Metabolic Impact of Subclinical Hypothyroidism in Obese Children and Adolescents

Objective Subclinical hypothyroidism is common in children and adolescents with obesity and has been considered to be its effect with no need for treatment. Its metabolic impact has not been evaluated. Therefore the present study was conducted to determine the metabolic impact of obesity related subclinical hypothyroidism. Methods Retrospective record review of obese children and adolescents between 5 and 18 y of age presenting to pediatric endocrine clinic was done. Four hundred four obese children and adolescents [251 boys, 11.8 (3.2); 5.1-18 y, BMI SDS 2.4 (0.7); 1.4-6.6] were assessed regarding thyroid functions, adiposity (clinical and DXA derived) and metabolic complications. Results Subclinical hypothyroidism was observed in 122 (30.2%) and was associated with higher fat percentage [49.2 (5.8) vs. 47.2 (6.4)p = 0.009], android to gynoid ratio [1.1 (0.1) vs. 1.0 (0.1),p = 0.007] and alanine aminotransferase (ALT) levels [49.3 (31.5) vs. 40.8 (38.1),p = 0.04]. Subjects with subclinical hypothyroidism had 1.9 times greater odds of having non-alcoholic steatohepatitis (47.3% vs. 31.8%,p = 0.005) with no difference in the prevalence of dyslipidemia, dysglycemia or hypertension. Subclinical hypothyroidism was the only determinant of non-alcoholic steatohepatitis on binomial logistic regression (WALD = 11.04,p = 0.001) with no impact of BMI SDS, waist circumference SDS, fat percentage or android to gynoid ratio. Thyroid stimulating hormone (TSH) was the most important determinant of ALT on linear regression (B = 3.027,p < 0.005). Conclusions Obesity related subclinical hypothyroidism predisposes to increased ALT and non-alcoholic steatohepatitis independent of severity adiposity. The impact of thyroid supplementation in this setting needs to be explored.