title: What's in a risk factor? "He who strikes the ball".
abstract: A major aim of epidemiology is to explore the prognosis and aetiology of diseases, in order to improve treatment and prevention. To avoid misleading interpretations of observed associations between a modifier and the occurrence of a disease, the all-purpose idiom "risk factor" should be replaced by 3 locutions with narrower meanings: a risk marker is a modifier which is associated (correlated) with disease prevalence (case-control studies) or incidence (cohort studies); a risk marker truly becomes a risk factor if its experimental correction (intervention studies) does improve the disease incidence or prognosis; a risk factor is promoted to the rank of cause if it is proved to be necessary (sine qua non) for the occurrence of the disease. A more rigorous vocabulary avoids premature claims for unsubstantiated treatments or preventions, and helps defining sound priorities in aetiological research.
authors.affiliation: Service de Médecine Interne, Université Paris 6, Hôtel-Dieu, Paris, France. loic.capron@htd.ap-hop-Paris.fr
authors.forename: L
authors.initials: L
authors.lastname: Capron
mesh_terms: D000328:Adult; D000367:Age Factors; D016022:Case-Control Studies; D015331:Cohort Studies; D003920:Diabetes Mellitus / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D003925:Diabetic Angiopathies / Q000453:epidemiology / Q000401:mortality; D006801:Humans; D008875:Middle Aged; D015203:Reproducibility of Results; D012307:Risk Factors