|Year : 2021 | Volume
| Issue : 6 | Page : 205-212
Association between types of helmet and outcomes in motorcyclists after traffic accidents
Shiun-Yuan Hsu1, Ching-Hua Tsai1, Chun-Ying Huang1, Ting-Min Hsieh1, Sheng-En Chou1, Wei-Ti Su1, Ching-Hua Hsieh2
1 Department of Trauma Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung City, Taiwan
2 Department of Plastic Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung City, Taiwan
|Date of Submission||18-Feb-2021|
|Date of Decision||22-Mar-2021|
|Date of Acceptance||31-Aug-2021|
|Date of Web Publication||30-Nov-2021|
Department of Plastic Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, No. 123, Ta-Pei Road, Niao-Song District, Kaohsiung City 833
Source of Support: None, Conflict of Interest: None
Background: The use of helmets has been promoted worldwide to protect motorcyclists from head-and-neck injuries and to reduce motorcycle accident-related mortality. However, the results of previous studies regarding the effectiveness of different types of helmets are controversial. This study aims to investigate the effectiveness of three types of helmets: half-helmets, open-face helmets, and full-face helmets, in protecting motorcyclists during traffic accidents.
Materials and Methods: A total of 6991 motorcyclists, who were hospitalized between January 1, 2015, and December 31, 2019, were enrolled in this study. They were divided into two groups: those who did not wear helmets (n = 506) and those who wore helmets (n = 6,485). The latter group was subdivided according to the type of helmet used: half-helmet (n = 3,027), open-face helmet (n = 2,528), and full-face helmet (n = 930). The primary outcome was inhospital mortality. The length of hospital stay and associated head-and-neck injuries were secondary outcomes.
Results: Half-helmets offered significantly less protection than full-face helmets, considering that patients using half-helmets had a significantly higher rate of the Abbreviated Injury Scale ≥ 2 injuries to the head region and significantly higher odds of sustaining subdural hematoma, subarachnoid hemorrhage (SAH), and intracerebral hematoma than patients using full-face helmets. However, higher odds of sustaining SAH were noted in patients using open-face helmets. There were no significant differences in the Glasgow Coma Scale score after injury or in the mortality rate in patients using either half-helmets or open-face helmets compared to those using full-face helmets.
Conclusion: This study revealed that half-helmets, but not open-face helmets, offered significantly less protection from head injuries than full-face helmets. However, the mortality rate and length of hospital stay after the injury did not differ among patients using the three types of helmets.
Keywords: Abbreviated Injury Scale, Glasgow Coma Scale, head injury, helmets, Injury Severity Score, mortality
|How to cite this article:|
Hsu SY, Tsai CH, Huang CY, Hsieh TM, Chou SE, Su WT, Hsieh CH. Association between types of helmet and outcomes in motorcyclists after traffic accidents. Formos J Surg 2021;54:205-12
|How to cite this URL:|
Hsu SY, Tsai CH, Huang CY, Hsieh TM, Chou SE, Su WT, Hsieh CH. Association between types of helmet and outcomes in motorcyclists after traffic accidents. Formos J Surg [serial online] 2021 [cited 2022 Jan 16];54:205-12. Available from: https://www.e-fjs.org/text.asp?2021/54/6/205/331639
| Introduction|| |
In Taiwan, there were 14,173,000 registered motorcycles in June 2021, which is approximately 63.1% of registered motor vehicles. Motorcyclists have higher injury rates; compared to car drivers, motorcyclists are eight times more likely to be injured per vehicle mile, and the fatality rate per trip is approximately sixty times higher.
Among motorcycle accident fatalities, head injuries were the most common cause of death.,,, The use of helmets to protect against head injuries and reduce mortality rate had been recommended globally.,,,, In Taiwan, the government introduced and amended helmet legislation in 1997 to enforce helmet wearing among motorcyclists. According to data collected from 56 major hospitals in Taiwan, the number of head injuries caused by motorcycle collisions decreased by 33% after the implementation of helmet legislation. In a study of 270,525 patients, multiple logistic regression analyses showed that wearing a helmet was an independent factor that protected motorcyclists from death. Motorcyclists who did not wear helmets were four times more likely to have head injuries and had a ten times higher risk of experiencing traumatic brain injuries than those who did. In addition, helmet use significantly decreased the risk of severe head injuries by almost 50%. A Cochrane review of the effectiveness of helmets demonstrated that there was a 69% and 42% reduction in the risk of head injury and death, respectively, for motorcyclists who wore helmets and were involved in traffic accidents.
It is well established that helmets offer protection for the head.,,,,,,,, However, head injury is still the main cause of death from motorcycle accidents. Currently, most countries, including Taiwan, have no legislation regarding the type of helmet that must be worn when riding a motorcycle. Full-face helmets that cover the entire head and have a chin bar are expected to provide better protection against head injuries than nonstandard helmets. Nevertheless, this type of helmet is uncomfortable to wear in the hot and moist weather in Taiwan. In addition, other factors may also contribute to the use of nonstandard helmets (open-face helmets or half-helmets), including helmet weight, cost, limitations in auditory/visual perception, and cultural norms., These factors should be considered when investigating the protection provided by full-face helmets and other nonstandard helmets. There are three common types of helmets: half-helmets, open-face helmets, and full-face helmets [Figure 1], and their effectiveness in protecting against head injuries varies. Some studies have shown that motorcyclists who use half-helmets or open-face helmets sustained an increased risk of facial and neck injuries when compared with those who used full-face helmets.,,,, However, a Cochrane review in 2008 demonstrated that the conclusions regarding the most effective helmet type in reducing injury risk were not supported by sufficient data. In Taiwan, a case–control study of motorcycle accident victims, including 562 patients with head injuries and 789 patients without head injuries, revealed that wearing a full-face helmet significantly reduced the risk of head injury, although such an effect was not observed in motorcyclists wearing partial-coverage helmets. However, this study was conducted in 1990, before the implementation of helmet laws. Furthermore, in 2011, Yu et al. determined that motorcyclists wearing half-helmets had twice the risk of sustaining head and traumatic brain injuries than those who wore full-face helmets. However, this study did not assess the actual injury severity. Instead, crash severity was determined by the expense involved in repairing the damaged motorcycle, the object that the motorcyclist collided with, and the type of collision. Furthermore, fatalities were not assessed. In 2015, based on the analysis of Taiwan's National Head Trauma Registry data, Lam et al. reported that full-face helmets offered the best protection from neck injuries. In 2020, according to a retrospective analysis of 725 patients from eight level I trauma centers in Taiwan, Lam et al. reported that the use of nonstandard helmets (half-helmets or open-face helmets) was associated with a higher risk of head injuries and an increased rate of injuries with an Injury Severity Score (ISS) ≥8 compared to patients wearing full-face helmets. However, these study results were based on a questionnaire in which types of helmet worn during accidents were reported.
|Figure 1: Types of helmets: (a) Half-helmet, (b) open-face helmet, and (c) full-face helmet|
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Therefore, to investigate the effectiveness of the three types of helmets in protecting motorcyclists' head during traffic accidents, we analyzed data on registered helmet types, injury severity, diagnosis of head-and-neck injuries, and mortality outcomes in patients from the trauma registry system of the hospital.
| Materials and Methods|| |
Study population and data collection
Of the 19,029 hospitalized trauma patients registered in the trauma registry system of the hospital between January 1, 2015, and December 31, 2019,,, there were 7,598 motorcycle riders [Figure 2]. After excluding patients with incomplete data (n = 607), 6,991 patients were enrolled in the study and were categorized into two groups: those who did not wear helmets (n = 506) and those who wore helmets (n = 6,485). The latter group was further subdivided according to the types of helmets used: half-helmets (n = 3,027), open-face helmets (n = 2,528), and full-face helmets (n = 930). Clinical information extracted from the trauma registry system, including sex, age, preexisting comorbidities (cerebrovascular accident [CVA], hypertension [HTN], coronary artery disease, congestive heart failure, diabetes mellitus, and end-stage renal disease), Glasgow Coma Scale, Abbreviated Injury Scale (AIS), ISS, and associated injuries in the head-and-neck regions (cranial fracture, epidural hematoma, subdural hematoma [SDH], subarachnoid hemorrhage [SAH], intracerebral hematoma [ICH], and cervical vertebral fracture). The primary outcome of this study was inhospital mortality. The length of stay (LOS) in the hospital and associated head-and-neck injuries were assessed as secondary outcomes. The AIS ranks specific anatomy-based injuries in trauma patients on a six-point ordinal scale ranging from minor (1 point), moderate (2 points), serious (3 points), severe (4 points), critical (5 points), and unsurvivable injuries (6 points). ISS represents the injury severity of trauma patients according to the scores calculated from the sum of the squares of the three highest AIS scores in different body regions., This study was approved by the Institutional Review Board (IRB) of Chang Gung Memorial Hospital (approval number: 202001076B0). The need for informed consent was waived according to the regulations of the IRB owing to the retrospective nature of the analysis of the registered data.
|Figure 2: Study flowchart illustrating the inclusion of motorcycle riders involved in accidents. These patients were divided into two groups: Those who wore helmets and those who did not wear helmets. Patients who wore helmets were divided into the following groups according to the type of helmet used: Half-helmet, open-face helmet, and full-face helmet|
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All statistical analyses were performed using IBM SPSS Statistics for Windows (version 23.0; IBM Corp., Armonk, NY, USA). Categorical data were compared using Pearson's Chi-square test or two-sided Fisher's exact test. The homogeneity of variance of the continuous variables was estimated using Levene's test. Continuous data were analyzed using the one-way analysis of variance with the Games–Howell post hoc test. The results were expressed as mean ± standard deviation, with GCS and ISS presented as the median and interquartile range (IQR, Q1–Q3). The odds ratios (ORs) of mortality were calculated using 95% confidence intervals (CIs). The adjusted odds ratio (AOR) of mortality was calculated using logistic regression analysis by controlling for sex, age, and preexisting comorbidities. Statistical significance was set at P < 0.05.
| Results|| |
Characteristics and outcomes of motorcycle accident victims with and without helmets
As shown in [Table 1], a significantly higher number of patients without helmets were of the male gender and were older than patients with helmets. There was a significantly higher prevalence of preexisting comorbidities: CVA, and HTN, in patients without helmets than in those with helmets. A significantly lower GCS was found in patients without helmets than in those with helmets (median [IQR]: 15 [14–15] vs. 15 [15–15], respectively; P < 0.001). When stratified by GCS (3–8, 9–12, or 13–15), a significantly higher number of patients without helmets had scores of 3–8 and 9–12, while fewer patients with helmets had scores of 13–15. Patients without helmets had a significantly higher rate of AIS ≥2 injuries in the head and face regions compared to patients with helmets. In contrast, patients without helmets had a significantly lower rate of AIS ≥2 injuries in the extremities compared to patients with helmets. Based on ISS, patients were stratified into 1–15, 16–24, and ≥25 groups. In comparison to patients with helmets, the number of patients without helmets in the latter two groups was significantly higher, while fewer patients without helmets had scores of 1–15. Patients without helmets had a significantly higher ISS than those with helmets (median [IQR]: 10 [5–20] vs. 5 [4–12], respectively; P < 0.001). There was no significant difference in the rate of cervical spine fractures between patients with and without helmets. The odds ratio for mortality of patients without helmets was 4.42 times higher than that of patients with helmets (95% CI, 2.71–7.23; P < 0.001). After adjusting for sex, age, and preexisting comorbidities, the AOR for mortality of patients without helmets was 3.5 times higher than that of patients with helmets (95% CI, 2.12–5.79; P < 0.001). The patients without helmets had a significantly longer LOS in the hospital (10.4 days vs. 9.1 days, respectively; P = 0.010) than patients with helmets.
|Table 1: Characteristics and outcomes of motorcycle accident riders with and without helmets|
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Characteristics and outcomes of motorcycle accident victims with different types of helmets
[Table 2] shows that a significantly higher number of patients wearing half-helmets and open-face helmets were women in comparison to the full-face helmet group. Patients wearing half-helmets were significantly older than those wearing full-face helmets, although this difference was not observed between the half-helmet and open-face helmet groups. There was no significant difference in GCS scores in patients wearing either half-helmets or open-face helmets compared to those wearing full-face helmets. When stratified by GCS scores (3–8, 9–12, or 13–15), there were no significant differences between patients wearing half-helmets and open-face helmets. However, a higher number of patients wearing open-face helmets had scores of 13–15 compared to those wearing full-face helmets. Regarding trauma with moderate injury (AIS ≥2) based on body regions, a significantly higher rate of injuries was found in the head region. A lower rate of injuries in the abdomen and extremities was observed in patients wearing half-helmets compared to patients wearing full-face helmets. However, there were no significant differences in the rates of AIS ≥2 injuries for different body regions between patients wearing open-face helmets and full-face helmets. Further investigation is required to elucidate whether the differences observed were attributed to patients' characteristics (more patients wearing half-helmets were older and female than those wearing full-face helmets) or the use of helmets (the scenario or response to the accidents may vary among patients with different types of helmets). Patients wearing half-helmets had a significantly higher ISS than patients wearing full-face helmets (open-face helmets vs. full-face helmets; median [IQR]: 8 [4–13] vs. 5 [4–10], respectively; P = 0.035), with a significant difference found in patients with an ISS of 16–24. Nonetheless, there was no significant difference in the ISS between the patients wearing open-face and full-face helmets. In addition, when controlling for sex, age, and comorbidities, there were no significant differences in the AOR for mortality in patients wearing either half-helmets or open-face helmets in comparison to those wearing full-face helmets (half-helmets vs. full-face helmets: AOR, 1.10; 95% CI, 0.50–2.45; P = 0.810; open-face helmets vs. full-face helmets: AOR, 0.70; 95% CI, 0.29–1.71; P = 0.436). There was no significant difference in the LOS in the hospital between patients wearing either half-helmets or open-face helmets in comparison to those wearing full-face helmets.
|Table 2: Characteristics and outcomes of motorcycle accident riders based on helmet type|
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Associated head-and-neck injuries in motorcycle accident victims with different types of helmets
[Table 3] shows injuries to the head-and-neck regions in patients depending on the type of helmet used. Patients wearing half-helmets had significantly higher odds of sustaining SDH (OR, 1.98; 95% CI, 1.42–2.77; P < 0.001), SAH (OR, 1.91; 95% CI, 1.35–2.72; P < 0.001), and ICH (OR, 1.71; 95% CI, 1.00–2.93; P = 0.048) than those wearing full-face helmets. In addition, patients wearing open-face helmets were significantly more likely to sustain SAH (OR, 1.46; 95% CI, 1.01–2.10; P = 0.041) than those wearing full-face helmets. There was no significant difference between the rate of occurrence of cervical spine fractures in patients wearing half-helmets or open-face helmets compared to those wearing full-face helmets.
|Table 3: Associated headandneck injuries in motorcycle accident riders depending on helmet type|
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| Discussion|| |
Our study results validated the protective function of helmets against head injuries in motorcyclists involved in traffic accidents. Patients who did not wear a helmet had a significantly higher rate of head injury with an AIS ≥2, lower GCS, higher ISS, and higher mortality rate compared to patients who wore helmets. Regarding the effectiveness of different types of helmets on patient outcomes, half-helmets offered significantly less protection than full-face helmets, considering that patients wearing half-helmets had a significantly higher rate of AIS ≥2 injuries in the head region and significantly higher odds of sustaining SDH, SAH, and ICH than patients wearing full-face helmets. In addition, there was no significant difference in the rate of head injuries between patients wearing open-face helmets and full-face helmets. However, patients wearing open-face helmets had higher odds of sustaining SAH. Moreover, there were no significant differences in GCS after injury or in hospital mortality rate and LOS in patients wearing either half-helmets or open-face helmets than in those wearing full-face helmets.
Notably, most studies had demonstrated that full-face helmets provide better protection against head injuries than other types of helmets. In a study of 738 motorcyclists involved in traffic accidents in Korea, although patients wearing full-face or open-face helmets had a lower maximum AIS score for head injuries than those who did not wear a helmet, only patients who used full-face helmets had a reduced incidence of severe and minor head injuries. Another study of 156 motorcycle accident victims showed that patients wearing full-face helmets had a significantly reduced occurrence of traumatic brain injuries compared to those wearing open-face helmets. In a meta-analysis of six eligible studies, among the 6,529 patients involved in motorcycle accidents, the occurrence of head-and-neck injuries in patients wearing full-face helmets was significantly lower than in those wearing half-helmets and open-face helmets. However, some studies presented results similar to ours. A study of 151 patients involved in motorcycle accidents showed that although there was a lower incidence of traumatic brain injury in patients who wore full-face helmets when compared with patients who used other types of helmets, the difference in the incidence of traumatic brain injury was not significant. In addition, there were no differences in ISS, LOS, or mortality between the two groups of patients.
Although an earlier study by Goldstein revealed a higher rate of neck injuries in motorcyclists wearing helmets, several studies showed that the use of helmets was not associated with an increased risk of injury, and even reduced the risk of cervical spine injuries.,,, Previous research illustrating the effect of helmet types on cervical spine injury remained controversial. A 1979 study report suggested that wearing full-face helmets may cause an impact force that dissipates onto the trunk, thereby reducing the risk of cervical spine injury. In a study of 5225 motorcycle accident victims with head injuries, the patients who used a helmet, either full-face or partial-coverage, had significantly reduced cervical spine injuries compared to those who did not use helmets. Nonetheless, few studies have revealed a significant relationship between helmet type and cervical spine injury.,,,,, In this study, the results showed that there was no significant difference in the rate of cervical spine fractures in patients wearing either half-helmets or open-face helmets than in patients wearing full-face helmets.
While calculating the AOR of mortality using logistic regression analysis, the severity of injuries in patients was not controlled for helmet use and mortality. This adjustment relied on the assumption that the incidence of injuries to body regions other than the head was independent of the occurrence of head injuries or the use of helmets. However, this assumption might not be valid in reality., Previous studies showed that the protection provided by full-face helmets against head injuries would reduce the severity of injuries to other body regions, as well as overall body injury. However, other studies demonstrated that there was no difference in the severity of overall body injury between motorcyclists with full-face helmets and other types of helmets., Our findings showed a significantly higher ISS in patients wearing half-helmets than in patients wearing full-face helmets. Nonetheless, there was no significant difference in ISS between patients wearing open-face and full-face helmets. Studies on the association between the characteristics and risks of motorcycle accident-related injuries and the type of helmet used were limited. However, the severity of the injury might depend on the type of helmet used. In a study of 738 motorcycle accident victims in Korea, riders with full-face helmets were traveling at an overall higher speed at the time of the crash than patients without helmets or with other types of helmets. Therefore, unknown conditions, including speed and crash severity, would be a limitation in the analysis of the registered data in our study.
Our study had other limitations. First, some selection bias might be present due to retrospective design of this study. Second, the trauma database did not record the patients who were declared dead on arrival at the emergency room. Therefore, only inhospital mortality was considered. This might lead to selection bias during data analysis. Third, interventions such as resuscitation and surgery could lead to a different outcome; however, we could only assume that the outcome of management was uniform across the studied patients. Fourth, the use of antiplatelet agents or anticoagulants might have an impact on the survival of patients with ICH. The lack of information regarding the use of these drugs in the study population might lead to bias in the outcome measurements. Furthermore, motorcyclists wearing loosely fastened helmets were reported to have a higher risk of head injuries than those wearing firmly fastened helmets. However, factors such as the quality of helmets, improper fastening, or displacement of the helmet during accidents were unknown and might result in bias in the outcome measurement. Finally, this study only included hospitalized patients; those who had minor injuries or who could walk home after the incident were excluded because they were not admitted to the hospital or did not visit the emergency department. Therefore, sample selection bias may arise from reports based on the analysis of police-reported or emergency room-reported data.
| Conclusion|| |
This study revealed that protection from head injuries provided by half-helmets was significantly lower than that provided by open-face and full-face helmets. However, there were no significant differences in GCS after injury or in the mortality rate and LOS in the hospital for patients wearing either half-helmets or open-face helmets compared to those with full-face helmets.
We would like to thank the Biostatistics Center, Kaohsiung Chang Gung Memorial Hospital, for their assistance with the statistical analyses of this study.
Financial support and sponsorship
This research was supported by grants from Chang Gung Memorial Hospital (CMRPG8K1191 to SYH and CMRPG8K1041 to CHT).
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3]