Dietary antioxidant intake and incidence of early age-related maculopathy: the Blue Mountains Eye Study

Abstract

Objective: To investigate associations between dietary intake, including modest supplement intake, of antioxidant vitamins and zinc at baseline and the 5-year incidence of early age-related maculopathy (ARM).

Design: Population-based cohort study.

Participants: From 1992 through 1994, 3654 persons aged 49 years or more (82% of those eligible) living in two postcode areas west of Sydney, Australia, were examined for the Blue Mountains Eye Study baseline. Five years later, 2335 persons (75% of known survivors) were reexamined.

Methods: A 145-item Food Frequency Questionnaire (FFQ) was used to assess nutrient intakes. Of the 2335 people who attended a follow-up visit, 1989 (85%) had completed a FFQ at baseline. The nutrients examined in this study included: alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein and zeaxanthin, lycopene, retinol, vitamin A, vitamin C, and zinc.

Main outcome measures: Early ARM was assessed by masked grading of stereo retinal photographs. Definitions for incidence closely followed those used in the Beaver Dam Eye Study.

Results: Early ARM developed in 192 persons (8.7% 5-year incidence) who did not have either late or early ARM at baseline. Of these, 159 persons completed the FFQ at baseline. After adjusting for age, gender, family history of ARM, and smoking status at baseline, no associations, or any trends suggesting possible association, were found between baseline intake of the nutrients examined, apart from vitamin C, and the 5-year incidence of early ARM. Compared with the lowest quintile, increasing baseline intakes of vitamin C, from diet and supplements, was associated with an increased risk of incident early ARM (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.0-3.0; and OR, 2.3; 95% CI, 1.3-4.0 for the fourth and fifth quintiles, respectively).

Conclusions: Our cohort study of an older population could not find evidence of protection associated with usual dietary antioxidant or zinc intakes (including use of supplements) on the 5-year incidence of early ARM.