Association of Vitamin D Supplementation with Cardiovascular Events: A Systematic Review and Meta-Analysis

Background: low vitamin D status has been associated with an increased incidence of cardiovascular events. However, whether vitamin D supplementation would reduce the incidence of cardiovascular events remains unclear. Purpose: To perform a systematic review and meta-analysis of the effect of vitamin D supplementation on the mortality and incidence of cardiovascular events. Data Sources: We searched Medline, Embase, and the Cochrane Central Register of Controlled Trials from their inception until 3 May 2022. Study Selection: Two authors searched for randomized clinical trials that reported vitamin D supplementation's effect on cardiovascular events outcomes. Data Extraction: Two authors conducted independent data extraction. Data Synthesis: We identified 41,809 reports; after exclusions, 18 trials with a total of 70,278 participants were eligible for analysis. Vitamin D supplementation was not associated with the mortality of cardiovascular events (RR 0.96, 95% CI 0.88-1.06, I-2 = 0%), the incidence of stroke (RR 1.05, 95% CI 0.92-1.20, I-2 = 0%), myocardial infarction (RR 0.97, 95% CI 0.87-1.09, I-2 = 0%), total cardiovascular events (RR 0.97, 95% CI 0.91-1.04, I-2 = 27%), or cerebrovascular events (RR 1.01, 95% CI 0.87-1.18, I-2 = 0%). Limitation: Cardiovascular events were the secondary outcome in most trials and thus, might be selectively reported. Conclusion: In this meta-analysis of randomized clinical trials, vitamin D supplementation was not associated with a lower risk of cardiovascular events than no supplementation. These findings do not support the routine use of vitamin D supplementation in general.