Vitamin D Use Does Not Reduce Risk of Cardiovascular Disease

Despite past research suggesting a possible association, a recent study has found that vitamin D use does little to reduce the risk of cardiovascular disease events (CVD).

After examining data from more than 83,000 patients, investigators determined that vitamin D supplementation was not associated with reduced risk of major adverse cardiovascular events, stroke, or all-cause mortality.

The findings echo those of a study into vitamin D supplementation among patients at risk for diabetes presented at ADA 2019 earlier this month.

Investigators sought to prove whether there was an association between low serum vitamin D levels and elevated risk of cardiovascular disease events. Using PubMed, the Cochrane Library, and Embase, investigators examined randomized clinical trials that reported the effect of long-term, which was defined as a year or more, vitamin D supplementation on CVD events and all-cause mortality.

A total of 7816 articles were identified and, based on inclusion criteria, that number was reduced to 21 randomized clinical trials that were included within the analyses. Of the 21 trials included, 8 included postmenopausal women, 9 included older patients, 2 trials included patients with chronic kidney disease, 2 trials included patients with heart failure, and 1 included patients with chronic obstructive pulmnary disease.

From the 21 trials, 83,291 patients were included in the study — 41,699 received vitamin D supplementation and 41,622 received placebo therapy. The mean age was 65.8 years and 61,943 (74.4%) participants were female.

The primary end point of the study was a composite of major adverse cardiovascular events (MACE), as defined by each trial. The secondary end points were myocardial infarction (MI), stroke/cerebrovascular accident, CVD mortality, and all-cause mortality.

After examining results, investigators found no significant difference in MACE incidence based upon receipt of vitamin D supplementation. Additionally, a sensitivity analysis also found nonsignificant results. A meta-regression analysis found a significant association of reduced MACE with advanced age. Investigators noted that vitamin D supplementation, when compared with placebo, was not associated with a reduced risk of MI, stroke, CVD mortality, or all-cause mortality.

Investigators pointed out multiple limitations within their study. Most of the trials examined did not have prespecified CVD as the primary endpoint and were underpowered for CVD events. Additionally, the definition of MACE was variable in the included trials and many lacked data on heart failure. Results of the subgroup analyses had low data counts and additional larger trials are needed for definitive conclusions. Lastly, investigators lacked patient-level data and could not examine some subgroups.

In a related commentary, Arshed Quyyumi, MD, and Ibhar Al Mheid, MD, both of Emory University School of Medicine, wrote that the results support the idea that vitamin D supplements are often viewed as wrongfully viewed as a panacea but that physicians should remember they are still useful.

“(The study) supports efforts aimed at curbing wasteful spending on vitamin D testing and treatment in populations not at risk for deficiency and/or for the purpose of preventing CVD morbidity and mortality,” Quyyumi and Mheid wrote. “At the same time, it also should be emphasized that vitamin D therapy in patients with chronic kidney disease and hyperparathyroidism is definitely indicated, and such therapy has established cardiovascular benefits, including blood pressure reduction, reduced electrolyte derangements, and overall reduced cardiovascular mortality rates in patients on hemodialysis.”

This study, titled “Vitamin D Supplementation and Cardiovascular Disease Risks in More Than 83 000 Individuals in 21 Randomized Clinical Trials,” was published in JAMA Cardiology.