Endemic goiter, thiocyanate overload, and selenium status in school-age children.

Iodine deficiency (ID) and related disorders are still major, yet unresolved health concerns. Recently, in a systematic survey of school-age children (SAC), we reported severe to moderate ID, in Ankara and three cities from Black Sea region of Turkey. The current study attempted to evaluate selenium (Se) status, thiocyanate (SCN-) overload, and their possible contribution to the goiter endemics and thyroid hormone profile observed in these cities. Thyroid ultrasonography was performed and serum Se, SCN(-), thyroid hormones, sensitive TSH (sTSH) levels, and, urinary iodine concentrations (UICs) were determined from 251 SAC (9-11 yr old). Thyroid volumes (TVs) exceeding recommended upper normal limits and median UIC indicated goitre endemics and moderate to severe ID in the areas studied. Mean serum SCN(-) concentrations were found to be greater than the controls from the literature. The UIC/SCN(-) ratio was found to be lowest in Bayburt and Trabzon denoting that SCN(-) overload may contribute to the goiter endemics. Serum Se concentrations represent a marginal deficiency in the four areas studied. No significant correlations between serum Se concentrations and the other parameters studied (i.e., TV, SCN(-), thyroid hormones, sTSH, UIC) was detected. In conclusion, this study showed that selenium is also marginally deficient in the iodine-deficient endemic areas studied, but this has little or no impact on the thyroid hormone profile and the goiter endemics. SCN(-) overload may contribute to the endemics, especially for the areas where iodine is severely deficient. An effective iodine supplementation program will not only resolve the goiter endemics but also the consequence of SCN(-) overload as well in the endemic goiter areas studied.