Large-scale greenway exposure reduces sedentary behavior: A natural experiment in China

As a global public health problem, sedentary behavior has attracted more and more attention. Although numerous studies have demonstrated many benefits of green spaces to health, causal evidence on how green spaces affect people's sedentary behavior is scarce. This study used a natural experiment to evaluate the impact of greenway intervention on sedentary behavior. Two waves of data were collected in 2016 and 2019 (before and after the intervention) at East Lake Greenway (102-km-long) in Wuhan, China, with 1020 participants in 52 neighborhoods. We adopted three major methods to evaluate the impact of greenway intervention on sedentary behavior, including Propensity Score Matching and difference-in-difference (PSM-DID) method (with both individual and neighborhood variables to match samples), continuous treatment DID method (with distance to the greenway as the continuous treatment), and mediation analysis (with moderate to vigorous physical activity or MVPA, and walking time as the mediator). The results revealed that the greenway intervention significantly reduced participants' sedentary time and the intervention has a distance decay effect. The closer to the greenway, the greater decrease in sedentary time after the greenway opening. Furthermore, we found that MVPA and walking time mediate the impact of the greenway intervention on the change in sedentary behavior. The effect of greenway intervention was more beneficial for those under the age of 60, those who were employed, or those who were married. Our findings provided robust evidence that exposure to urban greenways affects sedentary behavior and such green infrastructures help protect public health in high-density urban areas.