This is the multicentric cross-sectional fifth survey of a surveillance program entitled “Childhood and Adolescence Surveillance and Preventهon of Adult Non- communicable disease” (CASPIAN V) study (2015). Detailed methodology and executive procedures described previously [22], here we point to essential subjects.
Study participants
Using a multistage, stratified cluster sampling method, the study participants consisted of children and adolescents aged 7–18 years from primary and secondary schools of urban and rural areas of the country. We designed the proportional to size sampling method with equal sex ratio. Aim to that, within each province; the student's place of residence (urban or rural) and level of education (primary and secondary) applied.
Questioning procedures
Based on the World Health Organization- Global School-based student Health Survey (WHO-GSHS), two specific sets of questionnaires were developed for students and their parents. The student's questionnaire was obtained from the WHO-GSHS that was translated into Persian. The validity and reliability of questionnaires have been confirmed previously. After explaining the aims of the study and executive procedure, we obtained written informed consent from the parents and oral agreement from the students.
Definitions
Bullying assessed through questioning about: “During the past 3 months, how often did you bully at school?”. The possible choices defined as: “None” (considered as no), “One to two times” (considered as yes), “Two to three times” (considered as yes) and “Four times or more” (considered as yes) [23, 24].
According to the Global School-based Student Health Survey (GSHS) questionnaire of psychiatric distress and violent behaviors, victim detected by questioning on “During the past 3 months, how often did you get bullied at school?” The response choices categorized as; “None” (considered as no), “One to two times” (considered as yes), “Two to three times” (considered as yes) and “Four times or more” (considered as yes) [23, 24].
The methods and variables of calculating the family SES selected based on the categories approved in the Progress International Reading Literacy Study (PIRLS) for Iran[25]. The SES data was extracted from the parents' questionnaire. The participants' SES was determined based on the results of principle component analysis (PCA) variables of parents' education, occupation, possessing a private car, their school type (public/private), home type (private/rented) and having a personal computer at home. The SES score was a weighted average of the SES variables that were summarized under one main component of SES score. A lower score corresponded to a lower SES. The calculated score was categorized into tertiles to define SES levels. The first tertile was considered ‘low’, and the second and third ones as ‘middle’ and ‘high’ SES, respectively[24].
- Life dissatisfaction (LS)
To evaluating the Life dissatisfaction (LDS), the participants were asked to express their degree of life satisfaction according to a tenth-point scale from 1= very dissatisfied to 10 = very satisfied. Based on the results, below 6 scores considered as Life dissatisfaction (LDS) [26, 27].
Self -rated health (SRH) of students were assessed through questioning about “How would you describe your general state of health?” The response choices categorized as; “perfect,” “good,” “moderate,” and “bad” [26, 27]. We summarized the responses as either 'not poor'
(perfect or good) or 'poor' (moderate or bad) SRH
Statistical analysis
Quantitative variables are expressed as mean and standard deviation (SD) and qualitative variables as number (%). Chi-square test was used to compare the self -rated health, life satisfaction, and violent behaviors across the socioeconomic status variables. The association of socioeconomic status variables and violent behaviors, self -rated health, life satisfaction, evaluated using different logistic regression models. Model I was a crude model (without adjustment); in model II, the association was adjusted for all socioeconomic status variables and age, simultaneously. All statistical analyses were conducted based on survey data analysis methods. Data were analyzed using the STATA package V.11.0 (Stata Statistical Software: Release 11. College Station, Texas, USA: StataCorp LP Package) and a p-value <0.05 was considered significant.
Ethical concerns
Study protocols were approved by ethical committees and other relevant national regulatory organizations. The Research and Ethics Council of Isfahan University of Medical Sciences approved the study (Project Number: 194049). After a complete explanation of the study objectives and protocols, written informed consent and verbal consent were obtained from the parents and students, respectively.