Antioxidant vitamin and mineral supplementation for preventing age-related macular degeneration.

BACKGROUND

Some observational studies have suggested 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.

OBJECTIVE

The aim of this review is to examine the evidence as to whether or not taking vitamin or mineral supplements prevents the development of age-related macular degeneration.

METHODS

We searched the Cochrane Eyes and Vision Group specialised register, the Cochrane Controlled Trials Register - Central, MEDLINE, reference lists of identified reports and the Science Citation Index. We contacted investigators and experts in the field for details of unpublished studies. The most recent searches were conducted in June 1999.

METHODS

All randomised trials comparing an antioxidant vitamin and/or mineral supplement (alone or in combination) to control were included. We included only studies where supplementation had been given for at least one year.

METHODS

Both reviewers independently extracted data and assessed trial quality. Currently there is only one published trial included in the review so no data synthesis was conducted.

RESULTS

One trial is included in the review. This was a primary prevention trial in Finnish male smokers with four treatment groups: alpha-tocopherol alone, beta-carotene alone, alpha-tocopherol and beta-carotene, placebo. The add-on maculopathy study was conducted in a subset of the main trial cohort. 269 cases of maculopathy (14 late stage age-related macular degeneration) were identified. There was no association of age-related macular degeneration with treatment.

CONCLUSIONS

There is no evidence to date that people without age-related macular degeneration should take antioxidant vitamin and mineral supplements to prevent or delay the onset of the disease. The results of five large ongoing trials are awaited.