Why are death rates from coronary heart disease decreasing?

Many factors have probably contributed to the observed decline in mortality from coronary disease in the United States since 1968. The issue of whether the incidence of such disease is declining remains to be clarified. The efficacy of primary prevention of coronary artery disease by multiple risk factor modification has been tested in large-scale clinical trials. Among middle-aged, normotensive, hypercholesterolemic smokers, smoking cessation and reduction of cholesterol levels by dietary change are followed by a decreased incidence of coronary events. Groups at high risk because of the combination of hypertension, cigarette smoking, and hypercholesterolemia show reduced coronary disease mortality after drug treatment of hypertension combined with cessation or reduction of cigarette smoking and dietary reduction of cholesterol levels. Primary prevention may be more effective if efforts begin early in life before behaviors and physiologic characteristics that may increase risk become established.