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 (⩾64.0 vs <26.0 mg/day) (hazard ratio (HR) = 0.73, 95% confidence interval (CI), 0.57 to 0.94), EPA (⩾42.3 vs <12.7 mg/day) (HR = 0.74, 95% CI 0.59 to 0.94), and lower dGI (dGI, <75.2 vs ⩾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; Ptrend = 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.
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Funding Financial support for this project has been provided by the US Department of Agriculture under agreements, 1950-5100-060-01A (C-JC, AT) and R01-13250 and R03-EY014183-01A2 from the National Institutes of Health (AT); grants (AT) from the Johnson & Johnson Focused Giving Program and American Health Assistance Foundation, and to C-JC from the Ross Aging Initiative.
Competing interests None.
Provenance and Peer review Not commissioned; externally peer reviewed.
Contributors: C-JC and GG had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: C-J Chiu. Acquisition of data: RCM and AT. Analysis and interpretation of data: C-JC. Drafting of the manuscript: C-JC, AT. Critical analysis of the manuscript for important intellectual content: C-JC , RK, RCM and AT. Statistical analysis: C-JC. Administrative, technical or material support: GG.
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