Association of alcohol use with helmet use in cyclists: analysis of the National Trauma Data Bank.

Abstract

Background: Helmet use significantly reduces the risk of traumatic brain injury among cyclists; however, the influence of alcohol use on helmet-wearing adherence remains understudied in large national data sets. The goal of this study was to investigate the relationship between alcohol use and helmet use in injured cyclists.

Methods: This study is a retrospective cross-sectional analysis of 155 766 cyclists with traumatic injuries from the National Trauma Data Bank spanning 8 years (2017-2023). Cyclists were categorized by blood alcohol concentration (BAC) as follows: not screened, sober (BAC <0.02), impaired (BAC 0.02-0.08), intoxicated (BAC ≥0.08), and multidrug intoxicated (BAC ≥0.08 plus ≥1 positive drug screen). The primary outcome was helmet usage. Secondary outcomes included mortality, hospital and intensive care unit length of stay, Injury Severity Score, and adverse events. Comorbid substance use disorders were considered as covariates.

Results: Alcohol use was associated with a dose-response decrease in helmet use. Helmet adherence was 45.9% in sober cyclists (n=51 566), compared with 19.9% in impaired (n=1592), 9.8% in intoxicated (n=8327), and 6.2% in multidrug intoxicated cyclists (n=3823; p<0.001). Alcohol use was associated with higher mortality rates (OR=2.3; p<0.001) and a greater proportion of injuries in the head and neck region (OR=1.4; p<0.001). Alcohol use when cycling was significantly associated with comorbid alcohol, tobacco, and substance use disorders (p<0.001). An interaction effect was observed between alcohol use and comorbid alcohol use disorder, where individuals with a history of alcohol use disorder exhibited a lower baseline helmet use that further declined with increasing BAC.

Conclusions: Alcohol use demonstrated a significant dose-response relationship with helmet non-usage among cyclists, particularly among those with substance use disorders. This relationship represents a critical public safety concern requiring further investigation to address its public health implications.

Level of evidence: Retrospective Epidemiologic/Prognostic study, Level III.