Cholesterol and coronary heart disease. Future directions. The importance of high serum cholesterol levels as a risk factor for coronary heart disease and the benefit of lowering cholesterol levels for reducing risk are being increasingly accepted. A broad consensus to this effect has led to the establishment of the National Cholesterol Education Program. Although the available evidence fully justifies this program, its practical application to the American public has generated a series of new questions that must be explored. For example, it can be questioned whether reduction in coronary risk through lowering cholesterol levels extends to both sexes and all age groups. For people with high cholesterol levels, dietary modification is undoubtedly the first step of management, but the fraction of people responding adequately to dietary change remains to be determined. Finally, indications for drug therapy and choice of drugs need further exploration, particularly in the area of cost vs benefit. Thus, continuing research must be carried out in parallel with clinical and public health application of cholesterol education. 