Taking a low-dose aspirin every day has long been known to cut the chances of another heart attack, stroke or other heart problem in people who already have had one, but the risks don't outweigh the benefits for most other folks, major new research finds.
Although it's been used for more than a century, aspirin's value in many situations is still unclear. The latest studies are some of the largest and longest to test this pennies-a-day blood thinner in people who don't yet have heart disease or a blood vessel-related problem.
One found that aspirin did not help prevent first strokes or heart attacks in people at moderate risk for one because they had several health threats such as smoking, high blood pressure or high cholesterol.
Another tested aspirin in people with diabetes, who are more likely to develop or die from heart problems, and found that the modest benefit it gave was offset by a greater risk of serious bleeding.
Aspirin did not help prevent cancer as had been hoped.
And fish oil supplements, also tested in the study of people with diabetes, failed to help.
"There's been a lot of uncertainty among doctors around the world about prescribing aspirin" beyond those for whom it's now recommended, said one study leader, Dr. Jane Armitage of the University of Oxford in England. "If you're healthy, it's probably not worth taking it."