FRIDAY, April 24, 2015 (HealthDay News) -- Slightly more than half of middle-aged adults and seniors in the United States take aspirin daily to prevent heart attack, stroke or other serious illnesses, a new survey has found.
Leading medical associations recommend use of low-dose aspirin mainly to prevent a second heart attack or stroke. But many others who haven't had a heart problem also take aspirin regularly, researchers found.
A doctor who helped write the national guidelines for low-dose, or "baby," aspirin use said that the number of people found by the survey to be taking daily aspirin "seems about right to me."
"If 100 percent were taking it, I'd be really concerned," said Dr. Robert Bonow, a professor of cardiology at Northwestern University Feinberg School of Medicine in Chicago.
"Fifty percent in this age group seems appropriate to me, considering their risk factors," added Bonow, who helped write the guidelines issued by the American Heart Association and the American College of Cardiology.
Most appear to start taking daily aspirin after discussing the matter with a health care provider, said study lead author Craig Williams, a pharmacotherapy specialist at Oregon State University in Portland.
That's appropriate, he said.
"We would really advocate that patients engage in those discussions with their primary provider or a cardiologist, if they have one," Williams said. "We don't advocate patients make their own decisions about whether they should use aspirin or not, because it does have some dangerous side effects and it's not for everyone."
For one thing, even low-dose aspirin (81 milligrams) can cause stomach bleeding, the researchers warned. It's not a huge risk, Williams said, affecting only about five out of 1,000 older patients, but it's enough that the guidelines do not automatically recommend daily aspirin use for all adults to prevent a first heart attack or stroke.
Aspirin has two primary benefits for the heart and circulatory system, Bonow said.
The drug, a blood thinner, can prevent clots from forming in arteries that can cause a stroke or heart attack, he said. It also has anti-inflammatory properties that can prevent plaques inside arteries from becoming unstable and rupturing, which also can contribute to blockages.
All guidelines on aspirin use agree that every single person who has had a heart attack or a stroke caused by a blocked artery should take aspirin daily, Bonow said.
"The data are pretty overwhelming," said Bonow, a past president of the American Heart Association. "Taking aspirin reduces the risk of second heart attack by 25 percent to 30 percent," he added.
In people who've never had a heart attack or stroke, doctors weigh a variety of heart risk factors -- cholesterol levels, blood pressure, family history and smoking -- against the risk posed by gastrointestinal bleeding before recommending daily aspirin use, Bonow said.
In the survey, researchers quizzed more than 2,500 people between 45 and 75 years old about their aspirin use and their health history. The findings are published in the May issue of the American Journal of Preventive Medicine.
About 52 percent reported current aspirin use, and another 21 percent had used it at some point in the past.
Four out of five aspirin users were doing so to prevent a first heart attack or stroke, the researchers found. About 47 percent of those without a history of heart problems said they were taking aspirin.
The survey revealed that a talk with their doctor was the strongest factor that determined whether a person started taking aspirin.
"If you'd had a discussion with a health care provider about aspirin, you were four times more likely to be on aspirin," Williams said. Such a talk was the strongest predictor of regular aspirin use among people who had never suffered a heart attack or stroke, he added.
Only one-quarter of people who hadn't discussed aspirin with a health care provider decided to go ahead and take it on their own initiative, according to the study, partly funded by aspirin maker Bayer.
However, about one-third of aspirin users overall were taking a dosage stronger than baby aspirin, the survey revealed.
About 84 percent of aspirin users said they take the drug for heart attack prevention, and 66 percent for stroke prevention, the report indicated. Another 18 percent take aspirin for cancer prevention, and 11 percent for prevention of Alzheimer's disease.
The survey was sponsored by Partnership for Prevention and the Council on Aspirin for Health and Prevention. Aspirin maker Bayer provides grants to the Partnership but played no role in the survey, the researchers said.
For more about aspirin and heart disease, visit the American Heart Association.