Should we treat elevated thyroid stimulating hormone levels in obese children and adolescents?

To examine the prevalence of abnormal thyroid function tests among obese children and adolescents, and to study the effect of thyroid hormone supplementation on body weight, linear growth and lipid profiles in these children.

Thyroid function tests and lipid profiles were measured in 196 obese children and adolescents. Thyroid auto-antibodies were measured in children with hyperthyrotropinemia (elevated thyroid stimulating hormone (TSH) and normal free thyroxine-FT4). All children with hyperthyrotropinemia participated in a combined dietary-behavioral-physical activity weight management intervention. Fifteen of the obese children with hyperthyrotropinemia were also treated with thyroid hormone substitution for 6 months and were compared to non-treated subjects (n = 26).

Forty-one obese children had hyperthyrotropinemia (20.9%). Positive thyroid auto-antibodies were only found in 19.5% of these children. Treatment had no significant effect on body weight, linear growth and lipid profile, except for causing a greater decrease in triglyceride levels. TSH levels returned to normal ranges in the majority of children with hyperthyrotropinemia who participated in the combined intervention, irrespective of thyroxine treatment.

Hyperthyrotropinemia is relatively common in obese children, but autoimmune thyroid disease accounts for a minority of the cases. TSH levels returned to normal in the majority of patients even without thyroid hormone administration. No beneficial effects on body weight, body mass index, linear growth and body lipids were found in treated subjects, suggesting that thyroid substitution is not necessary in most cases.