Dietary glycemic index and the risk of age-related macular degeneration

• Published in: The American journal of clinical nutrition 2008-10, Vol.88 (4), p.1104-1110
• Main Authors: Kaushik, Shweta, Wang, Jie Jin, Flood, Victoria, Tan, Jennifer Sue Ling, Barclay, Alan W, Wong, Tien Y, Brand-Miller, Jennie, Mitchell, Paul
• Format: Article
• Language: English
• Subjects: adults; age-related macular degeneration; Aged; Biological and medical sciences; Blue Mountain Eye Study; breads; breakfast cereals; carbohydrate intake; Cohort Studies; Diet; dietary carbohydrate; Dietary Carbohydrates - administration & dosage; Dietary Carbohydrates - classification; Dietary Carbohydrates - metabolism; Dietary Fiber - administration & dosage; Dietary Fiber - classification; Dietary Fiber - metabolism; eye diseases; Feeding Behavior; Feeding. Feeding behavior; Female; Follow-Up Studies; Fundamental and applied biological sciences. Psychology; Glycemic Index; Humans; Incidence; longitudinal studies; Macular Degeneration - epidemiology; Macular Degeneration - etiology; Macular Degeneration - prevention & control; Male; Middle Aged; Multivariate Analysis; New South Wales - epidemiology; Nutrition; nutritional adequacy; oatmeal; Prospective Studies; protective effect; risk assessment; Risk Factors; senescence; Studies; Surveys and Questionnaires; Vertebrates: anatomy and physiology, studies on body, several organs or systems; vision disorders
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/88.4.1104

BACKGROUND: Dietary factors are known risk factors for age-related macular degeneration (AMD)--the leading cause of visual loss among persons aged greater-than-or-equal65 y. High-glycemic-index diets have been hypothesized as a risk factor for AMD, but prospective data are unavailable. OBJECTIVE: The objective was to examine the association between dietary glycemic index and the 10-y incidence of AMD in the Blue Mountain Eye Study population. DESIGN: This was a population-based cohort study with 3654 participants (greater-than-or-equal49 y) examined at baseline (1992-1994); 2335 patients were reexamined after 5 y and 1952 after 10 y. The Wisconsin System was used to grade 10-y incident early and late AMD from retinal photographs. A food-frequency questionnaire was used to collect dietary information at baseline, and an Australian database was used to calculate the mean glycemic index. RESULTS: Over 10 y, 208 of 1810 persons (cumulative incidence: 14.1%) developed early AMD. After age, smoking, other risk factors, and dietary constituents were adjusted for, a higher mean dietary glycemic index was associated with an increased 10-y risk of early AMD in a comparison of quartiles 1 and 4 [relative risk (RR): 1.77; 95% CI: 1.13, 2.78; P for trend = 0.03]. Conversely, a greater consumption of cereal fiber (RR: 0.68; 95% CI: 0.44, 1.04; P for trend = 0.05) and breads and cereals (predominantly lower glycemic index foods such as oatmeal) (RR: 0.67; 95% CI: 0.44, 1.02; P for trend = 0.03) was associated with a reduced risk of incident early AMD. No relation was observed with late AMD. CONCLUSIONS: A high-glycemic-index diet is a risk factor for early AMD--the recognized precursor of sight-threatening late AMD. Low-glycemic-index foods such as oatmeal may protect against early AMD.