vaccination

Study Purpose: This study looks at whether PFAS exposure is associated with childhood asthma and allergies. MMR vaccinations in early life may be protective against asthma and allergies, so it is taken into account.

Study Conclusion: PFAS exposure at age 5 was associated with a higher risk of asthma in MMR-unvaccinated children, but not among MMR-vaccinated children.

Perfluoroalkyl substance serum concentrations and immune response to FluMist vaccination among healthy adults

Study Purpose: This study looks at immune response to a flu vaccine and PFAS levels.

Study Conclusion: Findings from this study do not support a reduced immune response to the flu vaccine among healthy adults in relation to their PFAS levels.

Plasma concentrations of perfluoroalkyl substances and risk of inflammatory bowel diseases in women: A nested case control analysis in the Nurses' Health Study cohorts

Study Purpose: The purpose of this study is to examine the association between plasma PFAS concentrations and risk of IBD (inflammatory bowel disease) among women in two studies.

Study Conclusion: These results do not support the hypothesis that elevated PFAS exposure is associated with higher risk of ulcerative colitis. 

Perfluoroalkyl substances are increased in patients with late-onset ulcerative colitis and induce intestinal barrier defects ex vivo in murine intestinal tissue

Study Purpose: Environmental factors are believed to contribute to inflammatory bowel disease. This study investigates whether high levels of PFAS are associated with late-onset inflammatory bowel disease and disturbances of the bile acid pool. This study also explores the effect of PFOA on intestinal barrier function in murine tissue.

Study Conclusion: PFAS levels are increased in patients with late-onset ulcerative colitis and may contribute to the disease by inducing a dysfunctional intestinal barrier.

Prenatal exposure to perfluoroalkyl substances modulates neonatal serum phospholipids, increasing risk of type 1 diabetes

Study Purpose: This study examines the effects during pregnancy on markers of type 1 diabetes risk in children.

Study Conclusion: Findings suggest that PFAS exposure during pregnancy contributes to the risk and development of type 1 diabetes in offspring.

Persistent organic pollutant exposure and celiac disease: A pilot study

Study Purpose: This study looks at the association between pollutants and celiac disease.

Study Conclusion: PFOS and PFOA exposure may increase the risk of developing celiac disease.

Inflammatory bowel disease and biomarkers of gut inflammation and permeability in a community with high exposure to perfluoroalkyl substances through drinking water

Study Purpose: PFASs have been associated to affect the gut, which could influence the development of inflammatory bowel disease. This study looks at the association of PFAS and clinically diagnosed inflammatory bowel disease in a population with high PFAS exposure.

Study Conclusion: The study found no consistent evidence to support that PFAS exposure is a risk factor for inflammatory bowel disease.

PFOA and ulcerative colitis

Study Purpose: This study examines if ulcerative colitis patients had higher levels of PFOA than the general population of Crohn's disease patients.

Study Conclusion: There were higher PFOA levels in ulcerative colitis patients compared to Crohn's disease patients or the general population, in contrast to other PFAS.

Association between Serum Per- and Polyfluoroalkyl Substance Levels and Risk of Central and Peripheral Precocious Puberty in Girls

Study Purpose: Levels of PFAS were compared between girls with central precocious puberty (CPP), peripheral precocious puberty (PPP), and healthy controls.

Study Conclusion: This study suggests changes in various steroids and an increased risk of precocious puberty following exposure to PFAS, particularly PFBS. 

Associations between exposure to a mixture of perfluoroalkyl and polyfluoroalkyl substances and age at menarche in adolescent girls utilizing three statistical models

Study Purpose: Exposure to PFAS may interfere with endocrine function and may affect female puberty. However, the evidence on age at first period being associated with PFAS exposure is mixed. The objective of this study was to investigate the relationship between PFAS levels and age at first period among 12-19 year old girls.

Study Conclusion: This study observed that PFNA exposure may be related to later age at first period among adolescent groups. The underlying mechanisms must be further studied.

Associations of prenatal and postnatal exposure to perfluoroalkyl substances with pubertal development and reproductive hormones in females and males: The HOME study

Study Purpose: Prenatal and childhood exposure to PFAS may be associated with lower reproductive hormones and later puberty, but human studies evaluating these associations are lacking. This study examined associations of PFAS concentrations from pregnancy to child adolescence with puberty and reproductive hormones at age 12.

Study Conclusion: This study observed associations between PFAS levels in adolescence and later puberty in females. However, because PFAS can be eliminated from the body during periods, this may be impacting the findings.

Prospective associations of mid-childhood plasma per- and polyfluoroalkyl substances and pubertal timing

Study Purpose: Exposure to PFAS may disrupt pubertal timing. This study assesses associations between PFAS plasma concentrations in mid-childhood and markers of pubertal timing in male and female adolescents.

Study Conclusion: In this study, they found a higher plasma concentration of select PFAS at mid-childhood to be associated with later puberty in girls, but not boys.

Exposure to Perfluoroalkyl Substances during Fetal Life and Pubertal Development in Boys and Girls from the Danish National Birth Cohort

Study Purpose: This study looks at the associations between prenatal exposure to several PFASs and aspects of puberty in boys and girls.

Study Conclusion: These findings suggest that there are sex-specific associations of altered puberty and development with prenatal exposure to PFASs.

Per- and Polyfluoroalkyl Substances (PFAS) and Hormone Levels during the Menopausal Transition

Study Purpose: PFAS are widespread and may affect sex hormones and accelerate reproductive aging in midlife women. This study examines associations between PFAS concentrations and serum concentrations of FSH, estradiol, testosterone, and sex hormone-binding globulin from 1999-2016.

Study Conclusion: This study observed positive associations of PFOA and PFOS with FSH and inverse associations of PFNA and PFOA with estradiol in midlife women during the menopausal transition, consistent with findings that PFAS affect reproductive aging.

Associations of Perfluoroalkyl Substances with Incident Natural Menopause: The Study of Women's Health Across the Nation

Study Purpose: This study looks at the association between PFASs and natural menopause.

Study Conclusion: This study suggests that PFAS levels are associated with earlier natural menopause.

Quantitative bias analysis for epidemiological associations of perfluoroalkyl substance serum concentrations and early onset of menopause

Study Purpose: This study looks at the epidemiologic association between PFAS and altered timing of menopause might be explained by reverse causality

Study Conclusion: This study found that much of the portion of the association between PFAS levels and early onset of menopause in women is reverse of what was expected. Early onset menopause affects PFAS levels.

Exposure to perfluoroalkyl substances was associated with estrogen homeostasis in pregnant women

Study Purpose: Past studies have suggested that PFAS can act as endocrine disruptors. This study investigates the effects of serum PFAS on estrogen homeostasis during pregnancy.

Study Conclusion: This study explored associations between serum PFAS and estrogen homeostasis in Chinese pregnant women. Several serum PFAS were found to be associated with estrogen levels, suggesting that exposure to PFAS might disturb estrogen homeostasis during pregnancy. Exposure to PFAS have potential to cause a range of adverse health effects in mothers and fetuses by disturbing estrogen homeostasis and more studies are needed.

Joint effects of prenatal exposure to per- and poly-fluoroalkyl substances and psychosocial stressors on corticotropin-releasing hormone during pregnancy

Study Purpose: Prenatal exposure to PFASs has been associated with adverse pregnancy outcomes. Previous studies have suggested that join exposure to environmental chemicals and social stressors may lead to disparities in preterm birth. Elevated corticotropin-releasing hormone during mid-pregnancy may represent one biologic mechanism linking chemical and nonchemical stress exposures to preterm birth.

Study Conclusion: This cross-sectional study is the first to examine the relationship between PFAS exposure and CRH levels in mid-gestation. We found that these associations were stronger among women who experienced stress, which aligns with previous findings that chemical and nonchemical stressor exposures can have joint effects on health outcomes.

Perfluoroalkyl Chemicals, Menstrual Cycle Length, and Fecundity: Findings from a Prospective Pregnancy Study

Study Purpose: This study looks at the association between PFASs and menstrual cycle length and fertility.

Study Conclusion: Female preconception levels of PFOA and PFDeA were associated with changes in cycle length. Short and long cycles were associated with reduced fertility. There was some evidence that elevated levels of PFNA, PFOA, PFDeA, and PFOSA were associated with lower probability of pregnancy in some scenarios, but not all.

PFAS association with kisspeptin and sex hormones in teenagers of the HBM4EU aligned studies

Study Purpose: This study sought to evaluate the relationship between serum PFAS and reproductive hormones in teenagers.

Study Conclusion: The results of this study showed that PFAS, including PFAS mixture, were associated with higher TT levels in female adolescents, while associations with lower TT and E2 were found among male adolescents from HBM4EU Aligned studies.

Associations of per- and polyfluoroalkyl substances and alternatives with reproductive hormones in women of childbearing age

Study Purpose: Experimental studies suggest that PFAS may be endocrine-disrupting chemicals. However, the evidence in humans on the associations between PFAS and female reproductive hormones is sparse and limited to PFOS and PFOA.

Study Conclusion: This study found that exposure to PFAS alternatives was associated with altered levels of reproductive hormones in women of childbearing age.

Association between polyfluoroalkyl substances exposure and sex steroids in adolescents: The mediating role of serum albumin

Study Purpose: This study examines associations between PFAS levels and sex steroids in adolescents, and how this relationship may change with blood albumin levels.

Study Conclusion: This study demonstrated that increased PFAS exposure decreased adolescent testosterone and sex hormone binding protein levels, and suggests that albumin levels may affect this relationship.

Prenatal perfluoroalkyl substances exposure and maternal sex steroid hormones across pregnancy

Study Purpose: This study examines associations between maternal serum PFAS levels and sex steroid hormones at three time points during pregnancy.

Study Conclusion: PFHxS, PFNA, and PFDA may disrupt androgenic and estrogenic pathways in pregnancy in a sex-dependent manner.

Environmental exposure to per- and polyfluoroalkyl substances mixture and male reproductive hormones

Study Purpose: This study assesses the associations of PFAS mixtures with male reproductive hormones.

Study Conclusion: These findings provide evidence that PFAS mixtures may reduce E2 levels and certain PFASs may have negative effects on Leydig cells in young men. Additional studies are needed to confirm these findings.

Perfluoroalkyl substances and sex hormones in postmenopausal women: NHANES 2013-2016

Study Purpose: This study looks at the associations between serum PFAS concentrations and sex hormone levels in postmenopausal women.

Study Conclusion: This study indicates that n-PFOA and PFHxS were associated with higher levels of several sex hormone indicators in postmenopausal women.

The Influence of Persistent Organic Pollutants on Thyroidal, Reproductive and Adrenal Hormones After Bariatric Surgery

Study Purpose: This study looks at the associations between environmental pollutants (such as PFASs) and thyroid, reproductive, and adrenal hormones in a population treated with bariatric surgery.

Study Conclusion: These results suggest that environmental pollutants may have an influence on hormones after bariatric surgery. Because this study was small, more research is needed.

Prenatal exposure to perfluorodecanoic acid is associated with lower circulating concentration of adrenal steroid metabolites during mini puberty in human female infants. The Odense Child Cohort

Study Purpose: This study looks at the associations between maternal PFAS levels in early pregnancy and levels of androgens and gonadotropins (both sex hormones) in infants within the first few months of life.

Study Conclusion: Prenatal PFDA exposure was associated with lower DHEA levels and possibly lower androstenedione and DHEAS levels in female infants.

Perfluorooctanoic acid alters progesterone activity in human endometrial cells and induces reproductive alterations in young women

Study Purpose: This study looks at the relationship between PFASs and hormonal endometrium regulation.

Study Conclusion: These results suggest that PFAS disrupt progesterone-mediated endometrial function.

Association between in utero perfluoroalkyl substance exposure and Anti-Müllerian hormone levels in adolescent females in a British cohort

Study Purpose: This study looks at the association between in utero PFAS exposure and Anti-Mullerian hormone (AMH; a reproductive hormone) in female adolescents.

Study Conclusion: These findings suggest there is no association between in utero PFAS exposure and AMH levels in female adolescents.

Association of perfluoroalkyl substances exposure with reproductive hormone levels in adolescents: By sex status

Study Purpose: This study looks at the effect of PFASs on reproductive hormones in adolescents.

Study Conclusion: This study suggested that higher levels of PFASs are associated with lower testosterone and higher estradiol levels, and associations of PFASs with reproductive hormones were stronger in males than in females.

Association of perfluoroalkyl substances exposure in utero with reproductive hormone levels in cord blood in the Hokkaido Study on Environment and Children's Health

Study Purpose: Exposure to PFASs may disrupt reproductive function in animals and humans. This study looks at the associations of prenatal exposure to PFASs with cord blood reproductive hormones.

Study Conclusion: These results suggest that reproductive hormones may be affected by in utero exposure to PFOS and PFOA.

Perfluoroalkyl Substances, Sex Hormones, and Insulin-like Growth Factor-1 at 6-9 Years of Age: A Cross-Sectional Analysis within the C8 Health Project

Study Purpose: Exposure to some PFASs may alter levels of sex hormones and insulin-like growth factor-1 (IGF-1) in animals. IFG-1 is a hormone that helps promote normal bone and tissue growth and development. Human studies in this area are limited. This study looks at the relationship between PFAS levels and estradiol, total testosterone, and IGF-1 in children who lived near a PFOA contaminated site.

Study Conclusion: These findings suggest that PFASs are associated with lower levels of IGF-1 and sex hormones in children.

PFAS and Phthalate/DINCH Exposure in Association with Age at Menarche in Teenagers of the HBM4EU Aligned Studies

Study Purpose: The decrease in age at first period has been linked to endocrine disrupting chemical exposure. Evidence for the association between PFAS and phthalate exposure and the beginning of periods is inconsistent. This study looks at the association between PFAS and phthalate exposure and age at first period in teenagers.

Study Conclusion: Exposure to DEHP chemicals, but not PFAS, were associated with earlier age at first period in 12-18 year old teenagers.

Prenatal exposure to mixtures of persistent endocrine disrupting chemicals and early menarche in a population-based cohort of British girls

Study Purpose: In this study, they investigate the association between prenatal exposure to endocrine disrupting chemicals, including PFASs, PCBs, and pesticides with early menarche among female offspring.

Study Conclusion: The results of this study suggest the overall effect of prenatal exposure to persistent exposure to mixtures of endocrine disrupting chemicals is not associated with early menarche.

Plasma Perfluoroalkyl and Polyfluoroalkyl Substances Concentration and Menstrual Cycle Characteristics in Preconception Women

Study Purpose: This study looks at the association between PFAS exposure and menstrual cycle characteristics in women planning to become pregnant.

Study Conclusion: Certain PFASs are associated with abnormal menstruation.

Per- and Polyfluoroalkyl Substances and Anti-Müllerian Hormone Concentrations in Two Preconception Cohort Studies

Study Purpose: PFAS can cross the blood–follicle barrier and have been detected in follicular fluid. Greater serum PFAS concentrations have been associated with irregular menses, longer menstrual cycles, lower estradiol and progesterone concentrations, and premature ovarian insufficiency.To build on prior literature, we evaluated the association between PFAS and AMH among 357 noncontracepting individuals residing in diverse geographic areas with wider exposure variability and greater sample size. We evaluated the association between PFAS and AMH among 357 non-contracepting individuals residing in diverse geographic areas with wider
exposure variability and greater sample size.

Study Conclusion: Given that PFAS are excreted via placental transfer, postdelivery bleeding, and breastfeeding,there is active debate among epidemiologists as to whether restricting analyses to nulliparous participants avoids bias in studies investigating the reproductive effects of PFAS. As expected, we observed that PFAS concentrations were lower on average among parous than nulliparous participants. The difference in parity-specific associations may be particularly large in our study, given that nearly 89% of parous participants had their most recent birth <5 y before enrollment, with 50%  <2  y before enrollment. Nevertheless, our divergent parity-specific results indicate that environmental epidemiologists should avoid combining data from parous and nulliparous premenopausal participants when evaluating the effects of PFASon reproductive outcomes.

Associations between six common per- and polyfluoroalkyl substances and estrogens in neonates of China

Study Purpose: This study investigates the associations of PFASs and estrogen concentrations in newborns.

Study Conclusion: This study found associations between some PFASs and estrogen in newborns, but additional studies are needed to fully understand the effects of PFASs on estrogens.

Determinants of serum concentrations of perfluoroalkyl acids (PFAAs) in school children and the contribution of low-level PFAA-contaminated drinking water

Study Purpose: This study examines the health effects following low-dose PFAS exposure in school children.

Study Conclusion: 5th grade girls who reported onset of menstruation had lower PFHxS and PFOA levels than other girls.

High exposure to perfluorinated compounds in drinking water and thyroid disease. A cohort study from Ronneby, Sweden

Study Purpose: PFOS and PFHxS were found in the drinking water in Ronneby, Sweden. This study looks at the association between PFAS exposure in Ronneby and the incidence of thyroid disease.

Study Conclusion: There was no excess risk of hyperthyroidism among those with contaminated water.

Contact to perfluoroalkyl substances and thyroid health effects: A meta-analysis directing on pregnancy

Study Purpose: Human and laboratory studies suggest that PFAS may alter thyroid function, with negative effects on maternal and fetal development outcomes. However, data on the effects of PFAS on thyroid hormones remain controversial. This review of 13 studies explores the relationship between maternal exposure to PFAS and thyroid health effects, including thyroid stimulating hormone (TSH), triiodothyronine (TT3), thyroxin (TT4), free T3 (FT3), and free T4 (FT4).

Study Conclusion: In this study, there was a stable association between PFOS, PFOA, and PFDA exposure and TSH in pregnant women. Subgroup analysis showed that sample size, region, sample type, BMI, and sampling time were confounding factors affecting the association between exposure to PFAS and alterations in thyroid hormones. Studies with larger sample sizes showed stronger correlations.

Prenatal exposure to perfluorooctane sulfonate alternatives and associations with neonatal thyroid stimulating hormone concentration: A birth cohort study

Study Purpose: Cl-PFESAs and PFBS, used as PFOS alternatives, have been noted as thyroid hormone disruptors in experimental studies. However, the relationship between prenatal exposure to CL-PFESA and PFBS and TSH levels are not known in humans. The objective of this study was to study this relationship.

Study Conclusion: This study suggests a negative association between cord serum PFBS and 8:2 Cl-PFESA with TSH concentration in newborns, especially for boys.

Association between serum levels of TSH and free T4 and per- and polyfluoroalkyl compounds concentrations in pregnant women

Study Purpose: Many PFAS may disrupt maternal thyroid hormones in pregnancy. Concerns should be raised regarding PFAS exposure in pregnant women because thyroid hormones are involved in early development of the fetus. In this study, they measured the concentrations of 13 PFAS in serum from 123 pregnant women in China.

Study Conclusion: This study found that PFBA and PFDA were suggested to impact TSH levels in TPOAb-negative women. To the best of our knowledge, this is the first study to examine the effect of PFBA on TSH in pregnant women. PFBA can cross the placental barrier to the fetuses, suggesting that it may have more adverse effects on birth length and weight than long chain PFASs. Therefore, more attention should be paid to the health effects of short chain compounds in future studies.

Association of per- and polyfluoroalkyl substances with thyroid homeostasis during pregnancy in the SELMA study

Study Purpose: This study investigates the association of exposure to PFAS during pregnancy with markers of the maternal thyroid system.

Study Conclusion: These findings translate results from experimental studies suggesting that exposure to PFAS may interfere with the thyroid system during pregnancy. Further experimental studies should take into account human evidence to better understand the potential underlying mechanisms of thyroid disruption by PFAS exposure.

Higher free thyroxine associated with PFAS exposure in first trimester. The Odense Child Cohort

Study Purpose: During the first 20 weeks of gestation, the fetus is reliant on placental transfer of maternal thyroid hormones, mainly free thyroxine (FT4). However, previous studies investigating associations between exposure to PFAS and thyroid hormone status mainly focused on blood samples from late pregnancy or umbilical cord with mixed findings. This study aims to investigate associations between serum PFAS concentrations and thyroid hormones in early pregnancy as reflected by FT4 and TSH levels.

Study Conclusion: Exposure to PFOS, PFOA, and PFNA was associated with higher FT4 concentrations in women during early pregnancy. The implications of these findings remain to be clarified.

Maternal Perfluoroalkyl Substances, Thyroid Hormones, and DIO Genes: A Spanish Cross-sectional Study

Study Purpose: This study examines the relationship between first-trimester maternal PFAS and thyroid hormone levels and the role played by genetic polymorphisms in this association.

Study Conclusion: This study found higher PFOA levels to be associated with lower TT3 levels. Genes analyzed in this study did not appear to impact this association.

Umbilical cord serum perfluoroalkyl substance mixtures in relation to thyroid function of newborns: Findings from Sheyang Mini Birth Cohort Study

Study Purpose: This study looks at the possible associations of fetal exposure to PFAS individually and in mixtures with thyroid function in newborns.

Study Conclusion: This study observed thyroid disruption with some PFAS and mixtures of PFAS in cord blood.

Prenatal exposure to perfluoroalkyl substances and thyroid hormone concentrations in cord plasma in a Chinese birth cohort

Study Purpose: This study looks at the associations between prenatal PFAS exposure and thyroid hormone levels in umbilical cord blood.

Study Conclusion: This study suggests that prenatal exposure to many PFASs was associated with thyroid hormone levels in umbilical cord blood. Different PFASs had varied effects on fetal thyroid hormones.

Exposure to Perflouroalkyl acids and fetal and maternal thyroid status: a review

Study Purpose: This study looks at past studies on the relationship between prenatal and postnatal exposure to PFASs and thyroid hormones in mothers and/or infants.

Study Conclusion: Results of this study show a relationship between elevated PFAS concentrations and higher TSH levels, but lower T4 and/or T3 levels. Associations of infant thyroid hormones with PFAS concentrations were not consistent.

Perfluoroalkyl and polyfluoroalkyl substances and maternal thyroid hormones in early pregnancy

Study Purpose: This study aims to look at the relationship between PFAS and thyroid hormones in early pregnancy.

Study Conclusion: Several PFAS were associated with effects on maternal thyroid hormones in pregnant women, especially among women who were TPOAb positive.

Prenatal exposure to per- and polyfluoroalkyl substances and maternal and neonatal thyroid function in the Project Viva Cohort: A mixtures approach

Study Purpose: This study investigates the relationship between exposure to multiple PFAS during early pregnancy with maternal and neonatal thyroid function.

Study Conclusion: These findings support that there may be effects of prenatal exposure to multiple PFAS on maternal and neonatal thyroid function, but the overall effect may vary depending on the PFAS exposed to.

Maternal serum perfluoroalkyl substance mixtures and thyroid hormone concentrations in maternal and cord sera: The HOME Study

Study Purpose: This study looks at that association, using mixture modeling to assess the associations with individual PFAS, interactions among PFAS chemicals, and mixtures of PFAS.

Study Conclusion: These findings suggest that maternal PFAS levels in the second trimester of pregnancy are not strongly associated with thyroid hormones in mothers or infants.

Associations of Exposure to Perfluoroalkyl Substances With Thyroid Hormone Concentrations and Birth Size

Study Purpose: Thyroid function in pregnancy is necessary for fetal growth. Exposure to PFAS may decrease birth size and disrupt maternal and infant thyroid function, but the relationship is not completely clear. This study looks at the relationship between PFAS and birth size. It also looks at associations between PFAS and thyroid hormone concentrations.

Study Conclusion: Several PFAS were associated with increased thyroid hormones and lower birth sizes.

Perfluoroalkyl Substances and Maternal Thyroid Hormones in Early Pregnancy; Findings in the Danish National Birth Cohort

Study Purpose: The goal of this study was to look at maternal thyroid hormone levels and free T4 levels against PFAS chemicals in the first and second trimesters of pregnancy.

Study Conclusion: There were some associations between high exposure to PFAS and thyroid hormone levels in early pregnancy.

Association between perfluoroalkyl substance exposure and thyroid hormone/thyroid antibody levels in maternal and cord blood: The Hokkaido Study

Study Purpose: This study looks at the association between prenatal exposure to PFAS and the expression of thyroid hormones and thyroid antibodies in maternal and cord blood.

Study Conclusion: These results suggest that the thyroid disrupting effects of PFAS exposure and the susceptibility varies depending on maternal thyroid antibody levels.

Perfluoroalkyl and polyfluoroalkyl substances and fetal thyroid hormone levels in umbilical cord blood among newborns by pre-labor caesarean delivery

Study Purpose: Epidemiological evidence on the relationship between PFAS and thyroid hormone levels in cord blood is limited. This study aims to examine the association between cord blood PFAS concentrations and thyroid hormone levels in pre-labor cesarean deliveries.

Study Conclusion: These findings suggest that prenatal exposure to certain PFAS may disrupt fetal thyroid function; however, this may vary between sexes.

Maternal Plasma per- and Polyfluoroalkyl Substance Concentrations in Early Pregnancy and Maternal and Neonatal Thyroid Function in a Prospective Birth Cohort: Project Viva (USA)

Study Purpose: Prenatal exposure to some PFASs may disrupt maternal and neonatal function, which is needed for normal growth and neurodevelopment. This study looks at associations of PFAS exposure during early pregnancy with maternal and neonatal thyroid hormone levels.

Study Conclusion: Prenatal exposure to some PFASs during early pregnancy was inversely associated with maternal free T4 index and neonatal T4 in male infants. These results support the idea that prenatal exposure to PFASs influences thyroid function in both mothers and infants.

Exposure to perfluoroalkyl substances and thyroid function in pregnant women and children: A systematic review of epidemiologic studies

Study Purpose: Thyroid hormones are important for brain development during the fetal period and childhood. Several studies have assessed a possible association between exposure to PFAS and thyroid outcomes during the early stages of life. This study reviews this evidence.

Study Conclusion: There was an association between maternal or teenage male exposure to some PFAS and TSH levels based on current studies.

Placental Transfer of Perfluoroalkyl Substances and Associations with Thyroid Hormones: Beijing Prenatal Exposure Study

Study Purpose: This study looked at PFASs and thyroid hormone levels in maternal and infant cord blood samples around delivery.

Study Conclusion: Results suggest that prenatal exposure to PFASs could disrupt thyroid hormone levels in infants.

A co-twin control study of in utero exposure to poly- and perfluoroalkyl
substances and associations with neonatal thyroid-stimulating hormone 

Study Purpose: This study aimed to examine the associations of in utero PFAS exposure with neonatal thyroid-stimulating hormone (TSH), and to verify whether
genetic and familial factors contribute to these associations.

Study Conclusion: In summary, we found that higher maternal plasma levels of PFOA and PFDA were associated with increased neonatal TSH and intra-twin
TSH difference; higher cord plasma concentrations of PFOA, PFDA, PFUdA, and PFHxS were associated with higher neonatal TSH level among twins as individual and comparing twin pairs. While genetic and familiar factors contribute to these relationships, certain PFAS exposure might have an independent association with increased TSH.

Persistent organic pollutant exposure and thyroid function among 12-year-old children

Study Purpose: PCBs, OCPs, and PFAS are persistent organic pollutants (POPs) having numerous toxicological properties, including thyroid endocrine disruption. The aim of this study was to assess the impact of POPs on thyroid hormones among 12-year old children, while taking puberty into consideration.

Study Conclusion: Consistent with previous research, this study highlights associations between several POPs and thyroid function within the pubertal development during which complex hormonal changes occur. This is important as thyroid function disruption in early adolescence can have adverse effects at physiological, cognitive, and mental health levels. 

Prenatal exposure to endocrine-disrupting chemicals and thyroid function in neonates: A systematic review and meta-analysis

Study Purpose: Thyroid homeostasis is necessary for normal brain development. Exposure to endocrine disrupting chemicals (EDCs), such as PFAS, is associated with compromised maternal thyroid homeostasis, and may lead to adverse neurodevelopmental outcomes in newborns. Therefore, a review was conducted to better understand the relationship between maternal exposure to EDCs and neonatal thyroid hormones was performed. 

Study Conclusion: Based on the current evidence, these results suggest that global EDC exposure has no significant influence on neonatal thyroid hormone levels. However, prenatal exposure to organochlorines and PFAS is negatively associated with neonatal TT4 level. Prenatal PCB-153 exposure is positively associated with neonatal TSH level. Consequently, we recommend that larger-scale cohort studies should be established to identify the relationship between prenatal EDC exposure and neonatal thyroid hormones. 

The Relationship Between Perfluoroalkyl Substances Concentrations and Thyroid Function in Early Childhood: A Prospective Cohort Study

Study Purpose: Exposure to PFAS has been suggested to affect thyroid function, but information on PFAS exposure and thyroid function in early childhood is limited.

Study Conclusion: A relationship between early-life exposure to PFAS and thyroid function was found. Early-life exposure to PFAS was associated with decreased TSH and increased fT4 or T3 levels among preschool-age children.

Association between exposure to persistent organic pollutants during pregnancy and thyroid function during childhood: a pilot longitudinal study and literature review

Study purpose: long term consequences of PFAS on thyroid function are not entirely known. This study looks at the associations between PFAS exposure and birth and thyroid function a few months after birth.

Study Conclusion: These results suggest that the PFAS levels at birth are not associated with TSH levels later in life.

Exposure to perfluoroalkyl substances (PFAS) and associations with thyroid parameters in First Nation children and youth from Quebec

Study Purpose: This study evaluated levels of PFAS in relation to concentrations of TSH, free T4, and thyroglobulin.

Study Conclusion: High exposures to PFNA may disrupt thyroid function in children.       

Perfluoroalkyl substances in serum from South Korean infants with congenital hypothyroidism and healthy infants--Its relationship with thyroid hormones

Study Purpose: Exposure to PFASs may disrupt thyroid function, though the effects of individual PFAS is still unknown. This study looked at exposure to PFAS in infants and levels of thyroid hormones.

Study Conclusion: There was no clear association between most PFASs and thyroid hormones.

Exposure to perfluoroalkyl substances (PFAS) and association with thyroid hormones in adolescent males
Study Purpose: This study investigates the association between plasma concentrations of PFAS and levels of three thyroid hormones (T3, T4, and TSH) in adolescent males.

Study Conclusion: This study found presence of legacy and newer PFAS in the plasma of adolescent males and observed that higher concentrations of some PFAS (including PFOA, PFOS, and PFUnDA) and a mixture of PFAS were associated with a mild increase in thyroid hormone levels, particularly higher free T4 levels in boys with lower iodine intake. 

Chlorinated Polyfluorinated Ether Sulfonates and Thyroid Hormone Levels in Adults: Isomers of C8 Health Project in China
Study Purpose: Cl-PFESAs are a replacement for PFOS, however recent studies have shown that these replacements could interfere with thyroid function in animals. In this study, they focus on PFOS, PFOA, 6:2 Cl-PFESA, and 8:2 Cl-PFESA in the general adult population.

Study Conclusion: This study provided epidemiological evidence that exposure to Cl-PFESAs was associated with thyroid hormone levels in the general adult population, and the aforementioned dose–response associations were nonlinear. Our findings also support previous observational results of PFOS and PFOA in relation to thyroid hormone levels.

Associations between perfluoroalkyl substances and thyroid hormones after high exposure through drinking water
Study Purpose: This study looks at the possible association of thyroid hormones in relation to serum levels of PFAS in a Swedish general population, exposed through contaminated drinking water.

Study Conclusion: This study found no consistent results to support an association of PFAS with thyroid hormones.

Exposure to perfluoroalkyl substances and associations with serum thyroid hormones in a remote population of Alaska Natives

Study Purpose: This study aims to assess the relationship between PFAS levels and thyroid function.

Study Conclusion: Serum PFASs are associated with circulating thyroid hormone concentrations in a remote population of Alaska Natives. The effects of PFAS exposure on thyroid hormone levels may differ between sexes.

Association between perfluoroalkyl substances exposure and thyroid function in adults: A meta-analysis

Study Purpose: Epidemiological studies suggest that PFASs can disrupt thyroid hormones, though the association between PFAS exposure and thyroid function is not conclusive. This article is an analysis of several studies that investigates the association between PFASs exposure and thyroid function.

Study Conclusion: This review suggests that higher PFAS levels are associated with lower total T4 levels.

Association of exposure to perfluoroalkyl substances (PFAS) and phthalates with thyroid hormones in adolescents from HBM4EU aligned studies

Study Purpose: Studies have suggested that PFAS and phthalates may alter thyroid hormone levels, but studies in children and teenageer are limited. This study looks at the association between exposure to PFAS and phthalates with serum levels of thyroid hormones in European teenagers.

Study Conclusion: This is the first study on exposure to PFAS and phthalates and thyroid function in European teenagers. These results suggest that serum PFOA and some urinary phthalate levels are associated with thyroid hormones, particularly free T4 and T3 in females and free T4 and TSH in males. Further research is needed to better understand this association in young people.

The interference between effects of PFAS exposure on thyroid hormone disorders and cholesterol levels: an NHANES analysis

Study Purpose: Studies have shown that PFAS exposure can affect thyroid hormones and lipid levels. This study investigates whether these effects interfere with one another.

Study Conclusion: This study observed that the impacts of PFAS exposure on thyroid conditions and cholesterol levels were independent of one another, even though thyroid function and cholesterol metabolism are closely correlated. 

Per- and polyfluoroalkyl substances and the associated thyroid cancer risk: A case-control study in China

Study Purpose: The role of PFAS as thyroid carcinogens is not clear. Therefore, this study sought to investigate associations between PFAS and thyroid cancer risk.

Study Conclusion: When evaluating the effects of a mixture of PFAS on thyroid cancer risk, PFOS contributed most to increased risk of thyroid cancer. More research is needed to better understand this relationship.

Varied thyroid disrupting effects of perfluorooctanoic acid (PFOA) and its novel alternatives hexafluoropropylene-oxide-dimer-acid (GenX) and ammonium 4,8-dioxa-3H-perfluorononanoate (ADONA) in vitro

Study Purpose: In this study, the thyroid disrupting effects of PFOA and its alternatives GenX and ADONA with both rat thyroid cells and primary normal human thyroid cells.

Study Conclusion: Taken together, the data reveals that the thyroid disrupting effects is increased in the order of GenX>PFOA>ADONA.

The Impact of Smoking on the Association between Perfluoroalkyl Acids (PFAS) and Thyroid Hormones: A National Health and Nutrition Examination Survey Analysis

Study Purpose: This study looks at the effects of PFAS exposure on thyroid function. It also looks at the differences of these effects between smokers and non-smokers.

Study Conclusion: This study found that increased PFAS exposure was associated with increased free T4 levels in non-smokers, while no association was found in smokers.

Associations between longitudinal serum perfluoroalkyl substance (PFAS) levels and measures of thyroid hormone, kidney function, and body mass index in the Fernald Community Cohort

Study Purpose: This study looks at the association between PFAS and indicators of thyroid disruption, kidney function, and BMI.

Study Conclusion: PFAS levels were associated with altered kidney and thyroid function.

Associations of per- and polyfluoroalkyl substances and their alternatives with bone mineral density levels and osteoporosis prevalence: A community-based population study in Guangzhou, Southern China

Study Purpose: Evidence concerning associations of PFAS with bone mineral density (BMD) and osteoporosis is scarce. This study evaluates the associations of PFAS and PFAS alternatives with BMD levels and osteoporosis prevalence.

Study Conclusion: These findings suggest that greater PFAS exposure is associated with poorer bone health, especially in women and younger people.

Bone mass density following developmental exposures to perfluoroalkyl substances (PFAS): a longitudinal cohort study

Study Purpose: Environmental exposures to chemicals such as PFAS may play a role in bone development and future risk of osteoporosis. However, as evidence is limited, the role of developmental PFAS exposures in bone density changes in childhood is unclear. The objective of this study was to estimate associations between serum-PFAS concentrations measured in infancy and early childhood and areal bone mineral density (aBMD) measured at age 9 years in a birth cohort of children. 

Study Conclusion: The PFAS and bone mineral density associations identified in this and previous studies suggest that bone may be a target tissue for PFAS. Pediatric bone density has been demonstrated to strongly track through young adulthood and possibly beyond.

High exposure to perfluoroalkyl substances in drinking water is associated with increased risk of osteoporotic fractures - A cohort study from Ronneby, Sweden

Study Purpose: PFAS have been reported to decreased bone mineral density, but the relationship with osteoporosis and fractures is less studied. This study aimed to investigate the risks of osteoporotic fractures in a Swedish population with long-term exposure to PFAS through drinking water.

Study Conclusion: These results provide further evidence supporting the adverse effects of PFAS on osteoporosis. A better understanding of dose-response relationships as a basis for risk assessment is needed.

Association between perfluoroalkyl substances concentration and bone mineral density in the US adolescents aged 12-19 years in NHANES 2005-2010

Study Purpose: Reports on the association of PFAS exposure with adolescent bone health are scarce, and studies have primarily targeted maternal serum. This study evaluates the relationship between PFOA, PFOS, PFHxS, and PFNA levels and bone mineral density in adolescents.

Study Conclusion: In this sample of US adolescents aged 12-19 years, certain PFAS were associated with lower bone mineral density, and most of the associations were confined to females. The negative effect of PFAS on bone mineral density is more pronounced in those who are overweight/obese and have anemia.

Prenatal and early postnatal exposure to perfluoroalkyl substances and bone mineral content and density in the Odense child cohort

Study Purpose: Exposure to PFAS has been associated with lower bone mineral density in animal and human studies, but data from children are limited. This study determines associations between prenatal and early postnatal PFAS exposure and bone mineral density at age 7 years.

Study Conclusion: This study found negative associations for both prenatal PFAS exposure and child PFAS concentrations with bone mineral content and bone mineral density at age 7. Findings are of public health importance, as bone density is established in childhood, and a reduction in BMD during early childhood may have long-term implication for peak bone mass and lifelong bone health. 

Per- and polyfluoroalkyl substances exposure and bone mineral density in the U.S. population from NHANES 2005-2014

Study Purpose: Environmental exposures such as PFAS are considered potential risks for bone mineral density. This study examines associations between PFAS and bone mineral density among the US.

Study Conclusion: Serum PFAS concentrations and femur BMD were associated with gender and menopause status differences. Most negative associations were limited to premenopausal women, and most positive associations with femur BMD were found in men. Further epidemiological evidence and studies about the mechanisms are needed.

Serum PFAS and Urinary Phthalate Biomarker Concentrations and Bone Mineral Density in 12-19 Year Olds: 2011-2016 NHANES

Study Purpose: This study examines associations between serum PFAS and urinary phthalate biomarker concentrations and their mixtures with areal lower bone mineral density (aBMD) in adolescents.

Study Conclusion: Certain PFAS and phthalates may be associated with reduced bone mineral density in adolescent males. This requires further study.

Associations of Maternal Serum Perfluoroalkyl Substances Concentrations with Early Adolescent Bone Mineral Content and Density: The Health Outcomes and Measures of the Environment (HOME) Study

Study Purpose: PFAS may impair bone strength, but there are few studies on the topic. This study assesses associations of individual PFAS and their mixture during pregnancy with child bone mineral content and bone mineral density at 12 years old.

Study Conclusion: This study found that maternal PFAS concentrations during pregnancy may be associated with lower bone mineral accrual and strength in early adolescence.

PFAS and potential adverse impacts on bone and adipose tissue through interactions with PPAR-gamma

Study Purpose: This paper discusses potential health significance of PFAS based on interactions with PPARalpha, one of the mechanisms believed to be behind PFAS health effects.

Study Conclusion: PFAS exert toxic effects through interaction with nuclear receptors, including PPAR, and may play a role in increased adipogenesis and decreased bone quality. Chemicals that target PPARs may lead to changes in cell differentiation and bone development that contribute to metabolic disorder and bone weakness.

Endocrine disrupting chemicals and bone

Study Purpose: This review of literature aims to summarize recent discoveries of effects of commonly found environmental chemicals on bone.

Study Conclusion: This review provides accumulating evidence of bone disrupting effects of endocrine disrupting chemicals, such as PFASs and BPA.

Bone Disruption and Environmental Pollutants

Study Purpose: This review of literature aims to report the current status of knowledge about the effects of endocrine disrupting chemicals (EDCs) on bone health.

Study Conclusion: Because many of the studies are from animal studies, more research is needed to better understand the association between PFASs/EDCs and bone health.

Serum concentrations of perfluoroalkyl substances and their association with osteoporosis in a population in Jeddah, Saudi Arabia

Study Purpose: This study looks at the association between PFAS levels and osteoporosis.

Study Conclusion: These results suggest that exposure to PFOA, PFOS, PFNA, PFHxS, and PFUnDA was associated with osteoporosis in this population.

Endocrine disruption of vitamin D activity by perfuorooctanoic acid (PFOA)

Study Purpose: This study looks at the possible ways PFOA might interfere with Vitamin D.

Study Conclusion: The study findings suggest that PFOA has negative effects on the expression of genes involved in calcium transfer.

Endocrine disruption of vitamin D activity by perfluorooctanoic acid (PFOA)

Study Purpose: This study looks at the possible ways PFOA might interfere with Vitamin D.

Study Conclusion: Our findings suggest that PFOA has negative effects on the expression of genes involved in calcium transfer, which would disturb calcium absorption in the intestine, resulting in a negative feedback on the parathyroid glands.

Perfluoroalkyl substances and bone health in young men: a pilot study

Study Purpose: Studies have indicated that PFAS can accumulate in bones. This study looked at the association between PFAS exposure and bone health in young men in an area with high PFAS pollution.

Study Conclusion: Results suggest an increased osteoporosis risk in young men exposed to PFAS.

Per- and Polyfluoroalkyl Substance Plasma Concentrations and Bone Mineral Density in mid-childhood: A cross-sectional study (Project Viva, United States)

Study Purpose: To learn more about factors affecting children's bone mineral density may help reduce the chance of osteoporosis later in life.

Study Conclusion: The study observed that children with greater plasma concentrations of select PFASs had lower aBMD z-scores during mid-childhood.

Per- and Polyfluoroalkyl Substance Plasma Concentrations and Bone Mineral Density in Mid-childhood: A Cross-Sectional Study (Project Viva, United States)

Study Purpose: Learning more about factors affecting children's bone mineral density may help reduce the chance of osteoporosis later in life.

Study Conclusion: We found that children with greater plasma concentrations of select PFASs had lower z-scores during mid-childhood.

Perfluoroalkyl substances in human bone: concentrations in bones and effects on bone cell differentiation

Study Purpose: This study investigates PFAS levels and their possible link to bone.

Study Conclusion: This study found PFASs present in bone, which may have the potential to affect human bone cells partly at environmentally relevant concentrations.

Occurrence of Major Perfluorinated Alkylate Substances in Human Blood and Target Organs

Study Purpose: To explore relative PFAS concentrations in major organs, the study obtained anonymized tissue samples from forensic autopsies of unexpected deaths in Denmark. They assessed the most prevalent PFASs in the small tissue samples using a preparation procedure involving salting out the PFASs from the homogenized tissue into acetonitrile prior to online solid phase extraction (SPE), chromatographic separation, and quantitation by triple quadrupole mass spectrometry (LC−MS/MS). 

Study Conclusion: While active transport processes or barriers will generally affect tissue concentrations, our results confirm that physiological EDM is a useful, albeit simplistic, method to predict organ distribution in the absence of detailed data on membrane transporter affinities and permeabilities that would be required for reliable PBTK modeling. Furthermore, the existence of correlations  between PFAS concentrations in blood and major organs provides support for the use of blood levels as exposure biomarkers in risk assessment.

Association of Combined Metals and PFAS with Cardiovascular Disease Risk

Study Purpose: This study sought to investigate the impact of exposure to metals and per- and polyfluoroalkyl substances (PFASs) on cardiovascular disease (CVD)-related risk. PFASs, including PFOA,
PFOS, PFNA, and PFHxS, as well as metals such as lead (Pb), cadmium (Cd), and mercury (Hg),
were analyzed to elucidate their combined effects on CVD risk.

Study Conclusion: This study finds that combined exposure to metals and PFASs significantly elevates the likelihood of CVD risk. These results highlight the importance of understanding the complex interplay between multipollutant exposures and their potential implications for cardiovascular health.

Factors associated with per- and polyfluoroalkyl substances (PFAS) serum
concentrations in residents of New Hanover County, North Carolina: The
GenX exposure study

Study Purpose: understand what factors contributed to the PFAS blood levels observed in the GenX Exposure Study, we evaluated what demographic/lifestyle,
water usage, and other exposure characteristics were associated with
serum PFAS levels in people living in New Hanover County, NC, from
2017 to 2018.

Study Conclusion: Using data from the GenX Exposure Study, we constructed statisticalmodels using questionnaire variables that explained over 30% of the
variance of six PFAS: four legacy (PFOA, PFOS, PFHxS, and PFNA) and
two fluoroethers (Nafion byproduct 2, PFO5DoA). Years lived in the Lower Cape Fear region consistently predicted levels of PFAS. Only the model for PFO4DA, a fluoroether with a short half-life, was the explanatory value limited to 11%.

Elevated Levels of Ultrashort- and Short-Chain Perfluoroalkyl Acids in US Homes and People

Study Purpose: Perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), the two perfluoroalkyl acids (PFAAs) with 8 carbons in their structure, have been phased out on a global scale because of their high environmental persistence and toxicity. As a result, shorter-chain PFAAs with less than 8 carbons in their structure are being used as their replacements and are now widely detected in the environment, raising concerns about their effects on human health. In this study, 47 PFAAs and their precursors were measured in paired samples of dust and drinking water collected from residential homes in Indiana, United States, and in blood and urine samples collected from the residents of these homes.

Study Conclusion: Our findings show that the high abundance of ultrashort- and short-chain PFAAs in drinking water from municipal sources is a potential
environmental health problem that should be taken into consideration in assessing the risk of exposure to PFAS in the general population. In addition, a significant positive relationship between the TFA concentrations in dust and those in serum indicates that dust intake could also be an important exposure pathway for this compound.

Per- and polyfluoroalkyl substances and cardiometabolic diseases: a review

Study Purpose: The aim of this review is to provide a comprehensive summary of the current epidemiological evidence on associations between PFAS exposure and cardiometabolic diseases. We also aim to identify important considerations and address current knowledge gaps. Additionally, to highlight potential underlying molecular mechanisms, we integrate findings from molecular epidemiology using omics data with findings from laboratory studies and organize the combined knowledge using the adverse outcome pathway framework.

Study Conclusion: N/A

Per- and polyfluoroalkyl substances and sleep health in U.S. adults, NHANES 2005-2014

Study Purpose: PFAS may cause inflammation and disrupt the nervous system, which can influence sleep. This study looks at associations between PFAS exposure and sleep in U.S. adults.

Study Conclusion: There was not evidence to suggest exposure to PFOA, PFOS, PFNA, or PFHxS worsens self-reported sleep in U.S. adults. 

The role of perfluorooctane sulfonic acid (PFOS) exposure in inflammation of intestinal tissues and intestinal carcinogenesis

Study Purpose: There has been evidence that suggests that PFOS exposure may contribute to gastrointestinal inflammation that contributes to ulcerative colitis, which has been linked to colorectal cancer. This review provides an overview of studies on PFOS exposure and gastrointestinal inflammation, immune system responses, and cancer development.

Study Conclusion: There is limited evidence of an association between PFOS and gastrointestinal cancer. There is some evidence that suggests a link between long-term PFOS exposure and changes in cholesterol and inflammation. Further study is needed in this area.

Decreased levels of perfluoroalkyl substances in patients receiving hemodialysis treatment

Study Purpose: It has been suggested that hemodialysis may be a means of eliminating PFAS from the body; therefore, this study aimed to compare the serum PFAS concentrations of patients undergoing regular hemodialysis, patients with chronic kidney disease, and patients without chronic kidney disease.

Study Conclusion: Levels of T-PFOS, L-PFOS, PFDA, PFNA, PFHxS, PFOA, and PFUnDA were significantly reduced in patients receiving hemodialysis treatment. Hemodialysis played an important role in removing PFAS in patients with end stage renal disease. PFAS were also associated with increased vitamin D and liver biomarkers in both hemodialysis patients and persons not undergoing hemodialysis. Further study is needed to understand the effect of hemodialysis on PFAS elimination.

Environmental pollutant pre- and polyfluoroalkyl substances are associated with electrocardiogram parameters disorder in adults

Study Purpose: This study explores associations between PFAS levels and electrocardiogram (ECG) changes in adults.

Study Conclusion: This study provides evidence of an association between exposure to PFAS and changes in ECG parameters in adults. These findings suggest that exposure to PFAS may exacerbate adverse heart problems.

Folate concentrations and serum perfluoroalkyl and polyfluoroalkyl substance concentrations in adolescents and adults in the USA (National Health and Nutrition Examination Study 2003-16): an observational study

Study Purpose: PFAS are widely used in food packaging, textiles, and non-stick cookware. Folate might counteract the effects of environmental chemical exposures. This study explores the relationship between blood folate levels and PFAS concentrations.

Study Conclusion: This study found that as PFAS concentrations rise, folate levels decrease. These findings are supported by studies finding that PFAS compete with folate in the body for certain transporters. 

The variable associations between PFASs and biological aging by sex and reproductive stage in NHANES 1999-2018

Study Purpose: PFAS are endocrine disrupting chemicals (EDCs) that may influence biological aging by mimicking the activity of estrogens, which can decrease inflammation and oxidative stress and enhance activity of telomerase. This study tests the hypothesis that PFAS exposure is associated with measures of biological aging based on biological sex and reproductive stage. 

Study Conclusion: These findings suggest that increasing PFAS exposure may be associated with reduced measures of biological aging at relatively low levels of exposure regardless of reproductive stage (pre- or post-menopausal) and biological sex, which does not support the hypothesis.

A review of cardiovascular effects and underlying mechanisms of legacy and emerging per- and polyfluoroalkyl substances (PFAS)

Study Purpose: This review discusses adverse cardiovascular effects following PFAS exposure.

Study Conclusion: Extensive human and animal evidence suggests that accumulated levels of PFAS possibly contribute to an increased risk of cardiovascular disease (CVD) and related conditions such as cardiac toxicity, vascular disorder, hypertension, and dyslipidemia. The underlying biological mechanisms may include oxidative stress, signaling pathway disturbance, lipid metabolism disturbance, and so on. Various emerging alternatives to PFAS also play increasingly prominent toxic roles in cardiovascular (CV) outcomes that are milder, similar to, or more severe than legacy PFAS. 

Association of perfluoroalkyl substances with pulmonary function in adolescents (NHANES 2007-2012)

Study Purpose: Animal studies suggest PFAS have a toxic impact on lung development, but this association has not been assessed in humans. This study investigates the relationship between PFAS exposure with pulmonary function in adolescents aged 12-19 years.

Study Conclusion: These results suggest that exposure to PFNA may affect lung function in adolescents aged 12-15 years. Further study is needed in this area. 

Associations between per and polyfluoroalkyl ether sulfonic acids and vitamin D biomarker levels in Chinese newborns

Study Purpose: Skeletons develop extremely fast during fetal and neonatal stages; thus, fetuses and neonates are vulnerable to vitamin D metabolism dysregulation. Previous studies linked legacy PFAS with vitamin D biomarker status in adults and children; however, how PFAS, especially newer-short chain PFAS, influence vitamin D among newborns is unknown. This study investigated how PFAS influence vitamin D among newborns.

Study Conclusion: Legacy PFAS (like PFOA, PFOS) but not emerging PFAS (like GenX) were related to vitamin D biomarkers in newborns, with more pronounced associations in boys. Out of the 11 PFAS of interest, PFTrDA, PFBS, and PFHxS are top contributors to the overall effect on the total vitamin D level.

Association of exposure to perfluoroalkyl substances and risk of the acute coronary syndrome: A case-control study in Shijiazhuang Hebei Province

Study Purpose: Exposure to PFAS have been reported to increase the risk of atherosclerosis. Therefore, PFAS exposure may be linked to the risk of acute coronary syndrome (ACS), but this association remains uncertain. The objective of the present study was to investigate the association between PFAS exposure and ACS risk through a case-control study.

Study Conclusion: In summary, this study investigated the potential association between plasma PFAS concentrations and ACS risk in the Chinese population. We observed that an increased risk of ACS was associated with higher levels of PFOA and PFOS and lower levels of PFHxS and PFDA. However, the negative associations reported in this study should not be interpreted as protective, and there may be some unresolved confusion in these relationships. Further studies are needed to clarify these relationships. 

Effects of Lifetime Exposures to Environmental Contaminants on the Adult Gut Microbiome

Study Purpose: Emerging evidence indicates that alterations in gut microbiota can affect human homeostasis. However, data from human studies are scarce. This study followed 124 individuals born in the Faroe Islands between 1986 and 1987 who were followed approximately every 7 years from birth through age 28 years.  

Study Conclusion: This study did not find evidence to suggest lasting effects of early life exposure to PFAS and other chemicals on adult gut microbial composition, but proximal exposures may contribute to gut microbiome alterations. Future studies are needed to further investigate the relationship between PFAS exposure and the gut microbiome.

Epidemiology Evidence for Health Effects of 150 per- and Polyfluoroalkyl Substances: A Systematic Evidence Map

Study Purpose: The aim of this systematic evidence map (SEM) is to summarize the epidemiology evidence on approximately 150 lesser studied PFAS, to identify priorities for risk assessment and future studies.

Study Conclusion: Most of the PFAS in this evidence map have little to no epidemiology data available to inform evaluation of potential health effects. Although exposure to the 15 PFAS that had data was fairly low in most studies, these less-studied PFAS may be used as replacements for "legacy" PFAS, leading to potentially greater exposure. It is impractical to generate epidemiology evidence to fill the existing gaps for all potentially relevant PFAS. 

Association between fish oil supplements use and serum per- and polyfluoroalkyl substances (PFAS): Results from the National Health and Nutrition Examination Survey

Study Purpose: Although consumption of fish, seafood, and their byproducts is a known source of dietary PFAS exposure, little is known about the association between use of fish oil supplements and PFAS. Here, we examine those associations.

Study Conclusion: While fish oil users did not experience increased serum PFAS, there was an unexpected inverse association in some population subgroups. Further research will be needed to better understand this pattern.

Associations between PFAS occurrence and multimorbidity as observed in an electronic health record cohort

Study Purpose: PFAS are associated with health outcomes ranging from cancer to high cholesterol. However, there has been little study of how PFAS exposure might impact the development of multiple chronic diseases, known as multimorbidity. This study investigates the association of one or more PFAS in water systems serving the zip code of residence with chronic disease and multimorbidity.

Study Conclusion: Exposure to PFAS is associated with a range of chronic diseases as well as multimorbidity. Accounting for the joint impacts of PFAS on multiple chronic conditions may give an increasingly clear picture of the public health impacts of PFAS.

Exposure to Per- and Polyfluoroalkyl Substances and Mortality in U.S. Adults: A Population-Based Cohort Study

Study Purpose: PFAS are widespread environmental contaminants associated with diseases such as cancer and dyslipidemia. This study aims to explore the association between PFAS mixtures, PFOA, and PFOS and mortality in US adults by a nationally representative cohort.

Study Conclusion: There was a positive association between PFAS mixture exposure and mortality among US adults. Results also suggest that PFOS, not PFOA, contributed in large part to the strength of the PFAS–mortality association, especially for women and people without diabetes. The decline of PFOS exposure levels in the United States reduced the number of deaths associated with PFOS from 1999 to 2018.

Environmental exposure to per- and polyfluoroalkyl substances and sleep disturbance in pregnant women: A prospective cohort study

Study Purpose: This study aims to assess the associations between PFAS and sleep quality in pregnant women.

Study Conclusion: This study suggests that exposure to PFAS during pregnancy was significantly associated with increased risk of sleep disturbance.  PFBS was the most dominant PFAS in terms of the negative effects on sleep quality in the first and second trimester, and PFOS was the major contributor in the third trimester. Exposure to PFAS mixtures could increase the risk of sleep medicine use during pregnancy.

Health-related toxicity of emerging per- and polyfluoroalkyl substances: Comparison to legacy PFOS and PFOA

Study Purpose: This review presents recent research on the health-related impacts of PFAS exposure, highlighting compounds other than PFOA and PFOS that cause adverse health effects, updates the current state of knowledge on PFAS toxicity, and, where possible, elucidates cause-and-effect relationships.

Study Conclusion: Evidence derived from both animal models and humans suggests that PFAS may have a deleterious impact on both animals and humans. However, extrapolating animal studies and comparing them to human studies does not draw firm conclusions. Moreover, studies in humans provided contrasting results. Investigation of PFAS exposure in a chronically exposed population is needed to evaluate the biological toxicity of chronic exposure to PFAS. Investigating the mechanisms of actions, toxicokinetic and adverse outcome pathways must be extended to elucidate differences in responses among species, between the sexes, and life stages. Moreover, the major gaps in the current literature identified are the lack or limited studies that investigate the route of exposure as most of them were undefined, the critical time window of exposure, a mixture of PFAS, and various dose-response relationships between PFAS and target endpoint.

Vascular endothelium as a target for perfluoroalkyl substances (PFAs)

Study Purpose: PFAS have been linked with cardiovascular disease and cardiovascular risk factors. Older, long-chain PFAs have been phased out due to adverse cardiometabolic health effect and replaced by newer short-chain PFAs. However, emerging research suggests that short-chain PFAs may also have adverse cardiovascular effects. This study tests the hypothesis that serum concentrations of PFAS are associated with measures of vascular function.

Study Conclusion: Serum concentration of PFHpA, a new, short-chain PFAS, was associated with impaired vascular function among outpatients without cardiovascular disease. Our findings support a potential adverse cardiovascular effect of newer, short-chain PFAs.

Healthy eating index and diet diversity score as determinants of serum perfluoroalkyl acid (PFAA) concentrations in a national survey of Swedish adolescents

Study Purpose: Food is an important source of PFAS exposure for the general adult population, but we have little information on its importance for adolescents. Associations between serum PFAS concentrations and adolescent diet were determined in a nationally representative adolescent population from Sweden.

Study Conclusion: In this study, they conclude that Swedish adolescents that adhere to a more diverse and healthy diet appear to be more highly exposed to PFAS than those eating less healthy. Additional research is needed.

Effect of Plasma and Blood Donations on Levels of Perfluoroalkyl and Polyfluoroalkyl Substances in Firefighters in Australia: A Randomized Clinical Trial

Study Purpose: Elevated levels of blood perfluoroalkyl and polyfluoroalkyl substances (PFASs) have been associated with a range of adverse health outcomes. Firefighters have been exposed to PFASs in firefighting foams and have previously been shown to have higher PFAS levels in blood samples than the general population. No interventions have been shown to reduce PFAS levels. The goal of this study is to examine the effect of blood or plasma donations on PFAS levels in firefighters in Australia.

Study Conclusion: Plasma and blood donations caused greater reductions in serum PFAS levels than observation alone over a 12-month period. Further research is needed to evaluate the clinical implications of these findings.

The relationship between multiple perfluoroalkyl substances and cardiorespiratory fitness in male adolescents

Study Purpose: This study used national data from 2003-2004 to investigate the relationship between PFAS levels and cardiorespiratory fitness in 13-19 year-old adolescents.

Study Conclusion: In summary, in a representative sample of the US population, higher exposure to PFASs, mainly PFNA, was negatively related to cardiorespiratory fitness. These correlations were mainly found in males. Given the results of this study, we suggest the implementation of universal serum PFAS screening in adolescents. Further research is needed to explore the dose–response relationship between PFNA exposure and CRF and to reveal its underlying mechanism.

Per- and Polyfluoroalkyl Substances and Risk of Myocardial Infarction and Stroke: A Nested Case–Control Study in Sweden

Study Purpose: PFAS are widespread and persistent pollutants that have been associated with elevated cholesterol levels. However, data on incident cardiovascular disease (CVD) is lacking. This study investigated the association of exposure to PFAS with risk of myocardial infarction and stroke and, subsidiary, with baseline blood lipids.

Study Conclusion: This study indicated that exposure to PFAS, although associated with increased cholesterol levels, did not associate with an increased risk of myocardial infarction, stroke, or their composite end point. The findings improve our knowledge on potential health effects of environmental contaminants in the CVD context.

Environmental pollutant exposure associated with altered early-life gut microbiome: Results from a birth cohort study

Study Purpose: Recent studies have shown that the gut microbiota interacts with environmental pollutants, but the effect of early exposure on the neonatal microbiome remains unknown. This study investigates the association between maternal exposure to environmental pollutants and changes in early-life gut microbiome development.

Study Conclusion: This study shows that maternal exposure to pollutants--at the late gestational period and during birth--associates with alterations in the infant's microbiome development. Also, early-life stressors were found to aggravate the pollutant effect on the microbiome. Microbiome alterations found in fecal samples from breastfed infants suggest exposure via breastmilk.

Association between the total plasma isomers of per- and polyfluoroalkyl substances and erythrograms in young and middle-aged Taiwanese populations

Study Purpose: This study explores the relationship between PFAS exposure and erythrocytes.

Study Conclusion: The results imply that PFOA/PFOS isomers may increase the weight and volume of Hb/RBC and that some isomers may have an additive effect on the Hb levels. However, it is also possible PFAS detected at a higher concentration may be due to its binding to higher levels of Hb. Further study is needed.

Internal exposure to perfluoroalkyl substances (PFAS) in vegans and omnivores

Study Purpose: To examine the relationship of PFAS levels and cholesterol levels in vegans and omnivores, a study was designed with 36 vegans and omnivores in Germany.

Study Conclusion: Lower levels of PFOS and PFNA, but not PFOA and PFHxS were observed in vegans compared to omnivores. Food frequency information allowed the identification of relevant food groups contributing to the levels of these PFAS. The strong impact of a vegan diet on levels of lipids, especially LDL cholesterol, were confirmed by this study. The association of PFAS and LDL cholesterol was found to be negligible.

Exposure to Perfluoroalkyl Chemicals and Cardiovascular Disease: Experimental and Epidemiological Evidence

Study Purpose: This study is a review of studies examining the hypothesis that exposure to PFAS is associated with increased risk of cardiovascular events or alteration in cardiovascular structure and function. This also analyzes recent scientific evidence linking exposure to PFAS to altered platelet function, which represents a possible explanation for an excess of arterial thrombosis in PFAS exposed populations.

Study Conclusion: Cumulating evidence indicates that the cardiovascular system may be the target of PFAS toxicity by increasing the risk of atherosclerosis-related thromboembolic events. Several studies indicate that metabolic disorders, including hyperlipidemia, diabetes mellitus, obesity and increased blood pressure may translate into increased cardiovascular events in the exposed populations, possibly through the endocrine disrupting activity of PFAS.

Mixture effects of prenatal exposure to per- and polyfluoroalkyl substances and polybrominated diphenyl ethers on maternal and newborn telomere length

Study Purpose: This study examined associations between prenatal exposure to PFAS, PBDEs, and maternal and newborn telomere length.

Study Conclusion: Our results indicate that prenatal exposure to PFAS and PBDE mixtures is modestly associated with longer telomere length among newborns. In our study, these associations were observed only when restricting to maternal–fetal unit pairs. This has implications for disease risk across the life course, as newborn telomere length is predictive of telomere length later in life [11] and telomere lengthening has been associated with increasing cancer risk later in adulthood [48]. Future studies are needed to elucidate the long term health effects of environmental exposure-induced telomere lengthening.

Impact of the increasing concentrations of selected perfluoroalkyl acids on the observed concentrations of red blood cell folate among US adults aged ≥20 years

Study Purpose: This study estimates associations between the concentrations of red blood cell folate and the concentrations of PFASs for US adults aged 20 and older.

Study Conclusion: Increasing concentrations of select PFASs are associated with decreased levels of red blood cell folate. The degree to which concentrations of red blood cell folate decrease depends on the size of the PFAS.

Dietary patterns and PFAS plasma concentrations in childhood: Project Viva, USA

Study Purpose: Diet is thought to account for most adult exposure to PFASs. Children are particularly vulnerable to adverse health effects of PFAS and may have different eating habits than adults. However, studies of dietary patterns and PFAS in children are limited.

Study Conclusion: This study examined food intake in association with PFASs in children and identified dietary determinants that may be sources of PFAS exposure.

Per-and Polyfluoroalkyl Substances in Human Serum Samples of Selected Populations from Ghana

Study Purpose: The aims of this study were to assess serum concentrations of PFASs in select groups from Ghana, including workers engaged in the repair of electronics.

Study Conclusion: The PFAS concentrations observed in the study are low compared to other populations. Electronics workers had significantly higher PFOA concentrations than other participants.

Per- and polyfluoroalkyl substances and calcifications of the coronary and aortic arteries in adults with prediabetes: Results from the diabetes prevention program outcomes study

Study Purpose: This study investigates the contribution of PFAS to the development of arterial calcification in prediabetics.

Study Conclusion: In this study, prediabetic adults with higher levels of some PFASs had higher risk of coronary and thoracic aorta calcification. PFAS exposure may be a risk factor for adverse cardiovascular health among high-risk populations.

The concentration of several perfluoroalkyl acids in serum appears to be reduced by dietary fiber

Study Purpose: Fiber-rich food intake has been associated with lower levels of PFASs in some studies. This study looks at the relation of PFAS levels to intake of fiber.

Study Conclusion: These results suggest that dietary fiber intake increases the excretion of PFOA, PFOS, and PFNA.

Perfluoroalkyl substances and likelihood of stroke in persons with and without diabetes

Study Purpose: The goal of this study is to evaluate the relationship of PFASs with stroke, and whether diabetes influences this relationship.

Study Conclusion: In this study, an inverse relationship was associated with PFHxS/PFOS and stroke among those with diabetes. The data suggest that PFASs do not increase the risk of stroke among persons with or without diabetes.

Evaluating mixtures of urinary phthalate metabolites and serum per-/polyfluoroalkyl substances in relation to adolescent hair cortisol: The HOME Study 

Study Purpose: Our objective was to examine the prospective association of gestational and  childhood phthalate and PFAS mixtures with adolescent hair cortisol, an integrative measure of HPA axis activity. 38 We also investigated potential periods of heightened susceptibility to phthalates and PFAS during fetal development, childhood, and adolescence. We hypothesized that phthalates and PFAS would be positively associated with hair cortisol concentrations and these associations could vary by the developmental stage of exposure

Study Conclusion: In conclusion, our results— which suggest that higher urinary phthalate metabolites during childhood are associated with higher hair cortisol concentrations during adolescence— support the hypothesis that phthalate exposure may disrupt HPA axis homeostasis.

Metabolic Perturbations Associated with an Exposure Mixture of Per- and Polyfluoroalkyl Substances in the Atlanta African American Maternal-Child Cohort

Study Purpose: We conducted a high-resolution metabolomics analysis with advanced environmental mixture methods via quantile gcomputation to assess the single and potential joint effects of multiple PFAS on the maternal metabolome among 268participants in the Atlanta African American Maternal-Child Cohort.

Study Conclusion: In one of the first studies of its kind, we demonstrate the feasibility and utility of using methods designed for exposure mixtures in conjunction with metabolomics to assess the potential joint effects of multiple PFAS chemicals on the human metabolome. We identified more pronounced metabolic perturbations associated with the PFAS mixture than for single PFAS chemicals. Taken together, our findings illustrate the potential for integrating environmental mixture analyses and high-through put metabolomics to elucidate the molecular mechanisms underlying human health.

Neonatal per- and polyfluoroalkyl substance exposure in relation to retinoblastoma

Study Purpose: This exploratory study investigates 117 associations between PFAS we identified in dried neonatal blood spots (i.e., PFOS, PFOA, and 118 PFNA) and the risk of developing childhood retinoblastoma.

Study Conclusion: Our results suggested that PFOS and PFOA might contribute to retinoblastoma risk in children born in California.

Prenatal exposure to per- and polyfluoroalkyl substances and infant sleep disturbance: A prospective cohort study

Study Purpose: Prenatal PFAS exposure may adversely affect brain development, but the potential association between prenatal PFAS exposure and infant sleep has not been studied. This study explores the relationship between prenatal PFAS exposure with infant sleep disturbances during the first year of life.

Study Conclusion: These findings suggest that prenatal exposure to PFAS may increase the risk of sleep disturbances in infants.

Prenatal exposure to persistent organic pollutants and molar-incisor hypomineralization among 12-year-old children in the French mother-child cohort PELAGIE

Study Purpose: The relationship between tooth oral health and low levels of exposure to environmental chemicals such as PFAS was assessed.

Study Conclusion: Two pesticides were associated with a reduced risk of dental defects, whereas associations between PCBs and PFAS and enamel defects or molar-incisor hypomineralization were generally not seen.

Maternal plasma perfluoroalkyl substances concentrations in early pregnancy and cardiovascular development in offspring: A prospective cohort study

Study Purpose: High maternal plasma PFAS concentrations have been associated with adverse birth outcomes, but effects on early childhood cardiovascular health is not well understood. This study aimed to assess the potential association between maternal PFAS concentrations in early pregnancy and cardiovascular development in offspring.

Study Conclusion: These findings suggest that maternal plasma PFAS concentrations during early pregnancy were associated with cardiovascular development in offspring, including thinner cardiac wall thickness and carotid intima media thickness.

Early-life exposure to per- and polyfluoroalkyl substances and infant gut microbial composition

Study Purpose: Breast milk is rich in essential nutrients and immune-activating compounds but is also a source of toxicants such as PFAS. Evidence suggests that immune-related effects of PFAS may be due to alterations of gut bacteria. This study aimed to identify the association between exposure to PFAS through breast milk and the infant gut bacteria.

Study Conclusion: PFAS exposure may increase infant gut bacteria diversity and alter the abundance of biologically relevant bacteria. More study is needed in this area.

PFAS Concentrations and Cardiometabolic Traits in Highly Exposed Children and Adolescents

Study Purpose: Residents of northeast Italy were exposed to highly contaminated drinking water for decades. This study evaluated associations in this population between serum PFAS concentrations and metabolic outcomes.

Study Conclusion: This study supports the association between PFAS concentration and serum lipid levels, which is stronger for PFOS and PFNA and with a greater magnitude among children compared to adolescents, and a negative association of PFAS with BMI.

Association between maternal serum concentration of perfluoroalkyl substances (PFASs) at delivery and acute infectious diseases in infancy

Study Purpose: PFAS are persistent compounds that have been recognized as important immune hazards by animal studies. However, human studies regarding the impact on infant infections are inconsistent. This study investigates the associations between prenatal exposure to PFAS and acute infectious diseases including common cold, bronchitis/pneumonia, and diarrhea in early childhood.

Study Conclusion: Exposure to PFASs was associated with increased risks of diarrhea during the first year of life, and these effects were stronger among the breastfed infants. Due to the small sample size, our results should be interpreted with caution and additional studies on larger populations are needed to confirm our findings.

Early-Life Exposure to Per- and Poly-Fluorinated Alkyl Substances and Growth, Adiposity, and Puberty in Children: A Systematic Review

Study Purpose: This is a review of literature that assesses the effects of early-life PFAS exposure on prenatal and postnatal growth, adiposity, and puberty in children and adolescents. 

Study Conclusion: Further investigation is warranted to clarify PFAS-induced effects on growth and physical development in consideration of the critical time-window of exposure, concomitant exposure to chemical mixtures including various PFAS types, and possible non-monotonic dose-response relationship for growth and adiposity trajectories.

Gestational exposure to perfluoroalkyl substances and congenital heart defects: A nested case-control pilot study

Study Purpose: This study is the first to test associations between gestational PFAS exposure and the risk of congenital heart defects.

Study Conclusion: These findings suggest that gestational exposure to most PFAS was associated with greater risks for septal and conotruncal defects. However, a larger study is needed to confirm these findings.

Gestational and childhood exposure to per- and polyfluoroalkyl substances and cardiometabolic risk at age 12 years

Study Purpose: To study whether there is any connection between prenatal and early childhood PFAS exposure and heart health risk in adolescence.

Study Conclusion: Exposure to PFOA and PFHxS during gestation, compared to childhood, was more strongly associated with unfavorable cardiometabolic risk scores at age 12 years in this cohort of children with higher gestational PFOA exposure. Gestational and childhood PFOS and PFNA exposure were generally not associated with cardiometabolic risk scores at age 12 years. Gestational exposure to the four PFAS was aggregately associated with unfavorable cardiometabolic risk.

Associations between perfluoroalkyl acids in serum and lead and mercury in whole blood among US children aged 3-11 years

Study Purpose: Data for US children aged 3-11 during 2013-2014 were analyzed for values of blood lead and mercury in association with PFAS levels.

Study Conclusion: Because PFASs and lead/mercury are known to be neurotoxins and endocrine disruptors, exposure to both may lead to increased neuro-developmental deficits.

Urine concentrations of perfluoroalkyl acids in children and contributions of dietary factors: a cross-sectional study from Shanghai, China

Study Purpose: In this study, the specific urine levels of 10 PFAAs were obtained from 189 children (age 8-12 years) from two primary schools located in urban and suburban areas of Shanghai in 2019, and the contributions of dietary factors were investigated.

Study Conclusion: In this study, school children showed prevalent exposure to short-chain PFAAs such as PFHxA, PFHpA, PFBS, and several traditional long-chain PFAAs. Frequent consumption of red meats, tubers, sugared beverages, fish and seafood, and eggs contributed to higher concentrations of PFAAs, while frequent consumption of poultry and soy milk contributed to lower PFAA concentrations.

Perfluorooctanoic acid (PFOA) or perfluorooctane sulfonate (PFOS) and DNA methylation in newborn dried blood spots in the Upstate KIDS cohort

Study Purpose: This study examines relationships between PFOA and PFOS with DNA changes among nearly 600 infants.

Study Conclusion: There was limited evidence of an association between high concentrations of PFOA/PFOS and DNA changes in newborns in this study.

Exposure to Perfluorinated Alkyl Substances and Health Outcomes in Children: A Systematic Review of the Epidemiologic Literature

Study Purpose: This study summarized previous studies looking at the relationships between childhood exposure to PFAS and health outcomes in children.

Study Conclusion: There were inconsistent findings on associations between PFAS and neurodevelopmental outcomes.

Early-life exposome and lung function in children in Europe: an analysis of data from the longitudinal, population-based HELIX cohort

Study Purpose: This study looks at possible associations between prenatal and postnatal environmental exposures that may affect lung function in children.

Study Conclusion: Our results suggest that prenatal exposure to PFASs (perfluorononanoate and perfluorooctanoate) and postnatal exposure to copper, ethylparaben, DEHP and DINP metabolites, and house crowding are associated with a lower Forced Expiratory Volume (FEV₁) in childhood.

Albumin Proteins as Delivery Vehicles for PFAS Contaminants into Respiratory Membranes

Study Purpose: This study shows that bovine serum albumin (BSA) can bind both PFOS and PFOA and deliver them into model lipid films at the air–liquid interface. Protein-mediated PFAS delivery significantly altered the surface activity of these lipid systems, destabilized their physical structure, and enhanced their susceptibility to hydrolysis by phospholipase A2 (PLA2) enzymes.

Study Conclusion: In this work, we show that BSA can bind and deliver PFOA
and PFOS into both model surfactant films and lipid bilayers disrupting their structure and function. It should be noted that PFAS contaminants are capable of inducing similar disruptions in the absence of BSA. However, the use of a protein scaffold
has the potential to greatly enhance their solubility and bioavailability. 

Associations of Single and Multiple Per- and Polyfluoroalkyl Substances Exposure with Serum Pepsinogens Among Young and Middle-Aged Adults in Shanghai, China

Study Purpose: This study aimed to examine whether there is any relationship between PFAS and the level of serum pepsinogens in the general population. Further explored was the independent or combined  exposure effects of PFAS congeners, in the hope of revealing the potential role and mechanism by which 56 PFAS can affect the occurrence of gastrointestinal diseases.

Study Conclusion:  This study is the first to establish a correlation between PFAS exposure and peptic pepsinogens at the population level, offering new evidence on the potential roles and mechanisms of gastrointestinal health in PFAS-exposed populations

Serum concentrations of per- and polyfluoroalkyl substances and risk of
renal cell carcinoma in the Multiethnic Cohort Study 

Study Purpose: We previously reported a positive association between serum perfluorooctanoate (PFOA) concentrations and risk of renal cell carcinoma (RCC) within the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial, comprising predominantly White individuals enrolled in 1993–2001. To extend
our investigations to a larger and more racially and ethnically diverse population, we conducted a nested case control study of serum PFAS concentrations and RCC within the Multiethnic Cohort Study.

Study Conclusion: In this large nested-case control study of serum PFAS and RCC risk in a racially and ethnically diverse population, PFOA was not associated
with RCC risk overall, although we found suggestive positive associations among White participants and those who had blood drawn before 2002, which are consistent with our previous findings in PLCO.

 We also provided new evidence of a positive association between PFNA and RCC risk, which was strongest in African American participants followed by Native Hawaiian and White participants.

Exposure to perfluoroalkyl and polyfluoroalkyl substances and risk of stroke in adults: a meta-analysis

Study Purpose: This study reviews the evidence on an association between PFAS exposure and risk of stroke.

Study Conclusion: There was not evidence to suggest an association between stroke and exposure to PFOA, PFOS, and PFNA.

First observations of a potential association between accumulation of per- and polyfluoroalkyl substances in the central nervous system and markers of Alzheimer's disease

Study Purpose: This study explores whether there may be a relationship between PFAS exposure and Alzheimer's disease.

Study Conclusion: There were elevated levels of PFAS in patients with Alzheimer's disease signs compared to those without, though this study was in a small number of individuals, so further study is needed.

Leveraging Systematic Reviews to Explore Disease Burden and Costs of Per- and Polyfluoroalkyl Substance Exposures in the United States

Study Purpose: Evidence confirms the contribution of PFAS to disease burden. Therefore, it is important to document the costs of policy maker inaction on PFAS even in the presence of uncertainty. This study calculates disease burden and economic costs to PFAS exposure in the US in 2018.

Study Conclusion: This study identifies at least $5.52 billion in annual disease burden and associated social costs of current annual exposure to PFAS,  with our models revealing costs as much as $62.6 billion. Regulatory action to limit ongoing PFAS use and remediate contaminated water supplies may produce substantial economic benefits.

Plasma levels of per- and polyfluoroalkyl substances (PFAS) are associated with altered levels of proteins previously linked to inflammation, metabolism and cardiovascular disease

Study Purpose: PFAS have been linked to adverse immune and cardiometabolic health effects in animal and human studies, but findings have been mixed. The aim of this study was to investigate potential associations between plasma PFAS levels and levels of markers linked to inflammation, metabolism, and cardiovascular disease.

Study Conclusion: These findings suggest that PFAS exposure may influence levels of proteins previously linked to inflammation, metabolism, and cardiovascular disease in middle-aged persons.

Prenatal exposures to per- and polyfluoroalkyl substances and epigenetic aging in umbilical cord blood: The Healthy Start study

Study Purpose: Prenatal PFAS exposure may lead to epigenetic age acceleration (EAA), or the difference between an individual's calendar age and biological age. This study estimates the relationship between maternal PFAS levels with EAA in umbilical cord blood.

Study Conclusion: Maternal mid-pregnancy levels of PFDA were associated with decreased EAA in cord blood, suggesting a path by which PFAS exposure may affect infant development.

Combined Effects of Multiple Per- and Polyfluoroalkyl Substances Exposure on Allostatic Load Using Bayesian Kernel Machine Regression

Study Purpose: This study aims to investigate the combined effects of PFAS on allostatic load, an index of chronic stress that is linked to several diseases, such as cardiovascular disease and cancer. 

Study Conclusion: In this investigation, we found correlations between exposure to certain PFAS and allostatic load. The mixture of PFAS showed significant correlations with allostatic load. This study demonstrated that exposure to particular PFAS in combination might adversely promote the body's stress response.

Impact of exposure to per- and polyfluoroalkyl substances on fecal microbiota composition in mother-infant dyads

Study Purpose: This study set out to identify the gut bacterial species that associate with PFAS exposure before and after birth.

Study Conclusion: These findings suggest that PFAS exposure may influence adult gut microbiota composition, while the effect on the infant microbiome appear weak. PFOS and PFHpS showed the strongest connected with altered bacteria.

Per- and Polyfluoroalkyl Substances (PFAS) Mixture during Pregnancy and Postpartum Weight Retention in the New Hampshire Birth Cohort Study (NHBCS)

Study Purpose: PFAS are suspected to disrupt the metabolic system. This study examines the association between PFAS exposure during pregnancy and postpartum weight retention.

Study Conclusion: These results indicate that higher plasma PFOS concentrations during pregnancy may be associated with greater long-term weight retention after pregnancy. They further suggest that individuals with a higher pre-pregnancy BMI may be particularly vulnerable.

Association between perfluoroalkyl and polyfluoroalkyl internal exposure and serum α-Klotho levels in middle-old aged participants

Study Purpose: Exposure to PFAS causes oxidative stress, which is associated with adverse health effects Klotho protein plays an anti-aging role. This study assesses the levels of serum Klotho and PFAS exposure in adults.

Study Conclusion: In this sample of U.S. middle-aged and elderly populations, serum PFAS, especially PFNA, have been shown to negatively impact levels of Klotho, which is associated with cognition and aging. Further study is needed to clarify this relationship so we can better understand the effect of PFAS exposure on aging and aging-related diseases.

Poly- and perfluoroalkyl substances exposure during pregnancy and postpartum depression: Evidence from the Shanghai birth cohort

Study Purpose: Exposure to PFAS has been linked to psychiatric disorders in the general population. Because women in the postpartum period are susceptible to mental disorders, we aimed to investigate the association between exposure to PFASs during pregnancy and postpartum depression (PPD).

Study Conclusion: This study provides preliminary evidence on the associations between prenatal exposure to PFAS during early pregnancy and maternal post-partum depression. Despite not finding association among most PFAS chemicals, PFBS, PFHpA, and PFDoA were associated with a higher risk of post-partum depression. This highlights the need for further epidemiological or experimental studies to illustrate the potential impacts of PFASs exposure on depression.

Maternal per- and poly-fluoroalkyl substances exposures associated with higher depressive symptom scores among immigrant women in the Chemicals in Our Bodies cohort in San Francisco

Study Purpose: Maternal depression is highly prevalent during pregnancy and postpartum and is potentially sensitive to PFAS. The health risks associated with PFAS may be further amplified in historically marginalized communities, including immigrants. This study evaluates maternal concentrations of PFAS and whether there is an association with depression scores during pregnancy and if these effects differ between US born and immigrant women.

Study Conclusion: These findings provide new evidence that PFAS levels are associated with higher depression symptoms among immigrant women during pregnancy. Results can inform efforts to address environmental factors that may affect depression among US immigrants. 

What Happens In Utero Does Not Stay In Utero: a Review of Evidence for Prenatal Epigenetic Programming by Per- and Polyfluoroalkyl Substances (PFAS) in Infants, Children, and Adolescents

Study Purpose: The purpose of this review was to review human literature on the relationship between prenatal exposure to PFAS and epigenetic modification in infants, children, and adolescents under 18 years. 

Study Conclusion: There is moderate support for the notion that prenatal PFAS exposure alters DNA methylation in a manner that may perturb metabolic-related gene pathways. Moving forward, there is need for solution-oriented research that inform specific actions to prevent or mitigate risk. 

Sex-specific associations between legacy and novel per- and polyfluoroalkyl substances and telomere length in newborns in Wuhan, China: Mixture and single pollutant associations

Study Purpose: Telomere length at birth predicts later life telomere length, which is related to health. Prenatal exposure to environmental pollutants might affect telomere length, but the associations between intrauterine PFAS exposure and neonatal telomere length remained inconclusive. This study aimed to explore the associations between PFAS and telomere length in newborns.

Study Conclusion: In summary, intrauterine exposure to PFASs in mixture was associated with shorter neonatal TL, and the negative associations of 8:2 Cl-PFESA and PFOS with neonatal TL were observed only in boys.

Associations between serum perfluoroalkyl acid (PFAA) concentrations and health related biomarkers in firefighters

Study Purpose: Firefighters who used AFFF in the past have experienced elevated exposures to PFAS. The objective of this study was to examine the associations between health outcomes and serum concentrations of PFOA, PFHxS, PFHpS, and PFOS in firefighters.

Study Conclusion: PFAS serum concentrations were not associated with any of the self-reported health conditions. However, increasing levels of one or several of the assessed PFAS were associated with total cholesterol, LDL, urate and TSH in cross-sectional analysis. Further research is needed.

Per- and polyfluoroalkyl substances exposure and its influence on the intestinal barrier: An overview on the advances

Study Purpose: PFAS exposure through diet can be readily absorbed by the intestine and enter the circulatory system or accumulate directly at intestinal sites, which could interact with the intestine and cause the destruction of the intestinal barrier. This review summarizes current relationships between PFAS exposure and intestinal barrier damage with a focus on more recent studies.

Study Conclusion: PFAS can destroy the tight-junction structure of the intestinal tissues and alter mucin expression and mucus volume, increase intestinal permeability, and alter the number of immune cells. Exposure to PFAS can induce intestinal flora disorders and destabilize the stable intestinal environment. Although only limited studies were carried out, PFAS have exhibited adverse effects on the gut microbiome of infants and children, indicating potential risks of intestinal diseases for the general population. 

Associations of single and multiple perfluoroalkyl substances exposure with folate among adolescents in NHANES 2007-2010

Study Purpose: The accumulation of PFAS in the body has raised concerns about potential health impacts in children and young adults. However, no study has evaluated the associations of PFAS exposure with folate concentrations among adolescents.

Study Conclusion: In this study, they found that as exposure to PFOS and PFDA increased, folate concentrations decreased. These findings indicate that exposure to PFOS and PFDA may disrupt folate homeostasis.

Global DNA methylation mediates the association between serum perfluorooctane sulfonate and carotid intima-media thickness in young and middle-aged Taiwanese populations

Study Purpose: Recent studies have also identified a critical role for DNA methylation, a model of epigenetic regulation, in the development of CVD. Additionally, PFAS has been shown to affect DNA methylation. Our previous study reported the positive association between serum perfluorooctane sulfonate (PFOS) levels and mean carotid intima-media thickness (CIMT), a biomarker of arteriosclerosis, in a cohort composed of adolescent and young adult Taiwanese. However, the contribution of DNA methylation in the mechanism of PFOS-induced arteriosclerosis has never been explored in previous literature.

Study Conclusion: Our results showed that PFOS exposure has direct associations on arteriosclerosis and indirect direct associations on arteriosclerosis through DNA methylation. The results suggest that DNA methylation might regulate the relationship between PFOS and arteriosclerosis in the study subjects.

The Association of Per- and Polyfluoroalkyl Substances Serum Levels and Allostatic Load by Country of Birth and the Length of Time in the United States

Study Purpose: The aim of this study was to examine the association of PFAS concentrations and the burden of chronic stress, known as allostatic load, by the country of birth and length of time in the US. 

Study Conclusion: This study found that PFAS concentrations increased by the length of time residing in the U.S. Those born in other non-Hispanic counties had the highest PFAS levels among all the categories. In general, allostatic load and PFAS levels are mostly associated with the length of time in the U.S., with foreign-born individuals having increased levels of both the longer they stay.

Associations of serum perfluoroalkyl substances with concentrations of blood manganese and selenium

Study Purpose: This study aimed to estimate the associations of blood manganese and selenium with serum PFAS levels.  

Study Conclusion: Serum PFAS concentrations are associated with lower blood manganese in this population. Because PFAS are pro-oxidants causing increases in reactive oxygen species, and manganese is essential to human response to pro-oxidant stress, the negative association is potentially causal and concerning. 

Perfluoroalkyl acid and bisphenol-A exposure via food sources in four First Nation communities in Quebec, Canada

Study Purpose: The objective of this study was to document PFAS and BPA exposure in First Nations communities in Quebec compared to the general Canadian population to examine the associations between dietary consumption and chemical exposure. 

Study Conclusion: These results highlight the importance of better documenting food-processing and packaging methods, particularly for dairy products, and their contribution to endocrine disruptors exposures as well as to promote minimally processed and unpackaged foods to provide healthier food environments for youth in Indigenous communities and beyond.

Gestational Perfluoroalkyl Substance Exposure and DNA Methylation at Birth and 12 Years of Age: A Longitudinal Epigenome-Wide Association Study

Study Purpose: This study examines associations of gestational PFAS exposure with longitudinal DNA methylation measures at birth and in adolescence using the Health Outcomes and Measures of the Environment (HOME) Study.

Study Conclusion: In this study, PFAS was associated with differences in several DNA sites at birth and at 12 years of age in or near genes linked to some PFAS-associated health outcomes.

Perfluoroalkyl substances influence DNA methylation in school-age children highly exposed through drinking water contaminated from firefighting foam: a cohort study in Ronneby, Sweden

Study Purpose: A potential mechanism of toxicity for PFAS is through epigenetic changes, such as DNA methylation. No study has evaluated how PFAS influence DNA methylation among children of school age. In this study with school-age children exposed to PFAS-contaminated drinking water, they aimed to investigate whether exposure to PFAS was associated with alteration in DNA methylation and epigenetic age acceleration.

Study Conclusion: In conclusion, we found that PFAS exposure was associated with DNA methylation at specific genomic positions and regions in children at school age. Most DMPs and DMRs were hypermethylated in the high-exposure group compared to the control group.

Association of exposure to prenatal perfluoroalkyl substances and estrogen receptor 1 polymorphisms with the second to fourth digit ratio in school-aged children: The Hokkaido study

Study Purpose: This study investigated whether ESR1 polymorphisms modify the effects of prenatal PFAS exposure on 2D:4D. 

Study Conclusion: This study demonstrated that prenatal exposure to PFAS is associated with higher (feminized) 2D:4D, and that children with the AA genotype at rs9340799 or rs2077647 showed higher 2D:4D when exposed to PFOA or PFDoDA. These associations were apparent only among males. These findings suggest that prenatal exposure to PFAS affects 2D:4D and ESR1 polymorphisms modify the effects of prenatal exposure to PFAS on 2D:4D.

Association between maternal per- and polyfluoroalkyl substance exposure and newborn telomere length: Effect modification by birth seasons

Study Purpose: Telomere length is a marker of biological aging and disease that may be affected by prenatal exposure to environmental pollutants. This study explored the individual and combined effects of maternal PFAS exposure on newborn telomere length.

Study Conclusion: Maternal PFAS exposure showed little association with newborn telomere length. The results suggested that birth season may effect the association between PFOA exposure and newborn telomere length.

Cross-sectional associations between serum PFASs and inflammatory biomarkers in a population exposed to AFFF-contaminated drinking water

Study Purpose: The goal of this study is to estimate associations between serum PFAS and markers of inflammation among adults in a population exposed to aqueous film forming foam-contaminated drinking water.

Study Conclusion: This study observed preliminary evidence of altered inflammatory profiles among adults with elevated serum concentrations of PFAS due to contaminated drinking water. 

Mixed effects of perfluoroalkyl and polyfluoroalkyl substances exposure on cognitive function among people over 60 years old from NHANES

Study Purpose: Literature on the relationship between PFAS and cognitive function are inconsistent and the effects of PFAS on cognitive function are still unclear. We aimed to evaluate the effects of PFAS on cognitive function.

Study Conclusion: This study demonstrated that PFAS mixture at a low level of exposure might have a protective effect on cognitive function in the US general population. Additional cohort studies that measure the concentration of serum PFAS and cognitive function in the general population annually are needed to
confirm the relationship between PFAS exposure and cognitive function.

Perfluoroalkyl Substances and Abdominal Aortic Calcification

Study Purpose: The goal of this study is to evaluate if serum PFAS were associated with abdominal aortic calcification.

Study Conclusion: These findings do not provide support for a relationship of PFAS exposure to AAC, although the results show a need for gender-specific consideration in a larger dataset.

Assessment of exposure to perfluoroalkyl substances (PFASs) in dogs by fur analysis

Study Purpose: This study evaluates dog exposure to PFASs by analyzing fur samples.

Study Conclusion: PFOA and PFBuA had the highest concentrations in dog fur. The correlation between PFAS concentration and health of dogs must be studied further.

Use of glioma to assess the distribution patterns of perfluoroalkyl and polyfluoroalkyl substances in human brain

Study Purpose: This study conducted an assessment of PFAS in brain glioma tissues.

Study Conclusion: This study is the first to report PFAS in human brain glioma. These trends of PFAS in brain glioma were similar to those in health autopsy brain tissues and their concentrations increased with age.

Associations between polyfluoroalkyl substance and organophosphate flame retardant exposures and telomere length in a cohort of women firefighters and office workers in San Francisco

Study Purpose: Chemical exposures can affect telomere lengths, which has been associated with outcomes such as cancer. Firefighters are exposed to many hazardous chemicals and have higher rates of certain cancers. As a potential biomarker of effect, this study assesses associations between chemical exposures and telomere length in female firefighters and office workers in San Francisco.

Study Conclusion: Our findings suggest positive associations between PFAS and telomere length in women workers, with larger effects seen among firefighters compared to office workers. The OPFR metabolites BDCPP and BCEP are also associated with telomere length in firefighters and office workers. Associations between chemical exposures and telomere length reported here and by others suggest mechanisms by which these chemicals may affect carcinogenesis and other adverse health outcomes.

Understanding the Impact of Perfluorinated Compounds on Cardiovascular Diseases and Their Risk Factors: A Meta-Analysis Study

Study Purpose: Many studies have reported the association between PFAS exposure with the risk of developing cardiovascular diseases. However, these findings are still debated. Thus, this review analyzes the association of PFAS with CVDs and their risk factors in humans by systematic review and meta-analyses.

Study Conclusion: Although the risk of PFOA and PFOS were positively associated with cardiovascular disease and its risk factors, more observational studies shall be carried out to identify long-term effects of PFAS in cardiovascular disease development in patients.

Exposure, health effects, sensing, and remediation of the emerging PFAS contaminants – Scientific challenges and potential research directions

Study Purpose: In this discussion, researchers discuss challenges in studying PFAS.

Study Conclusion: Increasing awareness of the issues surrounding PFAS accumulation and exposure has led to widespread recognition that contamination from these chemicals is a major emerging environmental and health threat to communities across the country. Research into the effects of PFAS on the environment and human health and into determining best practices for detection and remediation are urgently needed to address the challenges of PFAS contamination. PFAS-related research is a fast-moving, dynamic, and cross-cutting area of study, and Connecticut and New York are two of the states that have established their own programs to investigate and prevent PFAS exposure. Our multi-disciplinary team, in conjunction with other regional efforts, is working to set the standard for future PFAS research and to encourage a broad range of scientific experts to bring research initiatives into play on a national scale.

Per-and polyfluoroalkyl substances (PFAS) in livestock and game species: A review

Study Purpose: This reviews information on PFASs in livestock and game as a source of dietary exposure in humans.

Study Conclusion: Due to limited information on the topic, the health effects of livestock consumption is still unknown.

Study protocol for a randomised controlled trial examining the effect of blood and plasma donation on serum perfluoroalkyl and polyfluoroalkyl substance (PFAS) levels in firefighters

Study Purpose: This is a randomised controlled trial of current and former Australian firefighters in the Metropolitan Fire Brigade/Fire Rescue Victoria, and contractors, with previous occupational exposure to PFAS and baseline elevated PFOS levels. The study is investigating whether whole blood donation every 12 weeks or plasma donation every 6 weeks will significantly reduce PFAS levels, compared with a control group.

Study Conclusion: This is a randomised controlled trial of current and former Australian firefighters in the Metropolitan Fire Brigade/Fire Rescue Victoria, and contractors, with previous occupational exposure to PFAS and baseline elevated PFOS levels. The study is investigating whether whole blood donation every 12 weeks or plasma donation every 6 weeks will significantly reduce PFAS levels, compared with a control group. We have used covariate-adaptive randomisation to balance participants’ sex and blood PFAS levels between the three groups and would consider a 25% reduction in serum PFOS and PFHxS levels to be potentially clinically significant after 12 months of whole blood or plasma donation. A secondary analysis of health biomarkers is being made of changes between screening and week 52 in all three groups.

Reverse osmosis and nanofiltration membranes for highly efficient PFASs removal: overview, challenges and future perspective

Study Purpose: This review provides outlook on advances in reverse osmosis and nanofiltration technologies for PFAS removal.

Study Conclusion: RO and NF membranes have started being used in water purification for PFAS removal, with promising results. However, they are not able yet to assure PFAS levels under the established guidance limits for drinking water. Problems still persist in fouling control, which hinders abilities for this to be applied at large scales.

Per-and polyfluoroalkyl substances (PFASs) in Swedish household dust and exposure of pet cats

Study Purpose: PFASs are in a wide range of products and have been found in indoor environments, and there is evidence that exposure to PFAS can have adverse effects. Pet cats have a high dust intake due to their grooming behavior and have been shown to be a suitable species for assessment of toddler's exposure. In this study, they used paired household dust and cat serum samples to establish whether dust is a relevant exposure pathway to PFASs.

Study Conclusion: This study found that dust could be an exposure pathway for the ingestion of some PFASs for cats, and the serum levels of PFASs could be of relevance for the cat's health.

PFAS soil and groundwater contamination via industrial airborne emission and land deposition in SW Vermont and Eastern New York State, USA

Study Purpose: This study aimed to understand the extent to which airborne PFAS emissions can impact soil and groundwater. This was conducted by sampling areas of conserved forest near Bennington, Vermont and Hoosick Falls, NY.

Study Conclusion: PFAS soil sampling revealed significant addition of PFOA in areas local to and downwind of factories that emitted PFAS to the atmosphere during baking of wet dispersions. The presence of elevated PFOA in groundwater seeps and springs within the green Mountain National Forest in the downwind region supports that air-emitted PFAS can cause groundwater contamination over large areas downwind of emission sites.

Household low pile carpet usage was associated with increased serum PFAS concentrations in 2005-2006

Study Purpose: This study aimed to examine the associations between serum pfas concentrations and the type of flooring among the general US population aged 12 years and older.

Study Conclusion: These results are representative of the general US population at the time of the survey, and show that type of flooring may affect PFAS exposure. This study found that low pile carpeting was associated with increased serum concentrations of PFHxS and MeFOSAA.

Per-and polyfluoroalkyl substances in serum and associations with food consumption and use of personal care products in the Norwegian biomonitoring study from the EU project EuroMix

Study Purpose: This study, conducted in Norway, examined the PFAS concentrations and associations with diet and use of personal care products.

Study Conclusion: The participants of the study were exposed to PFASs through their diet and personal care product use. Several PFASs were found to be associated with fish consumption. Sunscreen, mouthwash, and lip gloss/lip balm were found to be associated with some PFASs.

Health and social concerns about living in three communities affected by per- and polyfluoroalkyl substances (PFAS): A qualitative study in Australia

Study Purpose: In Australia, concentrations of PFASs have been found in environments close to sites where firefighting foams were historically used for firefighting. This has resulted in significant community concern about the potential long-term health effects of these chemicals. This study describes residents' perceptions and experiences of PFAS in three Australian towns where exposure has occurred.

Study Conclusion: 180 residents attended 15 focus groups in the three communities. They included 69 First Nations People. Study participants were concerned about potential physical health effects of exposure to PFAS, such as cancer clusters, unexplained deaths, potential exacerbation of existing health conditions, and the future health of their children. They expressed feelings of stress and anxiety about living with uncertainty related to the possible health and the socio-economic impacts of PFAS contamination in their communities. While research has concentrated on the physical health effects of PFAS, more attention needs to be given to the immediate psychosocial impacts of living in an affected community.

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PFAS are a group of chemicals used to make coatings and products that can resist heat, water, oil, grease, and stains. These coatings can be found in many products, such as clothing, furniture, adhesives, food packaging, non-stick cooking surfaces, and electrical wire insulation. Many PFAS, including PFOS and PFOA, are a concern because they do not break down in the environment, they can contaminate drinking water, and they can buildup in fish and wildlife.

PFAS have been found in bodies of water and in many types of animals, both aquatic and on land.

PFAS exposure can occur by consuming PFAS-contaminated water or food. Use of products containing PFAS may also lead to exposure. Common items with PFAS can include:

• Food packaging: microwave popcorn, fast food wrappers, takeout containers
• Household items: makeup, floss, waxes, paints, stains
• Stain-resistant products: carpets, rugs, and furniture
• Non-stick cookware, such as Teflon pans
• Outdoor gear or clothing with water repellent coatings
• Firefighting foams

Human health effects from exposure to low levels of PFAS are uncertain. Studies in animals exposed to higher levels of PFAS indicate that some PFAS may affect growth and development, reproduction, thyroid function, immunity, and liver function. Studies on the effects of PFAS exposure can also be found under the Research tab. More research is necessary, however, to further assess the human health effects of exposure to varying levels of PFAS.

Other great resources offering information on PFAS include:

• Centers for Disease and Control Prevention Per- and Polyfluorinated Substances (PFAS) Factsheet
• New York DEC Per- and Polyfluorinated Substances (PFAS)
• Agency for Toxic Substances and Disease Registry Per- and Polyfluorinated Substances (PFAS) Frequently Asked Questions

GenX is a chemical substitute for PFOA. Studies are being conducted and released on this chemical. More information can be found here.

PFAS Policy Dashboard

Please visit the National Academies website for more information.

The purpose of this study is to learn more about PFAS levels and health effects in study participants from across the United States. Participants will be asked to complete a health clinic visit that includes health evaluations along with blood testing to explore if PFAS could be related to health outcomes. Data collected will be combined with those from other participants in California, Colorado, Massachusetts, Michigan, New Jersey, and Pennsylvania to create a larger study population. Other NYS Department of Health blood testing programs in the Newburgh and Hoosick Falls Area have focused on measuring PFAS levels in participants related to drinking water with PFOA or PFOS contamination.

The Hoosick Falls Medical Monitoring Program is being conducted as part of the Hoosick Falls Settlement. Please visit the Hoosick Falls PFOA Settlement website for more information.

The NYSDOH Biomonitoring program measured how much PFAS you have been exposed to and compared PFAS blood levels in the village of Hoosick Falls and Hoosick area, and the City of Newburgh and to levels in the general population. If you would like to request a copy of your previous test results, please call NYSDOH at 518-402-7950.

The CDC and ATSDR are assessing the PFAS exposure in communities near current or former military installations. The exposure assessment will compare PFAS levels in blood and urine from the City of Newburgh to levels in the general population. The CDC and ATSDR will also identify and assess environmental factors that affect exposure. If you have any questions or concerns on the exposure assessment, contact Luis Rivera-Gonzalez, PHD, MS, ATSDR Division of Community Health Investigations Eastern Branch by phone at 732-906-6933 or email at [email protected].

The National Firefighter Registry (NFR) will be a large database of health and occupational information on firefighters that can be used to analyze and track cancer and identify occupational risk factors for cancer. While the enrollment system and questionnaire are still being developed, there is a plan to collect information about firefighters’ use of Aqueous Film Forming Foam (AFFF).

You can subscribe to the NFR Quarterly e-Newsletter to receive a free electronic newsletter with updates about the NFR.

Related Links

• NFR printable brochure
• NIOSH PFAS information page
• NIOSH firefighter information portal

Michigan’s MPART has a resource for identifying AFFF-containing PFAS.

The Fire Fighter Cancer Cohort Study specifically includes a component studying firefighters’ PFAS exposure. It is currently being conducted with fire service partners in Tucson, Amado, and Sahuarita, Arizona; Boston, Massachusetts; Palm Beach County, Florida; and Toms River, New Jersey.