Two cohorts of Belgian bank clerks were observed during 10 years, with follow-up examinations at 5 and 10 years. Cohort I consisted of 447 males, aged 40-59, free of coronary heart disease at entry. They belong to a private bank whereas the 768 males of cohort II work in semipublic savings bank. 5 and 10 years' incidence of new "hard' coronary events (sudden deaths, myocardial infarction fatal or nonfatal) were significantly higher for cohort I as compared to cohort II. These differences are not explained through the major coronary risk factors introduced in a multiple logistic function, as expected hard events in cohort I were 50% higher than predicted by the MLF computed for cohort II.