The epidemiology of atherosclerosis in 1987: unraveling a common-source epidemic

Epidemiologists studying the risk factors of coronary heart disease, as indicated by a heart attack, often presume that these risk factors combine in a susceptible host to increase the risk of the heart attack. The "biological" basis for the interaction of the key risk factors is often not considered in the analysis. A more rational model for the study of clinical heart disease, stroke, and peripheral vascular disease would be to separate the epidemiology of atherosclerosis from that of the clinical event. In the past, this has been extremely difficult because of the absence of techniques for the measurement of atherosclerosis in vivo, especially in well-defined populations. However, in recent years, greater emphasis on the quantification of atherosclerosis and its relationship to specific risk factors has improved our ability to study the underlying pathology that is atherosclerosis. Atherosclerosis is an example of a common-source epidemic. The environmental agent is the intake of cholesterol and saturated fat. The interaction of specific dietary factors and genetic determinants is the key to the evolution of atherosclerosis. There are marked variations in the evolution of the disease in different vascular beds as well as among individuals exposed to similar environmental factors. In the future, we will probably be able to study atherosclerosis as a continuous variable in populations and to relate the rate of progression, the extent of disease at any point in time, and topical distribution of atherosclerosis within individual vascular beds to specific genetic and environmental determinants.