Abstract
Background: Vitamin D deficiency and associated complications are widely prevalent in the Indian subcontinent. Hypovitaminosis D is known to play deleterious effects on cardiovascular and skeletal functions in human beings. Yet, its effect on carbohydrate metabolism and diabetes mellitus (DM) is less known.

Aim and Objectives: In the current case– control study, our primary aim is to find out the potential effect of hypovitaminosis D on glycemic control in type 2 DM (T2DM) patients.

Materials and Methods: The study population comprised 250 T2DM patients recruited primarily from Madhya Pradesh, India. The case group of 125 T2DM patients with hypovitaminosis D was compared with a control group of 125 T2DM patients with sufficient vitamin D. We mainly investigated the effect of hypovitaminosis D (both deficiency and insufficiency) on glycemic control in T2DM patients.

Results: We observed that both fasting and 2-h postprandial blood glucose were found to be elevated significantly in T2DM patients with hypovitaminosis D (P < 0.01). The glycated hemoglobin level was also elevated (P < 0.01) in the case group suggesting impaired glycemic control for a chronic period. An inverse association is found between glycemic status and serum vitamin D (OH)D3 levels.

Conclusions: Our results show the significance of maintaining sufficient plasma vitamin D levels, along with hypoglycemic medication in T2DM patients to improve their glycemic control and avoid diabetic comorbidities.