Dietary Zinc and Risk for Age–related Macular Degeneration

Abstract

Abstract: : Purpose: To evaluate the relationship between dietary zinc intake and prevalence of age–related macular degeneration (AMD) in the Age–Related Eye Disease Study (AREDS). Background: Zinc is a trace mineral highly concentrated in the retinal pigment epithelium. It may protect the retina in its essential action as a cofactor for enzymes with antioxidant properties. Methods: We conducted a case–control analysis of the 4,513 AREDS participants. AMD severity at enrollment was assessed centrally from stereoscopic color fundus photographs. Subjects completed a semi–quantitative food frequency questionnaire at enrollment. Nutrient intake estimates were energy–adjusted with the nutrient density model. We used multiple logistic regression methods to evaluate the relationship of dietary zinc with AMD status. Results: The likelihood of neovascular (NV) AMD was significantly decreased among people reporting highest zinc intake, relative to those reporting lowest zinc intake after statistical adjustment for nonnutrient–based covariates (OR = 0.69; 95% CI, 0.49 – 0.98). This relationship was not significant in multivariable models containing these covariates and nutrient–based factors (lutein/zeaxanthin and docosahexaenoic acid) independently associated with NV AMD (OR = 0.75; 95% CI, 0.53 – 1.08). Conclusions: Higher dietary intake of zinc was not associated with a statistically significant decreased likelihood of having NV AMD, after adjusting for nonnutrient– and nutrient–based covariates of NV AMD.

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