A healthy lifestyle can halve the chance of heart disease even for those genetically at risk, experts have found.
One person in five has a combination of genes that puts them at high-risk of suffering a heart attack.
But a major study led by experts at Harvard University and Massachusetts General Hospital found even these people are still in control of their fate.
Keeping fit, not smoking and staying slim nearly halved their risk of suffering a major coronary event over the next decade, the researchers found.
The findings, based on data from more than 55,000 people, stresses the importance of lifestyle as a risk factor.
Lead author Dr Sekar Kathiresan, whose work is published in the prestigious New England Journal of Medicine, said: ‘The basic message of our study is that DNA is not destiny.
‘Many individuals – both physicians and members of the general public – have looked on genetic risk as unavoidable, but for heart attack that does not appear to be the case.’
The researchers, who presented their findings last night at the American Heart Association’s Scientific Sessions meeting in New Orleans, used the results of four huge datasets, which tracked different groups of US citizens for at least 20 years.
Each participant was assigned a genetic risk score, based on whether they carried any of 50 gene variants linked to elevated heart attack risk.
Across the studies, those with the highest fifth of genetic scores were nearly twice as likely as those with the lowest fifth of scores to suffer a major coronary event.
But when the scientists looked at lifestyle, they found this additional risk almost disappeared.
Of those with the highest-risk genes, if participants did not smoke, had a healthy diet and took regular exercise, their chance of having a heart attack dropped by 46 per cent – putting them at roughly the same risk as those without the dangerous genes.
Dr Kathiresan said: ‘Some people may feel they cannot escape a genetically determined risk for heart attack, but our findings indicate that following a healthy lifestyle can powerfully reduce genetic risk.’
Experts in Britain are working on a blood test which could identify people with these genetic-risk factors a decade in advance of symptoms appearing.
The scientists, who are led by the medical director of the British Heart Foundation Sir Nilesh Samani, hope that people who know their risk might be persuaded to change their lifestyle before it is too late.
Coronary heart disease, in which the major arteries become clogged, affects more than 2.3million people in Britain, and 69,000 die from heart attacks every year as a result.
Yet people tend not to take action until they start to suffer warning signs, notably raised cholesterol, high blood pressure and the development of type two diabetes.
A genetic test on nearly 50,000-minute differences in DNA, gathered via a blood sample, could help doctors highlight people at risk well before they start showing any symptoms.
The team, which is spearheaded by Leicester University, has already shown that such blood samples are accurate – but it may be some time before a test is available on the NHS.
Sir Nilesh last night welcomed the new results.
‘This study shows that genetic risk and lifestyle risk are independent – but in combination, they can each be modified,’ he said.
‘So if you have a high genetic risk and a poor lifestyle your overall risk will be exaggerated.
‘But if you have a healthy lifestyle, you have the power to control your overall risk.’
