Comparative Validity of Physical Activity Assessment Methods for Individuals with Schizophrenia

Abstract

Individuals with schizophrenia are less physically active than the general population. In order to accurately assess the relationship between health and physical activity (PA), identify PA determinants, and develop interventions, valid and reliable methods of assessing PA must be identified. Previous research has reported that the Short-Form International Physical Activity Questionnaire (IPAQ) demonstrates similar measurement properties in this population as it does in the general population. Cognitive deficits are common among individuals with schizophrenia, and 7-day recall may be challenging. PURPOSE: The purpose of this study was to replicate and expand on the initial validation study by examining reliability over a 4-week period, and to test whether a 24-hour recall protocol improved criterion validity correlation coefficients in comparison to 7-day recall. METHODS: One hundred and eight participants completed the IPAQ at baseline and 4 weeks later. Participants wore an Actigraph GT3X+ accelerometer on their waist for 7 days in the week prior to the final IPAQ administration. A 24-hour recall modification of the IPAQ was administered after the final IPAQ assessment. Spearman’s correlation coefficients were calculated based on the minutes of moderate to vigorous PA (MVPA) determined by each method of measurement. RESULTS: Test-retest reliability for the self-administered IPAQ was ρ=.47, p<.001 for total minutes of moderate to vigorous PA. Correlation between the final IPAQ assessment and objectively measured PA was ρ=.31, p=.002. MVPA reported in the 24-hour recall correlated significantly with MVPA on the previous day ρ=.24, p=.041. CONCLUSIONS: Compared to a previous validation study, IPAQ criterion validity was similar but less reliable over a four-week period. Notably, 24-hour recall was not associated with improved criterion validity correlation coefficients. Findings provide further support that the IPAQ may be suitable as a surveillance tool to assess levels of physical activity among individuals with schizophrenia. Overall, the IPAQ demonstrated similar measurement properties as that reported among the general population. Use of the IPAQ will help increase epidemiological research and may be a suitable assessment tool for health care providers. Supported by a CIHR Operating Grant