Taking Aspirin does not help prevent heart attacks or strokes in people with diabetes, according to a new study that contradicts current recommendations.

Aspirin has proven effective in helping to reduce the risk among people who have already had a heart attack or stroke. Less is known about its value in people who have not developed cardiovascular disease but are at high risk, such as people with diabetes.

To learn more, researchers in Scotland studied 1,276 men and women over 40 years of age, some of whom were randomly given either Aspirin or a placebo. Participants all had Type 1 or Type 2 diabetes, but no symptoms of cardiovascular disease.

Of the 638 people in the Aspirin group, 116 had heart attacks or strokes compared with 117 that occurred among the same number of subjects who took the placebo, the team reported in this week's issue of the British Medical Journal.

There were also 43 deaths from heart disease or stroke among those who took Aspirin, compared with 35 in the placebo group.

"This trial does not provide evidence to support the use of Aspirin or antioxidants in primary prevention of cardiovascular events and mortality in the population with diabetes studied," Dr. Jill Belch, a professor of vascular medicine at the University of Dundee in Scotland, and her colleagues concluded.

"Aspirin should, however, still be given for secondary prevention of cardiovascular disease in people with diabetes."

Antioxidants were not expected to help prevent heart attacks or strokes, given that previous studies showed no benefits.

"Although Aspirin is cheap and universally available, practitioners and authors of guidelines need to heed the evidence that Aspirin should be prescribed only in patients with established symptomatic cardiovascular disease," William Hiatt of the University of Colorado wrote in a journal editorial accompanying the study.

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.

The research was funded by Britain's Medical Research Council. Drug manufacturers donated the medications, placebo tablets and study nurse team.