Iodine status in Turkish populations and exposure to iodide uptake inhibitors

PLoS One. 2014 Feb 5;9(2):e88206. doi: 10.1371/journal.pone.0088206. eCollection 2014.

Abstract

Perchlorate, nitrate, and thiocyanate are competitive inhibitors of the sodium iodide symporter of the thyroid membrane. These inhibitors can decrease iodine uptake by the symporter into the thyroid gland and may disrupt thyroid function. This study assesses iodine status and exposure to iodide uptake inhibitors of non-pregnant and non-lactating adult women living in three different cities in Turkey (Istanbul, Isparta and Kayseri). We measured iodine and iodide uptake inhibitors in 24-hr urines collected from study participants (N = 255). All three study populations were mildly iodine deficient, with median urinary iodine (UI) levels of 77.5 µg/L in Istanbul, 58.8 µg/L in Isparta, and 69.8 µg/L in Kayseri. Perchlorate doses were higher in the study population (median 0.13 µg/kg/day), compared with a reference population (median 0.059 µg/kg/day), but lower than the U.S. EPA reference dose (0.7 µg/kg/day). Urinary thiocyanate levels increased with increasing exposure to tobacco smoke, with non-smokers (268 µg/L) significantly lower than light smokers (1110 µg/L), who were significantly lower than heavy smokers (2410 µg/L). This pilot study provides novel data indicating that study participants were moderately iodine deficient and had higher intakes of the iodide uptake inhibitor perchlorate compared with a reference population. Further investigation is needed to characterize the thyroid impact resulting from iodine deficiency coupled with exposure to iodide uptake inhibitors such as perchlorate, thiocyanate and nitrate.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Environmental Exposure / analysis*
  • Female
  • Humans
  • Iodine / metabolism
  • Iodine / urine*
  • Nitrates / analysis*
  • Nitrates / metabolism
  • Perchlorates / analysis*
  • Perchlorates / metabolism
  • Pilot Projects
  • Symporters / antagonists & inhibitors*
  • Symporters / metabolism
  • Thiocyanates / analysis*
  • Thiocyanates / metabolism
  • Thyroid Gland / metabolism
  • Turkey

Substances

  • Nitrates
  • Perchlorates
  • Symporters
  • Thiocyanates
  • sodium-iodide symporter
  • Iodine
  • thiocyanate
  • perchlorate

Grants and funding

This study was supported by funds from Acibadem University, Erciyes University, Suleyman Demirel University, and CDC. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.