摘要：Objectives. We evaluated the effect of North American public bicycle share programs (PBSPs), which typically do not offer helmets with rentals, on the occurrence of bicycle-related head injuries. Methods. We analyzed trauma center data for bicycle-related injuries from 5 cities with PBSPs and 5 comparison cities. We used logistic regression models to compare the odds that admission for a bicycle-related injury would involve a head injury 24 months before PBSP implementation and 12 months afterward. Results. In PBSP cities, the proportion of head injuries among bicycle-related injuries increased from 42.3% before PBSP implementation to 50.1% after ( P < .01). This proportion in comparison cities remained similar before (38.2%) and after (35.9%) implementation ( P = .23). Odds ratios for head injury were 1.30 (95% confidence interval = 1.13, 1.67) in PBSP cities and 0.94 (95% confidence interval = 0.79, 1.11) in control cities (adjusted for age and city) when we compared the period after implementation to the period before. Conclusions. Results suggest that steps should be taken to make helmets available with PBSPs. Helmet availability should be incorporated into PBSP planning and funding, not considered an afterthought following implementation. In the past decade, public bicycle share programs (PBSPs) have become increasingly common in North American cities. 1 Often implemented by government agencies, either independently or through a public–private partnership, these networks of bicycles are available for shared use to individuals at some nominal cost relative to the duration of the rental. Such programs are commonly referred to as BIXI programs in Canada (Bicycle-Taxi), and programs in the United States include B-cycle, DecoBike, and CaBi (Capitol Bikeshare in Washington, DC). Traumatic brain injuries (TBIs) account for the majority of bicycle-related deaths and one third of bicycle-related injuries. 2 In 2012, an estimated 81 909 bicycle-related head injuries were treated in US emergency departments. 3 Bicycle helmets have been shown to reduce the risk of head, brain, and severe brain injury by 63% to 88%. 2 Observational data suggest that fatal TBI risk increases 3-fold when an injured cyclist was not wearing a helmet. 4 Educational and advocacy efforts have led to the implementation of mandatory helmet legislation for bicyclists aged younger than 18 years in many American cities and states and in several Canadian cities or provinces. Although no US statewide laws currently exist for adult bicyclists, in Canada, 4 provinces (British Columbia, New Brunswick, Nova Scotia, and Prince Edward Island) have legislation requiring helmets for bicyclists of all ages. 5 The popularity of PBSPs in the United States has been met with enthusiasm from the public health community because they provide cardiovascular exercise and an active lifestyle. 6,7 Reduced traffic congestion and emissions are added environmental benefits. 7,8 It is evident that the presence of PBSPs increases cycling activity among individuals living near available bicycles. 9–11 However, PBSPs do not typically provide helmets, and in an evaluation of the barriers and facilitators to the use of a PBSP in Brisbane, Australia (where helmet use is mandatory), 61% of focus group respondents cited helmet inaccessibility or lack of desire to wear one as the main barriers to using the program. 12 Accordingly, some PBSPs and cities offer courtesy helmets or free helmet giveaways, 12,13 and a pilot project in the District of Columbia offers tourists loaner helmets. 14 However, these efforts appear to be limited and are the exception, rather than the rule. Observational studies indicate that the majority of PBSP users do not wear helmets, and thus have significantly higher odds of riding unhelmeted than private bicycle users. 9,13,15–17 Recent research in a single North American city suggests that PBSP implementation was not associated with self-reported collisions or near-misses; however, that study was underpowered and was subject to recall bias. 18 With more PBSPs potentially resulting in more unhelmeted bicyclists, it is possible that cities with these programs may experience an increase in bicycling-associated head injuries compared with cities with no such programs. Our objective was to assess the effect of PBSPs on the occurrence of bicycle-related head injuries.
