Abstract
Purpose: :
Because foods provide many nutrients, which may interact with each other to modify risk for multifactorial diseases such as age-related macular degeneration (AMD), we sought to develop a composite scoring system to summarize the combined effect of multiple dietary nutrients on AMD risk. This has not been done previously.
Methods: :
Considering dietary intakes of vitamins C and E, zinc, lutein/zeaxanthin, docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and low-dietary glycemic index (dGI) from the Age-Related Eye Disease Study (AREDS) baseline information (4,003 eligible participants contributing 7,934 eyes), we assigned each nutrient a percentile rank score then summed them into a Compound score for each participant. Using eye as the unit of analysis, we evaluated the association between the Compound score and risk of prevalent AMD. Validation, fitness, and performance of the model were evaluated using bootstrapping techniques, adjusted quasilikelihood under the independence model criterion (QICu), and the c-index, respectively.
Results: :
Our results showed that higher Compound scores were associated with lower risk for early AMD, indicated by drusen, and advanced AMD. Validation analyses indicated that these relationships are robust (the average 50-time bootstrapping per quartile odds ratios [ORs] = 0.727, 0.827, and 0.753, respectively, for drusen, and 0.616, 0.536, and 0.572, respectively, for advanced AMD). Model selection analyses suggested that the Compound score should be included, but that measures of dietary beta-carotene should not be included.
Conclusions: :
We found that consuming diets which provide low dGI and higher intakes of the above-mentioned nutrients were associated with the greatest reduction in risk for prevalent drusen and advanced AMD, while dietary beta-carotene did not affect these relationships. These findings warrant further prospective studies.
Keywords: age-related macular degeneration • nutritional factors • clinical (human) or epidemiologic studies: systems/equipment/techniques