Evaluation of Epidemiology Concerning Prevention and Therapy of Atherosclerosis

Abstract

The major contributions of epidemiology to the understanding of atherosclerosis and its clinical consequences have been made in the last 25 years, although epidemiological observations under different names date back much further (Stamler, 1970). The newer knowledge concerns the relative role of genetic factors and the circumstances of living, the distribution of the disease in populations and social subgroups and, above all, the risk factor concept. From the beginning, the aim was prevention of premature disease. The emphasis was rightly on primary prevention in view of the toll from early death, the reduced life expectancy of patients with coronary disease and the difficulty of reversing or arresting the progress of lesions. Nevertheless, the distinction between primary and secondary prevention is largely artificial. The development of arterial lesions is mostly a continuous process in which the clinical event is to a considerable extent incidental, while the distribution of risk factors and associated risk is also continuous. From the point of view of prevention, therefore, the critical issue is not whether an event has already occurred or not but how much disease is already present, realizing, of course, that lesions in a person with manifest disease are likely to be more advanced. In the subsequent discussion, the established terms primary and secondary prevention will continue to be used for reasons of convenience, keeping in mind the partly arbitrary nature of the division. Moreover, it is recalled that the aim is not so much to prevent as to postpone the onset of clinical disease to a time when its occurence is no more premature.