[Photo by Ji Zhe/Asianewsphoto]

High-dose vitamin D supplementation given monthly does not prevent cardiovascular disease, results of a large randomized trial suggested Wednesday.

People with low vitamin D status have previously been linked to increased incidence of cardiovascular disease, but so far, randomized clinical trials of vitamin D supplementation have not found an effect, possibly because of using too low a dose of vitamin D.

The new study, published in the U.S. journal JAMA Cardiology, included more than 5,100 adults with an average age of 66 years, 25 percent of whom were vitamin D deficient.

These participants were randomly divided into two groups and given either oral vitamin D3 or placebo with an initial dose of 5.0 mg followed by monthly doses of 2.5 mg.

After 3.3 years of follow-up, cardiovascular disease occurred in 303 participants, or 11.8 percent, in the vitamin D group and 293 participants, or 11.5 percent, in the placebo group.

Similar results were seen for participants with vitamin D deficiency at study entry and for other outcomes such as heart attack, angina, heart failure, hypertension, and stroke.

"This result does not support the use of monthly high-dose vitamin D supplementation for this purpose (prevention of cardiovascular disease)," Robert Scragg of the University of Auckland, New Zealand, and colleagues wrote in their study. "The effects of daily or weekly dosing require further study."