Dietary Compound Score and Risk of Age-Related Macular Degeneration in the Age-Related Eye Disease Study
Received 3 April 2008; received in revised form 6 December 2008; accepted 8 December 2008.
Purpose
Because foods provide many nutrients that may interact 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.
Design
Cross-sectional study.
Participants
From the 4003 participants in the Age-Related Eye Disease Study (AREDS), there were 7,934 eyes included in this study.
Methods
Considering dietary intakes of vitamins C and E, zinc, lutein/zeaxanthin, docosahexaenoic acid, eicosapentaenoic acid, and low-dietary glycemic index (dGI) from AREDS baseline information, 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 quasi-likelihood under the independence model criterion, and the c-index, respectively.
Main Outcome Measures
Stereoscopic fundus photographs of the macula were taken and graded at baseline using the AREDS protocol and AMD Classification System.
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 = 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 β-carotene should not be included.
Conclusions
We found that consuming diets that provide low dGI and higher intakes of these nutrients were associated with the greatest reduction in risk for prevalent drusen and advanced AMD, whereas dietary β-carotene did not affect these relationships. These findings warrant further prospective studies.
Financial Disclosure(s)
Proprietary or commercial disclosure may be found after the references.
1Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging, Department of Ophthalmology School of Medicine, Tufts University, Boston, Massachusetts
2AREDS Coordinating Center, the EMMES Corporation, Rockville, Maryland
3Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
Correspondence: Chung-Jung Chiu, DDS, PhD, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, 711 Washington Street, Boston, MA 02111
Manuscript no. 2008-428.
Financial Disclosure(s): Financial support for this project has been provided by the U.S. 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 and Johnson Focused Giving Program and American Health Assistance Foundation, and to C-JC from the Ross Aging Initiative. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views or policies of the US Department of Agriculture, nor does mention of trade names, commercial products, or organizations imply endorsement by the US Government.
ABSTRACT