Thyroid function and plasma concentrations of polyhalogenated compounds in Inuit adults.

Full Abstract

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.

Author information

Author/s: Dallaire, Renée (R); Dewailly, Eric (E); Pereg, Daria (D); Dery, Serge (S); Ayotte, Pierre (P);

Affiliation: Public Health Research Unit, Centre hospitalier universitaire de Québec-CHUL, 2875 boulevard Laurier Edifice Delta, Québec, Canada.

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Environmental health perspectives (Environ Health Perspect), published in United States. (Language: eng)

Reference: 2009-Sep; vol 117 (issue 9) : pp 1380-6

Dates: Created 2009/09/14; Completed 2009/11/16;

PMID: 19750101, status: MEDLINE (last retrieved date: 11/16/2009)

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