Archives of Academic Emergency Medicine. 2021; 9(1): e43 OR I G I N A L RE S E A RC H Comparing the Severity of Injury and Trauma Pattern be- tween Scooter and Street Motorcycle Riders; a Prospective Cohort Study Mansour Bahardoust1, Arman Karimi Behnagh2, Abolfazl Bagherifard1, Mehrdad Khodabandeh3, Sayed Ali Emami3, Shakiba Ghasemi Assl2, Farid Najd Mazhar1∗ 1. Bone and Joint Reconstruction Research Center, Shafa Orthopedic Hospital, Iran University of Medical Sciences, Tehran, Iran. 2. Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran. 3. Neuromusculoskeletal Research Center, Department of Physical Medicine and Rehabilitation, Iran University of Medical Sciences. Received: April 2021; Accepted: May 2021; Published online: 8 June 2021 Abstract: Introduction: The popularity of motorcycle riding in Iran is increasing. However, there is a lack of informa- tion about the safety of different motorcycle types. This study aimed to compare the severity of injury and trauma pattern between scooter (vespa) and street (standard) motorcycle riders. Methods: In a prospective co- hort study, a comparison of demographics, injury severity, trauma pattern, and clinical characteristics between 324 riders (162 Vespa and 162 standard motorcycles) admitted to emergency departments was undertaken. The risk factors associated with severe injuries in the two groups were also determined. An emergency medicine spe- cialist determined the severity of trauma based on the abbreviated injury scale (AIS). Results: The Odds Ratio (OR) of severe injuries was significantly higher in the standard motorcycle riders’ group (OR: 3.09; 95% CI: 1.9- 4.21; p: 0.013). The frequency of lower extremity fractures was significantly lower in the Vespa group (OR: 4.11; 95% CI: 2.01-6.25; p = 0.012). The frequency of admission to the intensive care unit was significantly higher in the standard motorbike riders’ group (OR: 1.64; 95% CI: 1.11-2.51; p = 0.033). The multivariate analysis indicated that motorcycle type, the speed at the time of the accident, use of helmet, and age of riders are the most impor- tant predictors of trauma severity in riders (p<0.05). Conclusion: The pattern of injury varies between standard and Vespa motorcycles. The standard motorcycle riders were prone to a higher risk of adverse outcomes such as severe injuries. Due to the particular structure of scooters, the rate of lower limb injuries was significantly lower than standard motorcycles. Keywords: Wounds and Injuries; Emergency Treatment; Accidents, Traffic; Motorcycles; Mortality Cite this article as: Bahardoust M, Karimi Behnagh A, Bagherifard A, Khodabandeh M, Emami S A, Ghasemi Assl S, Najd Mazhar F. Comparing the Severity of Injury and Trauma Pattern between Scooter and Street Motorcycle Riders; a Prospective Cohort Study. Arch Acad Emerg Med. 2021; 9(1): e43. https://doi.org/10.22037/aaem.v9i1.1229. 1. Introduction Trauma is regarded as one of the major causes of death in developed countries, ranking high on the list of mortality and morbidity causes in younger populations. Traffic in- juries are the leading cause of death in children and young adults (ages 5-29). Although ranked as the sixth major global mortality cause, it is predicted that fatality of traffic injuries ∗Corresponding Author: Farid Najd Mazhar; Bone and Joint Reconstruc- tion Research Center, Shafa Orthopedic Hospital, Iran University of Med- ical Sciences, Tehran, Iran. Tel/Fax: +98 21 33542041, Email: najd- mazhar.f@iums.ac.ir, ORCID: https://orcid.org/0000-0001-8496-9852. will increase and it will rise to the fourth spot (1). More than half of all road traffic deaths occur in vulnerable road users: pedestrians, cyclists, and motorcyclists (2). Injuries sustained in two-wheeled vehicle accidents are often more severe than those sustained in automobile accidents (3). Be- sides, globally, the probability of motorcycle riders being in- jured is about three times more than car occupants and they are sixteen times more probable to die due to road traffic in- juries (4). Low- and middle-income countries are disproportionately more burdened by the significant mortality and morbidity inflicted by motor-vehicular accidents (MVA) (5, 6). The most common causes of motorbike-related MVA’s are illegal This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem M. Bahardoust et al. 2 overtaking, excessive speeding, alcohol intoxication and sub- stance abuse, motorbike type and safety, and not wearing standard protective gear such as helmets (7, 8). In Iran, mo- torbikes are widely used, resulting in an increased frequency of motorbike-related MVAs that impose a high burden of dis- ease on the healthcare system (5, 6, 9). The MVA-associated mortality in motorcyclists, mainly oc- curs due to head traumas and helmets can reduce the re- garded rate (10). Moreover, musculoskeletal injuries are common among motorized two-wheeled vehicle riders, and they are frequently associated with head and neck injuries. The lower extremities are the most common sites of or- thopaedic injuries in a motorcycle collision. The incidence in some studies ranges between 40% and 60%, and limb entrap- ment is regarded as the most common mechanism of injury (11). The range and variety of motorcycle models continue to grow. However, in this study, we focused on two types, stan- dard and common street-legal motorcycle types and Vespa scooter (Figure 1). Scooters are primarily designed for use at low and medium speeds on urban streets. Relatively small in size with small-diameter wheels, their step-through design and general appearance differ significantly from full-sized motorcycles (12). Vespa scooters are designed with a par- ticular guard for the legs. Moreover, compared to standard motorcycles, Vespa scooters, have lower speed, smaller en- gine capacities, and also smaller wheel with high manoeuvre capability, which provide an advantage of better safety pro- file. The number of studies tackling the differences in MVA- related trauma based on motorbike type is somewhat lim- ited. However, few reports have documented less severe trau- mas in Vespa motorbikes compared to others. The current literature is mainly focused on the fatality of different motor- cycle types and the coverage of other aspect of motorcycle- related collisions is limited. This prospective study aimed to compare the fatality and orthopaedic injury rates between Vespa motorbikes and other conventional street-legal motor- bikes. 2. Methods 2.1. Study Settings and design This prospective cohort study enrolled 324 motorbike riders involved in an intra-city motor-vehicular accident resulting in upper and lower limb fracture(s) admitted to the emer- gency departments (EDs) of hospitals affiliated to Iran Uni- versity of Medical Sciences, Tehran, Iran, between May 2019 and May 2020. After assessing eligibility criteria, the patients were divided into two groups, based on the type of motor- bike involved: the first group (n=162) comprised of Vespa- riders, while the second group (n=162) were riding stan- dard motorbikes. To gain access to their medical records, patients were asked to fill out a written informed consent form. The study protocol was approved by Ethics com- mittee of Iran University of Medical Sciences (Ethics code: IR.IUMS.REC.1398.288). 2.2. Study Population Patients were enrolled through cluster sampling of EDs and during the study recruitment period all the patients with fol- lowing criteria were recruited for this study: 1) involvement in an MVA while riding a Vespa or standard motorbike; 2) ad- mission to ED; 3) availability of complete accident reports; 4) availability of complete motorbike documentation; 5) age between 18-50 years. Our exclusion criteria were as follows: 1) incomplete accident report; 2) occurrence of an incident out of the city bounds; 3) admission to EDs for reasons other than MVA (i.e., falling). The patients were matched for age, intoxication, speed, and engine power to control confound- ing factors. 2.3. Data Source and Measurements Demographic data, age, gender, type of motorbike (scooter or standard), the speed at the time of the incident, intoxica- tion with alcohol or other substances, mechanism of trauma, and status of using safety equipment were gathered using a predesigned checklist. Besides clinical and radiologic find- ings, including fracture location and severity, duration of hospitalization, intensive care unit admission, the cause of death, place of death, and the interval between accident and death were gathered using patients’ records and if possible, a brief interview was done (if they were alive). Fracture type and treatment procedures were classified based on the ICD- 10 manual. The trauma mechanism was classified into three groups: driver error, vehicular factors, and environmental causes. The details on the accident-associated parameters, such as type of motorbike, mechanism of accident, and speed of each motorbike at the time of accident were provided by explor- ing the police reports about the accident scene. An emer- gency medicine specialist determined the severity of trauma based on the abbreviated injury scale (AIS) (13). AIS evalu- ates trauma severity based on the extent of anatomical in- juries. In this scaling system, various injuries are exclusively coded, and the overall severity is classified into six groups: mild, moderate, serious, severe, critical, and life-threatening. The data for each group was gathered separately. An or- thopaedic surgeon determined the definitive location of the fracture(s) by examining radiologic images (14). 2.4. Statistical Analysis All the statistical analyses were performed using SPSS soft- ware for Windows v22. Descriptive analysis was performed and results were reported as mean and median for quantita- tive data and frequency and regarded percentage for qualita- This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 3 Archives of Academic Emergency Medicine. 2021; 9(1): e43 tive data in both groups. The Kolmogorov Smirnov test was used to assess data normality. The t-test and non-parametric Mann Whitney U tests were used to compare normally dis- tributed and otherwise data. The Chi-square test was used to compare quantitative data between the groups. Significance was reported using odds ratios (OR) and a 95% confidence interval (CI). Logistic regression was performed to determine the most important risk factors of the severity of trauma. The P-values <0.05 were deemed statistically significant. 3. Results 3.1. Baseline characteristics of studied cases This study enrolled a total of 324 motorbike riders (162 scoot- ers and 162 standard motorcycles). The mean age of the study population was 28.01 ± 1.22 years (100% male). Table 1 compares the baseline characteristics of the study subjects between scooter and standard riders. The mean age for the Vespa and the traditional motorbike group were 27.90 ± 20.30 and 29.03 ± 21.22 years, respectively (p = 0.42). 104 (64.2%) standard and 98 (60.5%) scooters motorbike riders were ex- ceeding 60km/h. No significant differences were observed between the two groups regarding age (p = 0.42), accident speed (p =0.11), helmet use (p = 0.079), the main cause of death (p = 0.28), place of death (p = 0.11), or time of death (p = 0.083). Severity of trauma based on AIS score was greater in the standard motorbike group (p = 0.001). 3.2. Comparing the location of injury and clini- cal outcomes Table 2 compares the location of injury and clinical outcomes between the two groups. The frequency of lower extremity fractures was significantly lower in the scooter group (OR: 4.11; CI 95%: 2.01-6.25; p = 0.012). In the standard motorbike group, the most common fracture locations were the knee, the shin, the ankle, and the foot. However, the frequency of these fractures was significantly lower in the scooter group (P=0.001). The two groups were similar regarding trauma to the head and neck (p > 0.081) and other limbs (p > 0.05). The overall mortality (p=0.084) and duration of hospital stay (p=0.76) were similar in the two groups. The frequency of ad- mission to the intensive care unit was significantly higher in the standard motorbike riders’ group (17.9% versus 9.9%; p = 0.033). 3.3. Risk factors of severe and critical trauma In general, the trauma was severe or critical in 100 (30.9%) of riders, based on the AIS. We used adjusted logistic regression analysis to control confounders in evaluation of factors asso- ciated with severe trauma. All variables with statistical signif- icance in univariate analysis were included in Logistic regres- sion. The multivariate analysis indicated that age < 24 years (Odds: 2.53; 95%CI: 1.46 – 3.66; p = 0.012), accident speed ≥ 60 km/hours (Odds: 3.56; 95%CI: 2.12 – 5.10; p = 0.001), use of a helmet (Odds: 0.66; 95%CI: 0.46 – 0.87; p = 0.001), and standard motorcycle type (Odds: 1.47; 95%CI: 1.07 – 1.98; p = 0.018) were among the most important risk factors of trauma severity in this study. 4. Discussion This study characterized subnational data on patients admit- ted to the ED who were involved in standard street-based motorcycles or Vespa scooters. Our data suggest that Vespa scooters possess better safety profile in comparison to mo- torcycles. Although the two groups did not show any dif- ference in terms of mortality rate and duration of hospital stay, the number patients admitted to ICU was significantly higher in motorcycle riders, which implies much severe in- juries among the motorcyclists. Moreover, site analysis of the injuries showed that motorcycle riders experienced a higher frequency of injuries in lower extremities. Furthermore, anal- ysis of the factors associated with severity of injuries, re- vealed that type of vehicle was one of the factors that could affect the severity of the injuries and the riding of standard street-based motorcycles can lead to more severe injuries. The prevalence of using low-speed motorcycles such as scooters has been increasing. This mainly owes to the af- fordability and low fuel consumption of this type of vehicle (15). Previous reports on the safety profile of scooters re- vealed that this increase in riding this type of vehicle may lead to a higher burden of disease (15, 16). However, these reports mainly focused on low-speed motorcycles. Although the higher consumption rate of this type of motorcycle can inflate the regarded burden of disease, studies similar to our work revealed that overall, low-speed motorcycles such as vespa scooters showed better safety profiles (17, 18). The use of either types of motorcycle can be associated with injuries including fractures and internal organ damages. However, the pattern and distribution of injuries showed discrepancy between the two groups. According to our analysis, vespa riders had a higher percent- age of injuries to head/neck and upper extremities; however, these observations failed to have statistical significance. On the other hand, motorcycle riders showed considerably more injuries in lower extremities. Our findings are inconsistent with the different injury patterns previously described, with the upper extremity more common in motorcycle riders and injury to lower extremities were more common in scooter or moped riders (18, 19). The source of discrepancy can be that the type of scooter and also counting moped and scooter as one group would change the safety profile of the scooters re- ported in studies. Besides, head injuries, with a higher fre- quency among motorcycle riders, were considered the most This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem M. Bahardoust et al. 4 common cause of death in both groups (18). Like upper ex- tremity injuries, the percentage of injury to head and neck was higher in vespa group. An explanation for this obser- vation was provided by White et al. Based on their study, scooter riders were less likely to use safety equipment (18). Also, the previous reports showed that using safety equip- ment such as helmets could reduce the risk of death and se- vere injuries (10). Furthermore, in an epidemiologic study in Iran, 23% of all fatal traffic injuries belonged to motorcy- cle riders, among whom 59% of all mortalities were due to head injuries. Most motorcycle fatalities belonged to the 18- 24 years age group (29.1%), and also, the overall percentage of safety helmet use among motorcycle accident victims was estimated at 37.4% (9). In this study, the mortality rate was not different between the two study groups. However, rid- ing a motorcycle can increase the risk of severe injuries. In a comparative study in Netherlands (19), it was demonstrated that the vehicle type being light moped was among the fac- tors that increased the risk of severe injuries. Interestingly, the speed at the time of accident and death did not differ significantly between the two study groups. Al- though the number of cases who died on the accident scene was higher in the motorcycle group (64.2% vs. 60.5%), this difference was not significant. Nonetheless, this finding may imply that the severity of accidents and, consequently, the regarded injury at the time of the accident were consider- ably higher among motorcycle riders. In another survey by Blackman et al. (17), the factors influencing accident sever- ity among motorcycle, moped, and scooter riders were evalu- ated. Our study and other reports showed that riding motor- cycles were associated with a higher rate of severe accidents in comparison to scooters. Moreover, they reported that one reason for such observation could be the use of each vehi- cle (17). For instance, scooters are mainly used for short dis- tances and usually at low speed. However, the motorcycle is primarily used in long distances and therefore, used at high speeds. Nonetheless, in their study and other surveys includ- ing the present study, speed did not play a pivotal role in the severity of injuries or mortality rates (10, 17, 18). There was no significant difference between the two groups regarding high or low speed riding in our study, and the prevalence of above 60 km/h was similar in the two study groups. Also, we observed that most of the collisions oc- curred at the speed range of 50-75 km/h. Nevertheless, this can mislead us since this categorization did not indicate the prevalence of very high speed, i.e., above 90 km/h in each group. Inconsistent with our observation, Blackman et al. (17) showed that speed above 80 km/h is associated with a high risk of a severe accident in motorcycle riders. Simi- larly, the speed limits for mopeds and scooters were 90 km/h and 70 km/h, respectively. There was another factor that af- fected the severity of the accidents regardless of the vehi- cle type. Younger age was associated with more severe ac- cidents. However, this finding was inconsistent with oth- ers reports in the literature, indicating that the older ages, specially above 75 years, is associated with undesirable out- comes among scooter and motorcycle riders (17, 19-21). One possible explanation for this discrepancy can be the fact that all the mentioned studies were conducted in western coun- tries. According to our literature search, in the middle east- ern countries, younger age is associated with severe injuries among the motorcycle riders (22). In a comprehensive anal- ysis of motorcycle pattern in Iran, it was demonstrated that the majority of motorbike injuries had happened in younger ages. It was demonstrated that the a great deal of young rid- ers did not have any motorcycle riding license making them vulnerable to motorbike-associated injuries (23). 5. Strengths and limitations Our study had some strengths and weak points. The main strong point of this study was a considerably large number of included participants in each group. Besides, this study was designed using a prospective methodology. Moreover, unlike the previous reports, the rate of pre-hospital deaths was de- termined in this study. Also, the effect of some confounders such as alcohol intoxication was adjusted in this study, which had not been achieved in studies pursuing similar objectives. The study’s main weakness was that the extraction of sev- eral variables such as the mechanism of the accident from police reports limited the classification of injuries based on accident mechanism. Also, we failed to follow the patients to understand the post-ED outcomes of the study participants, which could provide insight on the burden of disease pro- vided by each motorcycle type. 6. Conclusion This study suggests that riders of Vespa scooters and motor- cycles may have different patterns of injury. The motorcy- cles possess a higher risk of severe outcomes, such as higher fatality and severe injuries in comparison to Vespa scooters. Further evaluation of the injuries sustained by Vespa riders is required to understand their impact more fully. 7. Declarations 7.1. Data availability statement The datasets used and analyzed during the current study are available via the corresponding author on reasonable re- quest. 7.2. Acknowledgments Hereby, the authors would like to express gratitude to the Vice-Chancellor for research, Iran University of Medical Sci- This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 5 Archives of Academic Emergency Medicine. 2021; 9(1): e43 ences. 7.3. Funding The authors would like to express gratitude to the Vice- Chancellor for research, Iran University of Medical Sciences. 7.4. Author contribution All authors meet the standard criteria of authorship contri- bution based on the recommendations of the International Committee of Medical Journal Editor. All authors listed on the title page have read and approved the manuscript, attest to the validity and legitimacy of the data and its interpreta- tion, and agree to its submission to " Archives of Academic Emergency Medicine" for evaluation and review for possible publishing. 7.5. Ethics approval This study was reviewed and approved by the Ethics Committee of Iran University of Medical Sciences (IR.IUMS.REC.1398.288), and informed consent was ob- tained from participants before their inclusion in the study. 7.6. Conflict of interest The authors have no conflicts of interest to declare for this study References 1. Collaborators GBDCoD. Global, regional, and national age-sex-specific mortality for 282 causes of death in 195 countries and territories, 1980-2017: a systematic analy- sis for the Global Burden of Disease Study 2017. Lancet. 2018;392(10159):1736-88. 2. Organization; GsrorssGWH, IGO). WNNLCB-N-S. 3. Vlahogianni EI, Yannis G, Golias JC. Overview of criti- cal risk factors in Power-Two-Wheeler safety. Accid Anal Prev. 2012;49:12-22. 4. Ankarath S, Giannoudis PV, Barlow I, Bellamy MC, Matthews SJ, Smith RM. Injury patterns associated with mortality following motorcycle crashes. Injury. 2002;33(6):473-7. 5. James SL, Lucchesi LR, Bisignano C, Castle CD, Dingels ZV, Fox JT, et al. Morbidity and mortality from road in- juries: results from the Global Burden of Disease Study 2017. Injury Prevention. 2020;26(Supp 1):i46-i56. 6. Bahardoust M, Hajializade M, Amiri R, Mousazadeh F, Pisoudeh K. Evaluation of health-related quality of life after total hip arthroplasty: a case-control study in the Iranian population. BMC musculoskeletal disorders. 2019;20(1):46. 7. Denning GM, Jennissen CA. Pediatric and adoles- cent injury in all-terrain vehicles. Res Sports Med. 2018;26(sup1):38-56. 8. Lin MR, Kraus JF. A review of risk factors and patterns of motorcycle injuries. Accid Anal Prev. 2009;41(4):710-22. 9. Barzegar A, Ghadipasha M, Forouzesh M, Valiyari S, Khademi A. Epidemiologic study of traffic crash mortal- ity among motorcycle users in Iran (2011-2017). Chin J Traumatol. 2020;23(4):219-23. 10. Liu BC, Ivers R, Norton R, Boufous S, Blows S, Lo SK. Helmets for preventing injury in motorcycle riders. Cochrane Database Syst Rev. 2008(1):CD004333. 11. Petit L, Zaki T, Hsiang W, Leslie MP, Wiznia DH. A review of common motorcycle collision mechanisms of injury. EFORT Open Rev. 2020;5(9):544-8. 12. Morris CC. Motorcycle trends in the United States. United States. Bureau of Transportation Statistics; 2009. 13. Gennarelli TA, Wodzin E. Abbreviated injury scale 2005: update 2008: Russ Reeder; 2008. 14. Tazeabadi SA, Noroozi SG, Salehzadeh M, Bahardoust M, Farahini H, Hajializade M, et al. Evaluation of Judet view radiographs accuracy in classification of acetabular frac- tures compared with three-dimensional computerized tomographic scan: a retrospective study. BMC Muscu- loskeletal Disorders. 2020;21(1):1-6. 15. Siman-Tov M, Radomislensky I, Group IT, Peleg K. The casualties from electric bike and motorized scooter road accidents. Traffic injury prevention. 2017;18(3):318-23. 16. Weinert J, Ma C, Cherry C. The transition to electric bikes in China: history and key reasons for rapid growth. Trans- portation. 2007;34(3):301-18. 17. Blackman RA, Haworth NL. Comparison of moped, scooter and motorcycle crash risk and crash severity. Ac- cid Anal Prev. 2013;57:1-9. 18. White D, Lang J, Russell G, Tetsworth K, Harvey K, Bel- lamy N. A comparison of injuries to moped/scooter and motorcycle riders in Queensland, Australia. Injury. 2013;44(6):855-62. 19. Leijdesdorff HA, Siegerink B, Sier CF, Reurings MC, Schipper IB. Injury pattern, injury severity, and mortal- ity in 33,495 hospital-admitted victims of motorized two- wheeled vehicle crashes in The Netherlands. J Trauma Acute Care Surg. 2012;72(5):1363-8. 20. Savolainen P, Mannering F. Probabilistic models of mo- torcyclists’ injury severities in single- and multi-vehicle crashes. Accid Anal Prev. 2007;39(5):955-63. 21. Quddus MA, Noland RB, Chin HC. An analysis of motor- cycle injury and vehicle damage severity using ordered probit models. J Safety Res. 2002;33(4):445-62. 22. Khan KM, Jamil M, Memon IA, Idrees Z. Pattern of in- juries in motorbike accidents. Journal of Pakistan Or- thopaedic Association. 2018;30(03):123-7. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem M. Bahardoust et al. 6 23. Khorasani-Zavareh D, Sadeghi-Bazargani H. Epidemio- logical pattern of motorcycle injuries with focus on rid- ing purpose: Experience from a middle-income country. Journal of Research in Clinical Medicine. 2015;3(3):149- 56. Figure 1: Scooter (Vespa) versus standard (Street) type of motorcy- cles. Figure 2: Prevalence of traumatic injuries in scooter (Vespa) and standard (Street) motorcycle riders. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem 7 Archives of Academic Emergency Medicine. 2021; 9(1): e43 Table 1: Comparing the baseline characteristics of studied participants between scooter (Vespa) and standard (Street) motorcycle riders Variable Motorcycle Type P Standard (n:162) Scooter (n:162) Age ( Year) Mean ± SD 29.03 ± 21.22 27.90 ± 20.30 0.56 16-24 69 (42.6) 76 (46.9) 25-39 59 (36.4) 58 (35.8) 0.42 ≥40 34 (21.0) 28 (17.3) The speed at the time of the accident (Km/h) <60 58 (35.8) 64 (39.5) 0.11 ≥60 104 (64.2) 98 (60.5) Helmet use Yes 101 (62.4) 92 (56.7) 0.079 Helmet use in dead riders Yes 4/18 (22.2) 4/16 (25.0) 0.062 The direct cause of death Head and neck injury 13/18 (72.2) 12/16 (75.0) 0.28 Multiple injuries 5/18 (27.8) 4/16 (25.0) Death place On the scene of accident 11/18 (61.1) 8/16 (50.0) On the way 2/18 (11.1) 2/16 (12.5) 0.11 In a health facility 5/18 (27.8) 6/16 (37.5) Time to death (hours) < 24 12/18 (61.1) 10/16 (62.5) 0.83 ≥ 24 6/18 (39.9) 6/16 (37.5) Blood alcohol Positive 11 (6.8) 9 (5.6) 0.89 Addiction History Yes 15 (9.3) 14 (8.5) 0.19 Trauma Severity* Minor 44 (27.2) 64 (39.5) 0.035 Moderate 50 (30.9) 66 (40.8) 0.08 Serious 40 (24.7) 18 (11.1) 0.013 Severe 28 (17.2) 14 (8.6) 0.001 Data are presented as mean ± standard deviation or frequency (%).*: based on AIS score. Table 2: Comparing the baseline characteristics of studied participants between scooter (Vespa) and standard (Street) motorcycle riders Variable Motorcycle Type P Standard (n:162) Scooter (n:162) Fracture Location None 7 (4.3) 20 (12.3) 0.001 Upper extremity 65 (40.1) 82 (50.7) 0.88 Lower extremity 90 (55.6) 60 (37) 0.012 Head and neck 11 (6.8) 16 (9.9) 0.081 Chest 9 (5.6) 14 (8.6) 0.14 Shoulder, Elbow & Hand 45 (27.7) 52 (32.1) 0.11 Abdominal, lower back, and pelvic 5 (3.1) 6 (3.7) 0.21 Hip and thigh 5 (3.1) 4 (2.5) 0.38 Knee and Midfoot 57 (35.2) 34 (21 ) 0.001 Ankle and foot 16 (15.9) 16 (9.9) 0.018 Minor damage 5 (3.1) 20 (12.3) 0.001 Outcomes Death 18 (11.1) 16 (9.9) 0.084 Hospital stay (day) 6.6 ± 4.9 5.1±3.8 0.076 Admission to ICU 29 (17.9) 16 (9.9) 0.033 Data are presented as mean ± standard deviation or frequency (%). ICU: intensive care unit. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem M. Bahardoust et al. 8 Table 3: Multivariate logistic regression analysis of factors associated with severe and critical trauma in motorcycle riders Variable Odd 95% CI P Age < 24 years 2.56 1.46-3.66 0.012 Speed ≥ 60 (Km/h) 3.56 2.12-5.10 0.001 Use of helmet 0.66 0.46-0.87 0.001 Motorcycle (Standard type) 1.47 1.07-1.98 0.018 Odd: Adjusted odds ratio, CI: confidence interval. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: http://journals.sbmu.ac.ir/aaem Introduction Methods Results Discussion Strengths and limitations Conclusion Declarations References