Objectives: The aim of this study was to investigate the relationship between thyroid hormone levels and obesity, lipid levels and weight changes.

Patients and Methods: Five to eleven year old normal weight, overweight and obese children underwent measurements of thyroid stimulating hormone (TSH), free thyroxine (fT4), lipid profile and autoimmune thyroid antibodies. Children with high TSH were reevaluated one year later without any intervention. Results: Three hundred children (126 obese, 74 overweight, 100 normal weight) were evaluated in the study. The rates of high TSH levels were 1.0% in normal weight, 9.5% in overweight and 11.9% in obese group (p= 0.007). fT4 levels of all the children enrolled in the study were in normal range. None of the children had autoimmune antibody positivity. Obese children with high TSH had higher triglyceride levels than children with normal TSH (p= 0.028). One year later, a significant decrease in body mass index (BMI) was accompanied by a significant decrease in TSH levels.

Conclusion: TSH levels can be high in obese and overweight children. Obese and overweight children with elevated levels of TSH do not need to be treated pharmacologically, losing weight decreases TSH levels significantly.