Early Adiposity Rebound and Obesity in Children with Congenital Hypothyroidism

Background: Earlier adiposity rebound (AR) is correlated with obesity. Our goal is to examine rates of obesity and AR in congenital hypothyroidism (CHT) and analyze the risk factors of obesity. Methods: We retrospectively reviewed the cases with abnormal newborn screens of thyroid-stimulating hormone (TSH) from 1990 to 2005 and enrolled permanent CHT patients who continued to receive treatment after the 3rd year of life. We determined subgroups of obesity/being overweight and normal body mass index (BMI) by the latest BMI at 6-7 years of age. BMI at each age and the age of AR were compared with the general population in Taiwan. The statistical correlation of obesity with the age and BMI at both AR and first peak, and thyroid function was calculated. Results: A total of 90 cases of CHT were enrolled. The prevalence of obesity/being overweight was 32.2%. The age of AR was 4.94 ± 1.81 and 4.58 ± 1.86 years old in boys and girls, respectively. The age of AR in the girls with CHT was earlier than in girls in general, but no statistical significance was found in boys with CHT compared to the general population. Obesity was correlated with earlier age of AR, higher BMI at first peak and AR, and lower T4 after treatment, but not with the age of first peak of BMI, T4/TSH at diagnosis and AR, and TSH after treatment. Conclusion: Children with CHT have a higher risk of obesity due to earlier age of AR. We recommend that supervision and intervention on weight control should be provided to prevent the occurrence of obesity later.