Up to one in five men is carrying a gene from their father which increases their risk of coronary heart disease by 50 per cent, a study has found.
The increased risk is independent of factors such as high blood pressure or high cholesterol, the biggest causes of heart disease, which claims the lives of 50,000 men a year. But it does not mean men carrying the gene can ignore advice to eat healthily, take exercise and avoid smoking. The common risk factors apply to them as they do to other men – it is merely their misfortune that they carry an additional inherited risk.
Dr Maciej Tomaszewski of the University of Leicester, who led the study with colleagues from Australia, said it was likely that the gene carried on the male Y chromosome – which is only present in men and thus passed down the male line – affected the immune response and linked inflammatory reactions. That in turn could increase the heart disease risk.
"This gene variant is working through different mechanisms from the usual risk factors. It is difficult to say what the men affected can do about it because we don't yet understand its mechanism. The only advice we can give is to continue doing the good work in the department of lifestyle changes because that will reduce the risk of the known mechanisms," he said.
"But lifestyle choices are not only powerful determinants of blood pressure, cholesterol levels and weight, they also possibly contribute to the functioning of the immune system. If you work hard on your lifestyle, you may also see your immunity improve."
The research, published in The Lancet, could help explain the higher incidence of heart disease in men and its earlier onset – 10 years before women on average – which has puzzled scientists for decades. It has also renewed interest in the role of the male Y chromosome in health and disease.
Dr Tomaszewski said it was too early to suggest men should be tested for the gene. But its identification could lead to new treatments. "It could become a therapeutic target for the future," he said.
Virginia Miller of the Mayo Clinic in the US said consideration should now be given to changing the questionnaire for men whose heart disease risk was being assessed. Instead of asking: "Did your mother or father have a heart attack before 60?" the question should be: "Did your father have a heart attack before 60?" "Both sex and family do matter in inheritance of coronary heart disease," she wrote.