Organochlorine Compounds and Thyroid Function in Western New York State Anglers and Their Partners/SpousesEPA Grant Number: U916178
Title: Organochlorine Compounds and Thyroid Function in Western New York State Anglers and Their Partners/Spouses
Investigators: Bloom, Michael S.
Institution: The State University of New York at Buffalo
EPA Project Officer: Zambrana, Jose
Project Period: January 1, 2003 through January 1, 2006
Project Amount: $73,758
RFA: STAR Graduate Fellowships (2003) Recipients Lists
Research Category: Academic Fellowships , Fellowship - Public Health Sciences , Health Effects
The objectives of this research project are to: (1) identify biologically plausible associations between body burdens of organochlorine compounds (including polychlorinated biphenyls, dioxins, pesticides, and some metabolites) and biomarkers of thyroid function in humans; and (2) investigate the mechanism of these associations. Organochlorine compounds are ubiquitously distributed in the environment and may structurally resemble thyroid hormones. These compounds may influence thyroid function and physiology in both animals and humans.
Reports describe experimental studies in which the treatment of animal models with organochlorine compounds has resulted in thyroid toxicity. In human populations, observational studies of acute poisonings and background exposure levels have reported equivocal results with regard to thyroid toxicity. I will investigate: (1) associations between congener-specific organochlorine compounds and thyroid-stimulating hormone, total and free T4, and total T3 in 317 participants; (2) associations between organochlorine congeners and the rate of change in thyroid-function biomarker levels at two time points will be explored in 26 participants; and (3) associations between serum levels of congener-specific organochlorines, including dioxins, levels of thyroid-function biomarkers, and markers of autoimmune thyroid processes (TPO-Ab and anti-TGB), in 38 individuals. Participants were selected from among western New York state anglers, waterfowl and turtle hunters, and their partners; recruited as part of the New York State Angler Cohort Study (NYSACS). Self-reported data from questionnaires, as well as congener-specific toxicologic data and clinical laboratory data from donated sera samples, will be used. Pilot studies of samples from the NYSACS suggested associations between serum levels of organochlorine compounds and total T4. In addition, an increased prevalence of positive thyroid-function autoantibody tests, as compared with published reports, was suggested in the pilot data. The scientific literature will be used to drive variable selection. Univariate, bivariate, and stratified statistical analyses, adjusting for relevant covariates, will be conducted. Linear and log-linear multivariable models predictive of thyroid-function biomarkers will be constructed. Several methodological issues pertinent to studies of environmental organochlorine compounds and thyroid function in humans will be considered. This research will provide further evidence to clarify the issue of human thyroid disruption in association with environmental levels of organochlorine pollutants. In addition, further data concerning complex methodological issues pertinent to studies in this area will be provided.