title: Self-reported alcohol use is an independent risk factor for head and brain injury among cyclists but does not confound helmets' protective effect.
abstract: BACKGROUND
  Head and brain injury accounts for most morbidity and mortality related to bicycle accidents, much of which can be mitigated by helmet use; but other factors, such as alcohol use and type of accident, also correlate with injury.
  
  
  OBJECTIVE
  To examine the correlation between alcohol use, helmet use, riding environment, and rider characteristics, with the presence of head and severity of brain injury in a group of bicycle riders presenting to a regional trauma center after an accident.
  
  
  METHODS
  Data were collected at the bedside and from the medical records for all bicycle accident victims presenting during a 2 ½-year period to a regional trauma center. Data were analyzed in Stata version 10 (StataCorp LP, College Station, TX) using chi-squared, analysis of variance, Kruskal-Wallis, or Wilcoxon rank-sum where appropriate.
  
  
  RESULTS
  There were 427 patients enrolled, of which 82% were male, with a median age of 31 years. Two factors correlated with presence of head injury and severity of brain injury among bicycle riders presenting to the emergency department (ED) after an accident. For any head or brain injury, the odds ratios for helmet use and alcohol use were 0.5 (95% confidence interval [CI] 0.32-0.78) and 2.68 (95% CI 1.66-4.33). Of accidents presenting to the ED, helmeted riders were less likely to sustain a head or brain injury, and riders who reported alcohol use were more likely to sustain a head or brain injury.
  
  
  CONCLUSIONS
  Helmet use was protective for head or brain injury in non-drinking cyclists, but had a confounding effect in drinking riders.
authors.affiliation: Dell Children's Medical Center of Central Texas, Austin, Texas 78701, USA.
authors.forename: Pat
authors.initials: P
authors.lastname: Crocker
authors.forename: Ben
authors.initials: B
authors.lastname: King
authors.forename: Hassie
authors.initials: H
authors.lastname: Cooper
authors.forename: T J
authors.initials: TJ
authors.lastname: Milling
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects*; D000704:Analysis of Variance; D001642:Bicycling / Q000293:injuries*; D001930:Brain Injuries / Q000000981:diagnostic imaging / Q000209:etiology*; D016009:Chi-Square Distribution; D016001:Confidence Intervals; D006259:Craniocerebral Trauma / Q000000981:diagnostic imaging / Q000209:etiology*; D003430:Cross-Sectional Studies; D005260:Female; D015600:Glasgow Coma Scale; D006260:Head Protective Devices; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011446:Prospective Studies; D011859:Radiography; D012307:Risk Factors; D057566:Self Report; D018709:Statistics, Nonparametric; D055815:Young Adult