A study of community design greenness and physical activity in children using satellite GPS and accelerometer data

摘要

This study examined relationships between greenness exposure and free-living physical activity behavior of children in smart growth and conventionally designed communities. Normalized Difference Vegetation Index (NDVI) was used to quantify children’s (n=208) greenness exposure at 30-second epoch accelerometer and GPS data points. A generalized linear mixed model with a kernel density smoothing term for addressing spatial autocorrelation was fit to analyze residential neighborhood activity data. Excluding activity at home and school-time, an epoch-level analysis found momentary greenness exposure was positively associated with the likelihood of contemporaneous moderate-to-vigorous physical activity (MVPA). This association was stronger for smart growth residents who experienced a 39% increase in odds of MVPA for a 10^th to 90^th percentile increase in exposure to greenness (OR=1.39, 95% CI 1.36–1.44). A subject-level analysis found children who experienced >20 minutes of daily exposure to greener spaces (>90^th percentile) engaged in nearly 5 times the daily rate of MVPA of children with nearly zero daily exposure to greener spaces (95% CI 3.09–7.20).