The Heart Foundation does not recommend that people who do not have coronary heart disease take daily aspirin. They noted that despite this habit, life was not prolonged for these individuals and also the risk of getting a heart attack or a stroke for the first time was not reduced.
"We found there was no evidence that aspirin did healthy people any good in terms of living longer, remaining free of disability for longer, or preventing cardiovascular disease", he said.
He added: "It means millions of healthy older people around the world who are taking low-dose aspirin without a medical reason may be doing so unnecessarily, because the study showed no overall benefit to offset the risk of bleeding".
Over a four-year span starting in 2010, the trial enrolled more than 19,000 people in Australia and the U.S. who were 70 and older, or 65 for African-American and Hispanic participants because their risks of dementia or cardiovascular disease are higher.
Dr Gabriel Choi Kin, former president of the Hong Kong Medical Association, said the use of low-dose aspirin for healthy elderly people was controversial. It will do your heart health no good, as is popularly believed.
The results - which show that risks of major bleeding in low-dose aspirin users overwhelm any heart benefits - were reported online in the New England Journal of Medicine and presented Sunday at the European Respiratory Society International Congress in Paris.
However, bleeding, a well-known side-effect of aspirin, was borne out by the study, with a small increase (3.8 per cent) in cases of serious bleeding among aspirin takers versus (2.8 per cent) in those who took placebo.
It had previously been thought by many that a low daily dose of the blood-thinning medicine benefits older people. They are free of medical conditions requiring aspirin use and free of dementia and physical disability. "The concern has been uncertainty about whether aspirin is beneficial for otherwise healthy older people without those conditions". But when researchers looked at more than 19,000 people in Australia and the United States over almost five years, they found it wasn't so.
Participants were randomly assigned to receive 100 milligrams of aspirin each day or a placebo pill, and were followed for an average of 4.7 years. Numerous extra deaths were due to cancer, but Leslie Ford from the National Cancer Institute in Maryland said that until the team had analysed more data, the cancer findings "should be interpreted with caution".
Lead author Professor John McNeil says the results are clear: "If you don't need it, don't take it". Another negative observation was the increased risk of cancer-related death in those who were given aspirin every day.
But the odds of a major bleeding episode were 38 percent higher with aspirin. "These initial findings will help to clarify the role of aspirin in disease prevention for older adults, but much more needs to be learned". Hemorrhagic stroke, bleeding in the brain, gastrointestinal hemorrhages or hemorrhages at other sites that required transfusion or hospitalization occurred in 361 people on aspirin and in 265 taking the placebo. Previous studies have not shown such increases, and reductions in bowel cancer have been seen in some studies. It is important to note that the new findings do not apply to people with a proven indication for aspirin such as stroke, heart attack or other cardiovascular disease.