title: Motorcycle helmet use and the risk of head, neck, and fatal injury: Revisiting the Hurt Study.
abstract: Most studies find strong evidence that motorcycle helmets protect against injury, but a small number of controversial studies have reported a positive association between helmet use and neck injury. The most commonly cited paper is that of Goldstein (1986). Goldstein obtained and reanalyzed data from the Hurt Study, a prospective, on-scene investigation of 900 motorcycle collisions in the city of Los Angeles. The Goldstein results have been adopted by the anti-helmet community to justify resistance to compulsory motorcycle helmet use on the grounds that helmets may cause neck injuries due to their mass. In the current study, we replicated Goldstein's models to understand how he obtained his unexpected results, and we then applied modern statistical methods to estimate the association of motorcycle helmet use with head injury, fatal injury, and neck injury among collision-involved motorcyclists. We found Goldstein's analysis to be critically flawed due to improper data imputation, modeling of extremely sparse data, and misinterpretation of model coefficients. Our new analysis showed that motorcycle helmets were associated with markedly lower risk of head injury (RR 0.40, 95% CI 0.31-0.52) and fatal injury (RR 0.44, 95% CI 0.26-0.74) and with moderately lower but statistically significant risk of neck injury (RR 0.63, 95% CI 0.40-0.99), after controlling for multiple potential confounders.
authors.affiliation: University of California Berkeley, United States. Electronic address: tomrice@berkeley.edu.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Rice
authors.affiliation: University of California Berkeley, United States.
authors.forename: Lara
authors.initials: L
authors.lastname: Troszak
authors.affiliation: University of California Berkeley, United States; Motorcycle Accident Analysis, Playa del Rey, CA, United States.
authors.forename: James V
authors.initials: JV
authors.lastname: Ouellet
authors.affiliation: University of California Berkeley, United States.
authors.forename: Taryn
authors.initials: T
authors.lastname: Erhardt
authors.affiliation: University of California Berkeley, United States; University of Maryland School of Medicine, United States.
authors.forename: Gordon S
authors.initials: GS
authors.lastname: Smith
authors.affiliation: University of California Berkeley, United States.
authors.forename: Bor-Wen
authors.initials: BW
authors.lastname: Tsai
mesh_terms: D000063:Accidents, Traffic / Q000401:mortality* / Q000706:statistics & numerical data; D000328:Adult; D006259:Craniocerebral Trauma / Q000453:epidemiology*; D005260:Female; D006260:Head Protective Devices / Q000706:statistics & numerical data*; D006801:Humans; D015141:Los Angeles / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009049:Motorcycles; D019838:Neck Injuries / Q000453:epidemiology*; D012306:Risk; D055815:Young Adult
keywords: California; Fatality; Head injury; Helmet; Motorcycle; Neck injury