This project seeks to identify the consequences of exposure to PCBs and other environmental toxins on the health of children and youth as measured by their physical growth, maturation and cognitive/behavioral development. We hypothesize that prenatal and perinatal exposure to PCBs causes a decrease in physical and cognitive/social maturation. It is also hypothesized that body fat levels, endocrine status and exposure to other toxicants can alter the effects of PCBs.
One objective of this project is to identify the effects of PCB body burden on endocrines that reflect thyroid function and sexual maturation, and on the physical growth, maturation and cognitive development of children and youth. Another objective is to identify the role of body composition, specifically fat stores, in determining the level of PCBs in circulation and as a modifier of their effects.
A cross sectional study of Mohawk children and youth 10-16 years of age (anticipated n=400) permits the determination of the relationships of PCB level to endocrines (thyroxine, tri-iodothyroxine, thyrotropin, and beta-estradiol/testosterone), physical growth, maturation and cognitive behavior functioning as well as the influence of fat mass or percent fat on PCB levels and PCB effects.
Exposure to PCBs is determined by serum assay and by dietary questionnaire. The primary outcomes are assessed by direct examination (anthropometry and several measures of cognitive and behavior functioning), or in the case of endocrines, by blood analysis. Body composition (fat mass, percent fat) is determined using multiple anthropometric measures (primarily skinfolds, circumferences and bony breadths).
This project also collects information on other factors that affect the outcomes of interest and, when necessary, controls them through statisical methods. The study is determining levels of blood mercury (organic and inorganic), lead, and the level of fluoride in urine because the population at Akwesasne are exposed to these toxins that may affect growth and development.
Other influences (diet, socio-economic status, birth order and others) are assessed through questionnaire. Iron status is assessed through blood assay. Multiple regression techniques, particularly structural equation analysis, of this data permits control of the known influences on the outcomes of interest and the estimation of direct and indirect effects of PCBs on the intermediate and final outcomes of interest.
