Thyroid autoimmunity in children and adolescents with type 1 diabetes mellitus. Effect of age, gender and HLA type

Type 1 diabetes is often associated with additional autoimmune phenomena. However, data reported on the frequency of thyroid autoimmunity differ vastly. Therefore, the prevalence of thyroid autoantibodies was evaluated at a large pediatric diabetes center in Southern Germany. 2,305 determinations (TPO and TG, ELISA) were performed in 495 patients with type 1 diabetes (234 boys, 261 girls; age at last measurement: 15.4 +/- 0.3 years, duration of diabetes 7. 5 +/- 0.2 years). The prevalence of elevated thyroid antibodies increased dramatically with age: from 3.7% in patients less than 5 years of age up to 25.3% in the age group 15-20 years (p < 0.0001). For children older than 10 years, girls were significantly more affected than boys (p < 0.0001). Thyroid autoimmunity tended to be more prevalent in the subgroup of patients with the HLA type DR3/DR4 compared to patients with other HLA types (p = 0.08). In children older than 10 years, basal TSH concentrations were significantly elevated in antibody-positive patients (p < 0.05). In conclusion, thyroid autoimmunity is prevalent in children and adolescents with type 1 diabetes. Adolescent girls and young women are especially affected. Yearly routine determinations of thyroid antibodies are therefore recommended.