Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Department of Epidemiology and Biostatistics, Research Centre for Emerging and Reemerging infectious Disease Pasteur Institute of Iran, Tehran, Iran.
Horm Metab Res. 2021 May;53(5):335-340. doi: 10.1055/a-1393-5864. Epub 2021 Mar 23.
We aimed to assess if changes in thyrotropin (TSH) and free thyroxine (FT4) over 10 years of follow-up would be associated with changes in body mass index (BMI) and waist circumference (WC) or risk of obesity. We enrolled 2317 out of 4179 participants in Tehran Thyroid Study with serum TSH between 0.1-10 mU/l and without history of thyroid medication or surgery. Serum concentrations of FT4 and TSH were measured at baseline and three follow-ups (1999-2011). To account for within-subject correlation, the generalized estimating equation was used to assess the association between one standard deviation(SD) change in the main exposures [cumulative excess (CE)TSH and CEFT4] and changes in BMI and WC; calculated scores of CETSH and CEFT4 were included in models as time-varying exposures. Cumulative excess of TSH or FT4 was not associated with increased incidence of general or abdominal obesity. However, CEFT4 was negatively associated with BMI only in overweight and obese subjects. In GEE analysis, one unit increase in TSH was associated with 0.02 kg/m increase in BMI (95% CI: 0.01, 0.03), which remained significant only in women; although the association was not significant after adding FT4 to model. One unit increase in FT4 was associated with 1.5 kg/m decrease in BMI (95% CI:-1.8,-1.2) and 4.1 cm decrease in WC (95% CI:-5.1,-3.1) in both sexes independent of TSH and other confounders. Cumulative excess of TSH or FT4 indicated no risk for general or abdominal obesity. However, FT4 was negatively associated with BMI and WC independent of TSH.
我们旨在评估促甲状腺激素（TSH）和游离甲状腺素（FT4）在 10 年随访期间的变化是否与体重指数（BMI）和腰围（WC）的变化或肥胖风险相关。我们从德黑兰甲状腺研究中招募了 2317 名参与者，他们的血清 TSH 水平在 0.1-10mU/l 之间，且没有甲状腺药物或手术史。在基线和三次随访（1999-2011 年）时测量了 FT4 和 TSH 的血清浓度。为了考虑到个体内相关性，我们使用广义估计方程来评估主要暴露[累积过量（CE）TSH 和 CEFT4]的一个标准差（SD）变化与 BMI 和 WC 变化之间的关联；将 CETSH 和 CEFT4 的计算得分作为时变暴露纳入模型。累积 TSH 或 FT4 过量与一般或腹部肥胖的发生率增加无关。然而，CEFT4 仅与超重和肥胖受试者的 BMI 呈负相关。在 GEE 分析中，TSH 增加一个单位与 BMI 增加 0.02kg/m（95%CI：0.01，0.03）相关，仅在女性中仍然显著；尽管在向模型中添加 FT4 后，这种关联不再显著。FT4 增加一个单位与 BMI 降低 1.5kg/m（95%CI：-1.8，-1.2）和 WC 降低 4.1cm（95%CI：-5.1，-3.1）相关，无论 TSH 如何，男女均相关且不受其他混杂因素的影响。累积 TSH 或 FT4 过量对一般或腹部肥胖没有风险。然而，FT4 与 BMI 和 WC 呈负相关，与 TSH 无关。
