Protective effect of helmet use on mortality in bicycle crashes: A matched case-control study

In 2022; South Korea had 3.3 million daily bicycle users and around 13,000 crashes with 190 fatalities annually. While helmets are known to prevent head injuries, research on their effectiveness in preventing fatalities is lacking. This study explores factors influencing bicycle-related fatalities and examines if helmets reduce the risk of death in road traffic incidents.

This case-control study used data from the Emergency Department-based Injury In-depth Surveillance (EDIIS) from 2011 to 2021; analyzing 76,983 bicycle injury cases. Of these, 282 fatalities were identified as the case group, and 1,112 controls were randomly selected based on gender, age, and year of visit. The study examined risk factors for bicycle fatalities and used conditional logistic regression to assess the impact of helmet use on traumatic brain injury and in-hospital mortality.

In this study of 1,394 patients (282 cases and 1,112 controls), 11.1% were wearing helmets at the time of the crash. The majority of cases involved males (88%) and individuals aged 60-79 years (58.6%). Cases were more likely to occur between 00:00-06:00 and 18:00-00:00 and involved a higher proportion of non-helmeted riders (96.1% vs. 87.1%). Bicycle fatalities were more often due to collisions with automobiles (67.7%), while non-fatal injuries were mainly from crashes without a collision (45.8%). Head injuries were common in both groups, but traumatic brain injury (TBI) was significantly higher among cases (41.5% vs. 11.9%). Key factors associated with ED mortality included the time of injury, alcohol use, crashes on national highways, no helmet use, and collisions with automobiles. Helmet use was associated with a non-significant 35% lower risk of TBI and a significant 63% lower risk of ED mortality.

Key risk factors for fatal bicycle injuries included being aged 60-79, male, involved in nighttime crashes, collisions with automobiles, not wearing a helmet, and sustaining a traumatic brain injury (TBI). Helmet use was linked to lower rates of TBIs and reduced mortality. To decrease bicycle-related deaths, stronger legal regulations, educational efforts, and improved infrastructure are essential, along with further interventions and research to effectively tackle these issues.