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Gene, Smoking Combo Boosts Risk of Elderly Vision Loss
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MONDAY, March 20 (HealthDay News) -- A combination of smoking plus a specific gene variant could account for a third of cases of age-related macular degeneration (AMD), researchers say. AMD is the most common cause of visual impairment and legal blindness in older Americans. Interaction between a specific variant of the LOC387715 gene and cigarette smoking greatly increases AMD, say researchers at Duke University Medical Center and Vanderbilt University Medical Center. The finding emphasizes the importance of genetic factors in the onset of AMD, and suggests the potential to reduce the incidence of the disease through smoking prevention and cessation programs. "The most exciting aspect of this research is that it is the combination of the gene and smoking that really puts you at risk," study senior author Margaret Pericak-Vance, director of the Duke Center for Human Genetics, said in a prepared statement. "We demonstrate, for the first time, that a gene variant coupled with a modifiable lifestyle factor such as cigarette smoking confers a significantly higher risk of AMD than either factor alone," she said. The findings appear in the online edition of the American Journal of Human Genetics, and will be published in the May print issue of the journal. The study included 1,001 people with all forms of AMD and 394 healthy people in a control group. Researchers analyzed 185 variations in the DNA sequence of genes located in a region believed to be associated with susceptibility to AMD. The scientists found that 42 percent of the chromosomes of people with AMD and 26 percent of the people in the control group had a specific variant of LOC387715 statistically associated with the highest risk of developing AMD. In nonsmokers, this genetic variant increased AMD risk twofold. People who had the genetic variant and smoked had an eightfold increased risk of AMD, compared to nonsmokers without the variant. The actual function of the LOC387715 gene in the visual system is unknown, the researchers said. More information The U.S. National Eye Institute has more about AMD.
Last Updated: March 20, 2006 |