Last updated at 9:58 AM on 03rd March 2010
Terrifying: A daily intake of aspirin can reduce the risk of a heart attack in people with angina
Healthy people were warned yesterday against taking an aspirin a day in an attempt to prevent heart attacks or strokes.
They may be doing more harm than good because the risks of internal bleeding can outweigh the potential benefits, a study found.
Thousands of the 'worried well' – who have no history of heart problems – are believed to take aspirin as an 'insurance policy'.
But scientists at Edinburgh University found that daily use almost doubled the risk of dangerous internal bleeding, while having no effect on heart attacks or strokes.
Yesterday, Professor Peter Weissberg, of the British Heart Foundation, said: 'We know that a small daily dose of aspirin can reduce the risk of a heart attack in people with angina and in those who've had a heart attack.
'In these cases, this potential benefit outweighs the risk of internal
bleeding, which is a side effect of aspirin.
'This study sought to determine if people with evidence of artery disease in
their legs – which raises the risk of having a heart attack in future – would
also benefit from taking daily aspirin.
'The results show that they don't gain any heart-protective benefit from taking a daily dose of aspirin and were more prone to internal bleeding than people who took a placebo [dummy pill].
'The findings agree with our advice that people who do not have symptomatic or diagnosed artery or heart disease should not take aspirin, because the risks of bleeding may outweigh the benefits.'
In the study, 3,350 middle aged men and women were given either low-dose aspirin or a dummy pill every day.
'Worried well': Thousands of people are believed to take aspirin as an 'insurance policy' despite having no heart problems
They were selected after blood pressure tests suggested the arteries in their legs were furred up. But they had no symptoms of heart disease and had not suffered a heart attack.
Over eight years, they suffered 357 'cardiovascular events', including heart attacks and strokes.
There was no difference between the two groups in the rate of these problems, but 34 people on aspirin had a major haemorrhage requiring hospital treatment, compared with 20 taking the dummy pill.
A further 14 volunteers who were on aspirin developed a stomach ulcer compared with eight who were taking the placebo.
Study leader Professor Gerry Fowkes, whose research has been published in the Journal of the American Medical Academy, said it showed that people should not be given aspirin on the basis of tests on the blood pressure in their legs – unless their risk was shown to be high.
For many patients with higher blood pressure in their legs, cholesterol-busting statins would be better.
Last year, when he presented initial findings at a cardiology conference in Barcelona, Professor Fowkes said another six trials had shown the same results.
'Our research suggests aspirin should not be prescribed to the general population,' he added.
Millions of heart patients and diabetics are currently prescribed aspirin, in line with medical guidelines, because their doctors consider they are at high risk of a heart attack.
In patients who have suffered a heart attack in the past, aspirin has been shown in trials to reduce a repeat by a fifth.