Optimal and Safe Upper Limits of Iodine Intake for Early Pregnancy in Iodine-Sufficient Regions: A Cross-Sectional Study of 7190 Pregnant Women in China
Optimal and Safe Upper Limits of Iodine Intake for Early Pregnancy in Iodine-Sufficient Regions: A Cross-Sectional Study of 7190 Pregnant Women in China
复制标题
DOI：
10.1210/jc.2014-3704
复制
发表时间：
2015-04-01
影响因子：
5.8
通讯作者：
Teng, Weiping
中科院分区：
文献类型：
--
作者：
Shi, Xiaoguang;Han, Cheng;Teng, Weiping
背景：世卫组织技术磋会会建议孕妇和哺乳期妇女尿碘浓度（UIC）在250 - 499 μ g/L之间为过量碘摄入，UIC值为500 μ g/L为过量碘摄入，但这方面的科学证据不足。目的：探讨中国缺碘地区妊娠早期碘摄入的最佳安全范围。方法：对妊娠4 ~ 8周的7190例孕妇进行UIC、血清促甲状腺激素（TSH）、游离甲状腺素（FT4）、甲状腺过氧化物酶抗体（TPOAb）、甲状腺球蛋白抗体（TgAb）、甲状腺球蛋白（Tg）的测定。结果：UIC为150 ~ 249 μ g/L组明显甲状腺功能减退的发生率最低，对应于血清Tg浓度最低（10.18 μ g/L）。UIC为150 ~ 249 μ g/L组亚临床甲状腺功能减退（2.4%）和孤立性甲状腺功能减退（1.7%）的患病率较低。多因素logistic回归分析显示，碘摄入过量（UIC 250 ~ 499 μ g/L）和碘摄入过量（UIC 50 ~ 500 μ g/L）分别与亚临床甲状腺功能减退的风险增加1.72倍和2.17倍相关。同时，过量的碘摄入与孤立性甲状腺功能减退症的风险增加2.85倍相关。此外，TPOAb和TgAb阳性的流行呈u型曲线，从轻度缺碘到碘过量。结论：在碘充足地区，妊娠早期碘摄入上限不应超过UIC 250 μ g/L，因为这与亚临床甲状腺功能减退的显著高风险相关；UIC 500 μ g/L不应超过UIC 500 μ g/L，因为它与孤立性甲状腺功能减退的显著高风险相关。
Context: The WHO Technical Consultation recommends urinary iodine concentrations (UIC) from 250 to 499 mu g/L as more-than-adequate iodine intake and UIC >= 500 mu g/L as excessive iodine for pregnant and lactating women, but scientific evidence for this is weak.Objective: We investigated optimal and safe ranges of iodine intake during early pregnancy in an iodine-sufficient region of China.Method: Seven thousand one hundred ninety pregnant women at 4-8 weeks gestation were investigated and their UIC, serum thyroid stimulating hormone (TSH), free thyroxine (FT4), thyroidperoxidase antibody (TPOAb), thyroglobulin antibody (TgAb), and thyroglobulin (Tg) were measured.Results: The prevalence of overt hypothyroidism was lowest in the group with UIC 150-249 mu g/L, which corresponded to the lowest serum Tg concentration (10.18 mu g/L). Prevalences of subclinical hypothyroidism (2.4%) and isolated hypothyroxinemia (1.7%) were lower in the group with UIC 150-249 mu g/L. Multivariate logistic regression indicated that more-than-adequate iodine intake (UIC 250-499 mu g/L) and excessive iodine intake (UIC > 500 mu g/L) were associated with a 1.72-fold and a 2.17-fold increased risk of subclinical hypothyroidism, respectively. Meanwhile, excessive iodine intake was associated with a 2.85-fold increased risk of isolated hypothyroxinemia. Moreover, the prevalence of TPOAb positivity and TgAb positivity presented a U-shaped curve, ranging from mild iodine deficiency to iodine excess.Conclusion: The upper limit of iodine intake during early pregnancy in an iodine-sufficient region should not exceed UIC 250 mu g/L, because this is associated with a significantly high risk of subclinical hypothyroidism, and a UIC of 500 mu g/L should not be exceeded, as it is associated with a significantly high risk of isolated hypothyroxinemia.