Millions of healthy people taking aspirin to ward off illness in old age are unlikely to benefit from the drug, a major trial has found.
While a daily dose of the blood-thinning medicine can protect older people who previously had heart attacks, strokes, and angina pectoris, the researchers found that the drug did not extend the lifespan of healthy people over the age of 70 years.
In Australia and the US, more than 19,000 healthy people, mostly over 70, participated in the study. Half of the participants were asked to take 100 mg aspirin each day while the rest took placebo pill.
When examined almost five years later, physicians found that daily aspirin treatment did not reduce the risk of heart attack or stroke, and prolonged the number of years without dementia or physical disability compared to placebo.
Consistent with known side effects of the drug, more internal bleeding occurred in the aspirin group, with 3.8% of patients with severe medical conditions ranging from stroke to gastrointestinal bleeding compared to 2.7% in the placebo group.
"Despite the fact that aspirin has existed for more than 100 years, we did not know if healthy older people should take it as a preventative measure to keep them healthy longer," said John McNeil, who studied at Monash University in New York Melbourne.
"It means millions of healthy elderly people around the world who are taking low-dose aspirin for no medical reason, possibly unnecessarily, because the study showed no overall benefit in balancing the bleeding risk." Details of the study are published in three newspapers in the New England Journal of Medicine.
Doctors unexpectedly found that those taking aspirin died a little more frequently during the study (5.9%) than those who took placebo (5.2%). Many of the additional deaths were due to cancer, but Leslie Ford of the National Cancer Institute of Maryland, USA said until the team analyzed more data, the cancer findings should be interpreted with caution.
Stephen Evans, Professor of Pharmacoepidemiology at the London School of Hygiene and Tropical Medicine, said: "The surprising results here are the small increase in all-cause mortality, mainly from cancer including colorectal cancer. Previous studies have not shown such elevations, and some studies have shown a reduction The authors rightly suggest treating the unexpected effects with caution, but they also show that the benefit of aspirin in healthy people is at best limited and can be quite harmful, and this damage can be over the age of 73 years be strengthened. "
Peter Rothwell, director of the Center for the Prevention of Stroke and Dementia at the University of Oxford, said the results provided "the most reliable evidence of the balance between the risk and benefits of aspirin onset after age 70 in healthy people."