Rural and urban environmental exposures and the risk of progressive pulmonary fibrosis
Background: Non-occupational exposures are increasingly recognized as a driver of poor outcomes in patients with interstitial lung disease (ILD), including urban and rural populations. However, both populations also experience barriers to care and higher social vulnerability that may be associated with higher risk for progression. The impact of agricultural antigen exposure and concomitant social vulnerability has not been well characterized. Objectives: To evaluate the risk of progression in both urban and agricultural antigen-exposed communities in patients with ILD. Design: Retrospective cohort study. Methods: We identified individuals with a diagnosis of ILD in a large health system. Proximity to agricultural antigens was mapped utilizing satellite-derived crop data. Residence in a community impacted by structural disadvantage was estimated using the social vulnerability index (SVI). We used geographically weighted regression analysis to estimate the risk of progression, defined as a greater than 10% relative decrease in forced vital capacity within the 24 months from first documented diagnosis. Results: Residence in a high SVI community was associated with an increased risk of disease progression by FVC criteria in both agriculturally exposed and urban communities. The greatest risk of progression was seen in those residing in high SVI, rural communities (HR 1.19, CI: 1.09–1.31). Conclusion: Within a large cohort of geographically diverse patients with ILD, residential social vulnerability increased the risk of ILD progression with effects similar in individuals with agricultural antigen exposure and urban exposures.