Supplementation with vitamin D does not appear to provide cardiovascular protection, according to a recently published meta-analysis.
To date, several observational studies assessing the relationship between vitamin D levels and cardiovascular disease (CVD) have suggested that low serum vitamin D may increase a patient’s risk of major adverse cardiovascular events (MACE). However, due to the possibility of unmeasured confounding, these studies could not prove causation.
For this study, PubMed, the Cochrane Library, and Embase were searched from inception to December 15, 2018 for randomized clinical trials that assessed the association between long-term (≥1 year) vitamin D use and CVD events and all-cause mortality. The primary outcome measure of the study was MACE; secondary endpoints included rates of myocardial infarction (MI), stroke/cerebrovascular accident, CVD mortality, and all-cause mortality.
The analysis included 21 randomized clinical trials with a total of 83,291 patients (mean age [SD]: 65.8 [8.4] years; 74.4% female). Of these patients, 41,669 received vitamin D and 41,622 received placebo. The authors noted that only 4 studies included in the review had prespecified CVD as a primary outcome.
Results showed that compared with placebo, vitamin D supplementation was not associated with a reduction in MACE (risk ratio [RR]: 1.00; 95% CI: 0.95, 1.06; P = .85). Additionally, the analysis revealed that supplementation with vitamin D was not associated with a reduction in MI (RR: 1.00; 95% CI: 0.93, 1.08; P =.92), stroke (RR: 1.06; 95% CI: 0.98, 1.15; P =.16), CVD mortality (RR: 0.98; 95% CI: 0.90, 1.07; P =.68), or all-cause mortality (RR: 0.97; 95% CI: 0.93, 1.02; P =.23) compared with placebo.
“Results were generally consistent by sex, baseline 25-hydroxyvitamin D level, vitamin D dosage, formulation (daily vs bolus dosing), and presence or absence of concurrent calcium administration,” the study authors stated.
They concluded that trials investigating higher doses of vitamin D in an older population where CVD outcomes such as heart failure are assessed would be of interest, as few of the trials in this meta-analysis included data on this particular endpoint.
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