A large global study of 55,000 participants has found the odds are not stacked against you if you have a strong genetic link to heart disease.

Clean living can slash your risk for heart disease even if your genes are heavily stacked against you, a new US study has found.

The large study of over 55,000 people from around the world found that people with the most inherited risk cut their chances of having a heart attack or other heart problems in half if they did not smoke, ate well, exercised and stayed slim.

It also found the opposite is true: You can largely trash the benefit of good genes with unhealthy habits.

"DNA is not destiny, and you have control," said the study leader, Dr Sekar Kathiresan, genetic research chief at Massachusetts General Hospital.

"Many people assume that if your father had a heart attack, you're destined to have a problem," but the results show that's not the case, he said.

The study was discussed Sunday at an American Heart Association conference in New Orleans and published online in the New England Journal of Medicine.

It's long been known that genes and lifestyle affect heart risk, but how much influence each one has, and how much one factor can offset the other, are unknown.

Researchers combined information from four global studies, including one which involved checking imagery for plaque building up in heart arteries.

Participants were checked for 50 genes related to heart risks and placed in five groups based on how many they had. They also were sorted into three groups by healthy lifestyle factors - not being obese, exercising at least once a week, eating a healthy diet and not smoking.

The results: people with the most gene risk had nearly twice the chance of developing heart problems than people in the lowest gene risk group did. Roughly the same was true for those in the unfavourable lifestyle group versus the favourable one.

But the interesting part was the difference in risk when gene and lifestyle factors were combined.

"If you have an unfavourable lifestyle and high gene risk, your risk of having a heart attack over the next 10 years is 10 per cent," but with a good lifestyle, it was only five per cent in one of the groups in the study, Kathiresan said.