(CNN) If you're a healthy older adult looking for ways to reduce your risk of heart attack and stroke, don't turn to that age-old standby: daily low-dose aspirin. It's no longer recommended as a preventative for older adults who don't have a high risk or existing heart disease, according to guidelines announced Sunday by the American College of Cardiology and the American Heart Association.

"For the most part, we are now much better at treating risk factors such as hypertension, diabetes and especially high cholesterol," said North Carolina cardiologist Dr. Kevin Campbell, who wasn't involved in the new guidelines. "This makes the biggest difference, probably negating any previously perceived aspirin benefit in primary prevention."

Doctors may consider aspirin for certain older high-risk patients, such as those who have trouble lowering their cholesterol or managing their blood sugars, as long as there is no increased risk for internal bleeding, the guidelines say. European guidelines recommend against the use of anti-clotting therapies such as aspirin at any age.

"Clinicians should be very selective in prescribing aspirin for people without known cardiovascular disease," John Hopkins cardiologist Dr. Roger Blumenthal, who co-chaired the new guidelines, said in a statement. "It's much more important to optimize lifestyle habits and control blood pressure and cholesterol as opposed to recommending aspirin."

Using aspirin in younger age groups "is now a class 2b recommendation," Campbell said, "meaning that it is not necessarily the best course of action; there is much debate among experts, and the data is not definitive."

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