Thyroid ultrasound in diabetic patients without overt thyroid disease

Abstract

Purpose: To assess thyroid volume and to evaluate possible lesions in the gland structure using thyroid ultrasound in patients with diabetes mellitus type 1 (DM1) and 2 (DM2) without overt thyroid disease. Material and Methods: Consecutive adult patients with DM2 ( n = 98) and DM1 ( n = 30) without overt thyroid disease referred to our department because of poorly controlled disease and/or diabetic complications were prospectively analyzed. Thyroid volumes, gland echogenicity, thyroid nodules incidence, and TSH levels were compared with control groups ( n = 50 and 38) and matched according to sex and age. Results: Significant increases in median thyroid volume were observed in both subjects with DM1 (17.3 cm3, interquartile range (IR) 13.9–21.6 cm3 versus 14.4 cm3, IR 11.3–18.3 cm3; P<0.05) and DM2 (20.5 cm3, IR 14.9–27.1 cm3 versus 14.1 cm3, IR 11.3–18.3 cm3; P<0.001) in comparison to their control groups. Moreover, in the population of type 2 diabetics, thyroid nodules (OR 2.37, 95% CI 1.14–4.93), parenchymatous goiter (OR 5.40, 95% CI 1.20–24.30), and all kinds of thyroid goiter according to the WHO definition (OR 4.18, 95% CI 2.02–8.66) were remarkably more frequent. In our patients, reduced (but within normal range) TSH level occurred in DM1 (median 0.97 mIU/l, IR 0.61–1.58 mIU/l versus median 1.66 mIU/l, IR 0.76–2.09 mIU/l; P<0.05). The presence of a negative linear correlation between thyroid volume and TSH concentration was noticed in patients with DM2 ( RS = −0.38, P<0.01). Conclusion: In individuals with DM1 and DM2 treated for poorly controlled disease and/or diabetic complications, thyroid volumes were significantly higher than in the normal population. Moreover, nodular thyroid structure and parenchymatous goiter occurred more frequently in these type 2 diabetic patients.