Certain patterns of blood lipids, including elevated total cholesterol (TC), elevated low-density lipoprotein cholesterol (LDL), and low levels of high-density lipoprotein (HDL) cholesterol, are important risk factors for coronary heart disease (CHD). CHD is the leading cause of morbidity and mortality in the United States, causing nearly 500,000 deaths each year and requiring nearly 12 million hospital days of care per year. It is the leading cause of disabled life-years and is second only to injuries as a cause of life-years lost. The age-adjusted annual death rate for CHD is 100 per 100,000 persons overall and 140 per 100,000 persons among African Americans. The lifetime risk of having a CHD event, calculated at age 40, is estimated to be 49 % for men and 32 % for women in the United States. The large burden of disease from CHD and strong epidemiologic associations between CHD and abnormal lipid levels have prompted efforts to modify or reduce the risk of CHD events by treating lipid disorders. In this report, we examine the evidence concerning the benefits and harms of drug, diet, and exercise therapy in treating lipid disorders and reducing the risk of CHD events in patients with lipid disorders. The underlying goal of screening and therapy for lipid disorders is to reduce the burden of illness from CHD. Thus, other means of reducing CHD, such as hypertension prevention and control, smoking prevention and cessation, and possibly chemoprophylaxis with aspirin, must be considered along with treatment of lipid disorders in patients at risk for CHD. This review focuses on interventions that are delivered to individuals or small groups. Some of the interventions considered here, such as dietary advice or exercise therapy, may also have beneficial effects on CHD or other health problems that are mediated through means other than the modification of lipid disorders. The CDC Task Force is also considering these effects. Because of the important health impact of CHD and the role of lipid disorders in its development, routine universal or targeted screening for lipid disorders has been advocated. Data from the Behavioral Risk Factor Surveillance Survey show that measurement of serum cholesterol has become a common practice: 74% of adults report that they have had their cholesterol level measured, and 66% report that they have done so within the past year. The likelihood of having had one's cholesterol measured within 5 years increases with age: 40% of adults ages 18 to 24 years have been checked, compared with 66% of those 35 to 44 years and 87% of those 65 years and older. Overall, 29% of adults report that their providers have told them that they have elevated cholesterol levels. No trials have directly examined the (implied) overarching question of whether screening for lipid disorders among asymptomatic persons leads to improvement in CHD mortality or morbidity. The decision to screen for lipid disorders in such populations is, therefore, based on data that address 2 intermediate steps (ie, linkages in the analytic framework): the effectiveness of screening to detect lipid disorders and the effectiveness of treating lipid disorders to reduce CHD events. Three key questions arise from this framework. Key Question No. 1. Will treatment with drug therapy of patients (similar to those who would be identified by screening) without known CHD but with .abnormal. lipid levels improve outcomes compared with no treatment? Key Question No. 2. Will treatment with diet or exercise therapy of patients (similar to those who would be identified by screening) without known CHD but with .abnormal. lipid levels improve outcomes compared with no treatment? Key Question No. 3. Is there a reliable, accurate, acceptable, and feasible screening test (or tests) that can be used to detect lipid disorders? If so, who should be screened, and how often should screening be performed?