Changing sex ratio in acute coronary heart disease: data from Swedish national registers 1984-99

To examine trends in sex ratios for different manifestations of coronary disease.

National Swedish registers on hospital discharges and cause-specific deaths were used to calculate age- and sex-specific trends and sex ratios for coronary admissions and deaths.

Nineteen Swedish counties, average population 4.8-5.1 million in the investigated age groups.

All patients aged 25-84 years with first hospital admissions or deaths as a result of coronary heart disease in 1984-99, in total 432,871 cases.

Ratio men/women and rates (per 100,000) of acute myocardial infarction (AMI), acute admissions for angina and total of all acute admissions for any coronary disease.

Below age of 65 years AMI incidence decreased more for men than for women and rates of acute admissions for angina increased more in women than in men. In men and women above 65 years trends were almost identical. In 1984-87 the ratio men/women with respect to myocardial infarction was 5.6 at age 25-44 years, but decreased to 3.7 in 1996-99. Corresponding sex ratios for angina decreased from 3.2 to 1.8 and for total coronary heart disease from 4.7 to 2.8. Amongst men and women aged 45-54 years, the sex ratio with respect to myocardial infarction decreased from 5.6 to 4.1, for angina from 2.4 to 1.7 and for total acute coronary disease from 4.2 to 2.7. Ratios men/women decreased less at higher ages and remained unchanged throughout the period in the oldest age group.

Overall, we found decreasing sex ratios at ages below 65, but above age 65 years trends in men and women were similar. These developments could be due to changing criteria for admission and diagnosis, but true differences in the clinical manifestation of coronary disease, possibly in response to secular trends in risk factor levels, cannot be excluded.