Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 42 4 2004 08 15 267 271 H. Moayeri A. Rabbani 2015 09 28 Type I diabetes mellitus (DM) is frequently associated with autoimmune thyroid disease (ATD). Association of ATD and type I DM has been described with varying frequencies but there is still debate about the situation in the Iranian population. We investigated the prevalence of anti thyroid peroxidase (anti-TPO) antibodies and ATD in children and adolescents with type I DM. A total of 145 patients with type I DM were participated in this study. They were screened for anti-TPO antibodies and TSH levels. Signs and symptoms of hypothyroidism and hyperthyroidism and the presence of goiter were sought. A group of 50 healthy unrelated girls and boys aged 11-16 years served as controls. Anti-TPO antibodies were found in 34 (23.4%) diabetic patients and 1 subject (2%) in the control group (P https://acta.tums.ac.ir/index.php/acta/article/view/2733 https://acta.tums.ac.ir/index.php/acta/article/download/2733/2715