Lifetime prediction of coronary heart disease and heart disease of uncertain etiology in a 50-year follow-up population study

Objectives: The relationships of four basic risk factors with 50-year incidence of coronary heart disease (CHD) and Heart Disease of Uncertain Etiology (HDUE) were investigated in a population study. Material and methods: There were 1712 men aged 40–59 years in 1960 and 1677, heart disease free, were followed-upfor 50 years. Incidence of first event for CHD (sudden death, fatal and non-fatalmyocardial infarction, other fatal and non-fatal coronary syndromes) and HDUE (heart failure, chronic arrhythmia, blocks, “chronic CHD”, hypertensive heart disease) was estimated and the relationships of four basic risk factors analyzed. Results: In 50 years incidences of CHD and HDUE were respectively 26.9 and 20.6%. Cox proportional hazards models showed serum cholesterol as a strong CHD predictor (hazard ratio, HR, for 1 mmol/l difference 1.22 and confidence intervals, CI, 1.11 to 1.33), irrelevant forHDUE (HR 1.02 and CI 0.87 to 1.18). Age at entry was a stronger predictor for HDUE (HR for 5 year difference 1.65 and CI 1.46 to 1.86) than for CHD (HR 1.26 and CI 1.14 to 1.39). Systolic blood pressure and cigarette smoking had similar predictive power. The diagnosis of angina pectoris (AP) recorded at any time during the study was strongly associated with CHD but not with HDUE. A HDUE subgroup with AP had similar life-expectancy to CHD, suggesting the need to re-classify them as CHD. Conclusions: Due to important differences in predictors (risk factors) and expectancy of life CHD and HDUE are probably manifestations of different etiologies.