Dietary Glycemic Index and Carbohydrate Intake in Relation to Early Age–related Maculopathy

Abstract

Abstract: : Background: Dietary carbohydrate may play a role in the pathogenesis of age–related maculopathy (ARM). Objective: To examine the relationship between ARM and dietary carbohydrate quality, as measured by glycemic index (GI), and total carbohydrate intake. Design: One thousand forty three eyes from 526 Boston–area participants from the Nurses’ Health Study were included in the present study. The classification and the degree of ARM were quantified by the Age–Related Eye Diseases Study classification system. Long–term dietary information was based on an average from four semiquantitative food frequency questionnaires collected over a 10–y period before the eye examination. We used eyes as the unit of analysis, and generated odds ratios for prevalence of ARM using a generalized estimating approach to logistic regression to account for the lack of independence between the two eyes from the same subject. Results:After multivariate adjustment, long–term dietary GI was related to prevalence of maculopathy (including geographic atrophy, pigment abnormalities associated with ARM, choroidal neovascularization, and retinal pigment epithelial detachment), while total carbohydrate intake was not. The strongest association was observed between pigment abnormalities and dietary GI (OR = 2.75, 95 % CI: 1.22 – 6.21 comparing women in the highest and lowest dietary GI tertile categories; P_trend = 0.01). Neither dietary GI nor total carbohydrate intake was related to prevalence of drusen. Conclusions: Our results suggest that dietary GI is an independent risk factor for early maculopathy.

Keywords: age-related macular degeneration • aging • clinical (human) or epidemiologic studies: risk factor assessment