Vitamin D supplements may reduce the risk of major cardiovascular events such as heart attacks among people aged over 60, according to a new clinical trial. The researchers stress that the absolute risk difference was small, but say this is the largest trial of its kind to date, and further evaluation is warranted, particularly in people taking statins or other cardiovascular disease drugs.

The D-Health Trial was carried out from 2014 to 2020 and involved 21,315 Australians ages 60-84 who randomly received one capsule of either 60,000 IU vitamin D (10,662 participants) or placebo (10,653 participants) taken orally at the beginning of each month for up to 5 years.

Data on hospital admissions and deaths were then used to identify major cardiovascular events, including heart attacks, strokes, and coronary revascularization (treatment to restore normal blood flow to the heart).

The average treatment time was five years and more than 80% of participants reported taking at least 80% of the study tablets.

During the trial, 1,336 participants experienced a major cardiovascular event (6.6% in the placebo group and 6% in the vitamin D group).

The rate of major cardiovascular events was 9% lower in the vitamin D compared with the placebo group (equivalent to 5.8 fewer events per 1,000 participants).

The heart attack rate was 19% lower and the rate of coronary revascularization was 11% lower with vitamin D, but there was no difference in the rate of stroke between the two groups.

There was some indication of a stronger effect among those who were using statins or other cardiovascular drugs at the start of the trial, but the researchers say these results were not statistically significant.

Overall, the researchers calculate that 172 people would need to take monthly vitamin D supplements to prevent one major cardiovascular event.

The findings suggest that vitamin D supplementation may reduce the risk of major cardiovascular events. “This protective effect could be more marked in those taking statins or other cardiovascular drugs at baseline,” the researchers said, and they suggest that further evaluation is needed to help to clarify this issue. 

To read the study, published in the BMJ, click here