Antioxidant vitamin and mineral supplements for preventing age-related macular degeneration.Cochrane Database Syst Rev. 2012 Jun 13CD
There is inconclusive evidence from observational studies to suggest that people who eat a diet rich in antioxidant vitamins (carotenoids, vitamins C and E) or minerals (selenium and zinc) may be less likely to develop age-related macular degeneration (AMD).
To examine the evidence as to whether or not taking antioxidant vitamin or mineral supplements prevents the development of AMD.
We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 12), MEDLINE (January 1950 to January 2012), EMBASE (January 1980 to January 2012), Open Grey (System for Information on Grey Literature in Europe) (www.opengrey.eu/), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 26 January 2012.
We included all randomised controlled trials (RCTs) comparing an antioxidant vitamin and/or mineral supplement (alone or in combination) to control.
DATA COLLECTION AND ANALYSIS
Both review authors independently assessed risk of bias in the included studies and extracted data. One author entered data into RevMan 5 and the other author checked the data entry. We pooled data using a fixed-effect model.
We included four RCTs in this review; 62,520 people were included in the analyses. The trials were conducted in Australia, Finland and the USA and investigated vitamin E and beta-carotene supplements. Overall the quality of the evidence was high. People who took these supplements were not at decreased (or increased) risk of developing AMD. The pooled risk ratio for any antioxidant supplement in the prevention of any AMD was 0.98 (95% confidence interval 0.89 to 1.08) and for advanced AMD was 1.05 (95% CI 0.80 to 1.39). Similar results were seen when the analyses were restricted to beta-carotene and alpha-tocopherol alone.