title: Bicycle helmet laws are associated with a lower fatality rate from bicycle-motor vehicle collisions.
abstract: OBJECTIVE
  To assess the association between bicycle helmet legislation and bicycle-related deaths sustained by children involved in bicycle-motor vehicle collisions.
  
  
  METHODS
  We conducted a cross-sectional study of all bicyclists aged 0-16 years included in the Fatality Analysis Reporting System who died between January 1999 and December 2010. We compared fatality rates in age-specific state populations between states with helmet laws and those without helmet laws. We used a clustered Poisson multivariate regression model to adjust for factors previously associated with rates of motor vehicle fatalities: elderly driver licensure laws, legal blood alcohol limit (<0.08% vs ≥ 0.08%), and household income.
  
  
  RESULTS
  A total of 1612 bicycle-related fatalities sustained by children aged <16 years were evaluated. There were no statistically significant differences in median household income, the proportion of states with elderly licensure laws, or the proportion of states with a blood alcohol limit of >0.08% between states with helmet laws and those without helmet laws. The mean unadjusted fatality rate was lower in states with helmet laws (2.0/1,000,000 vs 2.5/1,000,000; P = .03). After adjusting for potential confounding factors, lower fatality rates persisted in states with mandatory helmet laws (adjusted incidence rate ratio, 0.84; 95% CI, 0.70-0.98).
  
  
  CONCLUSIONS
  Bicycle helmet safety laws are associated with a lower incidence of fatalities in child cyclists involved in bicycle-motor vehicle collisions.
authors.affiliation: Micheli Center for Sports Injury Prevention, Waltham, MA, USA. concussion.sportsmed@childrens.harvard.edu
authors.forename: William P
authors.initials: WP
authors.lastname: Meehan
authors.forename: Lois K
authors.initials: LK
authors.lastname: Lee
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Fischer
authors.forename: Rebekah C
authors.initials: RC
authors.lastname: Mannix
mesh_terms: D000063:Accidents, Traffic / Q000401:mortality*; D000293:Adolescent; D001642:Bicycling / Q000331:legislation & jurisprudence*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D033161:Government Regulation; D006260:Head Protective Devices; D006801:Humans; D015999:Multivariate Analysis; D016012:Poisson Distribution; D012044:Regression Analysis; D013219:State Government; D014481:United States / Q000453:epidemiology
keywords: FARS; Fatality Analysis Reporting System; NHTSA; National Highway Traffic Safety Administration