Monthly high-dose vitamin D supplementation does not prevent cardiovascular disease in the general population, according to a study published in JAMA Cardiology.

Robert Scragg, MBBS, PhD, from the School of Population Health at  the University of Auckland in New Zealand, and colleagues conducted a randomized, double-blind, placebo-controlled trial that recruited participants from family practices in Auckland, New Zealand, from April 5, 2011, through November 6, 2012, with follow-up until July 2015. Participants were aged 50 to 84 years. Of 47,905 adults invited from family practices and 163 from community groups, 5110 participants were randomized to receive vitamin D3 (n = 2558) or placebo (n = 2552).

Participants received oral vitamin D3 in an initial dose of 200,000 IU, followed a month later by monthly doses of 100,000 IU, or placebo for a median of 3.3 years. The primary outcome was the number of participants with incident CVD and death, including a prespecified subgroup analysis in participants with vitamin D deficiency. Secondary outcomes were myocardial infarction, angina, heart failure, hypertension, arrhythmias, arteriosclerosis, stroke, and venous thrombosis.

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Of the 5108 participants included in the analysis, the mean age was 65.9 years, 2969 (58.1%) were male, and 4253 (83.3%) were of European or other ethnicity, with the remainder being Polynesian or South Asian. Mean baseline deseasonalized 25(OH)D concentration was 26.5 ng/mL, with 1270 participants (24.9%) being vitamin D deficient.

In a random sample of 438 participants, the mean follow-up 25(OH)D level was greater than 20 ng/mL higher in the vitamin D group than in the placebo group. CVD occurred in 303 participants (11.8%) in the vitamin D group and 293 participants (11.5%) in the placebo group (hazard ratio, 1.02). Similar results were seen for participants with baseline vitamin D deficiency and for secondary outcomes.

“The results of this large population-based RCT indicate that vitamin D supplementation given in the dose and frequency we used does not prevent CVD, and the findings are consistent with previous RCTs of vitamin D supplementation and mendelian randomization studies,” the authors stated.


  1. Scragg R, Stewart AW, Waayer D, et al. Effect of monthly high-dose vitamin D supplementation on cardiovascular disease in the Vitamin D Assessment Study: A randomized clinical trial. JAMA Cardiol. 5 April 2017. doi: 10.1001/jamacardio.2017.0175