Effect of antioxidant vitamin supplementation on cardiovascular outcomes: a meta-analysis of randomized controlled trials

PLoS One. 2013;8(2):e56803. doi: 10.1371/journal.pone.0056803. Epub 2013 Feb 20.

Abstract

Background: Antioxidant vitamin (vitamin E, beta-carotene, and vitamin C) are widely used for preventing major cardiovascular outcomes. However, the effect of antioxidant vitamin on cardiovascular events remains unclear.

Methodology and principal findings: We searched PubMed, EmBase, the Cochrane Central Register of Controlled Trials, and the proceedings of major conferences for relevant literature. Eligible studies were randomized controlled trials that reported on the effects of antioxidant vitamin on cardiovascular outcomes as compared to placebo. Outcomes analyzed were major cardiovascular events, myocardial infarction, stroke, cardiac death, total death, and any possible adverse events. We used the I(2) statistic to measure heterogeneity between trials and calculated risk estimates for cardiovascular outcomes with random-effect meta-analysis. Independent extraction was performed by two reviewers and consensus was reached. Of 293 identified studies, we included 15 trials reporting data on 188209 participants. These studies reported 12749 major cardiovascular events, 6699 myocardial infarction, 3749 strokes, 14122 total death, and 5980 cardiac deaths. Overall, antioxidant vitamin supplementation as compared to placebo had no effect on major cardiovascular events (RR, 1.00; 95%CI, 0.96-1.03), myocardial infarction (RR, 0.98; 95%CI, 0.92-1.04), stroke (RR, 0.99; 95%CI, 0.93-1.05), total death (RR, 1.03; 95%CI, 0.98-1.07), cardiac death (RR, 1.02; 95%CI, 0.97-1.07), revascularization (RR, 1.00; 95%CI, 0.95-1.05), total CHD (RR, 0.96; 95%CI, 0.87-1.05), angina (RR, 0.98; 95%CI, 0.90-1.07), and congestive heart failure (RR, 1.07; 95%CI, 0.96 to 1.19).

Conclusion/significance: Antioxidant vitamin supplementation has no effect on the incidence of major cardiovascular events, myocardial infarction, stroke, total death, and cardiac death.

Publication types

  • Meta-Analysis

MeSH terms

  • Antioxidants / therapeutic use*
  • Ascorbic Acid
  • Cardiovascular Diseases / drug therapy*
  • Cardiovascular Diseases / mortality
  • Cardiovascular Diseases / prevention & control
  • Dietary Supplements*
  • Humans
  • Odds Ratio
  • Publication Bias
  • Randomized Controlled Trials as Topic
  • Risk
  • Vitamin E
  • Vitamins / therapeutic use*
  • beta Carotene

Substances

  • Antioxidants
  • Vitamins
  • beta Carotene
  • Vitamin E
  • Ascorbic Acid

Grant support

The authors have no support or funding to report.