Traditional Risk Factors Don't Explain MI Gender Gap

Traditional risk factors for coronary artery disease do not explain the higher lifetime risk for incident myocardial infarction (MI) observed among men, according to a Norwegian population-based study.

In Tromsø, Norway, men were more than twice as likely to have an MI even after adjusting for age and birth cohort (RR 2.72, 95% CI 2.50-2.96). Accounting for cholesterol levels on top still yielded a doubled risk for men (RR 2.07, 95% CI 1.89-2.26), reported Grethe Albrektsen, PhD, of the Norwegian University of Science and Technology, and colleagues in a study published online in JAMA Internal Medicine.

Meanwhile, adjusting for systolic blood pressure, diabetes, body mass index, and physical activity did not attenuate the relative risk of male patients at all. Their relative risk, however, did grow less pronounced the older they got:

• Age 35-54 (RR 3.64, 95% CI 2.85-4.65)
• Age 55-74 (RR 2.00, 95% CI 1.76-2.28)
• Age 75-94 (RR 1.66, 95% CI 1.42-1.95)

"The observed sex contrast in risk of MI cannot be explained by differences in established coronary heart disease risk factors," Albrektsen's group concluded.

"The gender gap persisted throughout life but declined with age as a result of a more pronounced flattening of risk level changes in middle-aged men. The minor changes in incidence rates when moving from premenopausal to postmenopausal age in women make it unlikely that changes in female hormone levels influence the risk of MI."

The Tromsø study included 33,997 adults (51% women) who were diagnosed with MI from 1979 to 2012. Participants were followed for a median of 17.6 years.