How race, ethnicity, and income moderate the relationship between urban vegetation and physical activity in the United States

Abstract

To facilitate physical activity interventions, researchers identify which factors associate with physical activity, such as vegetation levels of the surrounding environment. While most studies examining vegetation and physical activity find a positive correlation, the literature does not investigate how vegetation may have a varied effect on physical activity based on demographic composition. This study examined how race, ethnicity, and income moderate the relationship between both non-tree vegetation and tree canopy on the percentage of individuals participating in leisure-time physical activity per census tract. Physical activity data from 2013 to 2014 for 7842 census tracts across 25 US cities originated from the CDC's 500 Cities project. Aerial images from the USDA's National Agriculture Imagery Program were used to classify vegetation levels per tract. Demographic variables originated from the American Community Survey 2011–2015 5-year estimates. Tracts were stratified into four types (Black + low income, Hispanic + low income, White + high income, and remaining) and assessed through multilevel modeling as to whether tract type moderated the relationship between vegetation and physical activity. Results showed that non-tree vegetation negatively associated with physical activity across all census tract types, while tree canopy exhibited a mixed association with physical activity, based on tract type. These findings can spur further research into how vegetation impacts physical activity of different demographic groups, and potentially inform greenspace and tree planting installments in those areas at greatest risk for physical inactivity-related diseases.