Warning of risks taking aspirin if not told to by a doctor
Aspirin should not be taken to prevent heart disease unless on doctors' orders, scientists have warned after a major study found the drug "substantially" increases the risk of dangerous bleeds.
A review of 164,225 people in their 50s, 60s and 70s found that regularly taking the inexpensive drug boosts the chances of major bleeding by more than 40pc.
Aspirin has long been recommended for patients already known to suffer from heart conditions and those at high risk of stroke, with evidence indicating its blood-thinning qualities render the risk of side-effects worthwhile.
However, the new research by King's College London suggests that for middle-aged and older people currently in good health, the benefit of regularly taking the drug is not worth the risk of serious bleeding.
Aspirin is not routinely prescribed for "primary prevention" of heart disease or stroke.
Nevertheless, experts in the UK have estimated that tens of thousands of healthy people there take the inexpensive drug anyway.
Published in the 'Journal of the American Medical Association', the study of 53 to 74-year-olds included people taking aspirin, those taking a placebo and those on no treatment.
Regular use of aspirin was associated with an 11pc lower risk of cardiovascular events such as heart disease, heart attack and stroke.
This means that roughly 250 patients would need to be treated with the medication for five years to prevent a single cardiovascular event.
However, those taking aspirin were 43pc more likely to suffer a major bleeding episode than those not using the drug.
Dr Sean Zheng, who led the research, said: "This study demonstrates that there is insufficient evidence to recommend routine aspirin use."