Effect of cholecalciferol supplementation during winter months in patients with hypertension: A randomized, placebo-controlled trial

Abstract

BackgroundLow 25-hydroxy-vitamin D (25(OH)D) levels are inversely related to blood pressure (BP) and have been associated with incident hypertension. In people living at northern latitudes diminished cholecalciferol synthesis in the winter increases the risk of vitamin D deficiency. We wanted to test the hypothesis that daily cholecalciferol supplementation in the winter lowers BP in patients with hypertension.MethodsWe investigated the effect of 75g (3,000 IU) cholecalciferol per day in a randomized, placebo-controlled, double-blind study in 130 hypertensive patients residing in Denmark (56 N). Ambulatory BP (24-h BP) and arterial stiffness were measured before and after 20 weeks of treatment, that took place between October and March.ResultsA total of 112 patients (mean age 61 ± 10) with a baseline p-25(OH)D of 23 ± 10 ng/ml completed the study. Compared with placebo, a nonsignificant 3/1 mm Hg (P = 0.26/0.18) reduction was found in 24-h BP. In patients with vitamin D insufficiency (32 ng/ml) at baseline (n = 92), 24-h BP decreased by 4/3 mm Hg (P = 0.05/0.01). Central BP (CBP) estimated by applanation tonometry and calibrated with a standardized office BP was reduced by 7/2 mm Hg (P = 0.007/0.15) vs. placebo. No differences in carotid-femoral pulse wave velocity (PWV) or central augmentation index (AIx) were found between treatment arms. ConclusionsCholecalciferol supplementation, by a dose that effectively increased vitamin D levels, did not reduce 24-h BP, although central systolic BP decreased significantly. In a post-hoc subgroup analysis of 92 subjects with baseline p-25(OH)D levels 32 ng/ml, significant decreases in 24-h systolic and diastolic BP occurred during cholecalciferol supplementation. © 2012 American Journal of Hypertension, Ltd.