Circulating levels of cholesterol, specifically cholesterol associated with the low-density lipoprotein (LDL) fraction, have been established as a major etiologic factor in coronary heart disease in observational epidemiologic studies, in metabolic, pathologic, and genetic studies in humans and selected animal models, and in randomized clinical trials. The clinical trials that have demonstrated a reduction in coronary heart disease incidence from lowering LDL-cholesterol levels have been conducted primarily in middle-aged men with hypercholesterolemia or established coronary heart disease. Experimental evidence for the efficacy of cholesterol lowering in older men is confined to the analysis of small subgroups of clinical trials and is lacking for women of any age. The paucity of clinical trial data led the National Cholesterol Education Program's Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults in their 1987 Guidelines to allow for considerable physician judgement regarding the elderly.