Lifestyle and health factors that are linked with heart disease appear to have a greater impact on cardiovascular risk in women than men, according to a study being presented at the American College of Cardiology's Annual Scientific Session (ACC.25).

While factors such as diet, exercise, smoking and blood pressure have long been linked with heart disease risk, the new study is the first to show that these associations are collectively stronger in women than men. According to the researchers, the findings suggest that sex-specific screening or risk assessment approaches could give a more accurate picture of cardiovascular risk and better motivate people to adopt heart-healthy habits.

"For the same level of health, our study shows that the increase in risk [related to each factor] is higher in women than in men -- it's not one-size-fits-all," said Maneesh Sud, MD, PhD, assistant professor in the department of medicine, interventional cardiologist and clinician scientist at Sunnybrook Health Sciences Centre in Toronto and the study's lead author. "This is novel and something that hasn't been seen in other studies."

The study focused on eight factors associated with heart disease: diet, sleep, physical activity, smoking, body mass index, blood glucose, lipids and blood pressure. Overall, the results showed that women were more likely to have fewer negative risk factors and more positive ones compared with men. However, women with more negative risk factors faced a more pronounced increase in their chance of a heart attack, stroke or other cardiovascular event compared to men with a similar risk factor profile.

"We found that women tend to have better health than men, but the impact on outcomes is different," Sud said. "The combination of these factors has a bigger impact in women than it does in men."

The researchers analysed data from over 175,000 Canadian adults who enrolled in the Ontario Health Study between 2009-2017. None of the participants had heart disease at baseline and about 60% were women. Each participant was classified as having ideal or poor health in terms of each of the eight risk factors, and these scores were combined to calculate an overall risk factor profile as poor (fewer than five positive factors or more than three negative factors), intermediate (five to seven positive factors) or ideal (ideal across all eight factors).

During a median follow-up period of just over 11 years, researchers tracked the incidence of seven heart disease outcomes -- heart attack, stroke, unstable angina (chest pain that results from restricted blood flow to the heart), peripheral arterial disease (narrowed blood vessels in the arms or legs), heart failure, coronary revascularisation (procedures to open blocked arteries) and cardiovascular death -- among participants in each of the three groupings.

In the study population, significantly more women were categorised as having ideal health, with 9.1% of women and 4.8% of men scoring a perfect 8 out of 8. Women were also less likely to be categorised as having poor health, with 21.9% of women and 30.5% of men falling into this category. In terms of individual risk factors, women were more likely than men to have ideal diet, blood glucose, cholesterol and blood pressure, while women were slightly less likely than men to have ideal physical activity levels.

After adjusting for age, the results showed that participants of both sexes saw an elevated risk of heart disease if they had poor or intermediate health compared to those with ideal health, but these differences were more extreme in women than men. Women with poor health had nearly five times the risk of heart disease as women with ideal health, while men with poor health had 2.5 times the risk of heart disease as men with ideal health. Women with intermediate health had 2.3 times the risk as those with ideal health, while men with intermediate health had 1.6 times the risk as those with ideal health.

Further study is needed to understand how each factor might be affecting outcomes differently in men and women based on either biological or sociocultural factors, the researchers said.

The researchers plan to conduct additional analyses to determine whether there are any differences in risk factor impacts among people of different racial and ethnic groups or among women before and after menopause.