The current study is a cross-sectional comparative study. Exposure to adverse childhood experiences was the main variable which classified children into two groups: exposed and non-exposed. Behavior and cognitive abilities were the outcomes compared in the two groups. The study was conducted along the period from April 2015 to December 2016.
Calculation of sample size
There is a shortage of large-scale, international research on the prevalence of negative life events which may constitute potential childhood adversity. Vanaelst et al. [13] found that 53.4% and 40.3% of the children experienced at least one familial and social adversities or negative life events in 8 European countries, but this prevalence has changed by region and age group. No previous studies have estimated the prevalence of childhood adversity in Egyptian primary school children, so we are guessing that 50% of the primary school children aged 7–11 years have a history of childhood adversity.
Sample size is calculated using the equation published by Dawson-Saunders and Trapp:
$$ \mathrm{n}=\frac{\mathrm{t}2\times \mathrm{p}\times \left(1-\mathrm{p}\right)}{\mathrm{m}2} $$
where n = required sample size, t = confidence level at 95% (standard value of 1.96), p = estimated prevalence of the problem in the study area, and m = margin of error at 5% (standard value of 0.05).
Therefore, to detect a true difference of 5% with a confidence level of 95%, a power of 80%, and 10% losses, the assessment would require 60 children for each group (120 for both exposed group and non-exposed group).
The study was planned to recruit 120 students, but it was carried out on 114 students after the omission of subjects whose parents refused to participate.
Setting
This research was conducted within the framework of community services applied by the National Research Centre to El-Dokki inhabitants. Children were recruited from public primary schools located in El-Dokki district nearby the National Research Centre in Giza governorate. From a list of public primary schools in this district, a representative number of public schools (4 schools) were randomly chosen. In each school, children who had any chronic disease or any disability known to affect cognitive performance or impacting behavior were excluded [14, 15] (e.g., children with hearing or visual defects, children with history of neonatal traumatic brain injury or meningitis, children with endocrinal diseases or hormonal disturbances, or children with mental affection or motor disability). Then, a systematic random sampling of students from grade 3 to grade 5 was performed. Every 5th student in the class list was invited to participate till the sample size was completed.
Subjects
The invited students from both sexes who accepted to participate were recruited in the study. Their ages ranged from 7.5 to 11 years old. Younger children were not included because they were unable to answer the researcher’s questions in the pilot stage of this study. Similarly, older students were excluded to avoid the confounding effect of pubertal period on behavior. As well, children who had exposed to inevitable adversities were excluded (e.g., orphans).
Ethical concern
Approval by the Ethical Committees of the National Research Centre with the number (13-038), the Institute of Postgraduate Childhood Studies, and the Egyptian Ministry of Education was attained. In addition, written informed parental consents were obtained.
All children included in the study were subjected to the following.
A structured questionnaire for gathering relevant personal data
This questionnaire was filled out by the caregiver while the child was interviewed by the researcher. Data included name, age, sex, residence, maternal and paternal education and occupation, monthly income, and number of family members “for assessment of socioeconomic standard.” Thorough medical, perinatal, and developmental histories were obtained.
Adverse Childhood Experiences International Questionnaire
The original Adverse Childhood Experience Questionnaire (ACE-Q) was a short rating scale designed and first published by Felitti et al. [16]. It has provided a link between cumulative exposure of ACEs in subjects before the age of 19 and the development of adult physical and mental health problems [16]. ACE event scores were measured for neglect, abuse (physical, sexual, and emotional), and household dysfunction. Respondents were adults, parents of children, or youth themselves. Many questionnaires have been developed after the first ACE questionnaire. All of them were similar in core content and scoring methods and showed consistent associations with poor health outcomes. However, important variations in results of these tools were detected due to different nationalities, cultural background, economic status, age, gender, and professional groups examined [17]. An international questionnaire was developed by the WHO (ACE_IQ). This questionnaire was field tested in seven countries (China, the Former Yugoslav Republic of Macedonia, Philippines, Thailand, Saudi Arabia, South Africa, and Vietnam). In each country, the ACE-IQ was translated including back-translation into one official language. Respondents were all aged 18 years and over. Questions cover family background, household dysfunction; physical, sexual and emotional abuse and neglect by parents or caregivers; peer violence; witnessing community violence; and exposure to war or collective violence. It was shown that most of its items were easily understood by respondents and easily delivered by interviewers. The aim of the production of this standardized international questionnaire was to reflect the range of adversity prevalence across low-, middle-, and high-income countries. ACE-IQ is being validated through trial implementation as part of broader health surveys [18].
The ACE-IQ also enables the measurement of childhood adversities in all countries and allows comparisons between them, and to assess the associations between childhood adversities and health-risk behaviors and health outcomes in later life [18]. Although ACE-IQ is considered a good standardized measure of ACEs, potential distortion of results could exist due to memory defects, as the respondent is trying to remember old events.
ACE-IQ in the current study
In the current study, authors tried to avoid the effect of memory by asking children about the current ACE using the standardized measure (ACE-IQ). Some questions concerned with marriage, work, war, and community violence were omitted from the original form to be appropriate for young age students. Arabic translation of the questionnaire with back translation was achieved by peers efficient in the English language. The questionnaire comprised 23 questions with 4 responses for each question indicating the degree of exposure. The questions’ responses include never, once, few times, and many times. Exposure to one adversity is considered when the student’s response is many times, except for sexual abuse. Each student was face to face interviewed to answer the questionnaire. Duration of interview ranged from 20 to 30 min.
According to the number of adversities to which the student was exposed, subjects were classified into two groups: group A, the less exposed group including students who were exposed frequently to one or two adverse experiences, and group B, the highly exposed group including students with frequent or multiple exposure to more than three adverse experiences.
Assessment of socioeconomic standard
This was done according to the socio-economic level of the Egyptian family scale of Abd Elaziz El Shakhs [19]. It is based on parental education and occupation and family monthly income.
Behavioral screening using the Pediatric Symptom Checklist-17
PSCL was designed to facilitate the recognition of emotional and behavioral problems so that appropriate interventions can be initiated as early as possible. The PSC-17 consists of 17 items that are rated by parents as “never,” “sometimes,” or “often” present. A value of 0 is assigned to “never,” 1 to “sometimes,” and 2 to “often.” The total score is calculated by adding together the score for each of the 17 items. A PSC-17 score of 15 or higher suggests the presence of significant behavioral or emotional problems. Three subscales are recognized within the PSC: the PSC-17 Internalizing Subscale (cutoff score of 5 or more), the Attention Subscale (cutoff score of 7 or more), and the Externalizing Subscale (cutoff score of 7 or more) [20].
Cognitive functions assessment
Cognitive and intellectual functioning was assessed through the application of the Wechsler Intelligence Scale for Children (WISC-R), the Arabic version [21]. It is an individually administered intelligence test for children between the ages of 6 and 16 years. It is designed to assess and measure the child’s verbal, performance, and full-scale IQ through assessment of different functions (short- and long-term memory, comprehension, information, abstract thinking, problem-solving, and speed of information processing).
Statistical analysis
The data was collected and analyzed on personal computer using the Statistical Package for the Social Science (SPSS) version number 18. Description of quantitative (numerical) variables is in the form of mean ± standard deviation and range. Qualitative (nominal) variables were in the form of number and percentage. Student’s t test of 2 independent samples was used to compare 2 quantitative variables. Odds ratio was used to estimate the risk of developing abnormalities in relation to multiplicity of exposure. A P value of < 0.05 was considered significant.