Effect of oral vitamin D supplementation on glycemic control in patients with type 2 diabetes mellitus with coexisting hypovitaminosis D: A parellel group placebo controlled randomized controlled pilot study.

CONTEXT: Vitamin D supplementation in type 2 diabetes mellitus patients may lead to improved glycemic control by improving insulin secretion and decreasing insulin resistance.

AIMS: To investigate effect of oral vitamin D supplementation on glycemic control, in patients with type 2 diabetes mellitus and coexisting hypovitaminosis D.

SETTINGS AND

DESIGN

Randomized, Parallel Group, Placebo Controlled Trial carried out in a tertiary care hospital of Indian Armed Forces.

METHODS AND MATERIAL: Sixty patients with coexisting type 2 diabetes mellitus and hypovitaminosis D were randomized into cases and controls and were supplemented with oral Vitamin D and microcrystalline cellulose respectively for six months. Subjects' HbA1c and vitamin D levels were monitored at the beginning and end of the study, fasting plasma glucose (FPG) & post prandial plasma glucose (PPPG) during monthly OPD visits.

STATISTICAL ANALYSIS USED: Intra-group comparison was made by paired t test & unpaired t test was used for inter-group (A v/s B) comparisons. Repeated measures ANOVA was undertaken to compare values over time.

RESULTS

The two groups were comparable for all parameters at baseline. Case group showed significant decrease in mean HbA1c levels (7.29% to 7.02%; P = 0.01), mean FPG levels (131.4 to 102.6 mg/dl; P = 0.04) and mean PPPG levels (196.2 to 135.0 mg/dl; P < 0.001). Incidentally, significant improvement in systolic as well as diastolic blood pressure and total cholesterol was also noted in the cases, while for LDL cholesterol improvement tended towards significance (p = 0.05).

CONCLUSIONS

We found that oral vitamin D supplementation was associated with improved glycemic control and other metabolic parameters in patients with type 2 diabetes mellitus. Supplementation to achieve normal levels of vitamin D can be a promising adjuvant therapy for T2DM patients & coexisting hypovitaminosis D.