Retinal vascular changes following supplementation with alpha-tocopherol or beta-carotene

Abstract

Purpose: To examine if long-term supplementation with alpha-tocopherol (AT) or beta-carotene (BC) was associated with the prevalence of vascular changes in retinal arterioles. Methods: An end-of-trial subsample from a double-blind, placebo-controlled clinical trial designed to study the effects of alpha-tocopherol and beta-carotene on lung cancer incidence (ATBC Study). Setting: Source population of Helsinki and the surrounding province. Participants: 1072 men 50-69 years old and smoking at least 5 cigarettes per day at study entry. Interventions: Random allocation to one of four supplementation regimens: 50 mg per day alpha-tocopherol, 20 mg per day beta-carotene, both alpha-tocopherol and beta-carotene, or placebo. Median follow-up time was 6.6 years (range 5.2-8.0 years). Main outcome measure: Presence of vascular changes in retinal arterioles as determined from end-of-trial retinal color photographs. Results: Retinal vascular changes were most prevalent in the AT (161 men, 62%), and in the BC (163 men, 62%) groups. The prevalence rate was lowest in the AT plus BC group (161 men, 55%), and slightly higher in the placebo group (145 men, 57%). There was no statistically significant association of either AT (OR 0.9, 95% CI 0.7-1.2) or BC (OR 1.0, 95% CI 0.8-1.3) supplementation with the prevalence of retinal vascular changes after adjusting for major risk factors. Conclusions: Supplementation with alpha-tocopherol or beta-carotene for a median of 6.6 years does not protect against retinal vascular changes among smoking males.