Epidemiology for prevention.

This paper illustrates the basis of, expectations for and evaluation of prevention from an epidemiological perspective. Specifically, the extent to which epidemiologists could and should be involved in designing and evaluating public health interventions is addressed. Changes in the view on disease causation and epidemiology's role for the future of public health are discussed. Examples from cardiovascular epidemiology are used to illustrate the ever more complex, but still incomplete, knowledge on which prevention is based. A few current examples illustrate paradoxes where health information must balance academic discord. Methodological problems in the evaluation of intervention studies often fail to live up to the expectations of prevention. Outcome indicators of preventive projects must be developed and traditional appraisals of effects be supplemented with process analyses using both quantitative and qualitative methods. Social conditions for prevention are discussed and areas for further research are suggested.