Introduction: Type II diabetes is associated with impaired function of various organs, including thyroid. The present study aimed to investigate the serum levels of triiodothyronine (T₃), thyroxine (T₄), and thyroid stimulating hormone (TSH) in type II diabetes patients who referred to Diabetes Center of Sanandaj, Iran. In addition, the results were compared with non-diabetic healthy subjects.

Materials and Methods: This descriptive-analytic study was performed on 100 patients with type 2 diabetes who referred to the Diabetes Center of Tohid Hospital in Sanandaj and 100 healthy individuals. All the participants were selected through convenience sampling. The demographic data of the study subjects were collected using a questionnaire and blood samples were taken to determine the serum levels of T3, T4, and TSH. All the obtained data were analyzed by SPSS version 19..

Results: The findings of this study demonstrated that the prevalence of abnormal TSH, T4, and T3 hormones levels was 26, 18, and 15% in patients with type 2 diabetes, respectively. On the other hand the mentioned prevalence for TSH, T4, and T3 hormones was 4, 4, and 3% in the healthy subjects. The mean TSH levels in patients with type 2 diabetes mellitus (5.67±4.33 mIU/L) was significantly higher than that of controls (2.79±1.68 mIU/L) (P<0.001). Furthermore, the mean concentrations of T4 and T3 were significantly lower in subjects with type 2 diabetes mellitus with the means of 7.18±2.18 and 1.17±0.42 mIU/L, compared to the healthy individuals with the means of 7.97±1.67 and 1.3±0.33 mIU/L, respectively

Conclusion: According to the results of current study, the prevalence of thyroid dysfunction was significantly higher in type 2 diabetic patients, in comparison with the healthy participants. Considering the high prevalence of thyroid dysfunction in type 2 diabetic patients and the effect of thyroid function on sugar and lipid metabolism, it is recommended to evaluate thyroid function in diabetic patients.