Daily Dose: Vitamin D Supplementation and Major Cardiovascular Events in Older Adults

Patient Care brings primary care clinicians a lot of medical news every day—it’s easy to miss an important study. The Daily Dose provides a concise summary of one of the website's leading stories you may not have seen.

Last week, we reported on a study published in The BMJ that examined whether supplementing older adults with monthly doses of vitamin D altered the incidence of major cardiovascular (CV) events.

The study

Investigators used data from their original randomized placebo-controlled D-Health Trial, which they conducted to determine if monthly vitamin D supplementation can improve health outcomes in the general population of older adults. D-Health enrolled 21 315 participants aged 60-84 years compared with placebo.

The primary outcome was the occurrence of a major CV event, including myocardial infarction (MI), stroke, and coronary revascularization.

Participants were assigned 60 000 IU per month of vitamin D (n=10 658), or placebo (n=10 644) taken orally for up to 5 years. At 5 years, follow-up was completed by 80.2% of the vitamin D group and 77.6% of the placebo group. Also, the majority of participants in both the vitamin D group (84%) and placebo group (82%) reported taking at least 80% of the study tablets.

The findings

At 5 years, researchers observed a major CV event in 6.0% of the vitamin D group and 6.6% of those in the placebo arm. The rate of major CV events was lower among persons in the vitamin D group than those in the placebo arm, especially among those who were taking CV medication at baseline.

In addition, compared with the placebo group, the vitamin D group had lower rates of MI (HR 0.81, 95% CI 0.67-0.98) and coronary revascularization (HR 0.89, 95% CI 0.78-1.01), but not stroke (HR 0.99, 95% CI 0.8-1.23).

A note from authors

"Vitamin D supplementation might reduce the risk of major cardiovascular events, although the absolute risk difference was small and the confidence interval was consistent with a null finding. Further evaluation is warranted, particularly in people taking statins or other cardiovascular disease drugs."

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