Prevalence of coronary heart disease in Icelandic Men 1968-1986: The Reykjavik Study

Abstract

The prevalence of coronary heart disease (CHD) was determined in a general population sample of 9141 Icelandic men aged 34–79 years, and the prevalence of four different forms of CHD was estimated separately: symptomatic infarction fulfilling WHO–MONICA criteria for definite myocardial infarction; myocardial infarction detected by ECG changes only (unrecognized, silent infarction); angina pectoris detected by the Rose questionnaire and associated with ECG manifestations of myocardial ischaemia, either at rest or during exercise, but no manifestations of myocardial infarction; angina pectoris without ECG changes indicative of myocardial ischaemia. The study was conducted in five stages allowing evaluation of trends from 1968–1986 Age was a major determinant of the prevalence of all forms of CHD. Thus, the prevalence of myocardial infarction (symptomatic or silent) rose from undetectable levels in the youngest age group (30–34 years) to around 12% (7% symptomatic and 5% silent) in the oldest group (75–79 years) and the prevalence of all forms of CHD rose from 4% in the youngest age group to 23% in the age group 70–74 years. Age-standardized comparison was carried out on the prevalence of the different forms of CHD at different stages of the study in 50–64-year-old men who were represented in all stages of the study. There was a gradual increase in the prevalence of myocardial infarction from 3% (symptomatic and silent combined, CI 1.9–4–8) in 1968 to 4.9% in 1986 (CI 3.9–6.1) (PP<0.001). This decrease was of sufficient magnitude to more than offset the rise in infarct prevalence, resulting in a significant fall in the prevalence of all CHD from 14.3% (CI 11.5–17.8) in 1968 to9.9% (CI 8.5–11.5) in 1986 in 50–64-year-old men. This trend is in general agreement with the previously reported decline in age-standardized mortality from CHD and the incidence of myocardial infarction in Iceland.