Can Sidewalk and Crosswalk Availability Strengthen Association Between Physical Activity and National Walkability Index

The majority of U.S. adults do not meet the recommended amount of weekly physical activity. Urban design researchers have studied micro and macro scale features to understand if physical activity, mainly walking, can be bolstered with different initiatives. These studies have resulted in mixed findings. We used a large cross-sectional sample spanning the U.S. from the INSPACE collaborative to quantify the association between neighborhood context, as measured by sidewalk availability, crosswalk availability, and the National Walkability Index, and accelerometer measured physical activity. We set thresholds for moderate to vigorous physical activity and averaged them by day to generate the outcome measure. We estimated the association between context and activity using linear regression to adjust for individual-level age and sex and neighborhood-level income. When using a threshold dependent on age, location of device, and type of device, we found that on average an increase in sidewalk availability by 10% increased mean MVPA per day by approximately 0.63 minutes (95% robust CI: 0.06-1.2). The significance of this relationship held when adjusting for the National Walkability Index. However, when we performed a sensitivity analysis with an age-agnostic threshold, the association between neighborhood context and physical activity weakened whereas the age parameter strongly predicted physical activity. We uncovered an association between sidewalk availability and physical activity; however this could be an artifact of our age-dependent threshold defining moderate to vigorous physical activity per day. Nonetheless, our findings suggest further research on micro scale features may better illuminate determinants of neighborhood walking.