Gary A. Green, MD
Do antioxidant supplements reduce all-cause mortality in primary or secondary prevention?
Included studies compared antioxidant supplements (β-carotene, vitamin A, vitamin C, vitamin E, or selenium) with placebo or no intervention in healthy participants (primary prevention) or in patients with any disease (secondary prevention) who were ≥ 18 years of age. Studies of patients with acute, infectious, or malignant diseases except nonmelanoma skin cancer, or of children or pregnant women, were excluded. Outcome was all-cause mortality.
MEDLINE, EMBASE/Excerpta Medica, and Science Citation Index Expanded (all to Oct 2005); Cochrane Library (Issue 3, 2005); reference lists; and pharmaceutical companies were searched for randomized controlled trials (RCTs). 67 RCTs (n = 232 550, mean age 62 y, 55% men, based on 63 RCTs) met the selection criteria: 21 RCTs (n = 164 439) included healthy participants, and 46 RCTs (n = 68 111) included patients with various diseases. 47 RCTs had low risk for bias.
Random-effects meta-analysis showed that groups did not differ for all-cause mortality, but fixed-effects meta-analysis showed that antioxidants increased risk for mortality more than did placebo or no intervention (Table).
Antioxidant supplements do not reduce all-cause mortality in primary or secondary prevention.
Antioxidant supplements vs placebo or no intervention (control) in primary and secondary prevention*
*Abbreviations defined in Glossary. Weighted event rates, RRI, NNH, and CI calculated from control event rates and relative risks in article.
Green GA. Review: Antioxidant supplements do not reduce all-cause mortality in primary and secondary prevention. Ann Intern Med. 2008;149:JC3–9. doi: 10.7326/0003-4819-149-6-200809160-02009
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Published: Ann Intern Med. 2008;149(6):JC3-9.
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