Thyroid-stimulating hormone (TSH) level in nutritionally obese children and metabolic co-morbidity

Abstract

In recent years, there has been increasing focus on thyroid function in pediatric obese patients. Our aims were to investigate whether there is an association between serum thyroid-stimulating hormone (TSH) within the normal range and body mass index (BMI), and to determine if TSH levels correlate with metabolic risk factors in children. A retrospective cross-sectional analysis was carried out on 528 euthyroid, age- and sex-matched lean, overweight, or obese children. Anthropometric indices, blood pressure, fasting blood glucose, hepatic enzymes, lipid profiles, TSH, free triiodothyronine (fT3), and free thyroxine (fT4) were assessed from medical records and compared among groups. Subjects with known presence of diabetes, using medications altering blood pressure and glucose or lipid metabolism, with TSH levels >97.5 or <2.5 percentile, or with autoimmune thyroid disease were excluded. Hypertension, dyslipidemia, and elevated levels of hepatic enzymes were found to be more common in overweight and obese children (p<0.001), and those metabolic changes were significantly correlated with the increase in BMI (p<0.05). Serum concentrations of TSH and fT3 within the normal range were higher in overweight and obese children (p<0.01), and TSH was positively correlated with total cholesterol, triglycerides, and systolic blood pressure (p<0.05). Our findings suggest that obese children have higher serum TSH and fT3 levels even within the normal range, and that an increase in TSH is associated with dyslipidemia and higher systolic blood pressure. It remains to be seen whether TSH might serve as a potential marker of metabolic risk factors in obese pediatric patients.