Characteristics of bicycle crashes among children and the effect of bicycle helmets

Objective: Focusing on children (0-17 years), this study aimed to investigate injury and accident characteristics for bicyclists and to evaluate the use and protective effect of bicycle helmets. Method: This nationwide Swedish study included children who had visited an emergency care center due to injuries from a bicycle crash. In order to investigate the causes of bicycle crashes, data from 2014 to 2016 were analyzed thoroughly (n = 7967). The causes of the crashes were analyzed and categorized, focusing on 3 subgroups: children 0-6, 7-12, and 13-17 years of age. To assess helmet effectiveness, the induced exposure approach was applied using data from 2006 to 2016 (n = 24,623). In order to control for crash severity, only bicyclists who had sustained at least one Abbreviated Injury Scale (AIS) 2+ injury (moderate injury or more severe) in body regions other than the head were included. Results: In 82% of the cases the children were injured in a single-bicycle crash, and the proportion decreased with age (0-6: 91%, 7-12: 84%, 13-17: 77%). Of AIS 2+ injuries, 8% were head injuries and 85% were injuries to the extremities (73% upper extremities and 13% lower extremities). Helmet use was relatively high up to the age of 10 (90%), after which it dropped. Helmets were much less frequently used by teenagers (14%), especially girls. Consistently, the share of head injuries increased as the children got older. Bicycle helmets were found to reduce all head injuries by 61% (95% confidence interval [CI], 10: +/- 10%) and AIS 2+ head injuries by 68% (95% CI, 12: +/- 12%). The effectiveness in reducing face injuries was lower (45% CI +/- 10% for all injuries and 54% CI +/- 32% for AIS2+ injuries). Conclusions: This study indicated that bicycle helmets effectively reduce injuries to the head and face. The results thus point to the need for actions aimed at increasing helmet use, especially among teenagers. Protective measures are necessary to further reduce injuries, especially to the upper extremities.