Need a little extra incentive to kick the habit?
Just in time for New Year's resolutions, a UCLA study finds that even after age 80, smoking continues to increase one's risk for age-related macular degeneration (AMD), the leading cause of blindness in Americans over 65.
The American Journal of Ophthalmology publishes the findings in its January edition.
"The take-home message is that it's never too late to quit smoking," said lead author Dr. Anne Coleman, professor of ophthalmology at the Jules Stein Eye Institute at UCLA. "We found that even older people's eyes will benefit from kicking the habit."
AMD causes progressive damage to the macula, the center of the retina, which allows us to see fine details. When the macula degenerates, people experience darkness or blurring in their central vision, preventing them from being able to read, drive and recognize faces.
After age, smoking is the second most common risk factor for AMD. This study sought to determine whether age influences the effects of smoking on AMD risk.
Coleman and her colleagues followed a group of 1,958 women who underwent retinal photographs at five-year intervals, starting with a baseline exam at age 78. Four percent, or 75 of the women, smoked.
The researchers compared the retinal images at ages 78 and 83 to check for the appearance of AMD and evaluate whether smoking affected the women's likelihood of developing the disease.
"Age is the strongest predictor for AMD, yet most of the research in this field has been conducted in people younger than 75," Coleman said. "Our population was considerably older than those previously studied. This research provides the first accurate snapshot of how smoking affects AMD risk later in life."
Overall, women who smoked had an 11 percent higher rate of AMD than other women their age. In women over 80, however, those who smoked were five-and-a-half times more likely to develop AMD than women their age who did not smoke.
"We saw a slightly higher rate of AMD in women after age 80, but the rate was dramatically higher in older women who smoked," Coleman said. "The bottom line is that AMD risk increases with age. And if you smoke, your risk of developing the disease rises even more."
It has been hypothesized that cigarette smoking increases AMD risk by reducing serum antioxidant levels, altering blood flow to the eyes and decreasing retinal pigments.
"This study provides yet another compelling reason to stop smoking and suggests that it is never too late to quit," said Dr. Paul Sieving, director of the National Eye Institute.
The National Eye Institute and the National Institute on Aging funded the research.
About 1.75 million U.S. residents suffer from advanced AMD with vision loss; the number is expected to grow to almost 3 million by 2020.
Coleman's co-authors included Carol Mangione, Robin Seitzman and Fei Yu of UCLA; Steven Cummings and Katie Stone of the California Pacific Medical Center Research Institute; Jane Cauley of the University of Pittsburgh; Kristine Ensrud of the University of Minnesota; Marc Hochberg of the University of Maryland; Kathryn Pedula of the Kaiser Permanente Center for Health Research; and Edgar Thomas of the Retina Vitreous Associates Medical Group.
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