ARS | Publication request: Dietary glycemic index and carbohydrate in relation to early age-related macular degeneration

Submitted to: American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 18, 2005
Publication Date: April 1, 2006
Reprint URL: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16600942&query_hl=5&itool=pubmed_docsum
Citation: Chiu, C., Hubbard, L.D., Armstrong, J., Rogers, G., Jacques, P.F., Chylack, L.T., Hankinson, S.E., Willett, W.C., Taylor, A. 2006. Dietary glycemic index and carbohydrate in relation to early age-related macular degeneration. American Journal of Clinical Nutrition. 83(4):880-6.

Interpretive Summary: Since little information is known about the association between dietary carbohydrates and its effects on cataracts among people who do not have diabetes, this study was done to determine whether intake of dietary carbohydrates or the glycemic index (GI), the measure of carbohydrate intake, has an association with presence of nontransparent regions of the eye. The study design made for the Age-Related Eye Disease Study (AREDS) consisted of a modified food-frequency questionnaire to obtain dietary information from 3377 participants ranging from ages 60 to 80, 56% of them being women. The status of the lens was analyzed by using the AREDS System for Classifying Cataracts. The approach used to estimate logistic regression was applied to look at associations for eyes with only a single or pure type of lens opacity in order to account for the lack of independence between the eyes of a person. Dietary GI was associated with a higher frequency of all pure nuclear opacities and moderate nuclear opacities amongst patients in the highest quartile. In comparing the highest and the lowest quartile, the odds ratio increased somewhat for moderate cortical opacities, the degree of transparency in the cornea of the eye. Thus, data from the cross-sectional analysis of AREDS baseline indicates that there is a possible direct link between dietary glycemic quality to the prevalency of nuclear and coritcal lens opacities.

Technical Abstract: Little is known about the association between dietary carbohydrates and cataract in nondiabetic persons. The aim was to test whether recent dietary carbohydrate intakes or glycemic index (GI; a measure of carbohydrate intake quality) was associated with the presence of cortical or nuclear opacities. A modified Block food-frequency questionnaire was used to obtain dietary information from 3377 participants (aged 60¿80 y; 56% were women) in the Age-Related Eye Disease Study (AREDS). Lens status was evaluated by using the AREDS System for Classifying Cataracts. Associations were examined for eyes with only a single, or pure, type of lens opacity by using the generalized estimating approach to logistic regression to account for the lack of independence between the eyes of a person. For participants in the highest quartile, dietary GI was associated with a higher prevalence of all pure nuclear opacities [grade >2; odds ratio (OR): 1.29; 95% CI: 1.04, 1.59; P for trend = 0.02] and moderate nuclear opacities (grade >/= 4; OR: 1.43; 95% CI: 0.96, 2.14; P for trend = 0.052). The OR in a comparison of the highest with the lowest quartile of intake was 1.27 (95% CI: 0.99, 1.63; P for trend = 0.09) for cortical opacities of any severity (>0% of area opaque), and the OR increased somewhat for moderate cortical opacities (>5% of area opaque; OR: 1.71; 95% CI: 1.00, 2.95; P for trend = 0.056). Results from the cross-sectional analysis of AREDS baseline data suggest that dietary glycemic quality and dietary carbohydrate quantity may be associated with prevalent nuclear and cortical opacities, respectively.