Overweight and obesity in children and adolescents with chronic autoimmune thyroiditis

An association between overweight and thyroid dysfunction, including chronic autoimmune thyroiditis (CAT), has been previously described. Patients with overweight and obesity have a higher risk of increased thyroid-stimulating hormone (TSH) and anti-thyroid antibodies. Weight gain may also be a clinical sign of hypothyroidism. This study aimed to describe the frequency of overweight and obesity in children with CAT and to compare thyroid function and antibody titles according to body weight.

Clinical records from 78 patients with CAT who were followed up at a children's hospital in Mexico City were assessed. We collected demographic, anthropometric, and biochemical data, including thyroid function tests and antibodies. According to body mass index (BMI) percentiles, patients were classified as normal weight, overweight or obese according to BMI percentiles. Also, BMI changes at 6 and 12 months of follow-up were analyzed.

We observed 19.2% of the patients with overweight and 15.4% with obesity. Patients with obesity showed high TSH and low thyroid hormone levels. Also, the frequency of hypothyroidism at presentation was higher in this group. No significant difference was found in antibody titles between groups. A significant BMI percentile reduction was observed during follow-up of patients independently of thyroid function at diagnosis and treatment.

Obesity is related to hypothyroidism in patients with chronic autoimmune thyroiditis, although causality cannot be established through this observational study.