Millions of healthy older Americans take low-dose aspirin every day, believing that it may lower their risk of future cardiovascular disease (CVD) and stroke, but according to a study published online in the New England Journal of Medicine on September 16, doing so may raise their risk of major hemorrhage without providing any real protective benefit against CVD.

In the Aspirin in Reducing Events in the Elderly (ASPREE) trial, 9,525 patients took 100 mg of enteric-coated aspirin every day and 9,589 took placebo every day from 2010 through 2014. Participants were community-dwelling men and women in Australia and the U.S. who were at least 70 years old, or at least 65 years old if they were black or Hispanic in the U.S. The participants did not have CVD, dementia, or disability upon enrolling in the study.

After a median 4.7 years of follow-up, the rate of cardiovascular disease was 10.7 events per 1,000 person-years in the aspirin group, compared with 11.3 events per 1,000 person-years in the placebo group. For major hemorrhage, the rate was 8.6 events per 1,000 person-years in the aspirin group, compared with 6.2 events per 1,000 person-years in the placebo group. Furthermore, the relative effect of aspirin use, on hemorrhage risk remained constant over time, suggesting that the risk of bleeding does not decline with continued use.

In their discussion, the researchers noted that their two main results—the lack of a large protective benefit against CVD and a higher risk of bleeding—are in line with other studies with similar results.

Click here to access the study that was published in the New England Journal of Medicine.