The global number of bicycle users is increasing in all age groups for economic and health-related reasons, and because bicycle riding is an increasingly popular leisure activity. The number of bicycle users in Korea has continuously increased in line with the government’s goals to promote eco-friendly transportation policies and reduce urban traffic jams. In particular, there were 13,037 km of bicycle paths in 2010, and 23,000 km in 2018, a 76% increase. This was associated with a 36% increase in the number of bicycle commuters, from 20.5 million in 2005 to 27.9 million in 2015 [1-4].

The number of bicycle-related accidents has also increased according to data from the Korea Transport Institute. An analysis of bicycle accidents indicated there were 8,000 accidents in 2005 and 14,000 accidents in 2017, and about 300 deaths each year [5]. There were 3,300 accidents in Gyeonggi Province during 2017 alone, accounting for 22.9% of the nationwide total [6]. Although the number of bicycle-related accidents in Korea has increased due to the increased number of bicycle users, there is insufficient knowledge of the characteristics and prognostic indicators of these individuals. We analyzed the demographic characteristics, sites of injury, severity of injury, and prognosis of patients with bicycle-related accidents who visited a regional trauma center.

From 2012 to 2014, the number of patients admitted to emergency departments in Korea due to bicycle-related accidents increased in all age groups, and 20% of these patients were elderly and about 75% were men [1]. An analysis of current data on bicycle traffic accidents in different age groups from 2016 to 2018, based on data from the Korean National Statistical Office, indicated an increase from 10% to 20% for those under age 20 years and an increase from 20% to 30% for those over age 65 years [7]. These results in terms of age and sex are similar to those of previous reports from the United States and Australia [8-10].

Our study confirmed that most patients were males (85.4%), 21.3% of patients were under the age of 19 years and 27.7% were over the age of 65 years. The similar bicycle accident rates among different age groups reflect the increasing use of bicycles for various purposes, and are a consequence of the implementation of government policies that encourage the use of bicycles. Importantly, previous studies showed that children and elderly patients were most vulnerable to bicycle-related injuries and fatal outcomes [8,9,11-15]. Another of our notable findings is that only 12.6% of accidents occurred on bicycle paths and that 46.9% of accidents occurred on automobile roads. Because bicyclists mostly use bicycle paths for leisure riding, this suggests that most accidents occur among individuals who are riding a bicycle for non-leisure purposes, such as commuting to work.

In view of the increased use of bicycles by children, adolescents, and the elderly, it is necessary to implement measures that prevent bicycle accidents and to provide safety training that is specialized for different age groups. A previous study in Denmark concluded that the mortality rate due to bicycle accidents will be reduced only when a bicycle-related safety infrastructure is constructed from a city-wide perspective, and that these interventions should target both roads and bicycle paths [16].

Many studies have reported that head injuries are the leading cause of death or moderate disability due to bicycle accidents [10,11], and that wearing a helmet can reduce the severity of this injury [17,18]. A study in France reported that bicyclists who did not wear helmets had a 1.98- to 3.89-fold higher risk of head injury [19]. Another study in Canada reported that the mortality rate from bicycle accidents declined by 52% after enacting a law that mandated helmet-wearing [20].

Our analysis of the association between injury severity at different body locations and the presence of severe trauma (ISS ≥16) indicated that patients with more severe head, neck, and face injuries (AIS=3–6) were significantly more likely to have severe trauma (p=0.001), but there were no such associations for other body regions. In addition, only 13 of 125 patients who had head, neck, and face injuries were wearing helmets, and patients who did not wear helmets (112) had a 3.943 higher odds ratio for head, neck, and face injuries. We also found that among patients with head, neck, and face injuries, only 10.4% wore helmets. This is lower than the rate of wearing bicycle helmets in Germany (12–15%), Finland (13%), Canada (50%), the United States (54%), and Australia (75.4%) [17,21-25].

The Korean government has steadily improved the social and public infrastructure for bicycle users, developed various education programs that promote safety, and revised the Road Traffic Act. Since September 2018, it has been mandatory to wear helmets when riding a bicycle in Korea. However, due to the lack of enforcement, the rate of wearing helmets is similar to that of other countries where there are no such laws. Accordingly, interventions to increase the wearing of bicycle helmets in Korea should be considered.

Our analysis of injuries of different body regions indicated that head, neck, and face injuries occurred in 125 patients (52.3%), chest injuries occurred in 59 patients (24.7%), abdominal injuries occurred in 21 patients (8.8%), and injuries of the extremities occurred in 97 patients (40.6%). This result is similar to previous studies, which also reported that most bicycle-related injuries occurred in the head, neck, and face and in the extremities [26,27]. Our analysis of injury severity in different body regions indicated that chest injuries had a lower incidence rate than other sites, but was found to have a relatively high severity (76.3%, AIS=3–4) (Fig. 1). Most chest injuries were managed using conservative treatment without surgery. In contrast, among the 21 patients with abdominal injuries, only six patients severe injuries (28.6%, AIS=3–4). However, among the 25 patients who underwent surgery, five patients (20%) received abdominal surgery. Thus, the rate of abdominal surgery was greater than that of chest surgery. This suggests the need for rapid transfer to a regional trauma center and prompt preparation for surgery for these patients.

The present study had several limitations. Our study was retrospective and we had no information regarding each patient’s reason for using a bicycle, wearing or not wearing protective gear other than a helmet, speed at the time of the accident, and consumption of alcohol before the accident. Our results do not reflect the trends of all trauma centers, and different patterns may occur at other centers depending on the size of the city, the types of employment, and other factors. An analysis of the effect of age on the risk for accidents or mortality was not possible because of the small sample size. Finally, there was a possibility of selection bias because the patients with severe injury were likely to be transferred to a regional trauma center rather than to a nearby hospital.

We found that patients with the bicycle-related injuries had a high incidence of severe trauma (16.7%). Therefore, the government should implement comprehensive accident prevention measures, including age-specific accident prevention education programs and expanded promotion of bicycle safety. Furthermore, these patients should be transferred immediately to an appropriate regional trauma center.

Our study confirmed that wearing a helmet was associated with reduced severity of head, neck, and face injuries, but only 11.3% of our patients reported wearing helmets. We suggest that the law to wear helmets when riding a bicycle should be more strictly enforced.