Eye condition linked to regular use of aspirin
Millions of people take aspirin every year. But new research suggests there could be a link between daily use of aspirin and an eye condition called age-related macular degeneration (AMD).
BMJ Group News
What do we know already?
AMD is a common cause of poor eyesight in older people, caused by damage to the cells in a part of the retina called the macular. It usually progresses slowly but it is rare for it to lead to total blindness.
Several studies have tried to look at the link between taking aspirin and AMD, but they have had conflicting results.
Some studies have found no link between the two. Some have found more patients on aspirin had AMD than would normally have been expected, while other studies have found aspirin may protect against AMD. So we need larger studies to see if there is a link between aspirin and AMD, and how strong the link is.
In this large study, nearly 5,000 patients aged 65 or older were interviewed by researchers in seven European countries, including the UK. People described their own aspirin use, and were grouped into those who never used aspirin, those who used it monthly or less often, those who used it at least weekly but not daily, and those who used aspirin daily. The researchers then recorded how many people in each group had AMD.
What does the new study say?
After excluding the effect of age and sex, people who took aspirin daily were more than twice as likely to have AMD as people who said they never used aspirin.
Even after the researchers accounted for several other factors that we know can make people more likely to get AMD, such as high blood pressure and cholesterol, smoking, and heart disease, people who took aspirin every day were still more than twice as likely to have AMD.
How reliable is the research?
This is a large study that used several standardised techniques to collect data, diagnose AMD, and record how often patients said they took aspirin, and several important factors that could be linked to AMD were accounted for. But this type of study cannot tell us if taking daily aspirin actually causes AMD. It can only show that the two things are linked and that twice as many people in the study who took an aspirin every day had AMD as people who never took any aspirin.
They were not able to rule out the possibility that patients who were prescribed daily aspirin for an illness - such as arthritis or heart disease - may have been more likely to have AMD because of the nature of their illness. They also did not record all of the other illnesses that patients had, and there may have been other factors that the researchers did not account for.
Also, the design of the study means that people may still have been taking aspirin after they began having visual problems, which would have affected the results.
The researchers did not make a note of what dose of aspirin people took. It may be that the risk could come with using higher doses, but lower doses could be safer.
What does this mean for me?
If you are prescribed daily aspirin, or have to take daily aspirin for an illness you have, this research could be of concern. But we need more research to be more confident of the link. Symptoms of macular degeneration include distortions to vision, for example straight lines looking wavy, or blurry areas on a page of text. If you are getting these symptoms, see your optician or doctor. There are treatments available for the more severe forms of the disease.