Objective: To test whether alternate-day low-dose aspirin affects incidence of age-related macular degeneration (AMD) in a large-scale randomized trial of women.
Design: Randomized, double-masked, placebo-controlled trial.
Participants: Thirty-nine thousand eight hundred seventy-six healthy female health professionals aged 45 years or older.
Intervention: Participants were assigned randomly to receive either 100 mg aspirin on alternate days or placebo and were followed up for the presence of AMD for an average of 10 years.
Main outcome measures: Incident AMD responsible for a reduction in best-corrected visual acuity to 20/30 or worse based on self-report confirmed by medical record review.
Results: After 10 years of treatment and follow-up, there were 111 cases of AMD in the aspirin group and 134 cases in the placebo group (hazard ratio, 0.82; 95% confidence interval, 0.64-1.06).
Conclusions: In a large-scale randomized trial of female health professionals with 10 years of treatment and follow-up, low-dose aspirin had no large beneficial or harmful effect on risk of AMD.