Associations of neighborhood greenness with objectivity measured physical activity in urban and rural middle school youth

Introduction: Green neighborhoods may be important for promoting youth physical activity (PA) by supporting an active community design. However, little research has simultaneously explored multiple measures of greenness or differences between urban and rural youth. This study examined relationships between normalized difference vegetation index (NDVI), tree canopy, and land cover with objectively-measured PA in urban and rural youth.

Methods: PA data were collected for urban and rural middle-school youth (n=303) in 2 counties in North Carolina using ActiGraph accelerometers set at 30-second epochs. Average sedentary, light, and moderate-to-vigorous (MVPA) minutes/day were calculated for youth with four, 10-hour valid wear days. ArcGIS10 was used to calculate mean NDVI, tree canopy, and percentage low (20-49%), medium (50-79%), and high (80-100%) developed land cover for each participant’s 0.5-mile network neighborhood. Stratifying by urban versus rural, multiple linear regression examined associations between each neighborhood greenness measure and PA variable.

Results: Rural youth averaged more sedentary (630 min/day) and light (382 min/day) but less MVPA (27 min/day) activity than urban youth (586, 323, 31 min/day respectively). There were no significant associations between greenness measures and PA for urban youth. However, among rural youth, the percentage of low intensity developed land cover was negatively associated with average sedentary minutes/day (β=-.037,p<0.05), while percentage of tree canopy was positively associated with MVPA (β=0.15,p<0.05).

Conclusion/Discussion: Neighborhood greenness may be a vital quality of active neighborhoods. Future research should explore the specific dimensions of developed and green environments that contribute to greater PA and health among youth from diverse settings.