Are physical activity and everyday mobility independently associated with quality of life at older age?

Background: Physical activity and everyday mobility are concepts that overlap but tend to be located in different disciplinary fields. We used the English Longitudinal Study of Ageing (ELSA) to: identify whether physical activity and everyday mobility are separate constructs at younger (60-69) and/or older (>=70) age bands, and for men and women; derive measures of the two constructs from variables in the ELSA; and assess whether they are independently associated with quality of life (QoL). Methods: We derived composite measures for physical activity and everyday mobility from ELSA variables. 'Physical Activity' combined items recording directly-measured activity for movement (walk-speed) and self-report measures of physical mobility difficulties and amount of vigorous, moderate and mild physical activity undertaken. 'Everyday Mobility' combined self-report responses about activities likely to involve leaving the house. QoL was measured using the 'CASP-19' scale. Using Wave 9 of ELSA (data collection in 2018-2020), we used a factor analysis to explore the constructs, and a regression analysis to examine associations with QoL. Results: The factor analysis confirmed that these were discrete constructs, which explained between them 36% of the variance. This was robust across age bands, and in factor analyses for men and women separately. The regression analysis identified that lower physical activity and everyday mobility are independently associated with lower QoL, when controlling for a range of contextual variables including age. Conclusions: Findings suggest that a social model of QoL at older age should focus on the broader mobility determinants of QoL as well as individual levels of physical activity.