Elderly people who are in good health don't have to take an aspirin a day to reduce the risk of a first heart attack or stroke, upending years of medical advice.

The new research appears in the New England Journal of Medicine.  Australian and US researchers observed 19,114 people in the both countries who were in good health with no history of heart problems and were over the age of 70.  Half were given a daily low-dose aspirin for five years.  But that group did not show any reduced risk of heart problems, nor did they experience any other benefits.  Some even showed an increased number of major stomach bleeds.

"That's an issue in the elderly when people's blood vessels are a bit more fragile," said Professor John McNeil from Monash University.  "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.

"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," he continued, "These findings will help inform prescribing doctors who have long been uncertain about whether to recommend aspirin to healthy patients."

The researchers note that patients should consult with their doctors before making any changes to their medication regimen.