Vitamin D: A Critical Micronutrient for Vascular Health in Type 2 Diabetes Mellitus

Vitamin D deficiency may be responsible for endothelial dysfunction which in turn affects the onset and progression of vascular disease including coronary artery disease and its risk factor, directly or indirectly through various mechanisms. This study was undertaken to find out association between vitamin D and endothelial dilatation of brachial artery, which may help to suggest possible underlying mechanisms and may be of clinical importance in planning preventive and therapeutic strategies.

50 cases of type 2 diabetes mellitus aged 40-60 years were taken. 50 cases without type 2 diabetes mellitus matched for confounding factors were taken as controls. Venous blood samples were collected for the investigations including vitamin D levels. Then Participants were subjected to ultrasound examination for measurement of flow mediated dilatation (FMD) and endothelial independent dilatation after ingestion of glyceryl tri-nitrate (GTN). Unpaired student T test and correlation coefficient analysis were used to find out association between different variables.

The mean values of FMD were 18.85 ± 5.39% and 10.29 ± 4.91% in controls and cases respectively (p<0.001). The dilatation after GTN was observed to be 26.16 ± 4.25% and 18.74 ± 5.72% in controls and cases respectively (p<0.001). The mean levels of vitamin D among controls and cases were 25.41 ± 12.18 and 14.52 ± 8.28 ng/ml respectively. The correlation between endothelial dependent dilatation (FMD), endothelial independent dilatation (after GTN) and vitamin D was found to be more positive in cases (r=0.870, r=0.798) than controls (r=0.079, r=0.158).

Vitamin D deficiency state is higher among cases of type 2 DM. Endothelial dependent dilatation (FMD) was found to be lower among the patients of type 2 DM. The study gives us an insight to identify the diabetics with vitamin D deficiency which may be at higher risk of vascular complications including coronary artery disease.