Chronic exposure to dioxin-like compounds and thyroid function among New York anglers

Experimental studies suggest that dioxin-like compounds influence thyroid function, although human studies have presented equivocal results. Great Lakes sportfish consumers represent a population with greater potential for exposure to dioxin-like compounds than non-consumers. Thirty-eight licensed anglers participating in a dioxin exposure study, consumers and non-consumers, conducted as part of the New York Angler Cohort Study, donated blood and completed questionnaires regarding demographic, clinical, and sportfish consumption data. Sera were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), coplanar biphenyls (PCB), and PCB IUPAC #153, in addition to thyroid stimulating hormone (TSH), total and free thyroxine (T4 and fT4), total triiodothyronine (T3), and lipids. An inverse linear association between serum fT4 and the sum of dioxin-like congener concentrations (∑DIOXs) in serum (B = −0.3, 95% CI = −0.5, −0.1) was identified adjusting for PCB #153 and serum lipids (R2 = 0.3, p = 0.02, n = 37). The results of this study are preliminary but suggest an inverse association between dioxin-like compounds and fT4.