Prevalence of Thyroid Autoantibodies in Type 2 Diabetic Patients

Due to the increased prevalence of thyroid dysfunction in subjects with type 2 diabetes and also this fact that antibodies could potentially identify subjects at risk of thyroid dysfunction, this study was conducted to investigate thyroid autoimmunity in type 2 diabetic patients. Among patients referred to Yazd Diabetes Research Center, 4000 type 2 diabetic patients were recruited and clinical examination was carried out and samples for thyroid function test including thyroxin (T4), triiodothyronine (T3), thyroid stimulating hormone (TSH), T3 resin uptake (T3RU), thyroid peroxidase antibodies (TPO-Ab) and thyroglobulin antibodies (Tg-Ab) were obtained. Among 4000 type 2 diabetic subjects (1649 male and 2351 female), 1762(44%) were known to have thyroid disease. A total of 1466 (36.7%) had positive TPO antibodies and 1072 (26.8%) had positive Tg-Ab antibodies. The logistic regression of thyroid dysfunction on Tg-Ab as well as TPO-Ab status (positive vs. negative) was significant (P=0.0001). Our results showed strong association of thyroid dysfunction with autoantibodies, especially in patients with Tg-Ab positive. Therefore, the findings suggest that all subjects with type 2 diabetes, particularly those with positive antibodies, should undergo annual screening to detect asymptomatic thyroid dysfunction.