PFAS: Published Research Articles

This page will be updated monthly. All of the articles listed have been published between 2015 and now and are peer reviewed. Older articles are available upon request. If you have any questions, please contact us by phone at 1-833-732-7697, by text at 518-898-0276, or by email at [email protected]

Esta página se actualizará mensualmente. Todos los artículos enumerados se han publicado entre 2015 y ahora. Los artículos más antiguos están disponibles bajo petición. Si tienes algunas preguntas, póngase en contacto con nosotros.Por favor contáctenos por teléfono a 1-833-732-7697, mensaje de texto a 518-898-0276, o por correo electrónico a [email protected]

Paj sa a pral mete ajou chak mwa. Tout atik ki nan lis yo te pibliye ant 2015 e kounye a. Pi gran atik yo disponib sou demann. Si ou gen nenpòt kesyon, tanpri kontakte nou. Tanpri Kontakte nou sou Telefòn a 1-833-732, pa tèks a 518-898-0276, oubyen pa imèl a [email protected]


Dr. Katie Pelch and her team created a PFAS-TOX database that contains articles on PFAS and potential health outcomes that may be observed in humans, animals, or in-vitro. To maintain consistency between the PFAS-TOX database created by Dr. Pelch and our literature review webpage we have used their health outcome categories to organize our literature review webpage. If you have questions or want to discuss an article, please let us know and we will be happy to speak with you. We are able to set up a call in either Spanish or Haitian Creole. We can be reached by phone at 1-833-732-7697, by text at 518-898-0276, or by email at [email protected].

Infant and Childhood Health
Reproductive System

Reproduction includes effects on the reproductive system, reproductive function, pregnancy, and birth outcomes. Menstruation and puberty information can be found in the Hormones section. This section currently has 59 total papers: 53 from the last 5 years. Some studies include other endocrine-disrupting chemicals (EDCs) to measure outcomes following exposure to multiple toxicants. Although a study may find, or not find, an association between PFASs and other EDCs and reproductive outcomes, this does not mean it is, or is not, definitively a causative agent. Findings in studies are not necessarily generalizable among all sexes, ethnicities/races, smokers/non-smokers, and geographic areas; this should be considered when interpreting these results. Differences in findings between studies could be due to the population studied (demographics, geography, diet, etc.), size of the studies, differences in PFAS concentrations between studies, when samples were taken, or other factors.


 

Birthweight, birth size, and birth outcomes

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.

 

Preeclampsia and hypertensive disorders of pregnancy

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 disroders 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.

 

Fertility and treatment

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.

 

Women’s Health

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.

 

Placenta

A Critical Review on Transplacental Transfer of Per- and Polyfluoroalkyl Substances: Prenatal Exposure Levels, Characteristics, and Mechanisms
Study Purpose: This article provides an overview on levels and characteristics of prenatal exposure to PFASs throughout the world, summarizes relationships between structures of PFAS and placental transfer, and discusses possible mechanisms for placental transfer.
Study Conclusion: The transplacental transfer mechanism of PFAS is still inconclusive.

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. 

 

Other

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.

Breastfeeding

Breastfeeding covers PFAS and levels in human milk, breastfeeding duration, levels in dairy milk and formula, and trends over time. This section currently 32 total papers; 20 from the last 5 years. Although a study may find, or not find, an association between PFASs and breastfeeding outcomes, this does not mean it is, or is not, definitively a causative agent. Findings in studies are not necessarily generalizable among all ethnicities/races, smokers/non-smokers, and geographic areas; this should be considered when interpreting these results. Differences in findings between studies could be due to the population studied (demographics, geography, diet, etc.), size of the studies, differences in PFAS concentrations between studies, when samples were taken, or other factors.


 

Concentrations of perfluoroalkyl substances in donor breast milk in Southern Spain and their potential determinants
Study Purpose: This study assesses the concentrations of PFAS in breast milk from donors to a human milk bank and explore factors potentially related to this exposure.
Study Conclusion: Several PFAS, including short-chain compounds, are detected in pooled donor milk samples. Breast milk may be an important pathway for the PFAS exposure of breastfed infants, including preterm infants in NICUs. Despite the reduced sample size, these data suggest that various lifestyle factors influence PFAS concentrations, highlighting the use of PCPs.

Per- and Polyfluoroalkyl Substances (PFAS) in Breast Milk: Concerning Trends for Current-Use PFAS
Study Purpose: This study reviewed current levels of various PFAS in U.S. mothers' breastmilk.
Study Conclusion: Our results indicate that while the legacy PFOS and PFOA are still the most abundant PFAS in breast milk, similar to the studies from the early 2000s, the detection frequencies and concentrations of several current-use short chain PFAS have significantly increased since then.

Exposure to perfluoroalkyl substances through human milk in preterm infants
Study Purpose: This study aimed to quantify the potential exposure of preterm infants to PFASs through breast milk.
Study Conclusion: The exposure of preterm infants to PFASs through breast feeding might exceed values reported for older, healthier infants.

Regional occurrence of perfluoroalkane substances in human milk for the global monitoring plan under the Stockholm Convention on Persistent Organic Pollutants during 2016-2019
Study Purpose: The human milk monitoring component of the global monitoring plan under the Stockholm Convention on Persistent Organic Pollutants was implemented from 2016-2019 and had 44 human milk samples from 42 countries collected and analyzed for PFASs.
Study Conclusion: Statistical analysis showed that PFOS and PFOA levels in breast milk were significantly different between European countries and African and Latin American countries, as well as between high-income and low-income countries. PFOA tended to have higher concentrations in wealthier countries. No correlation was found for population density.

Endocrine-disrupting chemicals and breastfeeding duration: a review
Study Purpose: This study describes current literature investigating how chemicals such as PFAS affect mammary gland development and function, thereby impacting lactation duration.
Study Conclusion: Certain chemicals may play a role in mammary gland development, function, and lactation, which can affect breastfeeding duration. PFSAs may reduce breastfeeding duration through impaired mammary gland development.

Determination and assessment of human dietary intake of per and polyfluoroalkyl substances in retail dairy milk and infant formula from South Africa
Study Purpose: This study measured PFAS levels in dairy milk and infant formula to start quantifying how much exposure people receive through these products.
Study Conclusion: This study presents the first data on the occurrence and human dietary intake of PFAS in dairy milk and infant formulas on the African continent. The data showed that long chain perfluorocarboxylic acids are ubiquitous in South African dairy milk and infant formula. Compared to long chain (C9 – C14) PFAS, the concentrations of PFOA and PFOS were generally low.

Biomonitoring of PFOA, PFOS and PFNA in human milk from Czech Republic, time trends and estimation of infant's daily intake
Study Purpose: This is a longitudinal observation of three PFAS in human breast milk. It provides helpful information about these levels over time.
Study Conclusion: Significant time-related decreasing trends in the PFOS and PFOA levels in human milk were observed. Nevertheless, the body burden of infants from breastfeeding might pose an enhanced health risk to infants when the current PTWI values are applied. These findings strongly support the present EU efforts to phase out PFOA, it's salts and PFOA related compounds. Since PFOS exposure there has still been widely detected despite PFOS usage reduction measures, the major exposure routes should be further monitored and, if possible, eliminated.

Emerging per- and polyfluoroalkyl substances (PFAS) in human milk from Sweden and China
Study Purpose: To determine the level of PFAS in breast milk.
Study Conclusion: China saw higher levels of PFASs in breast milk samples than Swedish samples.

Early Life Exposure to Perfluoroalkyl Substances (PFAS) and ADHD: A Meta-Analysis of Nine European Population-Based Studies
Study Purpose: To see if infants exposed to PFOS or PFOA have a higher rate (prevalence) of ADHD diagnosis.
Study Conclusion: The study did not observe a significant increase in the prevalence of ADHD diagnosis in association with early life exposure to PFOS and PFOA, in a sample of almost 5,000 children from nine European population based studies.

Concentrations of perfluoroalkyl substances in human milk from Ireland: Implications for adult and nursing infant exposure
Study Purpose: This study attempted to better quantify PFAS levels in breast milk.
Study Conclusion: Concentrations in human milk in Ireland fall within the range of those reported previously for other countries, and exposure to PFASs of Irish nursing infants via consumption of human milk does not appear to constitute a health concern.

A transgenerational toxicokinetic model and its use in derivation of Minnesota PFOA water guidance
Study Purpose: This study attempts to create a model to guide water recommendations.
Study Conclusion: This study observed breastfed infant serum levels at 4.4-fold higher than in formula-fed infants, with both of these scenarios producing serum levels in excess of the adult steady-state level.

Poly- and perfluoroalkyl substance concentrations in human breast milk and their associations with postnatal infant growth
Study Purpose: This study examined the concentrations of PFASs in breast milk from 174 women and investigated the association between lactation exposure to these PFASs through breast milk consumption and the postnatal growth of infants.
Study Conclusion: This study demonstrated that lactation exposure to C8-C10 PFCAs, 8:2 FTOH, and 6:2 Cl-PFESA through breast milk consumption may affect postnatal infant growth.

Per- and polyfluoroalkyl substances in human breast milk and current analytical methods
Study Purpose: To review current information on PFAS in human breast milk, including the challenges of analysis and the possible modes of transfer from maternal blood.
Study Conclusion: Data suggests a global decline in PFAS levels in breast milk.

The serum concentrations of perfluoroalkyl compounds were inversely associated with growth parameters in 2-year old children
Study Purpose: This study investigates the relationship between the serum levels of PFASs and growth in 2-year-old children.
Study Conclusion: In conclusion, the serum concentrations of PFCs were inversely associated with growth parameters in 2-year-old children.

Perfluoroalkyl Acids (PFAAs) in Serum from 2-4-Month-Old Infants: Influence of Maternal Serum Concentration, Gestational Age, Breast-Feeding, and Contaminated Drinking Water
Study Purpose: This study investigates associations between PFAS levels in 2-4 month-old infants and factors that may contribute to these levels.
Study Conclusion: PFOA, PFNA, and PFHxS infant levels increased with exclusive breastfeeding in this study. Infants living in areas with PFAS-contaminated drinking water had higher PFBS and PFHxS levels. Prenatal and postnatal PFAS exposure appear to contribute to infant PFAS levels.

Perfluoroalkyl substances (PFASs) in breast milk from Korea: Time-course trends, influencing factors, and infant exposure
Study Purpose: In this study, PFASs were analyzed in breast milk samples collected during various lactation periods to determine maternal exposure levels, variations over time, and infant health risks.
Study Conclusion: PFOS, PFOA, PFUnDA, and PFNA were the predominant compounds found in these breast milk samples. The concentrations of PFASs in breast milk were correlated with maternal age, BMI, and the mother's number of children. Dietary behaviors, such as snack and milk consumption and the frequency of eating out, were associated with increased levels of PFASs. The daily intakes of PFOS and PFOA for infants through breast milk consumption were lower than the recommended threshold.

Perfluoroalkyl substances in Breast milk, infant formula and baby food from Valencian Community (Spain)
Study Purpose: This study reports levels of PFASs in breast milk, infant formulas, and baby food from a Spanish community in order to evaluate the infant exposure to these substances through the diet.
Study Conclusion: This study found PFBA in 100% of the samples of breast milk and other baby foods. The dietary intake of PFOS and PFOA varies significantly depending on the infant diet.

Exposure of Norwegian toddlers to perfluoroalkyl substances (PFAS): The association with breastfeeding and maternal PFAS concentrations
Study Purpose: To examine the PFAS blood levels in toddlers and to determine their relationship with maternal PFAS concentrations in pregnancy and breastfeeding duration.
Study Conclusion: These results suggests that transplacental transfer and breastfeeding are among the main determinants of PFOS, PFOA, PFHxS, and PFHpS levels in toddlers, while that was not the case for PFNA and PFUnDA.

Shorter duration of breastfeeding at elevated exposures to perfluoroalkyl substances
Study Purpose: To determine whether maternal exposure to PFASs affects the ability to breastfeed.
Study Conclusion: Increased maternal levels of PFAS are associated with a decreased duration of breastfeeding in this study.

Maternal serum perfluoroalkyl substances during pregnancy and duration of breastfeeding
Study Purpose: This study looks at the association between maternal PFAS exposure and breastfeeding duration.
Study Conclusion: Higher PFOA concentrations in mothers were related to shorter breastfeeding duration in this study.

Elevated levels of short carbon-chain PFCAs in breast milk among Korean women: Current status and potential challenges
Study Purpose: In this study, breast milks were sampled from lactating women and measured for PFASs.
Study Conclusion: Several short chain PFASs were detected at high levels. Their levels of detection were often comparable to levels of PFOS. For PFHpA, the use of cosmetics and non-stick frying pans were identified as significant sources of exposure among lactating women.

Nervous System and Behavior

Neurodevelopment covers mainly outcomes in children, including cognitive abilities, cognitive development, ADHD, neurologic disease, autism, IQ, reading skills, and behavior. This section currently has 28 total studies: 20 from the last 5 years. Although a study may find, or not find, an association between PFASs and neurodevelopmental outcomes, this does not mean it is, or is not, definitively a causative agent. Findings in studies are not necessarily generalizable among all sexes, ethnicities/races, smokers/non-smokers, and geographic areas; this should be considered when interpreting these results. Differences in findings between studies could be due to the population studied (demographics, geography, diet, etc.), size of the studies, differences in PFAS concentrations between studies, when samples were taken, or other factors.


 

ADHD

Early Life Exposure to Perfluoroalkyl Substances (PFAS) and ADHD: A Meta-Analysis of Nine European Population-Based Studies
Study Purpose: This study investigates the association between early life exposure to perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), and ADHD in a collaborative study including nine European population-based studies, encompassing 4,826 mother–child pairs.
Study Conclusion: There may be increased prevalence of ADHD in association with PFAS exposure in girls, in children from women who have had multiple children, and in children from low-educated mothers.

Prenatal exposure to perfluoroalkyl substances and associations with symptoms of attention-deficit/hyperactivity disorder and cognitive functions in preschool children
Study Purpose: This study looks at the associations between prenatal exposure to PFASs and symptoms of ADHD and cognitive functioning (language skills, estimated IQ, and working memory) in preschool children, and whether this association varies by sex.
Study Conclusion: The study did not find consistent evidence to conclude that prenatal exposure to PFASs are associated with ADHD symptoms or cognitive dysfunctions in preschool children aged three and a half years. The results showed some associations between PFASs and working memory, particularly negative relationships with nonverbal working memory, but also positive relationships with verbal working memory. The relationships were weak, as well as both positive and negative, which suggest no clear association.

Early-life exposure to persistent organic pollutants (OCPs, PBDEs, PCBs, PFASs) and attention-deficit/hyperactivity disorder: A multi-pollutant analysis of a Norwegian birth cohort
Study Purpose: This study investigates if early-life exposure to persistent organic pollutants is associated with an increase risk of attention-deficit/hyperactivity disorder (ADHD).
Study Conclusion: Early-life exposure to B-HCH and PFOS was associated with increased risk of ADHD, with suggestion of sex-specific effects for PFOS. The unexpected inverse associations between per- and perfluoroalkyl DDT and higher HCB levels and ADHD could be due to live birth bias.

Perfluoroalkyl substances in cord blood and attention deficit/hyperactivity disorder symptoms in seven-year-old children
Study Purpose: This study looks at the association between in utero exposure to PFASs and the development of neurobehavioral symptoms (such as ADHD) in early childhood.
Study Conclusion: Prenatal exposure to PFNA was associated with neurobehavioral symptoms related to ADHD among Asian seven-year-old children.

 

Behavior

Prenatal exposure to poly- and perfluoroalkyl substances (PFAS) and neurobehavior in US children through 8 years of age: the HOME Study
Study Purpose: Studies of PFAS and ADHD in children are inconsistent. This study examines associations between maternal serum PFAS concentrations and child behavior in mothers and their children.
Study Conclusion: Prenatal PFOS and PFNA were associated with hyperactive-impulsive type ADHD across two tests. PFHxS was associated with increased problems with both externalizing and internalizing behaviors. No associations were noted between PFOA and child neurobehavior.

Behavioral difficulties in 7-year-old children in relation to developmental exposure to perfluorinated alkyl substances
Study Purpose: This study looks at the associations between prenatal, 5 and 7-year-old PFAS exposures and behavioral problems in 7-year-olds.
Study Conclusion: Higher serum PFAS concentrations at ages 5- and 7-years were associated with parent-reported behavioral problems at age 7. No associations were observed between prenatal PFAS concentrations and SDQ scores.

Prenatal Exposure to Perfluoroalkyl Substances and Behavioral Development in Children
Study Purpose: This study explored the relationship between prenatal exposure to several PFASs and behavioral development at the age of 18 months.
Study Conclusion: These findings suggest that higher prenatal exposure to PFOA was related to less externalizing behavior in boys. Results were different for boys and girls. However, more research is needed as this was a small study population.

 

Autism

Prenatal exposure to per- and polyfluoroalkyl substances in association with autism spectrum disorder in the MARBLES study
Study Purpose: Prenatal exposure to PFASs has shown to potentially impact child brain development, but evidence is still inconsistent. This study looks at whether prenatal exposure to PFAS was associated with increased risk of autism.
Study Conclusion: In this high risk autism group, there was an increased risk of autism in children exposed to PFOA and PFNA.

Modeled prenatal exposure to per- and polyfluoroalkyl substances in association with child autism spectrum disorder: A case-control study
Study Purpose: This study looks at the associations between prenatal maternal exposure to PFAS with child diagnosis of autism.
Study Conclusion: In analyses where modeled prenatal maternal PFAS serum concentrations served as in utero exposure, it was observed that prenatal PFHxS and PFOS exposure were borderline associated with increased odds of child diagnosis of ASD. No associations were observed for other PFAS.

 

Other

Prenatal perfluoroalkyl substance exposure and neuropsychological development throughout childhood: The INMA Project
Study Purpose: This study evaluates the associations between prenatal PFAS exposure and neuropsychological development in childhood.
Study Conclusion: This study showed no clear-cut evidence of an association between prenatal PFAS exposure and adverse neuropsychological development in children up to the age of 7 years.

Exposure to Perfluoroalkyl Substances During Pregnancy and Fetal BDNF Level: A Prospective Cohort Study
Study Purpose: Brain-derived neurotrophic factor (BDNF) is an important factor in neurodevelopment, but its role in PFAS-induced neurotoxicity is unclear. This study investigates the association between prenatal PFAS exposure and fetal BDNF level in the umbilical cord blood.
Study Conclusion: Prenatal exposure to PFHxS was associated with an increased BDNF level in the umbilical blood, especially in male fetuses.

Chemical Mixture Exposures During Pregnancy and Cognitive Abilities in School-Aged Children
Study Purpose: Gestational exposure to chemical mixtures, which is prevalent among pregnant women, may be associated with adverse childhood neurodevelopment. However, few studies have examined relations between gestational chemical mixture exposure and children's cognitive abilities.
Study Conclusion: In this study, combined prenatal exposure to phenols, some phthalates, pesticides, and PFASs were inversely associated with children's cognition

Prenatal exposure to per- and polyfluoroalkyl substances and cognitive development in infancy and toddlerhood
Study Purpose: PFAS have shown neurobehavioral toxicity in experimental studies. Evidence on associations between prenatal PFAS exposure and child's cognitive development is inconsistent partly due to differences in assessment time points and tools used. This study examines associations of prenatal maternal serum PFAS concentrations with child's cognitive development assessed at multiple time points in infancy and toddlerhood.
Study Conclusion: Prenatal PFOA appears to negatively affect child's cognitive development in toddlerhood in this study population. Because a large number of the children in this study were at risk for atypical development, studies in the general population are needed to confirm findings.

Perfluoroalkyl chemicals in neurological health and disease: Human concerns and animal models
Study Purpose: This study summarized previous literature on PFAS impacts on neurobiological, neuroendocrine, and neurobehavioral outcomes.
Study Conclusion: This study found that there are many mechanisms through which PFASs may enter the brain and interact to impact neurological function.

The association between prenatal exposure to perfluoroalkyl substances and childhood neurodevelopment
Study Purpose: This study looks at the association between prenatal PFAS exposure and child cognitive outcomes at 5 different points in time. The population in this study was prenatally exposed to the World Trade Center disaster, where many pollutants including PFASs were released.
Study Conclusion: These results suggest a sex- and PFAS-specific between relationship between prenatal PFAS exposures and child neurodevelopment.

Childhood perfluoroalkyl substance exposure and executive function in children at 8 years
Study Purpose: This study tests whether prenatal and childhood exposure to PFAS are associated with cognitive abilities at 8 years old and whether this varies between boys and girls.
Study Conclusion: PFNA and PFOA at 8 years, but not 3 years, may be related to poorer executive function.        

Prenatal Exposure to Perfluoroalkyl Substances and IQ Scores at Age 5: A Study in the Danish National Birth Cohort
Study Purpose: This study looks at whether prenatal exposure to PFASs is associated with IQ in children.
Study Conclusion: Overall, there was no consistent evidence to suggest PFAS exposure is associated with child IQ scores at 5 years of age.

Prenatal and childhood exposure to per- and polyfluoroalkyl substances (PFASs) and child cognition
Study Purpose: Per- and polyfluoroalkyl substances (PFASs) are suspected developmental toxicants, but epidemiological evidence on neurodevelopmental effects of PFAS exposure is inconsistent.       
Study Conclusion: Suggested associations of prenatal and childhood PFAS exposure with lower childhood visual motor abilities. Other results were inconsistent, with higher prenatal PFASs associated in some cases with better cognitive outcomes.

Prenatal and childhood perfluoroalkyl substances exposures and children’s reading skills at ages 5 and 8 years
Study Purpose: This study looks at the association between prenatal and early childhood levels of PFAS with children's reading skills at ages 5 and 8 years old.
Study Conclusion: Prenatal and childhood serum PFOA, PFOS and PFNA concentrations were positively associated with better children’s reading skills at ages 5 and 8 years. No association was found between serum PFHxS and reading skills.

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.

Kidney and Liver Function
Urinary System

Kidneys work with other components of the urinary system to filter toxins and waste from the blood and eliminate them from the body. The Kidney section includes information on kidney function, hyperuricemia, gout, and chronic kidney disease as they relate to PFASs. It includes 12 total studies; 7 were published in the last 5 years. Although a study may find, or not find, an association between PFASs and kidney outcomes, this does not mean it is, or is not, definitively a causative agent. Findings in studies are not necessarily generalizable among all sexes, ethnicities/races, smokers/non-smokers, and geographic areas; this should be considered when interpreting these results. Differences in findings between studies could be due to the population studied (demographics, geography, diet, etc.), size of the studies, differences in PFAS concentrations between studies, when samples were taken, or other factors.


Per- and polyfluoroalkyl substances and kidney function: Follow-up results from the Diabetes Prevention Program trial
Study Purpose: To determine associations of plasma PFAS concentrations and glomerular filtration rate (GFR - a measure of kidney function) and evaluate whether a lifestyle intervention changes these associations.
Study Conclusion: Among adults with prediabetes, higher concentrations of PFASs were associated with lower GFR over approximately 14 years. A lifestyle intervention of diet and exercise did not modify this association. Individuals with hypertension may experience a more detrimental effect.

Impact of kidney hyperfiltration on concentrations of selected perfluoroalkyl acids among US adults for various disease groups
Study Purpose: National data from 2003-2016 for US adults were analyze to evaluate the impact of kidney hyperfiltration on the levels of PFASs.
Study Conclusion: This study observed that participants with hypertension had the highest PFAS levels, regardless the filtration rate of their kidneys. Those with anemia had the lowest PFAS levels.

Perfluoroalkyl acids, hyperuricemia and gout in adults: Analyses of NHANES 2009-2014
Study Purpose: This study investigates whether there is an association between levels of PFASs and gout, uric acid levels, or hyperuricemia.
Study Conclusion: There was an association between select PFAS and self-reported gout. There was also an association between several PFAS and hyperuricemia.

Dynamics of associations between perfluoroalkyl substances and uric acid across the various stages of glomerular function
Study Purpose: Hyperuricemia (elevated uric acid levels) is associated with increased risk of high blood pressure, metabolic syndrome, and future cardiovascular disease. This study looks at the associations between PFAs and uric acid levels across various levels of kidney function.
Study Conclusion: Increasing levels of every measured PFAS except PFHxS was found to increase levels of uric acid.

Perfluoroalkyl substances and kidney function in chronic kidney disease, anemia, and diabetes
Study Purpose: This study looks at the relationship between PFAS and kidney function and how this relationship varies with diabetes and anemia status.
Study Conclusion: PFAS were inversely associated with kidney function in chronic kidney disease patients and diabetics (increased PFAS levels had better kidney function)

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.

Positive associations of serum perfluoroalkyl substances with uric acid and hyperuricemia in children from Taiwan
Study Purpose: Hyperuricemia (elevated uric acid levels) is associated with increased risk of high blood pressure, metabolic syndrome, and future cardiovascular disease. This study looks at the risk of hyperuricemia after exposure to PFASs
Study Conclusion: PFOA was found to be associated with elevated levels of uric acid in children, especially boys.

Liver

The Liver section includes information on liver disease in adults and children, non-alcoholic fatty liver disease, and liver function as they relate to PFASs. It includes 9 total studies; 8 studies were published in the last 5 years. Although a study may find, or not find, an association between PFASs and liver outcomes, this does not mean it is, or is not, definitively a causative agent. Findings in studies are not necessarily generalizable among all sexes, ethnicities/races, smokers/non-smokers, and geographic areas; this should be considered when interpreting these results. Differences in findings between studies could be due to the population studied (demographics, geography, diet, etc.), size of the studies, differences in PFAS concentrations between studies, when samples were taken, or other factors.


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.

Metabolic and Digestive System
Hypertension

The Hypertension section includes information on blood pressure/hypertension as it relates to PFASs. This section has 8 total studies; 7 are published within the last 5 years. Although a study may find, or not find, an association between PFASs and hypertension outcomes, this does not mean it is, or is not, definitively a causative agent. Findings in studies are not necessarily generalizable among all sexes, ethnicities/races, smokers/non-smokers, and geographic areas; this should be considered when interpreting these results. Differences in findings between studies could be due to the population studied (demographics, geography, diet, etc.), size of the studies, differences in PFAS concentrations between studies, when samples were taken, or other factors.


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.

Lipids/Obesity

The Lipids and Obesity section includes information on metabolic syndrome, lipids (total cholesterol, triglycerides, HDL, LDL), dyslipidemia, lipoprotein and apolipoprotein, and obesity (including BMI, bariatric surgery, and weight loss) as they relate to PFASs. Lipoprotein and apolipoprotein carry lipids through the body. This section includes 51 total studies; 41 were published in the last 5 years. Although a study may find, or not find, an association between PFASs and lipid/obesity outcomes, this does not mean it is, or is not, definitively a causative agent. Findings in studies are not necessarily generalizable among all sexes, ethnicities/races, smokers/non-smokers, and geographic areas; this should be considered when interpreting these results. Differences in findings between studies could be due to the population studied (demographics, geography, diet, etc.), size of the studies, differences in PFAS concentrations between studies, when samples were taken, or other factors.


 

Obesity, body fat, and weight loss

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.

 

Lipids: cholesterol and triglycerides

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 concenern 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.

 

Metabolic syndrome

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.

 

Other

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.

Diabetes

The Diabetes section includes information on prediabetes, type 2 diabetes, type 1 diabetes, gestational diabetes, and glucose homeostasis/insulin sensitivity as they relate to PFASs. It includes 30 total studies; 27 are published within the last 5 years. Although a study may find, or not find, an association between PFASs and diabetes outcomes, this does not mean it is, or is not, definitively a causative agent. Findings in studies are not necessarily generalizable among all sexes, ethnicities/races, smokers/non-smokers, and geographic areas; this should be considered when interpreting these results. Differences in findings between studies could be due to the population studied (demographics, geography, diet, etc.), size of the studies, differences in PFAS concentrations between studies, when samples were taken, or other factors.


 

Type 1 diabetes

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.

 

Type 2 diabetes

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.

 

Gestational diabetes

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.

 

Other

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.

Cancers
Breast Cancer

Cancer occurs when cells grow uncontrollably and can affect many parts of the body. Cancer includes information on cancers of the kidney, testes, thyroid, breast, and liver as they relate to PFASs. Most studies on cancer and PFASs have focused on breast cancer. Many other cancers need to be studied. As cancer papers are published, they will be updated here. This section has 12 total studies; 10 were published in the last 5 years. Although a study may find, or not find, an association between PFASs and cancer outcomes, this does not mean it is, or is not, definitively a causative agent. Findings in studies are not necessarily generalizable among all sexes, ethnicities/races, smokers/non-smokers, and geographic areas; this should be considered when interpreting these results. Differences in findings between studies could be due to the population studied (demographics, geography, diet, etc.), size of the studies, differences in PFAS concentrations between studies, when samples were taken, or other factors.


Endocrine disrupting chemicals and breast cancer: a systematic review of epidemiological studies
Study Purpose: This study reviews literature about associations between endocrine disrupting chemicals and breast cancer.
Study Conclusion: This study identified exposures that could elevate the risk of breast cancer. Because EDCs are persistent in the environment and accumulate in the body, more research is needed on long-term impacts. Additionally, since food is often a route of exposure to EDCs, more research is needed on food and food packaging and links to breast cancer development.

A cross-sectional study of the association between perfluorinated chemical exposure and cancers related to deregulation of estrogen receptors
Study Purpose: This study examines the association between PFAS and estrogen related cancers (breast, prostate, ovarian, and uterine) and explored if non-occupational exposure was associated with increased odds of developing these cancers.
Study Conclusion: PFASs were associated with increased odds of ovarian and breast cancers. PFOA was more correlated with breast cancer and PFHS more with ovarian cancer.

A case-control study of perfluoroalkyl substances and the risk of breast cancer in Taiwanese women
Study Purpose: Breast cancer is a common cancer worldwide; however, the incidence of breast cancer is increasing in younger women. This study investigates whether PFAS and breast cancer are associated.
Study Conclusion: This study found that PFAS were associated with the breast cancer risk of estrogen receptor positive tumors in young Taiwanese women.

In utero exposure to poly- and perfluoroalkyl substances (PFASs) and subsequent breast cancer
Study Purpose: This study looks at levels of PFASs and risk of breast cancer.
Study Conclusion: High EtFOSAA and high maternal cholesterol increased risk of breast cancer. Maternal PFOS levels were associated with decreased daughters' breast cancer risk.

Breast cancer risk and serum levels of per- and poly-fluoroalkyl substances: a case-control study nested in the California Teachers Study
Study Purpose: This study looks at the risk of breast cancer associated with exposure to PFASs.
Study Conclusion: These results do not suggest that PFAS levels are related to breast cancer risk.

Polymorphism in xenobiotic and estrogen metabolizing genes, exposure to perfluorinated compounds and subsequent breast cancer risk: A nested case-control study in the Danish National Birth Cohort
Study Purpose: This study estimates the effect of changes in genes associated with hormone pathways on the risk of developing breast cancer.
Study Conclusion: These results suggest that changes in certain genes that are involves with estrogen can control the influence of PFOSA exposure on the development of breast cancer.

Other Types of Cancer

Serum Concentrations of Per- and Polyfluoroalkyl Substances and Risk of Renal Cell Carcinoma
Study Purpose: This study investigates the association between PFOA and other PFAS and renal cell carcinoma at concentrations in the general population.
Study Conclusion: Our findings add substantially to the weight of evidence that PFOA is a renal carcinogen and may have important public health implications for the many individuals exposed to this ubiquitous and highly persistent chemical.

Critical Review on PFOA, Kidney Cancer, and Testicular Cancer
Study Purpose: The review covers prior studies on PFOA and cancers of the kidney and testes.
Study Conclusion: This study found an increase in cancer risk of the kidney and testes with increased PFOA concentrations. While these associations are likely causal, these results are limited by the small number of studies on this subject, overlapping study populations in studies, and lack of measured PFOA concentrations in several studies.

PFAS and cancer, a scoping review of the epidemiologic evidence
Study Purpose: This study reviews evidence relating to PFAS and cancer to highlight directions for future research.
Study Conclusion: There is inconsistent evidence on the association between cancer and PFAS.

Endocrine Disrupting Chemicals and Thyroid Cancer: An Overview
Study Purpose: This study looks at prior literature on the association between chemicals such as PFAS and thyroid cancer.
Study Conclusion: There was no evidence that PFAS have a carcinogenic effect on the thyroid gland in humans.

Immune System and Hormones
Immunity

A healthy immune system can provide an effective response to infections and diseases within the body. The immune section includes studies on infections, asthma, inflammatory markers, antibodies, allergies, cytokines, adipokines, adipocytokines, atopic dermatitis, and immunotoxicity as they relate to PFASs. Information related to vaccines can be found in the COVID and Vaccines tab. Cytokines include interferon, interleukin, and growth factors, which are secreted by certain cells in the immune system and regulate processes within the body. Adipokines or adipocytokines, similarly, are cell signaling proteins, but are secreted in adipose tissue. Atopic dermatitis is also known as eczema and makes skin red and itchy. This section currently has 33 total studies: 29 from the last 5 years. Although a study may find, or not find, an association between PFASs and immune outcomes, this does not mean it is, or is not, definitively a causative agent. Findings in studies are not necessarily generalizable among all sexes, ethnicities/races, smokers/non-smokers, and geographic areas; this should be considered when interpreting these results. Differences in findings between studies could be due to the population studied (demographics, geography, diet, etc.), size of the studies, differences in PFAS concentrations between studies, when samples were taken, or other factors.


 

Asthma

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.

 

Allergies

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.

 

Atopic dermatitis

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.

 

Adipokines, cytokines, and adipocytokines

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.

 

Infections and infectious diseases

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.

 

Other

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.

COVID and Vaccines

COVID and Vaccines includes information on PFAS exposure and COVID-19 (severity, relation with water pollutants, mortality, and vitamin D disruption) and vaccine response for the flu, tetanus, diphtheria, Rubella, Measles, and Mumps. COVID-19 and PFAS is not well studied at this point in time. As papers are published in this area, they will be updated here. This section has 19 total studies; 13 were published in the last 5 years. Although a study may find, or not find, an association between PFASs and COVID-19/vaccine outcomes, this does not mean it is, or is not, definitively a causative agent. Findings in studies are not necessarily generalizable among all sexes, ethnicities/races, smokers/non-smokers, and geographic areas; this should be considered when interpreting these results. Differences in findings between studies could be due to the population studied (demographics, geography, diet, etc.), size of the studies, differences in PFAS concentrations between studies, when samples were taken, or other factors.


 

COVID-19 and COVID-19 Risk Factors

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.

 

Vaccines and vaccine response

 

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.

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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.

Autoimmune

Autoimmune includes type 1 diabetes, celiac disease, inflammatory bowel disease (IBD/IBS), and ulcerative colitis. Currently, there are not many studies in this section. As papers are published in this area, we will include them here. There are 4 total studies, all published within the last 5 years. Although a study may find, or not find, an association between PFASs and autoimmune outcomes, this does not mean it is, or is not, definitively a causative agent. Findings in studies are not necessarily generalizable among all sexes, ethnicities/races, smokers/non-smokers, and geographic areas; this should be considered when interpreting these results. Differences in findings between studies could be due to the population studied (demographics, geography, diet, etc.), size of the studies, differences in PFAS concentrations between studies, when samples were taken, or other factors.


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.

Hormones

Hormones includes information on male reproductive hormones (like testosterone), female reproductive hormones (such as estrogen), menopause, menstruation, and puberty as they relate to PFASs. This section has 26 total studies; 20 were published within the last 5 years. Although a study may find, or not find, an association between PFASs and autoimmune outcomes, this does not mean it is, or is not, definitively a causative agent. Findings in studies are not necessarily generalizable among all ethnicities/races, smokers/non-smokers, and geographic areas; this should be considered when interpreting these results. Differences in findings between studies could be due to the population studied (demographics, geography, diet, etc.), size of the studies, differences in PFAS concentrations between studies, when samples were taken, or other factors.


 

 

Puberty

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.

 

Menopause and post-menopause

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.

 

Pregnancy

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 non-chemical 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 non-chemical 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.

 

Sex and reproductive hormones

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.

 

Menstruation

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.

 

Other

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.

Thyroid

The Thyroid section includes information on thyroid function and/or thyroid hormone levels in newborns, children, and mothers. It also includes studies examining hyper and hypothyroidism, hypothyroxinemia, and thyroid function following high PFAS exposure via water. This section has 30 total papers: 23 from the last 5 years. Although a study may find, or not find, an association between PFASs and thyroid outcomes, this does not mean it is, or is not, definitively a causative agent. Findings in studies are not necessarily generalizable among all sexes, ethnicities/races, smokers/non-smokers, and geographic areas; this should be considered when interpreting these results. Differences in findings between studies could be due to the population studied (demographics, geography, diet, etc.), size of the studies, differences in PFAS concentrations between studies, when samples were taken, or other factors.


 

 

Hypothyroidism and hyperthyroidism

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.

 

Maternal and neonatal thyroid function and hormones

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 polyfluroalkyl 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.

 

Infants, children, and the thyroid

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.

 

Adult and general thyroid function and hormones

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.

 

Other

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.

Bone and Joint Health
Osteoporosis

Osteoporosis includes information on bone health, bone disruption, osteoporosis and bone density, and vitamin D activity as they relate to PFASs. This section has 8 total studies; 7 were published in the last 5 years. Although a study may find, or not find, an association between PFASs and osteoporosis outcomes, this does not mean it is, or is not, definitively a causative agent. Findings in studies are not necessarily generalizable among all sexes, ethnicities/races, smokers/non-smokers, and geographic areas; this should be considered when interpreting these results. Differences in findings between studies could be due to the population studied (demographics, geography, diet, etc.), size of the studies, differences in PFAS concentrations between studies, when samples were taken, or other factors.


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 perfuoro‑octanoic 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 Midchildhood: 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 michildhood.

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.

Arthritis

Arthritis includes information on osteoarthritis. Currently, there are not many studies in this section. As papers are published in this area, we will include them here. This section has 2 total studies; no studies were published within the last 5 years. Although a study may find, or not find, an association between PFASs and arthritis outcomes, this does not mean it is, or is not, definitively a causative agent. Findings in studies are not necessarily generalizable among all sexes, ethnicities/races, smokers/non-smokers, and geographic areas; this should be considered when interpreting these results. Differences in findings between studies could be due to the population studied (demographics, geography, diet, etc.), size of the studies, differences in PFAS concentrations between studies, when samples were taken, or other factors.


Association of Osteoarthritis with Perfluorooctanoate and Perfluorooctane Sulfonate in NHANES 2003–2008
Study Purpose: PFASs are linked to health impacts that may be related to osteoarthritis. This study looks at whether PFOA and PFOS exposure are associated with the prevalence of osteoarthritis, and whether associations vary between men and women.
Study Conclusion: Higher concentrations of PFOA were associated with osteoarthritis in women, but not men. PFOS was also associated with osteoarthritis in women only.

Association of osteoarthritis with serum levels of the environmental contaminants perfluorooctanoate and perfluorooctane sulfonate in a large Appalachian population
Study Purpose: PFOA and PFOS affect metabolism, inflammation, and other factors related to the development of osteoarthritis. This study looks at the association of osteoarthritis with PFOA and PFOS in a large adult population from PFOA contaminated water districts in Ohio.
Study Conclusion: This study found an association between higher PFOA levels and more reported diagnosis of osteoarthritis. Higher PFOS levels were associated with less reported diagnosis of osteoarthritis.

General Health and Other Topics
General Health

General and Other covers studies that do not fit into the other categories listed or that deal with general topics of health. Some included studies are not PFAS exposure/health outcome measurements, rather, studies that may be of interest. These topics include: congenital heart defects, levels in food, dietary patterns, household dust, effects in pets, soil and groundwater in Eastern New York, biomonitoring, type of flooring, children’s health, personal care products, health and social concerns among affected communities, PFAS removal, and stroke as they relate to PFASs. This section currently has 24 total studies. Although a study may find, or not find, an association between PFASs and these outcomes, this does not mean it is, or is not, definitively a causative agent. Findings in studies are not necessarily generalizable among all ethnicities/races, smokers/non-smokers, and geographic areas; this should be considered when interpreting these results. Differences in findings between studies could be due to the population studied (demographics, geography, diet, etc.), size of the studies, differences in PFAS concentrations between studies, when samples were taken, or other factors.


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.

Children's Health

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.

Other

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.

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.

Date Last Updated: June 8, 2021