Although regular use of the drug increases the risk of stomach bleeds by about a half, there is no valid evidence these are fatal, say scientists.
But a daily pill can reduce the occurrence of heart disease and cancer, the two leading causes of death and disability across the world, by around 20 to 30 per cent.
Low doses are given to cancer patients, alongside chemotherapy and radiotherapy, has also been found to be an effective additional treatment, reducing deaths from bowel tumours, and possibly other forms of the disease, by a further 15 per cent.
Stomach bleeds caused by aspirin are much less serious than those that can occur in people not taking the drug, the study showwd.
Professor Peter Elwood, of Cardiff University, said: “Although many people use aspirin daily to reduce the risk of health problems such as cancer and heart disease, the wider use of the drug is severely limited because of the side effect of bleeding from the stomach.
“With our study showing there is no increased risk of death from stomach bleeding in people who take regular aspirin, we hope there will be better confidence in the drug and wider use of it by older people, leading to important reductions in deaths and disablement from heart disease and cancer across the community.”
The study published in the journal Public Library of Science carried out a systematic review and pooled data from earlier randomised trials.
This type of research provides the strongest evidence for drawing causal conclusions because it draws together all of the best evidence.
Prof Elwood said: “Our meta analysis, incorporating new data from direct email contact with the authors of some of the randomised aspirin studies, indicates although aspirin increases the risk of gastrointestinal bleeding by around 60 per cent, low-dose aspirin is associated with a lower risk of fatality amongst patients who developed gastrointestinal bleeding.
“Furthermore, and most important, amongst the totality of all the subjects who had been randomised to take aspirin there was no increase in death from gastrointestinal bleeding compared with subjects who had been randomised to take no aspirin.”
He added: “Fortunately cerebral bleeds attributable to aspirin are rare.
“The risk ratio associated with aspirin is about equivalent to one or two haemorrhagic strokes per year in every 10.000 subjects on aspirin.”