AMD progression linked to carbohydrates

Patients at risk of advanced age-related macular degeneration (AMD) progression may benefit from consuming a smaller amount of refined carbohydrates, according to a study published in the October issue of the American Journal of Clinical Nutrition.

Chung-Jung Chiu and fellow researchers colleagues from Tufts University, Boston, The AREDS Co-ordinating Center, EMMES Corporation and the University of Wisconsin, USA prospectively evaluated the effect of baseline dietary glycemic index (dGI) on the progression of AMD.

dGI was calculated as the weighted average of GIs from foods and was evaluated as being above or below the sex median (women: 77.9; men: 79.3) for 3,977 participants in the Age-Related Eye Disease Study (AREDS) aged between 55 and 80 years. The 7,232 eyes without advanced AMD were classified into one of three AMD categories: Group 1 (non-extensive small drusen), Group 2 (intermediate drusen) and Group 3 (large drusen or pigmentary abnormalities). Multi-failure Cox proportional-hazards regression was used to model the time to the maximal progression in order to evaluate the relationship between dGI and the risk of AMD.

The multivariate-adjusted risk of progression over the eight-year follow-up period was significantly higher in the high-dGI group than in the low dGI group. The risk of progression for groups 1, 2 and 3 was 5%, 8% and 17% greater, respectively. The latter gives an estimate that 7.8% of new advanced AMD patients could be prevented if people consumed a low-dGI diet.

The researchers believe that patients at risk of AMD progression, especially those at a high risk of advanced AMD, could benefit from consuming less refined carbohydrates.