During Rapid Weight Loss in Obese Children, Reductions in TSH Predict Improvements in Insulin Sensitivity Independent of Changes in Body Weight or Fat

Background: Although serum TSH is often elevated in obesity and may be linked to disorders of lipid and glucose metabolism, the clinical relevance of these relationships remains unclear. Subjects: Subjects were obese children and adolescents (n = 206; mean age 14 yr) undergoing rapid weight and fat loss in a standardized, multidisciplinary, 2-month, in-patient weight loss program. Design: This was a prospective study that determined thyroid function, glucose and lipid parameters, leptin, anthropometric measures, and body composition measured by dual-energy x-ray absorption at baseline and at the end of the intervention. Results: At baseline, 52% of children had TSH concentrations in the high normal range (>2.5 mU/liter), but TSH was not correlated with body weight, body mass index sd scores, lean body mass, or body fat percentage. At baseline, independent of adiposity, TSH significantly correlated with total cholesterol (P = 0.008), low-density lipoprotein cholesterol (P = 0.013), fasting insulin (P = 0.0...