Background

Some injuries require urgent attention and are the leading cause of death for children and adolescents throughout the world [1-5]. According to data published by the World Health Organization (WHO) Global Burden of Disease, millions of children are affected by unintentional injuries annually and more than 2,000 children died from injuries daily in 2004 [2]. Tens of millions of children receive hospital treatment for non-fatal injuries yearly. Moreover, the burden of injury on children is socioeconomically unequal. More than 95% of all injury-caused deaths in children occurred in low-income and middle-income countries [1]. In China, a develo** country, injury has replaced diseases as the leading cause of death among elementary and secondary school students since the 1990s [6,7]. In particular, as road transport infrastructure developed, the incidence of road traffic injuries grew unexpectedly rapidly [8].

Injuries are a considerable threat to the health of children and adolescents and cause substantial economic loss for families and society [9]. The number of deaths of children from unintentional injuries is staggering. In the United States, more than 9,000 children die from unintentional injuries each year—about 25 deaths per day [10]. Non-fatal injuries may cause lifelong disability or chronic pain that limits the performance of daily activities. About 9 million children are treated for injuries in emergency departments yearly and more than 225,000 require hospitalization, incurring costs of around 87 billion USD in medical and societal expenses related to childhood injuries [5]. Additionally, the psychological burden caused by a family’s loss of a child is immeasurable.

Considerable evidence demonstrates that effective interventions can prevent the majority of childhood injuries. For example, setting minimum drinking age laws, lowering the blood alcohol concentration limit for drivers and reducing driving speeds around schools can effectively reduce childhood road traffic injuries [1,11]. A recent systematic review [12] indicated that prevention programs caused a significant reduction in adolescent injuries (relative risk (RR) = 0.62, 95% confidence interval (CI) [0.48, 0.81]), especially in girls. Both pre-season and in-season interventions were beneficial in reducing adolescent injuries. Another study showed that the average incidence of injury among secondary students reduced from 5.19% to 1.91% after a 5-month education and training program in Guangdong, China [13].

Because of the substantial epidemiological and economic burden of childhood injuries and because injuries are preventable, a study on the epidemiological characteristics and risk factors of childhood injury was necessary. While there were previous studies on this topic in China focusing on specific regions and populations, research on childhood and adolescent injuries in **amen, China had just begun and no relevant data sets were established. To provide a theoretical basis and empirical support for interventions, we aimed to (1) establish the prevalence and the major causes of injuries among elementary and secondary students in **amen, China; (2) identify the key indicators related to disparities in childhood and adolescent injuries; and (3) measure the economic and family burden of childhood and adolescent injuries. To accomplish these, we conducted an epidemiological study to understand the socio-demographic characteristics, risk factors and burden of injuries among elementary and secondary students in **amen, China.

Methods

Definition of injuries

In our study, we considered 14 types of injuries: traffic and road injuries, unintentional falls, collisions and strikes, sprains, cuts and sharp instrument injuries, crush injuries, drowning, suffocation, electrocution, burns and scalds, explosions, poisonings, animal attacks, and medical complications. Injury was defined following Wang SY (1998) [14] because the definition is suitable for China’s national condition and most commonly used in studies of injuries in China. An event is considered as injury if any of the following three events occurred: (a) being treated and diagnosed with injuries at a hospital; (b) receiving emergency treatment or care from family, teachers, or classmates; or (c) being absent from class for more than half a day because of injury.

Sampling strategy

Subjects in our study were students in elementary (grades 1–6) and secondary (grades 7–12) schools in **amen, China. Multi-stage stratified cluster random sampling was performed to recruit students in 2010. Recruiting was performed by district. **amen is one of five special economic zones in China, and it has six districts: Huli, Siming, Haicang, Jimei, **ang’an and Tong’an. According to economic conditions, the first two districts are classified as urban, the middle two districts as suburban, and the last two districts as exurban. At the first sampling stage, one urban, suburban, and exurban district was randomly selected. At the second stage, two elementary schools and two secondary schools were randomly selected from each selected district. At the third and last stage, we randomly chose one class from each grade in each school. Randomization was performed using simple random sampling in SPSS 17.0. All of the students in the sampled classes were enrolled in our study. Participants received a paper questionnaire and were asked to bring it home for their parents or guardians to answer the questions.

Measures

The content of the questionnaire included the following. (1) Students’ basic information: sex, age, height, weight, health status (good, fair, poor), personality (introversive, intermediate, extroversive), and number of siblings. (2) Students’ family background: parents’ age, education, occupations, marital status (married, divorced, separated, widowed), and incomes. (3) Occurrence of injuries in the past year: number of injuries, time and location of injury, injury type, events, and affected part of the body. (4) Burden of injuries: economic and family-related.

The economic burden of injuries was measured by direct economic burden, including medical and other expenses directly related to treatments for injuries; indirect economic burden, which refers specifically to family income loss due to parents’ or families’ absence at work caused by the children’s injuries; and intangible economic burden, measured by the amount of money the family is willing to pay to avoid injuries. The family’s burden of injuries was measured using the Family Burden Scale of Diseases (FBS) [15], which includes six dimensions: financial burden (FM1), disruption of family routine activities (FM2), disruption of family leisure (FM3), disruption of family interaction (FM4), effect on physical health (FM5), and effect on mental health (FM6). Each dimension contains two to six items, and each item has three responses: no impact, moderate impact and serious impact, scoring 0, 1 and 2, respectively.

Ethics statement

Informed consent was acquired on the first page of the questionnaire. All respondents participated voluntarily and provided informed consent. This study was approved by the ethical review committee of the School of Public Health, **amen University.

Data analysis

A chi-square test was used to analyze the association between the incidence of injury and impact factors. A multivariate logistic regression model was used to analyze significant variables from the chi-square test. Cronbach’s α coefficient was used to measure the internal consistency and reliability of the FBS. The six FBS dimensions were assessed as follows: (1) calculate the dimension scores by averaging the item scores within each dimension for each student; and (2) obtain the thresholds for each dimension by averaging all the students’ dimension scores. There was considered to be no impact if the dimension score for an individual student is 0, moderate impact if larger than 0 but less than the threshold, and serious impact at or above the threshold. We summarize the distributions of each dimension by reporting the frequency and relative frequency of each response. All statistical analyses were conducted using SPSS 17.0. Data was double-entered and validated by two trained research assistants using Epidata 3.1.

Results

Sampling characteristics

A total of 2,960 questionnaires were issued and 2,918 finished questionnaires were received. The response rate was 98.6%. Of the finished questionnaires, 2,816 (96.5%) were complete therefore usable. Table 1 summarizes the demographic characteristics of the 2,816 students, their incidence of injuries, and the results of chi-square tests. In total, 303 students suffered from 365 injuries within the year, giving a 10.8% incidence of injuries. Boys were more likely to suffer injuries than girls. Students who were in grades 4–9, were living in suburban or exurban environments, were extroversive, had sibling(s), were of poor health status, were living with more than 7 people, or had a household income greater than 4,000 RMB/month had a higher risk of injuries. Students whose parent(s) were low-educated (primary educated or below), performed manual labor, or were unmarried (divorced, separated or widowed) were more likely to suffer from injuries. Notably, the incidence of injuries was higher among extroversive students than introversive ones. Of the 303 injured students, most (84.2%) were injured once, were non-introversive (94.4%), and were not overweight (86.9%); more than half were boys (58.7%), more than half were in grades 4–9 (58.4%), nearly three quarters (74.3%) lived in suburban or exurban environments, half (50.8%) were from a one-child family, and 60% had a household income of less than 4,000 RMB/month.

Table 1 Demographic characteristics and chi-square test results for 2,816 participant students
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The characteristics of injury events are shown in Table 2. Here we group the months into four seasons because of seasonal variation in outdoor and indoor activities. We used morning, afternoon and evening as the three conventional time periods of the day. Of the 365 injuries, most (97.0%) were unintentional, more than one third occurred during the summer (June to August) (36.4%) and in school (35.1%), and more than half happened in the afternoon (55.3%) and affected the limbs (53.2%). The main causes of injury were unintentional falls (30.7%), collisions or strikes (18.8%), sprains (17.3%), and cuts or sharp instrument injuries (10.1%).

Table 2 Characteristics of student injury incidents by proportion and percentage
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Statistical analysis of injury impact factors

As Table 1 indicates, the significant impact factors for the incidence of injuries include sex, grade, residence, personality, number of siblings, health status, number of people living together, parents’ educational level, parents’ occupation, and parents’ marital status. Treating these impact factors as covariates, multivariate stepwise logistic regression was performed, and the results are presented in Table 3. The variables of parents’ education and parents’ occupation did not enter the model. Among the entered variables, sex, grade, residence, health status, personality, number of siblings, and parents’ marital status were statistically significant. The odds of injury were 1.8 times higher for boys than girls, 1.6 times higher for students living in exurban than in urban environments, 1.4 times higher for students in grades 4–9 than in grades 1–3, 2.9 times greater for extroversive students than introversive ones, 1.6 times greater for students with siblings than single children, and 2.8 times greater for students whose parents were of unmarried rather than married.

Table 3 Results of multivariate stepwise logistic regression for injury impact factors
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Economic burden of injuries

The direct economic burden of the 365 injuries among 303 students was 258,219.6 RMB (37,834.37 USD) total, 852.2 RMB (124.86 USD) per capita, and 707.5 RMB (103.66 USD) per incident. The outpatient expenses were 91,396.6 RMB (13,391.44 USD) (35.4%) and the hospitalization expenses were 147,885 RMB (21,668.13 USD) (57.3%). The expenses for travel, care, nutrition and rehabilitation supplies were 18,938 RMB (2,774.80 USD) (7.3%). The indirect economic burden of the 365 injuries was 88,948RMB (13,032.67 USD) total, 293.6 RMB (43.02 USD) per capita, and 243.7 RMB (35.71 USD) per incident. The intangible economic burden was 667,481.5 RMB (97,799.49 USD) total, 2,202.9 RMB (322.77 USD) per capita, and 1,828.7 RMB (267.94 USD) per incident. Altogether, the total economic burden (including the direct, indirect, and intangible economic burden) of the 365 injuries amounted to 1,014,649.1 RMB (148,666.5 USD) total, 3,348.7 RMB (490.65 USD) per capita, and 2,779.9 RMB (407.31 USD) per incident.

The economic burden of injuries with different characteristics is presented in Table 4. Although the incidence of injuries in students in grades 10–12 was lower, the direct and intangible economic burdens (1,146.3 RMB (167.96 USD) and 2,932.1 RMB (429.61 USD), respectively) associated with their injuries were higher. The indirect economic burden for students in grades 1–3 was higher (340.3 RMB (49.86 USD)). The total economic burden was higher (4,175.9 RMB (611.85 USD)) for students living in urban areas. Among the 14 causes of injury, the highest per capita economic burdens were caused by medical complications, poisoning, and traffic accidents.

Table 4 Average direct, indirect, intangible and total financial burden of student injuries per person-time (RMB) (1 RMB = 0.1465 USD)
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Table 5 presents the frequencies and relative frequencies of different responses to the six dimensions of FMS. The positive response rates (moderate impact and serious impact) rates were: financial burden (FM1) (58.8%), the disruption of family routine activities (FM2) (65%), the disruption of family leisure (FM3) (58.4%), and the disruption of family interaction (FM4) (46.2%). For the FMS overall, the positive response rate was 74.9%. The Cronbach α for the six dimensions (FM1–FM6) were 0.889, 0.912, 0.907, 0.926, 0.902, and 0.892, respectively, and 0.961 for the FMS overall.

Table 5 Family Burden Scale of Diseases (FBS) dimension measurements
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Discussion

Injury has become a public health problem that threatens elementary and secondary students’ health and causes substantial economic burden. Our study shows that the incidence of injuries in elementary and secondary students in ** students to obtain academic achievements, schools should work together with parents on strengthening student physique, cultivating safety awareness, and improving self-protection abilities. For instance, Bjӧrklund et al. introduced a school-based intervention program, “Together at school”, in Finland to promote elementary school students’ socio-emotional skills and mental health [24]. Finally, the local CDC should collaborate with schools to establish a system for monitoring the incidence and prevalence of injuries to collect relevant information to provide theoretical and empirical support for the prevention programs [25]. Injury control and prevention among elementary and secondary school students is essential and will help in multiple ways to reduce the burden on the family to build a harmonious family and society.

Because of time and man-power limitations, our study collected fewer than 3,000 usable questionnaires and conducted analyses based on these data. Therefore, our results might not be representative of all the elementary and secondary school students in **amen, China. Although the randomly chosen schools appared to be representative and we do not believe that the sample size has biased our results, closer investigation about their representation needs to be done in the future. We were aware of this limitation, and we encourage scholars and practitioners to conduct more extensive surveys to obtain more representative results.

Conclusion

The injury incidence among elementary and secondary students in **amen is lower than Guangdong and Zhejiang but high er than Bei**g and Shanghai. Injuries cause enormous economic and familial burdens and threaten students’ health and life. Childhood and adolescent injuries have become a serious public health problem and require the urgent attention of the government, society, schools, and families.