Does mandatory helmet requirement when riding e-scooters impact incidence, severity, patterns of injury and emergency department contacts in traffic incidents?

Background Electric scooters (e-scooters) have raised safety concerns due to increased traffic incident risks, injury severity and patterns. In our region, e-scooters were introduced in short-term rental programmes in 2019, followed by a mandatory helmet requirement in 2022. In this retrospective cohort study, we evaluated whether the helmet mandate affected the number, type, and severity of injuries among e-scooter riders represented by their registered emergency department contacts (EDC). Methods Data were retrospectively extracted from our hospital emergency registry and included helmet and rider status, age, sex, incident date, and ICD 10 injury codes and derived severity. Incidence rate ratios (IRRs) were estimated using Poisson regression with time as an offset variable to account for differing observation periods (2.5 years before and 2 years after helmet legislation). Results A total of 512 consecutive EDC were included (288 before and 224 after legislation). Helmet use increased significantly (30/288 vs 118/224; IRR 4.92, 95% CI 3.29–7.34). The annual incidence of EDC remained stable (IRR 0.97, 95% CI 0.82–1.16), as did major injury incidence (IRR 0.95, 95% CI 0.68–1.33). Only major head and neck injuries increased significantly (5/2.5 vs 16/2 years; IRR 4.00, exact 95% CI 1.47–10.92). Conclusion Mandatory helmet legislation substantially increased helmet use amongst EDC but was not associated with reductions in overall or major injury incidences. The observed increase in major head and neck injuries should be interpreted with caution due to small event numbers and resulting statistical uncertainty, and the absence of exposure data limits the interpretation of injury risk per ride.