Injury is the leading cause of death and disability in children and adolescents [1]. The mortality rate due to injury is used mainly as a major indicator for injury monitoring and evaluation. According to 2019 Korea Statistical Office data, the mortality rates among children aged 0, 1 to 9, and 10 to 19 years old due to injury were 16.6, 3.6, and 9.4 per 100,000 population, respectively [2]. Injuries accounted for a high proportion of the total mortality rates of these age groups, 6%, 34%, and 59%, respectively. According to another statistic on the mortality rate of injury of children younger than 14 years in Korea, deaths from injury per 100,000 population decreased from 24.3 in 1996 to 3.9 in 2016, ranking ninth of the 32 countries belonging to the Organization for Economic Cooperation and Development [3].

Mortality data from injury are objective and important, but these data reflect only a part of the total injury scenario. According to the Emergency Department (ED)-based Injuries In-depth Surveillance database of Korea from 2011 to 2017, death occurred in only 0.1% of patients under the age of 20 who visited the ED due to injury [4]. Fatal injuries account for only a minute portion of injuries and have different characteristics than nonfatal injuries [5]. According to the 2017–2018 National Injury Fact Book of Korea, the number of deaths from injury decreased for all ages, but hospitalization and outpatient visits for injuries increased [6]. According to these data, the overall injury mortality rate at all ages was 55 per 100,000, ED visits were 3,142, and inpatients were 2,177. Based on the data of the Korean National Health and Nutrition Examination Survey (KNHANES), the number of injured patients was 6,842 per 100,000. Although the data on ED-based injuries are meaningful [4,7], they reflect less than half of all injuries.

As such, the mortality data and ED data due to injury are insufficient for monitoring and effective prevention of injury. The KNHANES data include a questionnaire on the experience of injury. These data are representative of the Korean population, and the nonfatal injury data can supplement data on deaths. Therefore, we tried to confirm the incidence, risk factors, and characteristics of injury in children and adolescents using data from the KNHANES.

We conducted this study using data from the KNHANES. The KNHANES data managed by the Korea Centers for Disease Control and Prevention are sample survey data extracted using a 2-stage stratified colony sampling method that uses the survey zone and household as the extraction unit. These data are representative of the entire Korean population. Patients older than 1 year were interviewed about the experience of injury. We conducted the study based on data from 2007 to 2018: KNHANES IV (2007–2009), KNHANES V (2010–2012), KNHANES VI (2013–2015), and KNHANES VII (2016–2018). This study was approved by the Institutional Review Board of Kosin University Gospel Hospital (2021-04-031).

This study was conducted in children and adolescents aged 1 to 19 years from 2007 to 2018. We analyzed the response to the questionnaire about injury experience. The survey asked, “Have you had any accidents or poisoning that required treatment in a hospital or emergency department in the past year?” Subjects with more than one injury experience in the 1 year were defined as having an injury experience. The weighted percentage of injury experience was investigated according to survey period, age, sex, region of residence, household income, and type of insurance. In addition, it was asked whether the subjects were restricted in daily life and social activities due to health problems or physical or mental disabilities. Visual impairment, hearing impairment, depression/anxiety, mental retardation, language disorder, developmental disorder, and attention deficit/hyperactivity disorder (ADHD) were investigated as reasons of activity restriction. Among chronic diseases of children and adolescents, it was investigated whether the subjects had ever been diagnosed during their lifetime with ADHD by a doctor.

In addition, the month of occurrence, mechanism and intentionality of the injury, hospital treatment, and absence from school were investigated. Motor vehicle collision (MVC), falls/slip, collision, laceration/cut/penetration, burns, asphyxia, drowning, poisoning, and others were investigated to describe the mechanism of injury. Hospital treatment was divided into ED, outpatient, and hospitalization. For intentionality, we investigated whether the injury was unintentional, due to intentional self-harm, or caused by violence of others. In addition, the requirement for absence from school was investigated.

The KNHANES data were extracted via the multistage stratified cluster sampling method for sample representativeness and accuracy of estimation. Unlike simple random sampling design data, these data can maintain representativeness only when analysis is performed using weights, stratification variables, and colony variables. Therefore, we performed statistical analysis using a complex sample analysis method utilizing weights, stratification variables, and colony variables. Sampling weights were generated by considering a complex sample design, the nonresponse rate of the target population, and poststratification. The weighted percentage was calculated for subjects with experience of injury. As a statistical method, a complex sample crosstabs analysis was performed. Logistic regression analysis was performed for risk factors affecting the injury experience. For statistical analysis, IBM SPSS Statistics ver. 25.0 (IBM Co., Armonk, NY, USA) was used. P values less than 0.05 were judged to be statistically significant.

In our study, 8.1% of children and adolescents experienced nonfatal injury more than once a year, and 10% of them experienced injury more than twice. This result did not include fatal injury cases or cases not requiring hospital care. Therefore, this result is underestimated compared to the actual number of injuries. In addition, while the injury-related mortality rate has decreased [2,3], there was no significant decrease in the nonfatal injury experience rate over 12 years. According to data from the Korean Statistical Office, between 2007 and 2018, the number of births decreased from 497,000 to 327,000, and the number of children under 14 decreased from 8.7 million to 6.6 million [8,9]. Thus, the total number of injured persons decreased over 12 years, but the injury experience rate did not change significantly. In Korea, policies on child safety have been implemented since 2003, and include traffic safety, product safety, food safety, living space, and safety education. Although the death rate and MVC recently have decreased significantly, more long-term and practical planning and implementation are needed. The Child Safety Control Act was enacted in 2020, requiring establishment and implementation of a comprehensive child safety plan every 5 years [10].

In our study, the rate of injury experience was higher in males, urban residents, and those from low-income households. In Korea, the incidence of injury at all ages was higher among males [6]. For fatal injuries in 2016, the number in children younger than 14 years was 1.7 times higher for boys: 4.9 males and 2.8 females per 100,000 [3]. In the Centers for Disease Control and Prevention data, the incidence of injuries in boys was high among children and adolescents except those younger than one year [11]. In addition, the incidence of injury was high in urban areas; this differs from the results of comparing deaths of children due to unintentional injuries by region in the data of the Korean National Statistical Office [2]. In Seoul, Gyeonggi province, and other metropolitan areas, the mortality rate of children due to unintentional accidents is 2.0–3.2 per 100,000 population, lower than the 3.0–4.7 in other areas. This difference is believed to be due to differences in medical infrastructure. Considering that the incidence of MVC is higher in metropolitan areas, the regional difference is expected to be larger than the measured results.

In our data, the risk of injury was high when there were restrictions on activity due to visual impairment, hearing impairment, or developmental disorder. Consistent with previous findings, those diagnosed with ADHD had a high incidence of injury [12]. Focus and correction should be placed on the physical and social environments of children [13].

In our data, unintentional injuries accounted for 96.3% of all injuries. According to the data of 2019 Korean death statistics, deaths from intentional injury between the ages of 0 and 9 years accounted for 27.8%–29.5%, while that of those ages 10 and 19 accounted for 65.9% [2]. This means intentional injuries are more fatal than unintentional injuries. Moreover, the mechanisms of injury in our data were different from those in the death statistics data. Among unintentional injury that caused death in children and adolescents, MVC, suffocation, and drowning were common [3]. Among children younger than 1 year, suffocation accounted for more than 60%. The incidence of injuries with such a high-mortality rate was low in our study [14]. In particular, no one experienced drowning.

On the other hand, the results for patients who visited the ED were similar to our results in that more than 95% of injuries were unintentional [4]. As the mechanism of injury, cases of fall, slip, and collision accounted for about 2/3 of the total injuries at all ages [4]. This is similar to that in the study of Dorney et al. [5], fall and collision are the most common mechanisms that cause nonfatal injury in 1- to 19-year-olds in the United States.

In children and adolescents, the mechanism of injury also differed according to age [5,11,15]. In our study, burns occurred mainly in children younger than 4 years of age and MVC increased with age. According to the Centers for Disease Control and Prevention childhood injury report, fall was the most common cause of injury in children under the age of 15, and MVC was the most common cause thereafter [11]. In particular, the rate of suffocation was highest in children younger than 1 year of age, and the rates of fires, burns, and drowning were highest for children 4 years and younger [11,16]. This was similar to the rates of unintentional injuries in low-income countries in the World Report on Child Injury Prevention [17]. The reason that injury in children and adolescents differs according to age is that development and behavior are related closely to specific injuries [17]. In addition, as age increased, the number of cases of injury during leisure activities, exercise, or education increased gradually [4].

Injuries to children and adolescents are being recognized as predictable and preventable, moving away from the past concept of 'accidents,' and various improvement efforts are occurring around the world [17,18]. Prevention of high-mortality injuries such as suicide, MVC, and suffocation is important, as is that of higher-incidence rate injuries. Unintentional injury can be prevented in many cases. Supplementation and reinforcement of policies on wearing protective equipment and safe facility management are necessary; few cases of injury occur while wearing protective equipment. Provision of consistent preventive education according to age for caregivers, children, and adolescents especially is important. Pediatricians need to provide this important unintentional injury prevention education to parents during examinations of infants and toddlers.

The limitation of our study was that the data were collected through a questionnaire survey. Therefore, the accuracy and reliability might be low because or recall bias. In addition, the total number of injuries was not reflected sufficiently, and location, mechanism, and detailed outcome of injury were not investigated. Also, there was a limitation that fatal and mild injuries were excluded. Nevertheless, estimation of the incidence of injury in all children and adolescents through large-scale data reflecting the entire Korean population is meaningful.

In conclusion, 8.1% of children and adolescents who visited the hospital annually experienced injury, and this is probably an underestimation. Since there is no significant difference in the frequency of nonfatal injury over the past 12 years, we believe that more attention and efforts to prevent injury are needed.