Objective: To test whether beta carotene supplementation affects the incidence of age-related maculopathy (ARM) in a large-scale randomized trial.
Design: Randomized, double-masked, placebo-controlled trial among 22 071 apparently healthy US male physicians aged 40 to 84 years. Participants were randomly assigned to receive beta carotene (50 mg every other day) or placebo. Main Outcome Measure Incident ARM responsible for a reduction in best-corrected visual acuity to 20/30 or worse.
Results: After 12 years of treatment and follow-up, there were 162 cases of ARM in the beta carotene group vs 170 cases in the placebo group (relative risk [RR], 0.96; 95% confidence interval [CI], 0.78-1.20). The results were similar for the secondary end points of ARM with or without vision loss (275 vs 274 cases; RR, 1.01; 95% CI, 0.86-1.20) and advanced ARM (63 vs 66 cases; RR, 0.97; 95% CI, 0.69-1.37).
Conclusions: These randomized data relative to 12 years of treatment among a large population of apparently healthy men indicate that beta carotene supplementation has no beneficial or harmful effect on the incidence of ARM. Long-term supplemental use of beta carotene neither decreases nor increases the risk of ARM.
Trial registration: ClinicalTrials.gov NCT00000152.