Age and gender differences in incidence and case fatality trends for myocardial infarction: a 30-year follow-up. The Tromso Study

Background: Although the mortality of coronary heart disease (CHD) has declined in Western countries during the last decades, studies have suggested that the prevention and treatment of CHD may not have been as effective in women as in men. We examined gender-and age-specific trends in incidence, case fatality and the severity of first myocardial infarction (MI) in a large Norwegian population-based study. Design: Prospective population-based cohort study. Methods: A total of 31,323 participants enrolled between 1974 and 2001 were followed throughout 2004 for a total of 400,572 person-years. Suspected coronary events were adjudicated by a review of hospital records and death certificates. A total of 1669 events fulfilled standardized criteria of first-ever fatal or non-fatal MI. Results: In the age group 35-79 years, the age-adjusted incidence of MI declined significantly in men, whereas an increase was observed in women. For men and women >= 80 years the incidence rates remained unchanged. The severity of MI and the 28-day and 1-year case fatality rates declined significantly and similarly in men and women. Conclusion: Trends in MI incidence differed by sex and age; in the age group 35-79 years a marked decrease was observed among men but an increase was observed among women, while no change was observed among older patients. MI severity and case fatality were clearly reduced for both sexes. These data suggest that the burden of CHD is shifting from middle-aged men toward middle-aged women and elderly patients.