• The incidence of severe atherosclerosis is ascribable to a multiplicity of risk factors, cardinal among which is the serum cholesterol concentration. The dietary fat content, the serum cholesterol level, and the incidence of atherosclerosis are clearly correlated in different countries and in population cohorts. Within a population, the serum cholesterol level is a major independent risk factor for premature atherosclerotic disease. (Arch Surg 113:21-25, 1978)