Some factors have a greater impact on heart attack risk in women than they do in men

To look more closely at this association, researchers looked at data on almost half a million people enrolled in the UK Biobank -- a database of biological information from British adults.

The 471,998 people had no history of cardiovascular disease, were aged 40 to 69 years and 56% of them were women.

Over an average of seven years, 5,081 people (29% of whom were women) had their first heart attack, meaning that the incidence of heart attack was 7.76 per 10,000 person years in women compared with 24.35 per 10,000 person years in men.

High blood pressure, diabetes and smoking increased the risk of a heart attack in both sexes but their impact was far greater in women.

Smoking increased a woman's risk of a heart attack by 55% more than it increased the risk in a man, while high blood pressure increased a woman's risk of heart attack by an extra 83% relative to its effect in a man.

Type II diabetes, which is usually associated with poor diet and other lifestyle factors, had a 47% greater impact on the heart attack risk of a woman relative to a man, while type I diabetes had an almost three times greater impact in a woman.

The authors believe that theirs is the first study to analyse both absolute and relative differences in heart attack risk between the sexes across a range of risk factors in a general population, but they emphasise that it is an observational study, so no firm conclusions can be drawn about cause and effect.

"The presence of hypertension, smoking, and diabetes were associated with an increased risk of myocardial infarction in both women and men, but with an excess relative risk among women," the authors say.

"Women should, at least, receive the same access to guideline-based treatments for diabetes and hypertension, and to resources to help lose weight and stop smoking as do men."

In the UK, women with diabetes are 15% less likely than men with diabetes to receive all recommended care processes, and may be less likely to achieve target values when treated for cardiovascular risk factors.

While the overall impact of smoking, high blood pressure and diabetes on heart attack risk decreased in both sexes with age, the greater risk these factors had on the risk of heart attack in women relative to their impact in men persisted.

"Rising prevalence of lifestyle-associated risk factors, coupled with the ageing population, is likely to result in women having a more similar overall rate of myocardial infarction to men than is the case at present, with a subsequent significant additional burden on society and health resources," the authors warn.