Importance of coronary risk factors in the presence or absence of myocardial ischemia.

Smoking history, systolic blood pressure, and serum cholesterol concentration were studied for their value in predicting 5-year coronary mortality in middle-aged and older Finnish men. Total experience consisted of 188 deaths from ischemic heart disease during 20,245 person-years. Initially, the men were divided into 3 groups according to the degree of myocardial ischemia: (1) previous myocardial infarction; (2) ischemic heart disease without infarction; and (3) no myocardial ischemia. The 3 main risk factors were associated, independently of each other and of age, with the relative risk of coronary death similarly in the 3 groups, whereas their absolute impact on mortality was strong among men with ischemic heart disease and even stronger among those with a prior myocardial infarction. For example, the estimated excess coronary mortality attributable to smoking 10 to 19 cigarettes per day was 6.3 deaths per 1,000 person-years in the group with no ischemia, 14.6 in the ischemia group, and 43.1 in the infarction group. The results suggest that secondary prevention of ischemic heart disease may be important. Screening of coronary disease among middle-aged and older men also appears justified.