{Green walkability} and physical activity in UK Biobank

Abstract

BACKGROUND AND AIM: Urban greenspace provides opportunities for outdoor exercise and may increase physical activity levels, with accompanying health benefits. Walkability – a measure of an area’s suitability for walking – is also associated with increased physical activity, though is inversely correlated with greenspace cover. We aimed to integrate greenspace exposure into a walkability index and explore associations with physical activity in an urban adult cohort, UK Biobank. METHODS: We used cross-sectional data from UK Biobank cohort participants who resided in Greater London at baseline (2006-2010; N = 58,587). We assessed walkability within a 1000 m traversable network buffer surrounding each participant’s residential address to create a residence-based walkability index, which was scored on population density, street junction density, and business density in the network buffer. Additionally, we integrated vegetation cover (tree cover and low-lying vegetation cover) into this density-based walkability index to produce a {green walkability} index. We modelled associations of density-based walkability and {green walkability} with self-reported and accelerometer-measured physical activity, adjusted for individual and area-level confounders. RESULTS:Higher {green walkability} surrounding UK Biobank residential addresses in Greater London was associated with favourable International Physical Activity Questionnaire (IPAQ) responses, achievement of weekly UK government physical activity guideline recommendations, and increased time spent on moderate-and-vigorous physical activity (MVPA). For example, participants living in the highest versus lowest quintile of {green walkability} participated in 2.41 (95% confidence intervals: 0.22, 4.60) additional accelerometer-measured minutes of MVPA per day. Notably, however, associations of {green walkability} and self-reported physical activity outcomes were weaker compared to associations with density-based walkability. CONCLUSIONS:Our green walkability approach demonstrates the need to account for walkability and greenspace simultaneously to understand the role of the built environment on physical activity. KEYWORDS: Green space, Walkability, Built environment, Exposure assessment, Physical Activity, Accelerometer