Department of Epidemiology and Health Statistics, School of Public Health, Guangxi Medical University, Nanning 530021, Guangxi, China.
Department of Sanitary Chemistry, School of Public Health, Guangxi Medical University, Nanning 530021, Guangxi, China.
Biomed Res Int. 2018 Nov 14;2018:2032413. doi: 10.1155/2018/2032413. eCollection 2018.
Ethnic differences in the level of thyroid hormones exist among individuals. The American Thyroid Association (ATA) recommends that an institution or region should establish a specific thyroid hormone reference value for each stage of pregnancy. To date, a limited number of studies have reported the level of thyroid hormones in Chinese minorities, and the exact relationship between BMI and thyroid function in pregnant women is ill. This study was performed to establish trimester-specific reference ranges of thyroid hormones in Zhuang ethnic pregnant women and explore the role of body mass index (BMI) on thyroid function. A total of 3324 Zhuang ethnic health pregnant women were recruited in this Zhuang population-based retrospective cross-sectional study. The values of thyroid stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) were determined by automatic chemiluminescence immunoassay analyzer. Multivariate linear regression and binary logistic regression were constructed to evaluate the influence of BMI on the thyroid function. The established reference intervals for the serum thyroid hormones in three trimesters were as follows: TSH, 0.02-3.28, 0.03-3.22, and 0.08-3.71 mIU/L; FT4, 10.57-19.76, 10.05-19.23, and 8.96-17.75 pmol/L; FT3, 3.51-5.64, 3.42-5.42, and 2.93-5.03 pmol/L. These values were markedly lower than those provided by the manufacturers for nonpregnant adults which can potentially result in 6.10% to 19.73% misclassification in Zhuang pregnant women. Moreover, BMI was positively correlated with isolated hypothyroxinemia (OR=1.081, 95% CI=1.007-1.161), while the correlation between the BMI and subclinical hypothyroidism was not statistically significant (OR=0.991, 95% CI=0.917-1.072). This is the first study focusing on the reference ranges of thyroid hormones in Guangxi Zhuang ethnic pregnant women, which will improve the care of them in the diagnosis and treatment. We also found that high BMI was positively associated with the risk of isolated hypothyroxinemia.
个体之间的甲状腺激素水平存在种族差异。美国甲状腺协会（ATA）建议每个机构或地区都应为每个妊娠阶段建立特定的甲状腺激素参考值。迄今为止，只有少数研究报告了中国少数民族的甲状腺激素水平，并且关于孕妇的 BMI 与甲状腺功能之间的确切关系仍不清楚。本研究旨在建立壮族孕妇特定妊娠阶段的甲状腺激素参考范围，并探讨 BMI 对甲状腺功能的影响。在这项基于壮族人群的回顾性横断面研究中，共招募了 3324 名壮族健康孕妇。使用自动化学发光免疫分析仪测定促甲状腺激素（TSH）、游离甲状腺素（FT4）和游离三碘甲状腺原氨酸（FT3）的水平。构建多元线性回归和二元逻辑回归模型来评估 BMI 对甲状腺功能的影响。建立的血清甲状腺激素在三个孕期的参考区间如下：TSH，0.02-3.28、0.03-3.22 和 0.08-3.71 mIU/L；FT4，10.57-19.76、10.05-19.23 和 8.96-17.75 pmol/L；FT3，3.51-5.64、3.42-5.42 和 2.93-5.03 pmol/L。这些值明显低于制造商提供的非孕妇成年人的参考值，可能导致 6.10%至 19.73%的壮族孕妇分类错误。此外，BMI 与单纯性甲状腺素血症呈正相关（OR=1.081，95%CI=1.007-1.161），而 BMI 与亚临床甲状腺功能减退症之间的相关性无统计学意义（OR=0.991，95%CI=0.917-1.072）。这是第一项关注广西壮族孕妇甲状腺激素参考范围的研究，将改善他们在诊断和治疗中的护理。我们还发现，高 BMI 与单纯性甲状腺素血症的风险呈正相关。
