Older adults who use aspirin regularly for 10 years or more may have an increased risk of developing an age-related eye disorder that can lead to vision loss, a study found.
The risk of having wet age-related macular degeneration was about twice as high for those who regularly took aspirin a decade before researchers detected it in an eye exam compared with those who didn't take the medicine, according to research in the Journal of the American Medical Association.
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About 19 percent of U.S. adults take aspirin regularly for pain, arthritis and to prevent heart attacks, the authors wrote. People shouldn't stop taking the medication because its benefits are well-known, said lead author Barbara Klein. Instead, more studies are needed to understand how aspirin may contribute to the eye disorder, she said.
"There are a lot of people who take aspirin now for cardio-protective reasons," Klein, a professor of ophthalmology and visual sciences at the University of Wisconsin in Madison, said in a telephone interview. "Should this influence their taking this medicine to save their life? No, don't stop."
Macular degeneration is a leading cause of vision loss in people older than 60, according to the National Institutes of Health. It affects the part of the eye that allows people to see fine details and can lead to blindness. Treatment can slow down vision loss but not restore it.
About 9.1 million people in the U.S. older than 40 suffer from the condition, according to the Macular Degeneration Association. About 90 percent have the "dry" type where vision slowly becomes blurry. The rest have the "wet" type, where new blood vessels grow under the retina and leak fluid or blood. The wet type accounts for all blindness from the disease, the Sarasota, Fla.-based group said.
In the analysis, researchers used data from the Beaver Dam Eye Study, a long-term study of age-related eye diseases in Wisconsin. They included 4,926 people who were ages 43 to 86 at the start of the trial. Patient exams were conducted every five years over two decades. Patients were asked if they regularly used aspirin at least twice a week for more than three months.
The study found that aspirin use 10 years prior to the exam in which the researchers observed patients as having macular degeneration was associated with a small but significant increase in the risk of developing wet or neovascular age-related macular degeneration, the authors wrote.
The study found that 30 of 1,462 people in the study, or 2.05 percent, who used aspirin for a decade prior had neovascular age-related macular degeneration, while 31 of 4,065, or 0.76 percent, of those who didn't use aspirin developed the vision eye disorder. After adjusting for age and sex, the incidence of neovascular macular degeneration was 1.4 percent for the aspirin users and 0.6 percent for the nonusers, the authors said.
No association was seen between aspirin use and the dry form of the eye disorder or for shorter-term use of aspirin, Klein said.
Barrett Katz, a neuro-ophthalmologist at Montefiore Medical Center in Bronx, N.Y., who wasn't an author of the paper, said the findings show that regular aspirin use may be another small risk factor for age-related macular degeneration. Other risk factors include age, race, cigarette smoking, alcohol ingestion and genetics, he said.
More studies are needed to replicate these findings and to show what harm, if any, aspirin has on the vision of people with the disorder or if it causes age-related macular degeneration, Katz said.