Vitamin D deficiency is associated with mortality in patients with chronic kidney disease (CKD). Its supplementation might mitigate cardiovascular disease (CVD) risk in CKD. In this study, we investigated the effect of cholecalciferol supplementation on vascular function in patients with non-diabetic CKD stage 3-4 and vitamin D deficiency. In this randomized, double blind, placebo controlled trial, 120 patients of either sex, 18-70 years of age with non-diabetic CKD stage 3-4 and vitamin D deficiency [serum 25(OH)D ≤20ng/ml] were randomized (1:1) to receive either two directly observed oral doses of 300,000 IU of cholecalciferol or matching placebo at baseline and 8 weeks. The primary outcome was change in endothelium dependent brachial artery flow mediated dilatation (FMD) at 16 weeks. Secondary outcome measures included changes in pulse wave velocity (PWV) and circulating biomarkers. Cholecalciferol supplementation significantly increased endothelium dependent brachial artery FMD whereas no significant change was observed in the placebo group [between-group difference in mean change: 5.49% (95% CI: 4.34 to 6.64, p
