The trial published in JAMA Internal Medicine, tested whether high-dose supplementation with vitamin D3 (cholecalciferol) lowered blood pressure in older people with hypertension after previous epdiemiological evidence suggested a possible link between high blood pressure and a deficiency in the vitamin.
However, the new parallel group, double-blind, placebo-controlled randomised trial - led by Dr Miles Witham from the University of Dundee, UK - found the supplementation did not appear to improve blood pressure or markers of vascular health.
"No significant treatment effect was seen for mean office blood pressure ," said the researchers - who added that secondary measures of blood pressure and cardiovascular disease (CVD) were also non-significant.
"It is still possible, however, that vitamin D supplementation could have beneficial effects on cardiovascular health via non-blood pressure effects, and ongoing large randomized trials are due to report on this in the next few years," concluded Witham and his team - who also noted that there was no evidence of adverse events in the treatment group, and the total number of falls was non-significantly lower in the group receiving vitamin D.
The trial, randomly assigned a total of 159 patients (average age 77 years) with isolated systolic hypertension participated to receive either vitamin D (a total of 100 000 international units of oral cholecalciferol) or matching placebo every three months for one year.
The team monitored and analysed any differences in office blood pressure, 24-hour blood pressure, arterial stiffness, endothelial function, cholesterol level, insulin resistance, and b-type natriuretic peptide level during the 12 month study period.
Witham and his team reported that no significant effect was seen for average office blood pressure, and or any of the secondary outcomes - including 24-hour blood pressure, arterial stiffness, endothelial function, cholesterol level, glucose level, and walking distance.
Source: JAMA Internal Medicine
Published online ahead of print, doi: 10.1001/jamainternmed.2013.9043
"Cholecalciferol Treatment to Reduce Blood Pressure in Older Patients With Isolated Systolic HypertensionThe VitDISH Randomized Controlled Trial"
Authors: Miles D. Witham, Rosemary J. G. Price, Allan D. Struthers, et al