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Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: systematic review and meta-analysis.
JAMA. 2007 Feb 28; 297(8):842-57.JAMA

Abstract

CONTEXT

Antioxidant supplements are used for prevention of several diseases.

OBJECTIVE

To assess the effect of antioxidant supplements on mortality in randomized primary and secondary prevention trials. DATA SOURCES AND TRIAL SELECTION: We searched electronic databases and bibliographies published by October 2005. All randomized trials involving adults comparing beta carotene, vitamin A, vitamin C (ascorbic acid), vitamin E, and selenium either singly or combined vs placebo or vs no intervention were included in our analysis. Randomization, blinding, and follow-up were considered markers of bias in the included trials. The effect of antioxidant supplements on all-cause mortality was analyzed with random-effects meta-analyses and reported as relative risk (RR) with 95% confidence intervals (CIs). Meta-regression was used to assess the effect of covariates across the trials.

DATA EXTRACTION

We included 68 randomized trials with 232 606 participants (385 publications).

DATA SYNTHESIS

When all low- and high-bias risk trials of antioxidant supplements were pooled together there was no significant effect on mortality (RR, 1.02; 95% CI, 0.98-1.06). Multivariate meta-regression analyses showed that low-bias risk trials (RR, 1.16; 95% CI, 1.04[corrected]-1.29) and selenium (RR, 0.998; 95% CI, 0.997-0.9995) were significantly associated with mortality. In 47 low-bias trials with 180 938 participants, the antioxidant supplements significantly increased mortality (RR, 1.05; 95% CI, 1.02-1.08). In low-bias risk trials, after exclusion of selenium trials, beta carotene (RR, 1.07; 95% CI, 1.02-1.11), vitamin A (RR, 1.16; 95% CI, 1.10-1.24), and vitamin E (RR, 1.04; 95% CI, 1.01-1.07), singly or combined, significantly increased mortality. Vitamin C and selenium had no significant effect on mortality.

CONCLUSIONS

Treatment with beta carotene, vitamin A, and vitamin E may increase mortality. The potential roles of vitamin C and selenium on mortality need further study.

Authors+Show Affiliations

Bjelakovic G
The Cochrane Hepato-Biliary Group, Copenhagen Trial Unit, Center for Clinical Intervention Research, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark. goranb@junis.ni.ac.yu
Nikolova D
No affiliation info available
Gluud LL
No affiliation info available
Simonetti RG
No affiliation info available
Gluud C
No affiliation info available

MeSH

AdultAntioxidantsAscorbic AcidDietary SupplementsHumansRandomized Controlled Trials as TopicSeleniumVitamin AVitamin Ebeta Carotene

Pub Type(s)

Journal Article
Meta-Analysis
Research Support, Non-U.S. Gov't
Review
Systematic Review

Language

eng

PubMed ID

17327526

Citation

Bjelakovic, Goran, et al. "Mortality in Randomized Trials of Antioxidant Supplements for Primary and Secondary Prevention: Systematic Review and Meta-analysis." JAMA, vol. 297, no. 8, 2007, pp. 842-57.
Bjelakovic G, Nikolova D, Gluud LL, et al. Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: systematic review and meta-analysis. JAMA. 2007;297(8):842-57.
Bjelakovic, G., Nikolova, D., Gluud, L. L., Simonetti, R. G., & Gluud, C. (2007). Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: systematic review and meta-analysis. JAMA, 297(8), 842-57.
Bjelakovic G, et al. Mortality in Randomized Trials of Antioxidant Supplements for Primary and Secondary Prevention: Systematic Review and Meta-analysis. JAMA. 2007 Feb 28;297(8):842-57. PubMed PMID: 17327526.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: systematic review and meta-analysis. AU - Bjelakovic,Goran, AU - Nikolova,Dimitrinka, AU - Gluud,Lise Lotte, AU - Simonetti,Rosa G, AU - Gluud,Christian, PY - 2007/3/1/pubmed PY - 2007/3/6/medline PY - 2007/3/1/entrez SP - 842 EP - 57 JF - JAMA JO - JAMA VL - 297 IS - 8 N2 - CONTEXT: Antioxidant supplements are used for prevention of several diseases. OBJECTIVE: To assess the effect of antioxidant supplements on mortality in randomized primary and secondary prevention trials. DATA SOURCES AND TRIAL SELECTION: We searched electronic databases and bibliographies published by October 2005. All randomized trials involving adults comparing beta carotene, vitamin A, vitamin C (ascorbic acid), vitamin E, and selenium either singly or combined vs placebo or vs no intervention were included in our analysis. Randomization, blinding, and follow-up were considered markers of bias in the included trials. The effect of antioxidant supplements on all-cause mortality was analyzed with random-effects meta-analyses and reported as relative risk (RR) with 95% confidence intervals (CIs). Meta-regression was used to assess the effect of covariates across the trials. DATA EXTRACTION: We included 68 randomized trials with 232 606 participants (385 publications). DATA SYNTHESIS: When all low- and high-bias risk trials of antioxidant supplements were pooled together there was no significant effect on mortality (RR, 1.02; 95% CI, 0.98-1.06). Multivariate meta-regression analyses showed that low-bias risk trials (RR, 1.16; 95% CI, 1.04[corrected]-1.29) and selenium (RR, 0.998; 95% CI, 0.997-0.9995) were significantly associated with mortality. In 47 low-bias trials with 180 938 participants, the antioxidant supplements significantly increased mortality (RR, 1.05; 95% CI, 1.02-1.08). In low-bias risk trials, after exclusion of selenium trials, beta carotene (RR, 1.07; 95% CI, 1.02-1.11), vitamin A (RR, 1.16; 95% CI, 1.10-1.24), and vitamin E (RR, 1.04; 95% CI, 1.01-1.07), singly or combined, significantly increased mortality. Vitamin C and selenium had no significant effect on mortality. CONCLUSIONS: Treatment with beta carotene, vitamin A, and vitamin E may increase mortality. The potential roles of vitamin C and selenium on mortality need further study. SN - 1538-3598 UR - https://www.unboundmedicine.com/medline/citation/17327526/Mortality_in_randomized_trials_of_antioxidant_supplements_for_primary_and_secondary_prevention:_systematic_review_and_meta_analysis_ DB - PRIME DP - Unbound Medicine ER -