Abstract
Purpose: :
The Age-Related Eye Disease Study (AREDS) showed that high-dose supplements of antioxidants and/or zinc are protective against advanced age-related macular degeneration (AMD). Our objective was to evaluate how dietary intake affects AMD risk in AREDS supplement users.
Methods: :
Dietary information was collected at baseline and fundus photographs were taken and graded during the 8-y trial period from 2,924 eligible AREDS AMD trial participants. Using Cox proportional-hazards regression, we related the risk of AMD progression to dietary intake in the four arms of the trial.
Results: :
Independent of AREDS supplementation, higher intakes of docosahexaenoic acid (DHA, ≥ 64.0 vs. < 26.0 mg/d) (hazard ratio [HR] = 0.73, 95% confidence interval [CI], 0.57, 0.94) and eicosapentaenoic acid (EPA, ≥ 42.3 vs. < 12.7 mg/d) (HR = 0.74, 95% CI, 0.59, 0.94) and lower dietary glycemic index (dGI, < 75.2 vs. ≥ 81.5) (HR = 0.76, 95% CI, 0.60, 0.96) were associated with lower risk for advanced AMD progression. This protection was particularly profound in AREDS ‘antioxidants’ users for EPA (HR = 0.51, 95% CI, 0.32, 0.81; Ptrend = 0.02) and in AREDS ‘zinc only’ users for dGI (HR = 0.56, 95% CI, 0.36, 0.89; Ptrend = 0.01). Participants consuming lower dGI and higher DHA or EPA had the lowest risk (P for synergistic interaction < 0.001). Only participants in the ‘placebo’ (P for antagonistic interaction = 0.006) benefited from higher DHA intake against early AMD progression (HR = 0.58, 95% CI, 0.37, 0.92; Ptrend = 0.01).
Conclusions: :
Our findings suggest consuming a diet rich in DHA for early AMD prevention. For people at risk of advanced AMD, in addition to the AREDS supplement lower dGI accompanied with higher intakes of DHA and EPA may provide the best protection.
Clinical Trial: :
www.clinicaltrials.gov NCT00000145
Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • lipids