Original Article: Thematic IssueUnderstanding Causal Inference: The Future Direction in Sports Injury PreventionShrier, Ian MD, PhDAuthor Information Submitted for publication July 4, 2006; accepted January 4, 2007. From the Centre for Clinical Epidemiology and Community Studies, Lady Davis Institute for Medical Research, the Department of Family Medicine, and the Department of Medicine, SMBD-Jewish General Hospital, Montréal, Canada. Reprints: Ian Shrier, MD, PhD, Centre for Clinical Epidemiology and Community Studies, SMBD-Jewish General Hospital, 3755 Ch. Côte Ste-Catherine, Montréal Qc., Canada. H3T 1E2 (e-mail: [email protected]). Clinical Journal of Sport Medicine: May 2007 - Volume 17 - Issue 3 - p 220-224 doi: 10.1097/JSM.0b013e3180385a8c Buy Metrics Abstract Although physical activity reduces mortality and morbidity, injuries associated with activity may increase both short- and long-term musculoskeletal disability. On the basis of basic science and injury epidemiology studies, authors have made conclusions about cause and effect (causal inferences) and have suggested various interventions to decrease the rate of injuries. However, recent advances in epidemiology suggest that the regression/stratification approach to adjustment for confounding does not provide an appropriate foundation for causal inference; therefore, hypotheses based on traditional analyses may be misleading. The purpose of this article is to provide an overview of the basic concepts of injury epidemiology related to causes, risk factors, and confounding, and to conceptually explain the more recent advances that allow for appropriate interpretations of cause and effect. Copyright © 2007 Wolters Kluwer Health, Inc. All rights reserved.