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Abstract

Objectives:

Alterations in thyroid function appear to play a central role in adaptation to Arctic environments. Increased thyroid activity in indigenous circumpolar populations is associated with upregulated metabolism, including elevated basal metabolic rate (BMR); however, little is known about the possible health consequences of these climate-induced changes on thyroid function. The focus of the present study is to determine the prevalence of autoimmune thyroid disorders and their lifestyle and metabolic correlates among a sample of indigenous Yakut adults from northeastern Siberia.

Methods:

Anthropometric dimensions, health data, and plasma samples were collected among 281 adults (143 women, 138 men; ≥18 years old) from the rural community of Berdygestiakh (62°N, 127°E; pop. 4,900), Sakha Republic (Yakutia), Russia. BMR measurements were available for 96 women and 98 men. Free triiodothyronine (T3), free thyroxine (T4), thyroid stimulating hormone (TSH), and anti-thyroid peroxidase antibody (TPOAb) levels were determined using enzyme immunoassay.

Results:

Twenty-two percent of women and 6% of men had clinically elevated (>30 IU/ml) TPOAb. TPOAb was positively correlated with TSH (P < 0.01), T3 (P < 0.05), and T4 (P < 0.05) in women and showed a positive trend with T4 (P = 0.06) in men. Monthly household income was significantly positively correlated with TPOAb in men (P < 0.01) and showed a trend among women (P = 0.06).

Conclusions:

Although preliminary, these findings document higher than expected TPOAb levels among Yakut women and suggest possible consequences of increased thyroid activity associated with circumpolar adaptation and social change. Am. J. Hum. Biol. 2011. © 2011 Wiley-Liss, Inc.