Today’s aging baby boomers might be less likely to develop AMD than previous generations, according to research presented at the Association for Research in Vision and Ophthalmology 2010 Annual Meeting.
Researchers analyzed participants aged 45 years or older from the Beaver Dam Offspring Study as well as participants from the parental cohorts of the Beaver Dam Eye Study and the Epidemiology of Hearing Loss Study. A total of 9,930 observations for participants born between 1905 and 1962 were included in the data analysis.
The researchers concluded that the prevalence of AMD declined with a higher birth year and was lowest for individuals from the most recent generations. The calculated age- and gender-adjusted AMD birth cohort effect remained consistent after compensating for such independent risk factors as obesity, education level and heavy alcohol consumption. Further, the birth cohort effect remained after adjustment for additional childhood factors such as sunlight exposure, parental home ownership and method of transportation to school.
“This rapid decline in age-related macular degeneration, which was 68% lower for each generation, suggests that modifiable risk factors play important roles in the etiology of AMD,” says lead researcher Karen J. Cruickshanks, M.D., professor of epidemiology at the University of Wisconsin School of Medicine and Public Health in Madison. “Childhood exposure to environment contaminants—for instance, growing up in houses that used wood, coal or kerosene for cooking—may contribute to the risk for AMD.”
Overall, “Our data suggest that the rates of AMD may be declining. For example, for individuals born between 1935 and 1939, the prevalence was 12%, but for individuals born between 1950 and 1954, it was 4%,” added Dr. Cruickshanks. “This suggests that we can find ways to prevent this serious blinding disorder of aging—we can modify environmental and lifestyle factors.”
While these results appear promising, critics have suggested that the data could be misleading because the baby boomers simply have not gotten old enough yet. “Age is a factor in AMD, and we know that the magnitude is going up, so these kinds of cohort studies can be difficult to interpret,” says Johanna Seddon, M.D., professor of ophthalmology at Tufts University School of Medicine in Boston. “It will be interesting to see if these results are borne out in longitudinal studies.”
Cruickshanks KJ, Klein R, Nondahl DM, et al. Generational differences in AMD: Evidence for modifiable risk factors. Paper presented at the Association for Research in Vision and Ophthalmology 2010 Annual Meeting, May 3, 2010; Ft. Lauderdale, Fla.