Vitamin D Levels and Microvascular Complications in Type 2 Diabetes Mellitus Patients: A Study from North Keral

Introduction: Vitamin D plays an important role in glucose metabolism. Several pleiotropic effects of Vitamin D have been studied like regulation of cell proliferation, suppression of cell mediated immunity, Glial cell line-derived neurotrophic factor, stimulation of nerve growth factor, suppression of Renin-angiotensin-aldosterone system (RAAS), reduction of albuminuria, immunomodulatory effects, and anti-inflammatory effects.(1)Thus, vitamin D is implicated in the pathogenesis of retinopathy, neuropathy and nephropathy. Materials and Methods: A Cross-sectional case-control study of 206 patients (>30 years), who met the American Diabetes Association, 2011 criteria (2) for type 2 DM, was conducted. Subjects were evaluated for the presence of microvascular complications by clinical evaluation, urine examination, fundus examination, clinical neuropathy scoring, and various biochemical tests. 25-OH cholecalciferol levels were done and cut off level for vitamin D deficiency was 30 ng/ml. 72 Vitamin D sufficient and 134 Vitamin D deficient cases were studied. Results: A total of 134 T2DM cases with Vitamin D deficiency were studied. 72 age matched T2DM patients with sufficient Vitamin D levels served as controls. The mean age of cases under study was 47.58 ± 9.63 years compared to 51.24 ± 8.75 years of controls. 61.2% were females, whereas 38.8% were males in the case group while in the control group, 69.4% were males, and 30.5% were females. The mean duration of diabetes in the cases studied was 57.08 ± 18.13 months. It was 52.69 ± 17.98 months in the Vitamin D sufficient controls.  Significant statistical associations were established using Chi square test between Vitamin D status and development of microvascular complications like Diabetic nephropathy, retinopathy and neuropathy in Type 2 Diabetes Mellitus at p < 0.05. Conclusion and Implication: Vitamin D is an important factor in modifying the risk of Type 2 DM and its microvascular complications, especially Diabetic retinopathy, neuropathy and nephropathy. Administration of vitamin D supplements may prove to be a beneficial adjuvant therapy in mitigating microvascular complications. Frequent Monitoring of Vitamin D status can decrease the burden of co-morbidities in T2DM and thus can decrease the mortality rate associated with T2DM. However; the exact role of vitamin D in these processes requires further investigations. Keywords: Diabetes, Nephropathy, Neuropathy, Retinopathy, Vitamin D