Background: Vitamin D deficiency is a global public health concern. Many recent studies indicate that vitamin D deficiency is related to the higher risk of chronic diseases such as coronary heart disease cardiovascular disease (CVD), type 2 diabetes (T2DM), and metabolic syndrome. Aim: This article explored the published evidence of prevalence of vitamin D deficiency among type 2 diabetes patients and its effect on glycemic control. Methodology: Pub Med, Science direct and Web of science data bases were searched to identify studies published from 2013- 2017 regarding the prevalence of vitamin D deficiency in patients with T2DM. A total of twenty five studies conducted among Type 2 diabetic patients from thirteen countries were included based on the inclusion criteria. Main findings: Twenty out of twenty five articles reviewed have revealed the prevalence of vitamin D deficiency in T2DM patients. Two articles that studied the correlation between vitamin D levels and T2DM found that vitamin D levels have an inverse relationship with diabetic markers, such as hemoglobin A1C, fasting blood glucose. Two of the studies could not find a similar correlation. Three case control studies revealed that vitamin D deficiency was found in both cases and controls. Conclusion: Thus it can be concluded that, vitamin D deficiency is widely prevalent in type 2 diabetic population globally and it is the need of the hour to identify and treat such deficiencies with can play a major role in glycemic control.
