Aspirin is generally recommended to prevent non-fatal heart attacks among people who have already had a heart attack or stroke. (CBC)

Healthy people shouldn't take Aspirin to prevent heart disease, a new review suggests.

Aspirin and ASA are generally recommended to prevent non-fatal heart attacks among people who already had a heart attack or stroke. But the value of its long-term use by healthy people is uncertain, given the increased risk of internal bleeding.

Prof. Colin Baigent of the University of Oxford and his colleagues performed a review of studies documenting serious vascular events like heart attacks and strokes, and major bleeds in six trials involving 95,000 people at low to average risk, and 17,000 people at high risk.

Their findings appear in this week's issue of the medical journal The Lancet.

Among 10,000 people with heart disease, the British researchers found that low dose Aspirin will prevent as many as 200 strokes and heart attacks over one year.

But in 10,000 healthy people, low dose Aspirin will prevent seven strokes and heart attacks. Among healthy men and women, that modest benefit is cancelled out by an increased risk of internal bleeding, the researchers said.

Guidelines not justified

In the secondary prevention studies among people who had already had a stroke or heart attack and were at high risk for another, Aspirin reduced the risk of serious vascular events by about a fifth — a benefit that clearly outweighed any small extra risk of bleeding. That finding backs current guidelines for Aspirin's use.

"The currently available trial results could well help inform personally appropriate judgments by individuals about their own use of long-term Aspirin, they do not seem to justify general guidelines advocating the routine use of Aspirin in all healthy individuals above a moderate level of risk for coronary heart disease," the study's authors concluded.

There is no good evidence that the benefits of long-term use of Aspirin exceed the risks by an appropriate margin for tens of millions of healthy men and women of all ages worldwide who could potentially be affected, Baigent said.

Health Canada and the U.S. Food and Drug Administration say Aspirin is indicated for primary prevention to reduce the risk of a first non-fatal heart attack in people deemed at risk by their physicians, which the packaging also suggests.

In a commentary accompanying the review, Prof. Ale Algra and Dr. Jacoba Greving of the University Medical Centre in Utrecht, Netherlands, agreed that in most cases, Aspirin is not justified for primary prevention.

"Patients might not wish to be medicalised — such considerations are important in the decision to take Aspirin or not," the pair wrote.

They stressed the importance of making lifestyle changes such as quitting smoking, eating a healthy diet and getting regular exercise, in addition to considering drugs like Aspirin or cholesterol-lowering statins.