People taking aspirin were just as likely to suffer their first heart attack or stroke as others with a similar risk profile who were not on the medication. But the drug did increase the rate of gastrointestinal bleeding, researchers discovered.
Although aspirin has a proven protective effect for people who have already suffered a heart attack or stroke, the same can't be said for those at moderate risk of their first heart attack—such as being a smoker or having raised cholesterol levels or blood pressure.
Researchers from the Brigham and Women's Hospital in Boston recruited 12,546 men and women with an average age of 64 who had a 30 per cent risk of their first heart attack in the following 10 years. Over the following five years, half were given aspirin every day and the rest instead took a placebo pill—but there was hardly any difference in the number of heart attacks experienced by both groups, with 269 heart attacks or strokes in the aspirin group, and 281 attacks among those given the placebo.
But there were 61 cases of gastrointestinal bleeding in the aspirin group, and 29 in the placebo group.