Review of lipid-lowering clinical trials in relation to observational epidemiologic studies.

A review of the experimental clinical trials and observational cohort evidence relating serum cholesterol level and its reduction to risks of coronary heart disease (CHD) discloses strong similarities among the quantitative and qualitative relationships found in these studies. Not only are the risk functions similar, but the percent reduction observed is the same as that predicted from the population experience and is proportional to the degree of cholesterol lowering. Furthermore, the risk function is continuous from the highest to the lowest serum cholesterol levels studied. These findings confirm the lipid hypothesis and indicate that lowering serum cholesterol reduces CHD risk. The understanding and control of CHD requires a dual approach: (1) identification and treatment of high-risk individuals, and (2) modification of environmental and behavioral determinants to achieve more favorable distributions of serum cholesterol in populations.