title: Prevalence of bicycle helmet use by users of public bikeshare programs.
abstract: OBJECTIVE
  Public bikeshare programs are becoming increasingly common in the United States and around the world. These programs make bicycles accessible for hourly rental to the general public. We seek to describe the prevalence of helmet use among adult users of bikeshare programs and users of personal bicycles in 2 cities with recently introduced bikeshare programs (Boston, MA, and Washington, DC).
  
  
  METHODS
  We performed a prospective observational study of adult bicyclists in Boston, MA, and Washington, DC. Trained observers collected data during various times of the day and days of the week. Observers recorded the sex of the bicycle operator, type of bicycle, and helmet use. All bicycles that passed a single stationary location in any direction for a period of between 30 and 90 minutes were recorded.
  
  
  RESULTS
  There were 43 observation periods in 2 cities at 36 locations; 3,073 bicyclists were observed. There were 562 (18.3%; 95% confidence interval [CI] 16.4% to 20.3%) bicyclists riding shared bicycles. Overall, 54.5% of riders were unhelmeted (95% CI 52.7% to 56.3%), although helmet use varied significantly with sex, day of use, and type of bicycle. Bikeshare users were unhelmeted at a higher rate compared with users of personal bicycles (80.8% versus 48.6%; 95% CI 77.3% to 83.8% versus 46.7% to 50.6%). Logistic regression, controlling for type of bicycle, sex, day of week, and city, demonstrated that bikeshare users had higher odds of riding unhelmeted (odds ratio [OR] 4.4; 95% CI 3.5 to 5.5). Men had higher odds of riding unhelmeted (OR 1.6; 95% CI 1.4 to 1.9), as did weekend riders (OR 1.3; 95% CI 1.1 to 1.6).
  
  
  CONCLUSIONS
  Use of bicycle helmets by users of public bikeshare programs is low. As these programs become more popular and prevalent, efforts to increase helmet use among users should increase.
authors.affiliation: Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA. cfischer@bidmc.harvard.edu
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Fischer
authors.forename: Czarina E
authors.initials: CE
authors.lastname: Sanchez
authors.forename: Mark
authors.initials: M
authors.lastname: Pittman
authors.forename: David
authors.initials: D
authors.lastname: Milzman
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Volz
authors.forename: Han
authors.initials: H
authors.lastname: Huang
authors.forename: Shiva
authors.initials: S
authors.lastname: Gautam
authors.forename: Leon D
authors.initials: LD
authors.lastname: Sanchez
mesh_terms: D000328:Adult; D001642:Bicycling / Q000706:statistics & numerical data*; D001900:Boston / Q000453:epidemiology; D004219:District of Columbia / Q000453:epidemiology; D005260:Female; D006260:Head Protective Devices / Q000706:statistics & numerical data*; D006801:Humans; D016015:Logistic Models; D008297:Male; D015995:Prevalence; D011446:Prospective Studies; D012737:Sex Factors; D013997:Time Factors