Taking at least one aspirin every week is linked to development of age-related macular degeneration, according to a new study.
Researchers, however, caution that there's still not enough evidence to say taking the popular pain reliever leads to the condition, which is the leading cause of blindness in older people.
"I don't think the current evidence is strong enough to conclude cause. We still need to accumulate more evidence," said Dr Jie Jin Wang, the study's lead author from the University of Sydney.
Currently, over 100 billion aspirin tablets are consumed every year, Dr Wang and her colleagues write in JAMA Internal Medicine. They add that it's commonly used in the prevention of heart attacks or strokes.
In 2011, a European study found seniors who take a daily aspirin were twice as likely to develop vision loss, compared to those who did not.
How the research was done
Dr Wang said that her team saw that 2011 report and wanted to confirm its findings by using information it had collected on a group of Australians over a 15-year period.
Overall, Dr Wang and her colleagues had information on 2 389 people who were over 45 years old. Of those, 257 said they took at least one aspirin every week.
At the end of the study, 63 people had developed wet macular degeneration. The researchers found 5.8% of regular aspirin users ended up with wet macular degeneration, compared to 2.3% of people who did not regularly take aspirin.
That difference remained even when the researchers adjusted for the participants' age, sex, weight, blood pressure, history of smoking and heart disease.
Limitations and mixed results
In a commentary published with the new study, Dr Sanjay Kaul and George Diamond caution that the study had limitations and previous studies found mixed results when looking at aspirin use and vision loss.
They write that the evidence is not convincing enough for doctors to change how they prescribe aspirin, especially with its benefits in preventing heart attacks and strokes.
"In the final analysis, decisions about aspirin use are best made by balancing the risks against the benefit in context of each individual's medical history and value judgments," they write.
Dr Wang agreed that the findings are not strong enough to support a change in clinical practice, but she said some doctors may want to keep a closer watch on patients at high risk for macular degeneration who are also using aspirin.
Dr Jack Cioffi, chair of Columbia University Medical Center's department of ophthalmology in New York, agreed with the commentary and said people should stay on aspirin if their doctors have them on it.
"Even if there is an increased incidence of macular degeneration, it's relatively small," said Dr Cioffi, who was not involved with the new research.
He also added that people shouldn't start taking aspirin for no particular reason, either.
"I think this is a cautionary note, and it reminds us that every medicine has a risk-benefit profile that we have to be aware of - even aspirin," said Dr Cioffi.
(Reuters Health, January 2013)
Could daily aspirin harm seniors' eyes?
Aspirin tied to lower lung cancer risk in women