Smoking and Diabetes 'Pose Bigger Heart Attack Risk for Women'

Peter Russell

November 08, 2018

Hypertension, smoking, and diabetes may be more significant risk factors for a heart attack in women than in men, new research suggested.

The incidence of myocardial infarction (MI) is lower in women than in men at younger ages, but rates between the sexes become closer with increasing age.

Previous studies have suggested that male and female sex could have a bearing on various risk factors for coronary heart disease (CHD). Compared with men, women had a higher ratio of relative risk of CHD, but meta-analyses have been unable to accurately determine the relative risks between men and women, and how those risks might vary according to age.

UK Biobank Data

To explore the association further, a research team led by the University of Oxford tracked 471,998 people enrolled in the UK Biobank who were aged 40 to 69 with no history of cardiovascular disease.

Over an average of 7 years, 5081 people (28.8% of whom were women) had their first MI. 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.

The lower risk of MI in women compared with men was apparent across all age groups, but attenuated slightly with increasing age.

Blood Pressure, Diabetes, and Smoking

Hypertension, diabetes, smoking, and BMI increased the risk of MI in both sexes, but their impact was greater in women.

In women, systolic blood pressure and hypertension, smoking status and intensity, and diabetes were associated with a higher risk of MI compared with men.

The higher hazard ratio for women compared with men was:

The study, published in The BMJ , found an almost threefold higher risk (2.91) for women with type 1 diabetes than for men.

Women who smoked more than 20 cigarettes a day had twice the relative risk of MI than equivalent men, the researchers reported. They found that hypertension stages 1 and 2, smoking 10-19 cigarettes daily, and type 2 diabetes were each 40% more strongly associated with the risk of MI in women than men.

No evidence was found to suggest that any of the hazard ratios decreased with age.

Clinical Implications

The authors said that the findings should alert clinicians to be vigilant to female patients who are elderly, who smoke, have diabetes, or have hypertension.

They said their findings "highlight the importance of equitable access to guideline based treatments for diabetes and hypertension, and to weight loss and smoking cessation programmes for women and men in middle and older age".

They concluded that "a 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 MI to men in the future, with a major additional burden on society and health resources".

Commenting on the study, Prof Metin Avkiran, associate medical director at the British Heart Foundation, said: "Regardless of your sex, risk factors such as high blood pressure, smoking and diabetes increase the risk of a heart attack. These findings should not distract from a concerted effort to better detect and manage risk factors that can be changed.

"It’s absolutely vital that everyone has equal access to the best advice and treatment regardless of age, gender or socioeconomic status. This is an important reminder that heart disease does not discriminate, so we must shift perceptions that it only affects men."

Sex differences in risk factors for myocardial infarction: cohort study of UK Biobank participants, BMJ 2018. Paper.


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