Misconceptions regarding case-control studies of bicycle helmets and head injury.
A number of published case-control studies have reported that bicycle helmets are associated with a reduced risk of head injury and brain injury among bicyclists who crashed. A paper in this journal offered several criticisms of these studies and of a systematic review of these studies. Many of those criticisms stem from misconceptions about the studies that have been done and about case-control studies in general. In this manuscript we review case-control study design, particularly as it applies to bicycle helmet studies, and review some aspects of the analysis of case-control data.
Cummings
Peter
P
Harborview Injury Prevention and Research Center, University of Washington, Seattle, USA. peterc@u.washington.edu
Rivara
Frederick P
FP
Thompson
Diane C
DC
Thompson
Robert S
RS
D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D001642:Bicycling / Q000293:injuries*; D001930:Brain Injuries / Q000517:prevention & control; D016022:Case-Control Studies; D015986:Confounding Factors, Epidemiologic; D006259:Craniocerebral Trauma / Q000517:prevention & control*; D006260:Head Protective Devices; D006801:Humans; D016017:Odds Ratio