A Study to Evaluate the Effect of Vitamin D Supplementation on Insulin Sensitivity and Secretion

A Pilot Study to Evaluate the Effect of Vitamin D Supplementation on Insulin Secretion and Peripheral Insulin Sensitivity

The purpose of the study is to evaluate the change in insulin sensitivity and secretion indices (early markers for development of diabetes) after 4 weeks of a megadose of Vitamin D. This will also help to calculate sample size for and choose an appropriate index for a larger randomized control trial which may be required subsequently.

Accumulating evidence suggests that serum Vitamin D levels may be inversely related to the prevalence of diabetes, to the concentration of glucose , insulin resistance and metabolic syndrome.The available trials have been conducted using small sample sizes in different subgroups (hemodialyzed patients , healthy volunteers , gestational diabetes and post menopausal women ) document variable results with a positive result in some (hemodialysis and gestational diabetes) and no effect in other settings(healthy volunteers and postmenopausal women).We therefore, planned this trial to study the effect of vitamin D supplementation (240,000 IU) on insulin secretion and peripheral insulin sensitivity.This will also help to calculate sample size for and choose an appropriate index for a larger randomized control trial which may be required subsequently. Study design and comparison:Single group, open label intervention trial involving assessment of insulin sensitivity and secretion in 30 volunteers before and after 4weeks of a megadose of Vitamin D. The pre and post intervention results will be compared using the paired t test.

Inclusion Criteria: Male ≥30 years of age Waist circumference ≥80 cm Exclusion Criteria: Diabetic- Fasting Blood Sugar >126 mg/dl or on anti-diabetic medication BP>140/90 or on anti-hypertensive medication Receiving Vitamin D or calcium supplementation Chronic disease-renal/hepatic/malignancy/gastrointestinal On any medication within the last one month which could potentially influence insulin secretion, insulin sensitivity, Vitamin D or Calcium metabolism Febrile illness or infective morbidity in the past 10 days