Background: Little experience exists on valid and reliable tools for assessment of the determinants of underweight and overweight in children and adolescents living in the Middle-East and North Africa (MENA). This study aimed to develop a valid and wideranging questionnaire for assessment of these parameters in a nationwide sample of Iranian children and adolescents.
Methods: This national study was conducted in 31 provinces in Iran. The first phase consisted of focus group discussion with 275 children and adolescents and their parents. After a qualitative content analysis, the initial items were extracted. In the next step, the face validity was assessed by expert panelists using the quantitative method of the Impact Score. To assess the content validity, the content validity rate (CVR) and the content validity index (CVI) were determined. The internal consistency was examined by Cronbach alpha, and its test-retest reliability was determined. The socio-demographic variables, perinatal factors, lifestyle factors, family history, knowledge and attitude were assessed. Dietary intakes were assessed by a validated 168-item semi-quantitative food frequency questionnaire. A validated questionnaire for quality of life was filled in anonymously.
Results: A team of expert researchers conducted the data analysis of 576 interviews by using qualitative content analysis method. The analysis process began by determining the semantic units about the concepts studied. The initial questionnaire was developed in four domains by including Likert scale questions. In the face validity step, all questions of the primary questionnaire obtained a score of more than 1.5. In the phase of CVR assessment, 6 questions obtained a score of less than 0.62, and were omitted. The rest of questions were assessed for CVI, and got a score of more than 0.75. Cronbach's alpha coefficient of the whole questionnaire was 0.97, and the Pearson correlation coefficient of the test-retest phase was 0.94.
Conclusion: The developed questionnaire is a valid and reliable tool for assessment of the determinants of weight disorders in a nationally representative sample of children and adolescents in the MENA.
Keywords: Children and adolescents; overweight; questionnaire validity; underweight.