Dietary antioxidants and primary prevention of age related macular degeneration: systematic review and meta-analysis

doi:10.1136/bmj.39350.500428.47

BMJ 2007;335:755 (13 October), doi:10.1136/bmj.39350.500428.47 (published 8 October 2007)

Research

Dietary antioxidants and primary prevention of age related macular degeneration: systematic review and meta-analysis

Elaine W-T Chong, PhD candidate¹, Tien Y Wong, professor of ophthalmology¹, Andreas J Kreis, ophthalmology fellow¹, Julie A Simpson, senior lecturer², Robyn H Guymer, associate professor of ophthalmology¹

¹ Centre for Eye Research Australia, University of Melbourne, Victoria 3002, Australia, ² Centre for Molecular, Environmental, Genetic and Analytic Epidemiology, University of Melbourne

Correspondence to: T Y Wong, twong{at}unimelb.edu.au

Objective To evaluate the effectiveness of dietary antioxidantsin the primary prevention of age related macular degeneration(AMD).

Design Systematic review and meta-analysis.

Data sources Search of seven databases without limits on yearor language of publication, and retrieval of references in pertinentreviews and articles.

Methods Two reviewers independently searched the databases andselected the studies, using standardised criteria. Randomisedclinical trials and prospective cohort studies were included.Of the 4192 abstracts initially identified, 12 studies (nineprospective cohort studies and three randomised clinical trials)met the selection criteria and were included. Data extractionand study quality evaluation were independently reviewed, usingstandardised criteria. Results were pooled quantitatively usingmeta-analytic methods.

Results The nine prospective cohort studies included 149 203people, with 1878 incident cases of early AMD. The antioxidantsinvestigated differed across studies, and not all studies contributedto the meta-analysis of each antioxidant. Pooled results fromprospective cohort studies indicated that vitamin A, vitaminC, vitamin E, zinc, lutein, zeaxanthin, ${alpha}$ carotene, $beta$ carotene, $beta$ cryptoxanthin, and lycopene have little or no effect in theprimary prevention of early AMD. The three randomised clinicaltrials did not show that antioxidant supplements prevented earlyAMD.

Conclusions There is insufficient evidence to support the roleof dietary antioxidants, including the use of dietary antioxidantsupplements, for the primary prevention of early AMD.

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