Association between blood vitamin D and myocardial infarction: A meta-analysis including observational studies

The association between blood vitamin D levels and the risk of myocardial infarction (MI) is controversial. This meta-analysis aimed to describe the relationship between MI risk and blood vitamin D levels.

Online databases were searched in PubMed, EMBASE and Web of science till February 2017 for observational studies in relation to reporting the vitamin D levels in MI cases and non-MI controls. The weighted mean difference (WMD) or odds ratio (OR), with 95% confidence interval (CI), were calculated to evaluate the relationship between MI risk and blood vitamin D levels.

Eight observational studies with 9913 individuals, consisted of 3411 MI patients and 6502 non-MI controls, were included in our study. The pooled results revealed that blood vitamin D levels were significantly lower in MI patients when compared with non-MI controls (WMD=-3.40; 95% CI: -5.87 to -0.92, P=0.007). Subgroup analyses indicated MI patients were also associated with lower levels of blood vitamin D in America and Asia. Furthermore, when compared to non-MI controls, sufficient blood vitamin D appeared to protect against the occurrence of MI (OR=0.44; 95% CI: 0.25 to 0.76, P=0.004) in MI patients. Subgroup analyses also showed that sufficient blood 25(OH)D levels was a protective factor for MI in America and Asia.

Present study suggested that the levels of blood 25(OH)D were significant lower in MI patients, especially in America and Asia, and sufficient blood vitamin D levels might protect against the occurrence of MI.