Hrev_master [page 14] [Emergency Care Journal 2025; 21:12915] Emergency Care Journal 2025 volume 21:12915 Abstract The aim was to determine the relationship between the severity of the score and the child sitting position in the vehicle. In this ret- rospective cohort study, the severity score was obtained from HIS. After entering the data into STATA/SE version 14, univariate regression models were used to identify the potential confounding variables. Poisson regression estimators were applied to depict the relationship between safety devices, seating position of the child, and the severity indices. Out of 257 child occupants under 6 years, only 4.1% of the children used child seats and 7.7% used seat belts. There was a statistically significant positive relationship between ISS and middle rear seat (P = 0.026) and left rear seat (P = 0.000). A positive relationship existed between ISS and the right rear seat. Hospitalization of children sitting on the middle rear seat was longer than the others. The right rear seat was found to be the safest seat for children. The pattern of child accidents is different in the study region compared to other places. Local interventions should be implemented using evidences obtained from road traffic acci- dents. Thus, the governments should explore new strategies to increase the use of child seats by parents. Introduction Car accidents are one of the leading causes of death in infants and children, accounting for 22.3% of all related deaths. According to the World Health Organization, motor vehicle accidents were considered the leading cause of death in children under 7 years of age in most countries{Goodwin, 2015 #2390} in 2015.1 In the United States, one in five child deaths is caused by traf- fic accidents.2 In Iran, traffic accidents are one of the principal causes of death of children under 5.3 Children in motor vehicles are more vulnerable to injuries than adults due to their small body size.4,5 Their head is relatively large and the ratio of their facial dimensions to the brain dimensions in children is different, which causes a higher center of gravity in children. Children’s neck has a thin structure and their vertebrae have a lot of cartilages in contrary to adults.6 Moreover, children’s body structure is such that less part of the abdomen is protected by the pelvis and ribs. Children’s ribs are less likely to break and bend than those of adults, which may cause extremely damage to the heart and lungs during a car acci- dent.7 Based on the position of sitting in the car, an unprotected child can be pushed forward with a force of 30 to 60 times more than his/her weight and hit the driver or the passenger next to the driver at a speed of 50 km/h.8 The seating position in the car can increase the risk of injury during an accident9. The risk of accidents Correspondence: Naema Khodadadi-Hassankiadeh, Guilan Road Trauma Research Center, Trauma Institute, Poursina Hospital, Namjoo St, Postal Code: 4193713194, Rasht, Guilan, Iran. Tel.: +98.9113378344 - Fax: +98.1333368773 E-mail: n_khodadady@yahoo.com Key words: injury severity index, seating position, children, vehicle. Contributions: LK and BZ provided conception and design. FB and MH collected data. EH has given his expertise in data management and analysis. NK and LK authored the result section of manuscript. NK had full access to the data, controlled the decision to publish, and accepted full responsibility for the conduct of this study as the guarantor. All authors reviewed the results and approved the final version of the manuscript. All authors reviewed the results and approved the final. Funding: no funding has been received for this work. Conflict of interest: the authors declare no conflict of interest. Availability of data and materials: all data generated or analyzed during this study are included in this published article. Ethics approval and consent to participate: the study was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments or comparable eth- ical standards. This study was approved by the Ethics Committee of Guilan Medical University (IR.GUMS.REC.1399.052). Oral informed consent was obtained from all legal guardians subjects. Because this was a retrospective study with a telephone interview. Acknowledgments: the authors would like to offer their special thanks to Ms. Fatemeh Javadi for translating the manuscript. Received: 10 August 2024. Accepted: 7 January 2025. Early view: 20 February 2025. This work is licensed under a Creative Commons Attribution 4.0 License (by-nc 4.0). ©Copyright: the Author(s), 2025 Licensee PAGEPress, Italy Emergency Care Journal 2025; 21:12915 doi:10.4081/ecj.2025.12915 Publisher's note: all claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher. The relationship between the injury severity based on injury severity score and child seating position in the vehicle Leila Kouchakinejad-Eramsadati,1 Behzad Zohrevandi,1 Faranak Bashi Shahabi,2 Enayatollah Homaie Rad,3 Marieh Hosseinpour,1 Naema Khodadadi Hassankiadeh1 1Guilan Road Trauma Research Center, Trauma Institute, Guilan University of Medical Sciences, Rasht; 2School of medicine, Guilan University of Medical Sciences, Rasht; 3Social Determinants of Health Research Center, Trauma Institute, Guilan University of Medical Sciences, Rasht, Iran in different seating positions of the car is highly dependent on the direction of the accident, the characteristics of the vehicles under study.10,11 the condition of the roads, and safe driving culture, which vary in different countries.12 The child’s sitting position is associated with the risk of injury.13 Therefore, the risk of injury and death are similar for the rear and front passengers of the car in side collisions.11 Research has shown that the place of safety seat directly affects the Injury Severity Score (ISS) and the Glasgow Coma Scale (GCS) according to the direction of impact to the car and its change in speed.10 More fatalities were reported for the rear seat than for the front-seat occupants. In head-on collisions, there is evidence that the relative risk of death is higher in the rear passen- gers than in the front passengers. Rear seat occupants often suffer serious injuries to the thoracic, abdominal, and head areas, usually associated with the use of seat belts.11 Rear seats have high risks of injury due to falls. Children sitting in the back row are injured by impact of the front and rear passengers.14 Studies have shown that car occupants have a lower risk of death and injury in the back seat than in the front seat, especially in cars that have no airbags or the occupant has no restraint.15 The risk of car accidents affect the vulneribity the occupants sitting in different parts of the vehicle, vary in different countries. Thus, due to the importance of the issue and the insufficient infor- mation on evidence-based decision-making, this study sought to determine the relationship between ISS and LOS with the child sit- ting position in the private car. Materials and Methods Study design This retrospective cross-sectional study was conducted after receiving the code of ethics from the Clinical Research Ethics Committee of Guilan University of Medical Sciences IR.GUMS.REC.1399.052 in Rasht Pursina Hospital, which is a referral hospital in Guilan Province, which is located in the north of Iran. All car accidents that occurred in a three-year period and met the entry criteria were included in the study. Eligibility criteria Data all of private car accidents which one child injured was referred to hospital were collected from 2019 to 2022 (a three-year period). The rest of the entry criteria were: the private car accidents has one or more than one occupant /=25 = Profound.17 If ISS > 15, major trauma is defined.18 In the present study, ISS score was calculated by a general medicine. In this way, the three regions with the most damage from the child’s record in the HIS were determined, then based on the ISS book, a score was considered for each regions, and finally, the square of the scores of the three members were added together, and the final ISS score was given to each child. Second, using the database data, the phone numbers were extracted and called with trained interviewers. The information that was not registered in the HIS and education of the parents(high school diploma, undergraduate and university education), type of child safety equipment at the time of the accident (seat belt, airbag, child seat and none) child seating position(front seat, left rear seat, right rear seat and middle rear seat) was obtained through a tele- phone interview. In the telephone interview, parents or guardians were interviewed using predetermined questions. Oral consent was obtained before asking the questions. Sample size The total number of injured children in this period was 306. However, from the 306 calls, 17 refused to answer the questions, 32 phones were off, and others did not answer the calls after three times of calling. At the end 257 cases answered to the questions. Analysis For analyzing the data for avoiding collinearity and having bet- ter degrees of freedom, first univariate regression models were estimated to identify the potential confounding variables. According to the results, none of the demographic variables (except for age and sex) were associated with ISS and LOS. Second, Poisson regression estimators were used to depict the rela- tionship between safety equipment’s, seating position of the child, and the severity indices (ISS and LOS). All of the analyses were performed using STATA/SE version 14.1. Results The present study included 257 occupants under 6 years of age who were referred to Pursina Hospital of Rasht due to private car accident during the last three years. The mean age of children was 2.9±0.13 years. Considering frequency in terms of sex, 54.1% (n=139) of the injured children were boys. Most children (64.8%, 151) were transferred to the hospital by 115 emergency services and the rest by private vehicle (15.9%, n=37). The highest number of private car accident occurred on roads out of the city (59.2%, n=122) followed by the private car accident inside the city (27.2%, n=56) and rural areas (13.6%, n=28). Only 4.1% (n=8) of the chil- dren used child seats and 7.7% (n=15) used seat belts. Maternal education in 73.1% (n=144) was high school diploma and under- graduate and 26.9% (n=53) had university education. The majority of their fathers (69.4%, n=134) had high school diploma and undergraduate education and 30.6% (=59) had university educa- tion. Most of the children’s seating position was the front seat (37.2%, n=74) followed by the right rear seat (25.6%, n=51), left rear seat (24.6%, n=49) and middle rear seat (12.6%, n=25) (Table1). The findings of the study revealed a relationship between the severity of injury based on ISS and the seat position of the child in the private car after controlling the confounding variables of age, Article [Emergency Care Journal 2025; 21:12915] [page 15] type of safety equipment, and child’s sex using Poisson regression estimator. The results indicated that there was a statistically signif- icant positive relationship between ISS and middle rear seat (P = 0.026) and left rear seat (P = 0.000). According to these results, the severity of accidents (according to the ISS) was higher in the mid- dle rear seat and then in the left rear seat. A positive and statistical- ly significant relationship was noticed between ISS and female sex (P=0.000) so that the severity of accidents was higher in girls (Table 2). Figure 1 displays the predicted value of the ISS in a regression model with independent variables of age, sex, and safety equip- ment, based on seating position in the vehicle. The predicted ISS value in the right rear seat is the lowest possible, indicating that the seat is safer for children. The most unsafe seat was the middle rear seat. However, the level of the confidence interval in this chair was high (Figure 1). There was not statistical relationship between LOS and type of safety equipment in children, But there was statistical relationship between LOS and Middle rear seat position children (p-value= 0.001). The LOS was significantly longer in injured girls than in boys. (P=0.000) (Table 3). Figure 2 shows the adjusted value of the LOS and the child’s seating position in the vehicle. The same results were analyzed based on the LOS and it was found that hospitalization of children sitting on the middle rear seat was longer than the others. The right rear seat was found the safest seat for children (Figure 2). Article Table 3. Relationship between LOS with type of safety equipment, seating position, age and sex of children. LOS Variable IRR Standard deviation p Safety equipment Seat belt Base Airbag 0.000 0.000 0.998 Child seat 0.430 0.275 0.187 None 1.041 0.254 0.870 Seating position Front seat Base Left rear seat 0.888 0.151 0.485 Right rear seat 0.773 0.139 0.153 Middle rear seat 1.849 0.345 0.001 Child age 0.941 0.033 0.085 Sex-Female 1.481 0.233 0.000 Constant coefficient 1.801 3.353 0.000 Table 1. Demographic characteristics of children under 6 years of age in private car accidents (N=257). Description N (%) Sex Female 118(45.9) Male Transfer to hospital EMS 139(54.1) Clinic Ambulance 151(64.8) Private vehicle 44(18.9) Others 37(15.9) Location of accident City 1(0.4) Rural 56(27.2) Out of city 28(13.6) Safety equipment Seat belt 122(59.2) Airbag 15(7.7) Child safety seat 2(1) None 8(4.1) Seating position Front seat 170(87.2) Left rear seat 74(37.2) Right rear seat 49(24.6) Middle rear seat 51(25.6) Middle rear seat 25(12.6) Table 2. Relationship between ISS with safety equipment, seating position, age and sex of children. ISS Description IRR Standard deviation p Safety equipment Seat belt Base Airbag 2.191 1.183 0.146 Child seat 0.533 0.179 0.061 None 1.237 0.217 0.224 Seating position Front seat Base Left rear seat 1.265 0.134 0.026 Right rear seat 1.037 0.115 0.747 Middle rear seat 1.604 0.201 0.000 Child age 0.996 0.022 0.865 Sex-Female 1.481 0.119 0.000 Constant coefficient 2.54 1.039 0.023 [page 16] [Emergency Care Journal 2025; 21:12915] Discussion In present study, only 4.1% of children had safety seats. In an Iranian study by Moradi et al. (2019), the use of child seats was 18.7% in the capital and it was significantly higher in parents liv- ing in North Tehran who had higher monthly income, trained about child safety seats, and fathers who had more driving experience. Children’s age, weight and height were also factors that influenced the use of child safety seats. The main reason for parents to use a child safety seat was knowing the benefits of this device.3 In anoth- er study in a similar cultural setting, 80% of parents stated that they had never used a child safety seat, and only 13% had always used it. Meanwhile, more than 93% believed that the use of child safety seats is necessary and prevents children from being injured in acci- dents. 38% of parents were not aware of child safety devices in cars, almost 91% of parents reported that their use would increase if child safety seats were made mandatory. The child safety seat law, if implemented, will increase the chance of using a child safe- ty seat by 6.5 times.19 In the U.S.A., children who were not prop- erly restrained in a car had a higher death rate than children who were properly restrained. In states where the use of child seats was mandatory for children ≤6 years, deaths were higher than in states where the law was mandatory for children ≤8 years.20 In the present study, 7.7% of children under six years of age had used a safety belt. Similarly, in one study, seat belt use was only 5.7% in children who had an accident and were transported to a Level I pediatric trauma center.21 Previously, in a study in north- ern Iran, the use of restraint systems in school bus was low for stu- dents, and it was significantly higher in Sport Utility Vehicles (SUVs) and high income families.22 In a study that examined the risk of injury to children in accidents, children who were not restrained at all were 4 to 5 times more likely to be injured than children who were properly restrained, and children who were not properly restrained were about 1.1 to 1.9 times more likely to be injured. Therefore, the effects of restraint type decrease with age.23 Based on the results of our study, the severity of accidents based on ISS was higher in the middle rear seat and then in the left rear seat mostly in girls. In one study, on the contrary the mean ISS for children restrained in the front seat in vehicles older than 2000 was 0.494. The average ISS for the second left and second right row seats was 0.374 and 0.322, respectively. The seats in the mid- dle of the second row had a lower ISS than all the above seats. In general, the safest seat for a child was the middle seat in the second row, whether restrained or not.24 In another study by Kallan et al., there was an inverse relationship between the middle seat and older ages (39% for occupant’s < 1-year-old vs. 18% for 3-year-old occupants). regardless of the number of extra row occupants, the child occupants in the middle seat were 43% less likely to be injured than the children sitting in each of the left and right rear seating positions.25 In Mitchell et al.’s study, the distribution of injury severity and type of injury for rear and front-seat occupants was quite similar except for the abdomen, back, spine, back, and pelvic injuries which were more for the rear seat occupants. Most of the damages were to the head and chest. Front passengers (51.3%) had the most injuries. Rear seat occupants had a higher severity of injury than the front seat occupants.26 In present study, in addition to the ISS, we performed our anal- yses based on the LOS. It was previously reported that all three types of trauma scores have one positive effect on hospital LOS (GCS, ISS, and RTS)and Performance of ISS and NISS anatomical scoring systems is good in predicting hospital LOS and need for surgery.27,28 Also the research performed by Navabi et al. suggested that the injury severity was associated with increased hospital stay.29 The study proved that the LOS was longer for children sit- ting in middle rear seat than other seats. Almost similar to the results we saw about ISS. In a similar study, the relative risk of death depended on more factors. The relative risk of death was lower for restrained children younger than 8 years in the rear seat compared to right-front seat occupants, but higher for restrained children 9-12 years of age. There was no evidence of a difference in the risk of rear- and front-seat death for occupants aged 13 to 54 years, but there was evidence of an increased relative risk of death in adults aged 55 and older in rear-facing compared to right-front- facing occupants.30 Article Figure 1. Adjusted value of ISS in different seating position of children. The predicted ISS value in the right rear seat is the lowest possible, indicating that the seat is safer for children. The most unsafe seat was the middle rear seat. However, the level of the con- fidence interval in this chair was high. Figure 2. Adjusted value of LOS in different seats of children. The LOS children sitting on the middle rear seat was longer than the others. The right rear seat was found the safest seat for children. [Emergency Care Journal 2025; 21:12915] [page 17] There was also a statistically significant positive relationship between LOS and the female sex, which demonstrated that placing the child in the back seat causes injuries that may lead to longer hospitalization mostly for girls. Although the LOS does not demonstrate the severity of the injury, studies have exhibited a strong association between the two variables, especially in injuries due to traffic accidents. Morrison et al. worked on the TBI children who reported that girls had worse outcomes than boys and girls had more accidents.31 In another study, after controlling for occupant age and gender, the relative risk of death was significantly greater for restrained rear-seat occupants than front-seat occupants in 2007 and newer vehicles, and was significantly greater in rear-end and right-side crashes.30 The reason for the difference in the results is related to the type of private cars in Iran. To protect the passengers in the middle of the back, there is no safety device installed, not even a seat belt. Therefore, the child is practically unprotected and exposed to severe injuries. Therefore, both ISS and LOS have determined that the rear right seat is a safe seat for children under six years of age. In the present study, ISS and LOS did not determine the risk of injury depending on the type of protective device used for the child. Of course, the amount of use of protective equipment was also very small. Therefore, we cannot recommend which type of protective device for our children would have resulted in less ISS and LOS and would have been safer.The current best recommen- dations for use by children of all ages are rear-facing, forward-fac- ing child seats, booster seats, lap and shoulder belts, respectively.23 In present study, we did not check whether the accident was a rollover, ejection or other types and from which direction the car was hit as we did not have a plan to investigate this issue from the beginning. We wanted to determine the best seat position for the child to sit in the car according to the characteristics of accidents in our country, so there was no need to investigate and control the variable of the location of the accident. Moreover we did not have the information of those children who had an accident but were not injured, but only the information of the children who had even injuries need hospitalization due to the accident. The study was conducted in Guilan, a province with a high population density and vehicle traffic accident, which makes the findings less generaliz- able to other provinces of the country. The possibility of recall bias should not be ignored. Conclusions In Iran, no law has yet been approved for the use of child seats. Most families use cars without child seats to seat their children, because of the frequency of its use was very low, so it had no sig- nificant relationship with ISS and LOS. It is recommended that legislators and policy makers should pass this law considering the importance of the issue. The government should explore new strategies to increase the use of child seats by parents. The safe seat of private cars for children in our country is different from devel- oped countries. Car engineers should pay attention to the design of cars that have good protection facilities for children<6 age in mid- dle and left rear seats. 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