Role of vitamin D deficiency in type 2 diabetes: Association or coincidence?

Abstract

Background. Vitamin D has received considerable attention for its possible role in myriad of clinical conditions especially non-communicable chronic diseases. however, it is the role in the pathogenesis of type 2 diabetes (T2DM), which has generated a lot of enthusiasm to unravel the association between the two. Aim. To determine the prevalence of hypovitaminosis D and its relation with the glycemic control in T2DM patients attending a tertiary care hospital in Kashmir. Methods. A total of 108 cases of T2DM and 101 healthy controls aged between 35-65years were investigated in this study. 25-hydroxyvitamin D (25OHD), glycosylated hemoglobin (hbA1c) and fasting serum insulin levels were determined using standardised and automated assays. insulin resistance (ir) and beta-cell function (B) were estimated by the homeostasis model assessment (hOMA). results. The mean serum level of 25OhD was significantly lower in T2DM group compared to controls (20.55 ± 12.27 vs 27.62 ± 5.32 ng/mL; P = 0.001). The prevalence of hypovitaminosis D was significantly higher in patients with T2DM (79.5% vs 62.7%; P = 0.031). Overall 51.1% and 28.4% patients with diabetes and 41.2% and 21.6% controls had vitamin D deficiency and insufficiency respectively. Vitamin D was found to have a significantly positive association with serum fasting insulin level and hOMA-B in both cases (P = 0.019), (P = 0.026) and controls (P = 0.022), (P = 0.008) respectively. Prolonged glycemic control as determined by hbA1c demonstrated a significant inverse correlation with vitamin D level in both cases (r = -0.225;P = 0.035) and controls (r = -0.373; P = 0.007). Conclusion. We conclude that vitamin D deficiency (VDD) is a very common health problem and is relatively more common in patients with T2DM. There is an inversed association between vitamin D and glycemic control. Vitamin D status thus appears to affect glucose homeostasis. Vitamin D screening and supplementation is a plausible way to mitigate the impact of VDD on glucose homeostasis in T2DM.