Smokers appear to have an increased long-term risk and greater progression of the eye disease age-related macular degeneration, according to a new article.
Smoking had already been identified as one of the few modifiable risk factors for age-related macular degeneration (AMD), a leading cause of vision loss in older Americans, according to background information in the article. Smoking may contribute to AMD through several pathways, including by reducing antioxidant levels, decreasing blood flow around the eye or affecting the pigments (coloration) in the retina.
Ronald Klein, M.D., M.P.H., and colleagues at the University of Wisconsin School of Medicine and Public Health, Madison, studied 4,926 residents of Beaver Dam, Wis., who were ages 43 to 84 years in 1987 to 1988. The participants were initially examined in 1988 to 1990 and then were re-examined every five years for the next 15 years. The presence and status of AMD was measured with photographs of the retina.
At the beginning of the study, 21 percent of the men and 18 percent of the women were smokers. Smokers had a 47 percent increase in their odds of developing early AMD, which is the least severe form of the disease. They also developed AMD at a younger age (69.2 years) than former smokers (72.3 years) and those who had never smoked (74.4 years). Smoking at the beginning of the study was also associated with the cumulative progression of AMD over the 15 years of the study. "There were few associations of specific characteristics of smoking (e.g., intensity, pack-years smoked, duration and age at initiation and quitting) with AMD outcomes," the authors write.
"In summary, while controlling for other factors, smoking appears to be related to the incidence and progression of AMD in our population," they conclude. "This has important health care implications, because early AMD is associated with an increase in the risk of developing late AMD and smoking behavior is modifiable."
Journal reference: Arch Ophthalmol. 2008;126:115-121.
This study was funded by a grant from the National Eye Institute and by a grant from the National Institute of Aging and was also supported in part by Research to Prevent Blindness, New York, N.Y.
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