Aims: To investigate the prevalence of thyroid autoantibodies and their significance for the development of thyroid disorders in children and adolescents with Type 1 diabetes.
Methods: Antibodies to thyroglobulin (anti-TG) and thyroperoxidase (anti-TPO) were measured in 216 patients (113 boys; median age 12.9 years (range 1-22 years)) with Type 1 diabetes (diabetes duration 2.5 years (0-14 years)) in a cross-sectional study. Sixteen patients with significantly elevated anti-TPO titres were followed longitudinally (6.0 years (4-13 years)) including the measurement of anti-TPO, anti-TG, T(3), T(4), thyroid-stimulating hormone (TSH) and ultrasound assessment.
Results: Twenty-two patients (10.0%) had significantly elevated titres of anti-TPO, 19 (8.7%) of anti-TG and 13 (5.9%) of both autoantibodies. Girls had more frequently elevated anti-TPO antibodies than boys (P < 0.05). Eight of 16 patients (50%) developed thyroid disorders defined by a TSH elevation (> or = 4.5 microU/ml) and/or sonographic thyroid abnormalities during a median time of 3.5 years (2-6 years) after first detection of anti-TPO positivity. They were characterized by higher levels of anti-TPO (P = 0.001) and a more frequent coexistence of anti-TG antibodies (P = 0.002) than those with no development of thyroid disorder even after an observation period of 5.5 years (5-10 years).
Conclusions: Because 50% of children with diabetes and significant titres of anti-TPO develop thyroid problems within 3-4 years, examinations of thyroid antibodies should be performed yearly. In cases of significant antibody titres, thyroid function tests and ultrasound assessment are recommended in order to minimize the risk of undiagnosed hypothyroidism in these patients.