Women are more vulnerable to certain risk factors for heart attack than men

High blood pressure, smoking and diabetes are known risk factors for cardiovascular disease and all increase the risk of heart attack in both sexes. However, a new study published in the BMJ has found that they have more of an impact in women.

Overall, men are at greater risk of heart attack than women, but several studies have suggested that certain risk factors have more of an impact on the risk in women than in men.

To look at this more closely, 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 per cent 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 per cent 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 per cent relative to its effect in a man.

Type II diabetes had a 47 per cent 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 stated.

“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,” they added.

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.

Commenting on the study Dr Angie Brown, Medical Director with the Irish Heart Foundation said, that even though approximately a third of women in Ireland will die of cardiovascular disease, many women still view heart attack as mainly a man’s problem.

“This study was done in people between the ages of 40 and 69 so at the beginning of the study some of the women would have been pre-menopausal. Many women are unaware that they are protected by their hormones but after the menopause women’s risk of heart attack and stroke increases and catches up to that of men,” Dr Brown explained.

According to Dr Brown, in many cases women are even more vulnerable to risk factors for heart disease and stroke than men. Factors such as smoking, being overweight or obese, having high blood pressure, high cholesterol, being inactive or having diabetes and a family history of cardiac problems are known to increase the risk.

“For example, women metabolise nicotine a lot faster than men, so a cigarette will increase a woman’s risk of heart attack a lot more than it will in a man. Women who smoke are also twice as likely to have a heart attack than women who have never smoked. A large percentage of heart attacks in women under the age of 50 are due to smoking.

The same with diabetes – it increases a woman’s risk of having heart disease a lot more than it will for a man. Another risk factor that’s more important for women is family history of heart disease, which can be a stronger predictor in women than in men,” she explained

This study confirms this by showing the significant effect that smoking, high blood pressure and diabetes has on women’s risk of heart attack, Dr Brown said.

“The good news is that these risks can be treated so both men and women should stop smoking if they smoke and get their blood pressure, blood sugar and cholesterol checked and treated if necessary as well as cutting down on alcohol and exercising regularly, a significant number of heart attacks could be prevented.”