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

The prevalence of coronary heart disease (CHD) was determinedin a general population sample of 9141 Icelandic men aged 34–79years, and the prevalence of four different forms of CHD wasestimated separately: symptomatic infarction fulfilling WHO–MONICAcriteria for definite myocardial infarction; myocardial infarctiondetected by ECG changes only (unrecognized, silent infarction);angina pectoris detected by the Rose questionnaire and associatedwith ECG manifestations of myocardial ischaemia, either at restor during exercise, but no manifestations of myocardial infarction;angina pectoris without ECG changes indicative of myocardialischaemia. The study was conducted in five stages allowing evaluationof trends from 1968–1986 Age was a major determinant of the prevalence of all forms ofCHD. Thus, the prevalence of myocardial infarction (symptomaticor silent) rose from undetectable levels in the youngest agegroup (30–34 years) to around 12% (7% symptomatic and5% silent) in the oldest group (75–79 years) and the prevalenceof all forms of CHD rose from 4% in the youngest age group to23% in the age group 70–74 years. Age-standardized comparisonwas carried out on the prevalence of the different forms ofCHD at different stages of the study in 50–64-year-oldmen who were represented in all stages of the study. There wasa gradual increase in the prevalence of myocardial infarctionfrom 3% (symptomatic and silent combined, CI 1.9–4–8)in 1968 to 4.9% in 1986 (CI 3.9–6.1) (P<0.001). Converselythere was a statistically significant fall in the prevalenceof angina pectoris, with or without ECG-manifestations of myocardialischaemia, from 11.3% (CI 8.8–14.4) in 1968 to 5% in 1986(CI 4.0–6.2) (P<0.001). This decrease was of sufficientmagnitude to more than offset the rise in infarct prevalence,resulting in a significant fall in the prevalence of all CHDfrom 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 generalagreement with the previously reported decline in age-standardizedmortality from CHD and the incidence of myocardial infarctionin Iceland.