Relationships between Traumatic Symptoms and Environmental Damage Conditions among Children 8 Months after the 2011 Japan Earthquake and Tsunami

Background To evaluate relationships between traumatic symptoms and environmental damage conditions among children who survived the 2011 Great East Japan Earthquake and Tsunami. Methods The subjects were 12,524 children in kindergartens, elementary schools, and junior high schools in Ishinomaki City, Miyagi Prefecture, Japan. The Post Traumatic Stress Symptoms for Children 15 items (PTSSC-15), a self-completion questionnaire on traumatic symptoms, was distributed to the children and a questionnaire regarding environmental damage conditions affecting the children was distributed to their teachers. Of 12,524 questionnaires distributed, an effective response was obtained from 11,692 (93.3%). Results The PTSSC-15 score was significantly higher in females than in males among 4th to 6th grade students in elementary schools and among junior high school students. In terms of traumatic symptoms and environmental damage conditions, with the exception of kindergartners, children who had their houses damaged or experienced separation from family members had a significantly higher PTSSC-15 score than children who did not experience environmental damage. Except for kindergartners and 4th- to 6th-grade elementary school students, children who experienced evacuation had a significantly higher PTSSC-15 score. Conclusions This study demonstrated relationships between traumatic symptoms and environmental damage conditions in children who had suffered from the disaster. Factors examined in studying the relationship between environmental damage conditions and traumatic symptoms were gender, age, house damage, evacuation experience, and bereavement experience. It was critical not only to examine the traumatic symptoms of the children but also to collect accurate information about environmental damage conditions.

We collected information on the traumatic symptoms and environmental damage conditions experienced by children who lived through the earthquake and tsunami eight months after the disaster (November 2011). The information included: gender, age, and environmental damage conditions. This was gathered in the hope of enabling the investigation of relationships between environmental damage conditions and traumatic symptoms eight monthsafter exposure [8,20,26].
The aim of this study was to evaluate relationships between traumatic symptoms and environmental damage conditions in children eight months after the earthquake and tsunami.

Study Design and Setting
This study involved the observation of relationships between traumatic symptoms and environmental damage conditions among children after the 2011 Japanese earthquake and tsunami. Ishinomaki City is the second largest city (population, 162,822) in Miyagi Prefecture, Japan. As of February 15, 2012, the death toll in Ishinomaki City was 3,182 and 557 people were missing. The total number of collapsed houses and buildings, including halfcollapsed houses, was 33,378 and 7,298 temporary houses had been constructed.

Recruitment and Participants
This survey was conducted as part of the school education program under the initiative of the Board of Education in Ishinomaki City. Surveys were distributed to all children who attended five kindergartens, 43 elementary schools, and 21 junior high schools in Ishinomaki City, Miyagi Prefecture. The survey was carried out in November 2011 (eight months after the earthquake disaster) after temporary houses had been provided for all evacuees in need in Ishinomaki City and after all evacuation centers had been closed.
First, the survey method was explained to the principals of all of the schools by the Education Committee of Ishinomaki City. Then teachers distributed a letter explaining the survey, which had been constructed by the Education Committee, to all children and their parents. The letter clearly stated that the students' filling out the questionnaire would be considered for both the parents and the students as having given consent to the survey. The letter also specified that the survey results would be used to provide children with psychological care to facilitate their education at school and that the results would be published as a medical paper. Informed consent was obtained when the students filled out the questionnaire. This consent procedure was approved by the ethical committee of the National Center for Global Health and Medicine.
The Posttraumatic Stress Symptoms for Children 15 items (PTSSC-15), a self-completion questionnaire on traumatic symptoms, was distributed to 12,524 children registered at municipal schools in Ishinomaki City, and a questionnaire on the environmental damage experienced by the children was distributed to their teachers. Parents of kindergartners and 1 st -to 3 rd -grade elementary school students were asked to fill out the questionnaire while talking with their children. Informed consent for participation in the survey was obtained at the time that the completed questionnaires were received from the children. Answers were returned from 12,346 (98.6%) of the 12,524 children to whom questionnaires were distributed. Of the 12,346 children, effective response was obtained from 11,692 (93.3%). Answers for environmental damage with regard to all 12,524 children were returned from teachers.

Measures
A paper-based survey was conducted, asking questions regarding traumatic symptoms using a self-report form.
The self-report form consisted of the PTSSC-15 and a daily life questionnaire developed by the authors. The teacher-report form consisted of a disaster situation questionnaire for each student developed by the authors.

PTSSC-15
The PTSSC-15 is a self-completion questionnaire on the stress reactions in children after disasters. Posttraumatic Stress Symptom 10(PTSS10) [27] had fewer questions and was used as a screening test after the Hanshin Great Earthquake and is familiar in Japan [21]. In 105 Norwegian children (6-17 years old) devastated by the 2004 South East Asia Tsunami, PTSS10 was administered 10 and 30 months after the disaster [28]. Five questions that were considered to be important psychosomatic characteristics after disasters (flashback, appetite loss, somatic reaction such as headache and abdominal pain, attention deficit, and anxiety) were added to the PTSS10, and the PTSSC-15 consisting of 15 questions was constructed in Japan [29].
Each question is scored in six levels: 0 = completely disagree, 1 = mostly disagree, 2 = partially disagree, 3 = partially agree, 4 = mostly agree, and 5 = completely agree. Higher scores indicate more severe traumatic symptoms and depressive symptoms. Kishi et al [29] demonstrated the reliability and validity of the PTSSC-15 for Japanese children and adolescents. The cut-off value for the     presence of PTSD or being at high risk for PTSD is 23 points in Japan [29].

Environmental Damage Conditions
The authors and the educational committee in Ishinomaki City developed the questionnaire regarding environmental damage conditions experienced by the subject children. The form was designed to be completed by teachers. It asked about the conditions of disaster damage, bereavement experience, and life in evacuation centers. With regard to the environmental damage conditions of the children's houses, one of the following three answers was selected: ''no damage'', ''total collapse by the earthquake or tsunami (incapable of living in the house)'', ''half collapse by the earthquake or tsunami (necessary to repair the house in order to live in it)''.
Regarding the living conditions in evacuation centers, multiplechoice questions and answers were selected from the following options: ''no experience'', ''currently living in the evacuation center'', ''used to live in the evacuation center'', ''living in a temporary house'', and ''used to live in a temporary house''.
As to the bereavement experience (including the experience of unexplained disappearance due to the earthquake), multiple answers were allowed from the following eight responses: ''no experience'', ''father'', ''mother'', ''brothers and sisters'', ''grandfather and grandmother'', ''kindergarten and school classmates at the time of the earthquake'', ''teacher in charge of the class at the time of the earthquake'', and ''others''.

PTSSC-15, School Grades, and Gender
Children were divided into four grade groups: kindergartners, lower-grade (1 st to 3 rd grade) elementary school students, highergrade (4 th to 6 th grade) elementary school students, and junior high school students (7 th to 9 th grade). In each grade group and gender, the median PTSSC-15 score, and interquartile range were determined. The PTSSC-15 score was statistically compared between males and females by the Mann-Whitney U test for each grade group. Effect sizes were calculated based on the Mann-Whitney statistics.

PTSSC-15 and Environmental Damage Conditions
With regard to environmental damage conditions, the house damage, evacuation conditions, and bereavement experience were examined. Then the average PTSSC-15 score in each grade group and gender was calculated. As to the bereavement experience, the average PTSSC-15 score was calculated separately in the subjects who experienced bereavement. Children were categorized by house damage, evacuation conditions, and bereavement experience, and the difference in the average PTSSC-15 score between the groups was statistically analyzed by two-factor analysis of variance in each grade group and gender. In addition, the number of disaster experiences (house damage, evacuation conditions, and bereavement experience) of the children was examined and compared with the average PTSSC-15 score in each gender.
In all tests, a significance level of 0.05 was used in two-sided tests. Analyses were performed using PASW 18.0.

Descriptive Information
The participants included 11,692 children [5959 males, 5733 females] who were exposed to the 2011 Japanese earthquake and tsunami. Table 1 shows the gender, score of PTSSC-15, age, and environmental damage conditions (house damage, evacuation conditions, and bereavement experience) in 11,692 children. When teachers had no information about house damage, evacuation conditions, and bereavement experience, the answer was defined as ''unknown''.
Traumatic Symptoms, Gender, and Age Table 2 shows the average PTSSC-15 score in each grade group and gender. The PTSSC-15 score was significantly higher (p,0.001) in girls than in boys in the higher grade of elementary schools and junior high schools. These effect sizes were under 0.20.

Traumatic Symptoms and Environmental Damage Conditions
For comparison of traumatic symptoms and environmental damage conditions, the variables of house damage, evacuation experience, and bereavement experience were examined individually. The average PTSSC-15 score and having experienced house damage were compared in each grade group and gender (Table 3). Children in all age groups, except kindergartners, who had house damage had a significantly higher PTSSC-15 score than children without it (F(1,3567) = 54.63, p,0.001; F(1,3951) = 6.126, p,0.0013; F(1,3864) = 5.86, p,0.0016).
With regard to the evacuation experience, the relationship between the average PTSSC-15 score and evacuation experience is shown in Table 4 in each grade group and gender. Except kindergartners and higher-grade elementary school students, children who had evacuation experience showed a significantly higher PTSSC-15 score than children without it (F(1,3539) = 52.75, P,0.0001; F(1,3818) = 9.60,P,0.002).
Regarding the bereavement experience, the average PTSSC-15 score and bereavement experience are shown in Table 5  In addition, Table 6 shows the average PTSSC-15 score in children who had experienced the loss of various relationships. Table 7 shows the number of disaster experiences and the average PTSSC-15 score for each gender (F(3,11608) = 34.98, p,0.0001). There was a significant difference in the PTSSC-15 score with and without disaster experience and between males and females (F(3,11608) = 52.40, p = ,0.0001).

Discussion
This study showed relationships between traumatic symptoms and environmental damage conditions in children who had experienced damage and loss eight months after a severe natural disaster.
The number of children with a PTSSC-15 score higher than the cut-off value was 42.6%. Using only a self-completion questionnaire as a screening tool for PTSD after a huge disaster may result in an inflated number of children who appear to be at high risk for PTSD. Collecting information about the environmental damage experienced by the children and correlating that with their scores on the questionnaire may result in a more accurate prediction of which children are at high risk for PTSD.
Differences in traumatic symptoms due to gender and age were recognized in this study. According to the effect size, the difference due to gender is negligible, but difference due to age is large. The responders in the case of kindergartners and lower-grade elementary school students were the parents, and there is a possibility that not only the status of the children but also the psychological anxiety and status of their parents affected the responses. Therefore, it is necessary to comprehensively judge the status of children by considering not only their psychological status but also the psychological conditions of their parents.
We found that there were more severe traumatic symptoms in children who had experienced house damage and evacuation. House damage and evacuation experience as a result of the tsunami and earthquake may have directly influenced the psychological condition of the children in this study.
Furthermore, we found that bereavement experience was closely related to traumatic symptoms of the children. In particular, the results of this study suggest that children who lost their mother had traumatic symptoms most frequently among children with bereavement experience, and disappearance of the mother may have a great influence on the emotional growth of the child.
In studies on children after disaster damage, in addition to evaluating their direct experience of the earthquake and tsunami with regard to its size and magnitude, the impact of house damage, evacuation conditions, bereavement experience, and changes in family composition by the earthquake disaster, should be carefully investigated.

Limitations
This study was a survey with a self-completion questionnaire carried out in only one district in Japan and it is impossible to calculate the morbidity of PTSD in children after the 2011 Japanese earthquake and tsunami based on the results of the survey. Therefore, this study is insufficient as an epidemiological survey for psychiatric diagnosis. Examinations by child psychiatrists using operational diagnostic criteria and structured interviews are necessary for accurate psychiatric diagnosis. Moreover, the results of this study on children in Ishinomaki City do not reflect all characteristics of children who experienced the 2011 Japanese earthquake and tsunami.

Conclusion
This study elucidated relationships between traumatic symptoms and environmental damage conditions in children who survived the earthquake and tsunami. It is important not only to evaluate the traumatic symptoms with a self-completion questionnaire but also to confirmspecific information about the extent of environmental damage conditions that the children experienced after the disaster.