SMOKING AND LOW-BACK-PAIN - IS THE ASSOCIATION REAL

Study Design: A review was made of the epidemiological literature an t he association between smoking and low back pain (LBP). Objectives: Th e first objective was to identify studies that challenged their prelim inary results with additional test factors and to see what effect this had on the outcomes. The second objective was to identify test factor s that were unique to studies in which the original association disapp eared after multivariate analysis. Summary of Background Data: The lit erature on this subject is confusing and no systemic investigation see ms to have been made on the possibility of spurious data interpretatio n. Methods: Twenty-four articles reporting on 126 epidemiological stud ies (in 24 reports) on the association between smoking and LBP were sy stematically reviewed by the authors, independently and jointly. Resul ts: In eight of the thirteen studies that tested a preliminary positiv e association between smoking and LBP, this association remained after multivariate analysis, whereas it disappeared in after analysis in fi ve. Two variables, marital status and occupation, were uniquely presen t in some of the studies in which the initial positive association was lost. However, their study samples were probably nonrepresentative of the general population. Conclusions: A more strategic approach is nee ded in the study of the role of extraneous factors. In particular, mar ital status and occupation should be further investigated.