Does eating particular diets alter the risk of age-related macular degeneration in users of the Age-Related Eye Disease Study supplements?

Abstract

Background: Recent information suggests that the Age-Related Eye Disease Study (AREDS) supplement, enhanced intake of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), and reducing dietary glycaemic index (dGI) are protective against advanced age-related macular degeneration (AMD).

Methods: Dietary information was collected at baseline, and fundus photograph grades were obtained during the 8-year trial period from 2924 eligible AREDS AMD trial participants. Using the eye as the unit of analysis and multifailure Cox proportional-hazards regression, the risk of AMD progression was related to dietary intake in the four arms of the trial.

Results: Independent of AREDS supplementation, higher intakes of DHA (> or =64.0 vs <26.0 mg/day) (hazard ratio (HR) = 0.73, 95% confidence interval (CI), 0.57 to 0.94), EPA (> or =42.3 vs <12.7 mg/day) (HR = 0.74, 95% CI 0.59 to 0.94), and lower dGI (dGI, <75.2 vs > or =81.5) (HR = 0.76, 95% CI 0.60 to 0.96) were associated with a lower risk for progression to advanced AMD. Participants consuming a lower dGI and higher DHA or EPA had the lowest risk (p value for synergistic interaction <0.001). Only participants in the "placebo" (p value for antagonistic interaction = 0.006) benefited from a higher DHA intake against early AMD progression (HR = 0.58, 95% CI 0.37 to 0.92; P(trend) = 0.01).

Conclusions: The findings show an association of consuming a diet rich in DHA with a lower progression of early AMD. In addition to the AREDS supplement, a lower dGI with higher intakes of DHA and EPA was associated with a reduced progression to advanced AMD.

Trial registration number: NCT00000145.

Figure 1

Flow chart describing disposition of eligible participants at risk of age-related macular degeneration (AMD) progression from the Age-Related Eye Disease Study (AREDS) AMD trial.

Figure 2

Interaction between omega-3 fatty acids and dietary glycaemic index (dGI) on risk of developing advanced age-related macular degeneration (AMD). p Value for interaction = 0.0003 for docosahexaenoic acid (DHA) (A), 0.0001 for eicosapentaenoic acid (EPA) (B). Using those in the highest quartile group of the dGI (first quartile group of low-GI) and the lower 75% of the omega-3 fatty acids as the referent, the hazard ratios (95% CIs) are 0.84 (0.68 to 1.03), 0.84 (0.67 to 1.05), 0.88 (0.68 to 1.14), 0.94 (0.67 to 1.31), 0.64 (0.45 to 0.91), 0.58 (0.41 to 0.81) and 0.50 (0.34 to 0.73) for DHA. They are 0.85 (0.69 to 1.05), 0.84 (0.67 to 1.05), 0.92 (0.71 to 1.19), 1.06 (0.77 to 1.46), 0.69 (0.49 to 0.97), 0.61 (0.43 to 0.86) and 0.46 (0.31 to 0.68) for EPA.