title: Fit of bicycle safety helmets and risk of head injuries in children.
abstract: BACKGROUND
  Although bicycle helmets are effective in preventing head and brain injury, some helmeted individuals nevertheless sustain head injury. One of the possible reasons may be poor fit of the helmet on the head. This study was undertaken to examine the relationship between helmet fit and risk of injury.
  
  
  METHODS
  1718 individuals who were helmeted riders in a crash were queried on helmet fit and position. A sample of 28 children 2-14 years of age who sustained a head injury while wearing a bicycle helmet and 98 helmeted individuals of the same age treated in the same hospital emergency departments for injuries other than to the head, underwent anthropometric measurements of helmet fit. Measurements were made of the child's head, the helmet, and on a cast made of the child's head.
  
  
  RESULTS
  Individuals whose helmets were reported to fit poorly had a 1.96-fold increased risk of head injury compared with those whose helmets fit well. Children with head injuries had helmets which were significantly wider than their heads compared with children without head injuries. Helmet fit was poorer among males and among younger children.
  
  
  CONCLUSIONS
  Poor fit of helmets may be associated with an increased risk of head injury in children, especially in males. Helmets may not be designed to provide optimal protection.
authors.affiliation: Harborview Injury Prevention and Research Center, Seattle, WA 98104, USA. fpr@u.washington.edu
authors.forename: F P
authors.initials: FP
authors.lastname: Rivara
authors.forename: S J
authors.initials: SJ
authors.lastname: Astley
authors.forename: S K
authors.initials: SK
authors.lastname: Clarren
authors.forename: D C
authors.initials: DC
authors.lastname: Thompson
authors.forename: R S
authors.initials: RS
authors.lastname: Thompson
mesh_terms: D000293:Adolescent; D001265:Athletic Injuries / Q000209:etiology / Q000517:prevention & control*; D001642:Bicycling / Q000293:injuries*; D016022:Case-Control Studies; D002508:Cephalometry; D002648:Child; D002675:Child, Preschool; D006259:Craniocerebral Trauma / Q000209:etiology / Q000517:prevention & control*; D005260:Female; D006260:Head Protective Devices; D006306:Health Surveys; D006801:Humans; D008297:Male; D012307:Risk Factors; D012449:Safety; D014861:Washington / Q000453:epidemiology