Smoking continues to increase one's risk for age-related macular degeneration even after 80, according to a new study.
AMD causes progressive damage to the macula, the center of the retina that 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.
"The take-home message is that it's never too late to quit smoking. We found that even older people's eyes will benefit from kicking the habit," said lead author Dr. Anne Coleman, professor of ophthalmology at the Jules Stein Eye Institute at UCLA.
The new 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," Coleman added.
Overall, women who smoked had 11 percent higher rates of AMD than other women their same age. In women over 80, however, those who smoked were 5.5 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. The bottom line is that AMD risk increases with age. And if you smoke, your risk of developing the disease rises even more," Coleman said.
The American Journal of Ophthalmology publishes the findings in its January edition.