Age-related macular degeneration (AMD) is a leading cause of vision loss, currently affecting about two million older Americans.

AMD is caused by the deterioration of the light sensitive retina at the back of the eye and it is influenced by both genetic and lifestyle factors. A new study from Tufts University School of Medicine now reveals how these risk factors interact and help predict an individual’s risk of developing AMD as they get older.

The researchers worked with a group of 1,446 individuals already enrolled in the Age-Related Eye Disease Study (AREDS) and followed them up for 6.3 years, during which time 279 individuals progressed to advanced AMD and 1167 did not progress. They also studied 509 advanced AMD cases and 22 controls.  Information on age, sex, education, smoking and body mass index was gathered and it was also noted  whether participants were taking the AREDS supplement – a special formulation of zinc and antioxidants which can help slow progression of the disease.  Furthermore, DNA samples were taken so that each participant could be genotyped for six variants of five AMD-related genes.  The variants are known to either increase or decrease AMD risk.

The study shows that although there is a strong genetic component in AMD, healthy behaviors can modify the genetic influence.  For instance, for participants with one genotype, smokers had more than three times the risk of progressing to AMD compared to non-smokers. Smoking is a known risk factor for AMD.  The findings could one day be used to help doctors counsel those at risk of vision loss through AMD on ways of modifying this risk and also help tailor treatments and prevention, like the AREDS supplement, more closely to an individual’s needs. 

Source

Seddon J, Reynolds R et al Prediction model for prevalence and incidence of advanced age-related macular degeneration based on genetic, demographic, and environmental variables Investigative Ophthalmology & Visual Science 2009;50:2044-2053