The doctors included Aditya Bardia, MD, of the internal medicine department at the Mayo College of Medicine in Rochester, Minn. They studied data on about 22,500 postmenopausal women.
The women were enrolled in the Iowa Women's Health Study, a long-term health study of women living in Iowa. Starting in 1986, they completed surveys periodically about their medical history, diet, physical activity, smoking, and other factors.
The women were followed until 2002. During that time, 3,487 women were diagnosed with cancer. Women who reported ever using aspirin were 16% less likely to be in that group.
During the follow-up period, 3,581 women died of any cause, including nearly 1,200 cancer deaths and 734 deaths from heart disease.
Women who reported ever using aspirin were less likely to die of cancer or heart problems than those who never used aspirin.
Compared with women who never used aspirin, aspirin users were 13% less likely to die of cancer, 25% less likely to die of heart disease, and 18% less likely to die of any cause during the study.
Nonaspirin NSAIDs, in contrast, weren't tied cancer or heart disease death rates, for better or worse.
The study was purely observational, meaning that the researchers didn't directly test aspirin's ability to counter cancer. The study doesn't pinpoint the best aspirin dose to curb cancer.
If the findings are correct, aspirin may provide a modest but still important edge against cancer, cancer deaths, and heart disease deaths, note the researchers.
However, Bardia and colleagues caution that "these potentially positive benefits must be weighed against the potential risks associated with aspirin use, such as gastrointestinal bleeding and hemorrhagic (bleeding) stroke."