“Vitamin D and Cardiovascular Outcomes: A Systematic Review and Meta-Analysis”, 2011-07-01 (; backlinks; similar):
Context: Several studies found association between vitamin D levels and hypertension, coronary artery calcification, and heart disease.
Objective: The aim of this study was to summarize the evidence on the effect of vitamin D on cardiovascular outcomes.
Design and Method: We searched electronic databases from inception through August 2010 for randomized trials. Reviewers working in duplicate and independently extracted study characteristics, quality, and the outcomes of interest. Random-effects meta-analysis was used to pool the relative risks (RR) and the weighted mean differences across trials.
Results: We found 51 eligible trials with moderate quality. Vitamin D was associated with non-statistically-significant effects on the patient-important outcomes of death [RR, 0.96; 95% confidence interval (CI), 0.93, 1.00; p = 0.08], myocardial infarction (RR, 1.02; 95% CI, 0.93, 1.13; p = 0.64), and stroke (RR, 1.05; 95% CI, 0.88, 1.25; p = 0.59). These analyses were associated with minimal heterogeneity. There were no statistically-significant changes in the surrogate outcomes of lipid fractions, glucose, or diastolic or systolic blood pressure. The latter analyses were associated with statistically-significant heterogeneity, and the pooled estimates were trivial in absolute terms.
Conclusion: Trial data available to date are unable to demonstrate a statistically-significant reduction in mortality and cardiovascular risk associated with vitamin D. The quality of the available evidence is low to moderate at best.