Urban Cycling Expansion is Associated with an Increased Number of Clavicle Fractures.

BACKGROUND: The number of individuals turning to cycling for physical activity and commuting has been expanding across the US. However, studies have demonstrated that when compared to motor vehicle accidents, cyclists in major cities have a significantly increased risk of injuries requiring hospitalizations. The purpose of this study was to assess if a correlation exists between the growing cyclist volume in a densely populated metropolitan city and prevalence of clavicle fractures requiring inpatient hospital admissions. HYPOTHESIS: A correlation exists between the increased number of cyclists and the increasing number of clavicle fractures requiring inpatient hospital admissions. METHODS: Patients who sustained a clavicle fracture that required an inpatient admission were identified using the New York Statewide Planning and Research Cooperative System (SPARCS). The location of hospital admission was screened using New York City (NYC) hospital county codes, as only clavicle fractures presenting to NYC hospitals were included in the analysis. This study was exempt from Institutional Review Board (IRB) approval. Public transportation data was available through the Department of Transportation (DOT) and The Decennial Census. These databases are publicly available and are performed to assess if New Yorkers are using cycling as a mode of transportation. The cycling data included the following information in a given year: the number of people in NYC who use a bicycle as their primary mode of commuting to work, the number of daily cycling trips, total bicycle protected bike lane mileage, midtown Manhattan cycling counts and East River Bridge cycling counts. Spearman's correlation analysis was conducted between the numbers of patients with clavicle fractures per year and the described data for that specific year. Additionally, the number of bicycle-share program miles traveled per month and total number of cycling trips that month were obtained from the public bicycle-sharing program database from June 2013 through June 2015. Spearman's correlation analysis was conducted between the numbers of patients with clavicle fractures per month and total bicycle-sharing miles and trips traveled per month. RESULTS: The increasing daily cycling trips in NYC has a strong correlation with the increasing number of clavicle fractures in NYC (rs = .979, p < 0.001). The increasing use of a bicycle as transportation to work has a strong positive correlation with the increasing number of clavicle fractures in NYC (rs = .988, p < 0.001). There was a strong positive correlation between the mileage of bicycle lanes in NYC and the number of clavicle fractures (rs = .867, p = 0.001). A strong positive correlation exists between NYC clavicle fracture number and public bicycle-sharing miles (rs = .819, p < 0.001) and trips (rs = .811, p < 0.001). CONCLUSION: There are many physical benefits to cycling. Cycling, as a means of transportation, has been encouraged to decrease CO2 emissions from vehicular transportation. These benefits do not come without risks, as this study shows a correlation between increased cycling and clavicle fractures. CLINICAL RELEVANCE: Physicians and public health officials should be aware of the dangers of cycling in major cities in order to create safer routes for this environmentally beneficial route of transportation.