| 19750101 |
Dallaire R, Dewailly E, Pereg D, Dery S, Ayotte P: Thyroid function and plasma concentrations of polyhalogenated compounds in Inuit adults. Environ Health Perspect. 2009 Sep;117(9):1380-6. Epub 2009 May 12.
BACKGROUND: Several ubiquitous polyhalogenated compounds (PHCs) have been shown to alter thyroid function in animal and in vitro studies. So far, epidemiologic studies have focused on the potential effect of a small number of them, namely, polychlorinated biphenyls (PCBs) and some organochlorines (OCs), without paying attention to other important PHCs. OBJECTIVES: We investigated the relationship between exposure to several PHCs and thyroid hormone homeostasis in Inuit adults from Nunavik. METHODS: We measured thyroid parameters [thyroid-stimulating-hormone (TSH), free thyroxine (fT (4)), total triiodothyronine (tT (3)), and thyroxine-binding globulin (TBG)] and concentrations of 41 contaminants, including PCBs and their metabolites, organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), perfluorooctanesulfonate (PFOS), and a measure of dioxin-like compounds, detected in plasma samples from Inuit adults (n = 623). RESULTS: We found negative associations between tT (3) concentrations and levels of 14 PCBs, 7 hydroxylated PCBs (HO-PCBs), all methylsulfonyl metabolites of PCBs (MeSO (2)-PCBs), and 2 OCPs. Moreover, we found negative associations between fT (4) levels and hexachlorobenzene concentrations. TBG concentrations were inversely related to 8 PCBs, 5 HO-PCBs, and 3 OCPs. Exposure to BDE-47 was positively related to tT (3), whereas PFOS concentrations were negatively associated with TSH, tT (3,) and TBG and positively with fT (4) concentrations. CONCLUSION: Exposure to several PHCs was associated with modifications of the thyroid parameters in adult Inuit, mainly by reducing tT (3) and TBG circulating concentrations. The effects of PFOS and BDE-47 on thyroid homeostasis require further investigation because other human populations display similar or higher concentrations of these chemicals. |
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