Optimal Scale of Greenspace Exposure for Pulmonary Tuberculosis Treatment Success: Multi-scale Associations and...

Environmental exposures, particularly air pollutants, are important determinants of pulmonary tuberculosis (PTB) incidence and mortality. However, limited evidence exists on whether greenspace exposure influences PTB treatment outcomes, and little is known about how such effects vary across spatial scales or interact with air pollutants during treatment. This study examined the scale-specific associations between greenspace exposure and PTB treatment success and assessed whether greenspace modified the associations between air pollutants and treatment outcomes within 250, 500, and 1250 m residential buffers. Using data from 82,784 PTB cases in Zhejiang Province, we applied multivariate Cox proportional hazards models to estimate associations between greenspace exposure and treatment success across multiple spatial scales. Interaction analyses were further conducted to evaluate the joint effects of greenspace and air pollutants on PTB treatment outcomes. Greenspace exposure within the 1250 m buffer showed the strongest positive association with PTB treatment success. Compared with patients in the lowest quintile of greenspace exposure, those in the fourth quintile within the 1250 m buffer were significantly more likely to achieve treatment success (HR = 1.0701, 95% CI: 1.04 - 1.10). Significant positive interactions were also observed between greenspace and SO₂, with stronger interaction effects at the 1250 m scale than at the 250 m and 500 m scales. These findings suggest that the association between greenspace exposure and PTB treatment success is both scale-dependent and nonlinear, with the strongest benefit observed for fourth-quintile exposure within the 1250 m residential buffer rather than at the highest exposure level. By revealing the multi-scale and interactive roles of greenspace in PTB treatment outcomes, this study provides new evidence to support the integration of greenspace planning and air quality management in urban health strategies for infectious disease recovery.