Why do men and women differ in their risk of myocardial infarction?

Abstract

Cardiovascular disease is a global problem. To enable more effective prevention strategies for myocardial infarction (MI), the INTERHEART study looked for differences between countries, and between men and women, in risk factors for acute MI.1 It was a case–control study with 15 152 cases of acute MI and 14 820 controls from 262 centres from 52 countries. Information about nine risk factors was collected: smoking, self-reported hypertension and diabetes, measured waist/hip ratio, psychosocial factors, diet, physical activity, alcohol consumption, and measured apolipoprotein B/apolipoprotein A1 ratio.1 In their first report. the INTERHEART investigators concluded that these nine risk factors accounted for most of the risk for acute MI in both sexes, at all ages, and in all regions.1 When all nine risk factors were included in the analysis, the population-attributable risk for men ≤55 years was 93.1% and for women ≤65 years was 96.5%, indicating that most premature MI is preventable.1 The INTERHEART investigators have now extended their analysis of risk factors for MI in men and women.2 They addressed the specific question of why women have their first MI 9–10 years after men by examining whether differences exist between women and men in risk factor distribution across various age categories. The 12 460 cases were 18% fewer than the number in the initail report, and the 14 634 controls were similar in number to those in the initial report. There were some differences in definition of risk factors compared with the initial report and, rather than the different age cut-off points for younger and older men and women in their initial study,1 they used the same age cut-off point of 60 years for both men and … *Corresponding author. Tel: + 61 3 9288 2480, Fax: + 61 3 9416 2676, Email: dcampbell{at}svi.edu.au