Background: Observational studies report a relationship between increased aortic stiffness and low vitamin D levels. This suggests that aortic stiffness may be improved with vitamin D supplementation, but there is limited intervention data to support this hypothesis. This study aimed to determine the effect of vitamin D supplementation on aortic stiffness and associated central haemodynamic indices.

Methods: In a double-blind, placebo-controlled trial, 265 individuals (63±7, female 50%) with vitamin D deficiency were randomized to 12-months intervention (vitamin D 50,000 IU/month; n=132) or matching placebo (n=133). Aortic stiffness (carotid-femoral pulse wave velocity; aPWV), central haemodynamic indices (augmentation index, augmented pressure, central pulse pressure) and brachial blood pressure were measured at baseline, six and 12 months.

Results: At baseline there were no significant differences between the groups in aPWV (9.0±0.3 vs 9.1±0.2 m/s; P=0.6), nor any other central hemodynamic indices or brachial blood pressure (all P > 0.05). Intervention failed to make any clinical or statistically significant changes to aPWV (0.16±1.9 vs −0.12±2.2 m/s; P=0.4), or any other haemodynamic variable relative to control at six or 12 months (all P > 0.05).

Conclusions: Despite many observational studies to suggest that vitamin D supplementation could be a useful therapy for improving aortic stiffness and associated haemodynamic indices, 12-months intervention yielded no improvement in older people with vitamin D deficiency. These results do not support use of vitamin D supplementation to improve cardiovascular health in this patient population.