Charatcharoenwitthaya Natthinee, Ongphiphadhanakul Boonsong, Pearce Elizabeth N, Somprasit Charintip, Chanthasenanont Athita, He Xuemei, Chailurkit Laor, Braverman Lewis E
Departments of Medicine (N.C.) and Obstetrics and Gynecology (C.S., A.C.), Faculty of Medicine, Thammasat University, Pathumthani 10200, Thailand; Department of Medicine (B.O., L.C.), Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand; and Department of Medicine (E.N.P., X.H., L.E.B.), Boston University School of Medicine, Boston, Massachusetts 02118-2308.
J Clin Endocrinol Metab. 2014 Jul;99(7):2365-71. doi: 10.1210/jc.2013-3986. Epub 2014 Apr 4.
Thyroid hormone is critical for fetal neurodevelopment. Perchlorate and thiocyanate decrease thyroidal iodine uptake by competitively inhibiting the sodium/iodide symporter. It is clear that perchlorate and thiocyanate anions can influence thyroid function. However, as pollutants in the environment, their impact is conflicting.
The objective was to determine the effects of environmental perchlorate and/or thiocyanate exposure on thyroid function in first-trimester pregnant women.
A cross-sectional study was conducted in 200 pregnant Thai women with a gestational age of 14 weeks or less.
Urinary iodide, perchlorate, thiocyanate, and serum thyroid function tests were measured.
The women were aged 28.6 ± 6.1 years and the mean gestational age was 9.6 ± 2.7 weeks. Median urinary iodide, perchlorate, and thiocyanate concentrations were 153.5 μg/L, 1.9 μg/L, and 510.5 μg/L, respectively. Using Spearman's rank correlation analyses, there were positive correlations between serum TSH and urine perchlorate to creatinine (r = 0.20, P = .005) and TSH and thiocyanate to creatinine ratios (r = 0.22, P = .001). There were negative correlations between free T4 and the perchlorate to creatinine ratio (r = -0.18, P = .01) and free T4 and the thiocyanate to creatinine ratio (r = -0.19, P = .008). In multivariate analyses adjusting for log thiocyanate to creatinine ratio, log iodide to creatinine ratio, and gestational age, log perchlorate to creatinine ratio was positively associated with log TSH (P = .002) and inversely associated with log free T4 (P = .002). Log thiocyanate to creatinine ratio was a significant positive predictor of log TSH (P = .02) in women with a urine iodide level of less than 100 μg/L.
Low-level environmental exposure to perchlorate and thiocyanate is common in Thailand. Low-level exposure to perchlorate is positively associated with TSH and negatively associated with free T4 in first-trimester pregnant women using multivariate analyses. In multivariate analyses, thiocyanate exposure is also positively associated with TSH in a subgroup of pregnant women with low iodine excretion.
甲状腺激素对胎儿神经发育至关重要。高氯酸盐和硫氰酸盐通过竞争性抑制钠/碘同向转运体降低甲状腺对碘的摄取。很明显，高氯酸盐和硫氰酸根阴离子会影响甲状腺功能。然而，作为环境污染物，它们的影响存在争议。
本研究旨在确定孕早期孕妇暴露于环境中的高氯酸盐和/或硫氰酸盐对甲状腺功能的影响。
对200名孕周小于或等于14周的泰国孕妇进行了一项横断面研究。
检测尿碘、高氯酸盐、硫氰酸盐以及血清甲状腺功能指标。
研究对象年龄为28.6±6.1岁，平均孕周为9.6±2.7周。尿碘、高氯酸盐和硫氰酸盐浓度的中位数分别为153.5μg/L、1.9μg/L和510.5μg/L。采用Spearman等级相关分析，血清促甲状腺激素（TSH）与尿高氯酸盐/肌酐比值（r = 0.20，P = 0.005）以及TSH与硫氰酸盐/肌酐比值（r = 0.22，P = 0.001）之间呈正相关。游离甲状腺素（FT4）与高氯酸盐/肌酐比值（r = -0.18，P = 0.01）以及FT4与硫氰酸盐/肌酐比值（r = -0.19，P = 0.008）之间呈负相关。在对硫氰酸盐/肌酐比值的对数、碘/肌酐比值的对数和孕周进行校正的多因素分析中，高氯酸盐/肌酐比值的对数与TSH的对数呈正相关（P = 0.002），与游离甲状腺素的对数呈负相关（P = 0.002）。在尿碘水平低于100μg/L的女性中，硫氰酸盐/肌酐比值的对数是TSH对数的显著正性预测因子（P = 0.02）。
在泰国，孕妇低水平暴露于环境中的高氯酸盐和硫氰酸盐很常见。多因素分析显示，孕早期孕妇低水平暴露于高氯酸盐与TSH升高呈正相关，与游离甲状腺素降低呈负相关。在多因素分析中，硫氰酸盐暴露在碘排泄量低的孕妇亚组中也与TSH升高呈正相关。
