Association of high-normal thyroid-stimulating hormone levels with metabolic syndrome and abdominal obesity in euthyroid adolescents: insights from the Korea National Health and Nutrition Examination Survey.

PURPOSE: Metabolic syndrome (MetS) is increasingly prevalent among adolescents, and thyroid-stimulating hormone (TSH) levels influence metabolic health. This study investigates whether TSH levels are associated with MetS and its components in euthyroid adolescents. METHODS: We used data from the Korean National Health and Nutrition Examination Survey between 2013 and 2015. The study included 940 euthyroid adolescents aged 10-18 years, who were divided into 2 groups: high-normal TSH group (top 25% of euthyroid TSH levels) and nonhigh TSH group (remaining 75%). We analyzed the association between high-normal TSH levels and MetS and its components. RESULTS: TSH quartiles were related to MetS (P for trend=0.006). The prevalence of MetS was 3.5% in the high-normal TSH group and 1.9% in the nonhigh group (P=0.1929). Abdominal obesity was more prevalent in the high-normal TSH than in the nonhigh TSH group (16.2% vs. 9.6%, P=0.0153). Other MetS components were more prevalent in the high-normal TSH group, but the difference was not significant. High-normal TSH was significantly associated with abdominal obesity (adjusted odds ratio, 1.975; 95% confidence interval, 1.104-3.531, P=0.0218). CONCLUSION: In euthyroid adolescents, a significant trend was observed between TSH quartile and MetS. Specifically, high-normal TSH levels showed a significant association with abdominal obesity, a key component of MetS.