Effect of Vitamin D Treatment on Glycemic Control, Diastolic Functions, and Carotid Intima-Media Thickness in Patients with Type 2 Diabetes Mellitus

Objective: The purpose of this study was to investigate the influence of 25(OH)D3 levels on glycemic control, diastolic functions, and carotid intima-media thickness in patients with Type 2 diabetes mellitus. Material and Methods: Patients admitted to the endocrinology department, with the diagnosis of Type 2 diabetes mellitus, who were under follow-up for at least six months and also had 25(OH)D3 deficiency [25(OH)D3 levels <20 ng/mL] were included in this study. D3 supplement (50.000 IU) was administered to the patients every month up to six months. Carotid intima-media thickness was measured using the B-mode ultrasonography. Diastolic function was evaluated using the tissue doppler imaging by measuring tissue e wave/tissue a wave (e'/a') and annular E wave/tissue e wave (E/e') ratios. All the evaluations were made at baseline and at six months after vitamin D3 supplementation. Results: A total of 45 (27 females, 18 males; mean age: 56.2 +/- 7.8 years) patients were included in this study. The mean duration of diabetes was 8.5 +/- 6.8 (ranging from 7.0 to 9.0 years) years. It was found that even after D3 supplementation, fasting plasma glucose and Hemoglobin A1C levels did not change, yet, the carotid intimamedia thickness reduced (788 +/- 100 mu m vs. 745 +/- 116.8 mu m; p=0.009). Diastolic function parameters e'/a' (0.79 +/- 0.21 vs. 0.89 +/- 0.26; p=0.03) and E/e' (7.27 +/- 1.81 vs. 6.52 +/- 1.65; p=0.048) also improved significantly after the therapy. Conclusion: Vitamin D supplementation, in patients with Type 2 diabetes mellitus, who are also having vitamin D deficiency, seems to be beneficial in reducing the thickness of carotid intima-media, which is a well-known cardiovascular risk predictor, and in improving diastolic functions by vitamin D repletion. Further prospective well-designed studies with a larger patient population are needed to lead a firm conclusion in this regard.