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A3547 - Validity of the Global Physical Activity Questionnaire in Older Adults with Chronic Obstructive Pulmonary Disease
Author Block: S. Gore1, J. Blackwood2, A. Goldberg2, M. H. Huang2, M. Shoemaker2; 1Physical Therapy, MGH Institute of Health Professions, Charlestown, MA, United States, 2Physical Therapy, University of Michigan-Flint, Flint, MI, United States.
Rationale: Physical activity (PA) is a major independent, modifiable risk factor that has a protective effect on health outcomes in chronic obstructive pulmonary disease (COPD). Population-based survey of PA has been an important part of global health initiatives. Subjective measures of PA are widely used in population surveillance, owing to their relatively low cost, higher clinical utility and low burden on participants. The Global Physical Activity Questionnaire version 2 (GPAQv2) is one of the most commonly used PA questionnaires which has been recommended by the World Health Organization for PA surveillance globally across countries. At this time, there is a lack of population-based studies to assess the validity of this tool in older adults with COPD. The purpose of this study was to examine the construct validity of the GPAQv2 using population-based data from a cohort of older adults with COPD. Methods: All individuals age 65 and older who were interviewed in the National Health and Nutrition Examination Survey (NHANES) between the years 2007 and 2012 were included for this study. Individuals with COPD were identified from this group based on self-report of diagnosis and from spirometry values. The GPAQv2 was used to assess the total weekly PA expressed in metabolic equivalent (MET) minutes per week. Known-groups validity was assessed by testing the ability of GPAQv2 to identify the presence or absence of COPD among all older adults (N = 4329) included in the sample. Associations between related constructs of PA in COPD (lung function and shortness of breath) and GPAQ scores were examined to assess convergent validity in a group of older adults with COPD (N = 636). For discriminant validity, associations between GPAQ scores and an unrelated construct of total household income were examined. Results: The GPAQv2-derived total PA, sedentary time and activity levels were unable to explain the variance in all the main outcomes indicating a lack of known-groups and convergent validity. GPAQv2 demonstrated poor correlation with household income indicating the presence of discriminant
validity. Conclusions: The GPAQv2 did not demonstrate construct validity in the sample of older adults with COPD. Future research is needed to assess the validity of GPAQv2 in older adults with COPD by age and disease severity. Future research to establish validity of GPAQv2 against objective reference standards such as accelerometers is also warranted.