Habib Ashkan, Molayemat Mohadeseh, Habib Asadollah
School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
Department of Endocrinology, School of Medicine, Kazerun Branch, Islamic Azad University., First Floor, Zafar Building, Zand St, PO Box: 71384-37984, Shiraz, Iran.
Thyroid Res. 2020 Jun 13;13:9. doi: 10.1186/s13044-020-00084-9. eCollection 2020.
Subclinical hypothyroidism is defined as elevated TSH levels while T4 or FT4 levels are normal. Elevated TSH levels are linked with obesity in adults. In a recent meta-analysis in Iran, 6.1% of children below 18 had obesity. Due to the low number of studies on the subject in children we, designed the study to assess the relation between BMI Z-score and TSH levels in children and adolescence.
This cross-sectional study was performed in a pediatric endocrinology clinic in Shiraz. Children aged between 2 to 18 years that came to the clinic for routine growth assessment follow up from January till April 2018 were considered. 850 children including 365 boys and 485 girls were included.
Prevalence of subclinical hypothyroidism is increased in higher BMI groups. 9.9, 13.8, 17.2 and 20.5% of underweight, healthy weight, overweight and obese had subclinical hypothyroidism respectively. Obese and overweight participants had higher odds of subclinical hypothyroidism than those who were not (OR:1.649, = 0.010, CI95% 1.126-2.413). On the other hand, Subclinical hypothyroid participants had higher odds of overweight or obesity than those who were euthyroid (OR:1.650, P = 0.010, CI95% 1.128-2.413). When TSH is set as a dependent value, TSH level is increased (β = 0.126, r = 0.125, = 0.001) with an increase in BMI Z-score. When BMI Z-score is set as a dependent value, BMI Z-score is increased (β = 0.113, r = 0.243, P = 0.001) with an increase in TSH level.
BMI Z-score and elevated TSH levels are positively correlated however studies should be performed on establishing the causality.
亚临床甲状腺功能减退症的定义为促甲状腺激素（TSH）水平升高而甲状腺素（T4）或游离甲状腺素（FT4）水平正常。TSH水平升高与成年人肥胖有关。在伊朗最近的一项荟萃分析中，18岁以下儿童中有6.1%患有肥胖症。由于针对该主题的儿童研究数量较少，我们设计了本研究以评估儿童和青少年的体重指数（BMI）Z评分与TSH水平之间的关系。
本横断面研究在设拉子的一家儿科内分泌诊所进行。纳入了2018年1月至4月期间到该诊所进行常规生长评估随访的2至18岁儿童。共纳入850名儿童，其中包括365名男孩和485名女孩。
较高BMI组中亚临床甲状腺功能减退症的患病率增加。体重过轻、健康体重、超重和肥胖儿童中亚临床甲状腺功能减退症的患病率分别为9.9%、13.8%、17.2%和20.5%。肥胖和超重参与者患亚临床甲状腺功能减退症的几率高于非肥胖者（比值比：1.649，P = 0.010，95%置信区间1.126 - 2.413）。另一方面，亚临床甲状腺功能减退参与者超重或肥胖的几率高于甲状腺功能正常者（比值比：1.650，P = 0.010，95%置信区间1.128 - 2.413）。当将TSH设为因变量时，随着BMI Z评分的增加，TSH水平升高（β = 0.126，r = 0.125，P = 0.001）。当将BMI Z评分设为因变量时，随着TSH水平的增加，BMI Z评分升高（β = 0.113，r = 0.243，P = 0.001）。
BMI Z评分与TSH水平升高呈正相关，但仍需开展研究以确定因果关系。
