Risks in risk definitions

Abstract

Exact definitions of epidemiological concepts are necessary tools for exact studies. The present paper, stimulated by Beck's article in this journal (Community Dent Oral Epidemiol 1998; 26: 220-5), includes some further comments on this topic. For detailed risk analyses, one has to know a) whether the subjects are disease free or not at baseline in the groups to be compared, and b) whether the follow-up period is fair for all the study groups in prevention studies. An epistemological aspect is presented in a discussion of the roles of empirical evidence and theory in identifying evidence for or against some suspected risk factors.