Assessment of validity and reliability of questionnaire “compendium of physical activity” validation of the Danish for national cohort study of non-communicable diseases common in East Azarbaijan Province

Abstract

Background: Accurate self-report questionnaires to assess physical activity are conceptually important to evaluate associations between physical activity and disease outcomes in population-based studies .Noticing the importance of measuring physical activity in population level, this study was conducted to assess the psychometric properties of a self-report physical activity questionnarie for the pilot phase of the AZAR Cohort study. Methods: In this cross-sectional study, all 35-70 years old people living in Khameneh, a city in East Azarbaijan, Iran were invited to take part in the pilot phase of the AZAR Cohort study. A total of 952 people completed the selfreported physical activity questionnaire. Exploratory and confirmatory factor analysis (EFA and CFA) and known groups analysis were conducted to evaluate construct validity. Spearman’s correlation coefficient between scores of two scales was used to examine concurrent validity. Reliability was measured using Intraclass Correlation Coefficient (ICC) and Cronbach’s alpha coefficient. Data analysis was done using SPSS software version 23 and Amos version 23. Results: In EFA applying principal component analysis with varimax rotation, four factors were identified including recreational leisure time (variance = 52.73%), sedentary leisure time (variance = 38.68%), household/gardening work (variance = 38.66%), and occupation work (variance = 12.67%), were identified. The extracted factors were also supported by the CFA (CFI = 0.98, GFI = 0.936, RMSEA=0.057). The results indicated moderate concurrent validity (ρ = 0.62, P < 0.001). Further, total scores differentiated between the groups defined by job, marital status, and education levels (P < 0.05). ICC and Cronbach’s alpha were 0.59 and 0.7, respectively. Conclusion: These results showed acceptable and moderate psychometric properties of the self-reported physical activity questionnaire to assess physical activity in this population-based study.