Fig. 1: Determination of the study population. The study population was originally screened from 7 towns in the Québec City metropolitan area in 1974 for the Québec Cardiovascular Study. Data collected in 1985 were used as the baseline characteristics for the present prospective study. Volunteers were men who asked to be part of the original study but were not selected among the randomly identified participants. ECG = electrocardiogram, IHD = ischemic heart disease.