Taking low-dose aspirin as a preventative for heart attack or stroke is no longer recommended for adults age 70 or over, according to guidelines released Sunday.

The recommendations, issued jointly by the American College of Cardiology and the American Heart Association, are a reversal of previous guidance that endorsed taking a baby aspirin daily to prevent cardiovascular problems in adults over age 50. The two groups agreed that for older adults with low risk — no prior history of heart attack or stroke — the risk of gastrointestinal bleeding outweighs any heart benefit.

The change comes after a large international study found that even at low doses, long-term use of aspirin may be harmful — without providing any benefit — for older people who have not already had a heart attack or stroke.

“Clinicians should be very selective in prescribing aspirin for people without known cardiovascular disease,” said Dr. Roger Blumenthal, co-chair of the 2019 ACC/AHA Guideline on the Primary Prevention of Cardiovascular Disease, in a statement. “Aspirin should be limited to people at the highest risk of cardiovascular disease and a very low risk of bleeding.”

The committee reminded individuals that a healthy lifestyle is the most important way to prevent the onset of atherosclerotic cardiovascular disease, heart failure, and atrial fibrillation.

“The guidelines reinforce what we have known for more than a decade,” said Dr. Steven Nissen, chairman of the department of cardiovascular medicine at the Cleveland Clinic. “For patients without heart disease, the risks of aspirin, primarily bleeding, are significant. For most patients without heart disease at moderate risk, the benefits do not exceed the risks.”

Earlier this year, the AHA published a statistical update showing that nearly half of US adults have some form of cardiovascular disease. The increased risk was mostly attributed to high blood pressure.

“We follow a dictum in medicine of 'do no harm' and aspirin is not benign,” said Dr. Clyde Yancy, chief of cardiology at the Northwestern Memorial Hospital, in Chicago. “Understanding how best to use aspirin, or any other medication, is the kind of refinement that enables our best health.”

Nearly 80 percent of all cardiovascular disease can be prevented with lifestyle modifications, according to the Heart Association. Doctors recommend regular physical activity and following plant-based diets such as DASH, a meal plan that emphasizes fruits, vegetables and whole grains to lower heart disease risk.