Epidemiological research strategies for multiple factor studies.

Epidemiological approaches to the study of chronic diseases with multiple aetiology are reviewed. Sources of hypotheses, the place of epidemiology within the total framework of medical research, types of epidemiological studies, problems of methodology and the complexity of the simultaneous measurement of a multiplicity of factors and influences are discussed, with special reference to the psychosocial aspects of cardiovascular disease. Future strategies include prospective epidemiological investigation but also the parallel development of new predictive tests which link psychological stresses to disease mechanisms, providing a base for preventive action.