Self-reported Alcohol Use Is an Independent Risk Factor for Head and Brain Injury among Cyclists but Does Not Confound Helmets’ Protective Effect

BackgroundHead 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.ObjectiveTo 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.MethodsData 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.ResultsThere 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.ConclusionsHelmet use was protective for head or brain injury in non-drinking cyclists, but had a confounding effect in drinking riders.