A report that describes the relationship of age and risk alleles (variant gene forms) with the incidence and progression of age-related macular degeneration (AMD) during a 20-year period suggests that the overall five-year incidence of early AMD was 9.1 percent and late AMD was 1.6 percent, according to an article published Online First by Archives of Ophthalmology, a JAMA Network publication.
AMD is a leading cause of vision loss and an increasing number of studies have examined the relationships between AMD candidate genes and their interactions with environmental and host risk factors. Few long-term studies have examined the relationships of these genetic risk factors along the continuum of the disease from its earliest to its most advanced stages, according to the study background.
Ronald Klein, M.D., M.P.H., of the University of Wisconsin School of Medicine and Public Health, Madison, Wis., and colleagues describe the relationships of risk alleles in complement factor H (CFH) and age-related maculopathy susceptibility 2 (ARMS2) with the incidence and progression of AMD during a 20-year period in the Beaver Dam Eye Study.
In the study, 4,282 individuals between the ages of 43 and 86 years at a baseline examination in 1988-1990 were enrolled and participated in at least one examination spaced five years apart during the 20-year period. There were 2,820 (66 percent), 1,129 (26 percent) and 333 (8 percent) individuals with low, intermediate and high genetic risk for AMD, respectively, according to the results.
The study results indicate that using the multistate model of persons aged 45 years with no AMD in the low, intermediate and high AMD genetic risk groups, 33 percent, 39.9 percent and 46.5 percent, respectively, were estimated to develop early AMD. The results also suggest that 1.4 percent, 5.2 percent and 15.3 percent were estimated to develop late AMD by age 80 years.
“These population-based data provide estimates of the long-term risk of the incidence and progression of AMD and its lesions by age and genetic risk alleles for CFH and ARMS2. They also show that when early AMD is present, knowing the phenotype (the properties of an organism) contributes more to risk assessment than knowing the genetic risk based on these 2 AMD genes,” the study concludes.
Arch Ophthalmol. Published online November 9, 2012. doi:10.1001/archophthalmol.2013.713.