Particulate Matter Associations with Lung Function in Pulmonary Sarcoidosis.

Rationale: Sarcoidosis is a multisystem disease with pulmonary manifestations in >90% of patients. Environmental exposures are associated with sarcoidosis incidence, but the impact on clinical outcomes remains understudied. Objectives: To evaluate the association of exposures to ambient particulate matter [Formula: see text]2.5 μm in diameter (PM2.5) with lung function outcomes in pulmonary sarcoidosis. Methods: PM2.5 and constituent exposures were obtained by matching monthly satellite-derived hybrid measurements to each patient's residential address obtained from the time of enrollment, averaged over 5 years before registry enrollment and censoring. Linear models evaluated associations of pollutants with baseline lung function (FEV1, FVC, FEV1/FVC ratio, and DlCO). Linear mixed effects models analyzed associations of pollutants with rates of lung function change (FEV1, FVC, and DlCO change per year of follow-up). Measurements and Main Results: Two prospectively enrolled cohorts of mostly middle-aged, White, and nonsmoking adults with specialist-diagnosed pulmonary sarcoidosis were used. The U.S. cohort (n = 400) experienced higher 5-year preenrollment median PM2.5 exposures (12.3 μg/m3) than the Canadian cohort (n = 112) (8.0 μg/m3). Each 1-μg/m3 increase in PM2.5 was associated with 0.93% predicted lower baseline FEV1 (95% confidence interval, -1.76 to -0.10; P = 0.03) and 1.53% predicted lower FVC (95% confidence interval, -2.26 to -0.79; P < 0.001) in the U.S. cohort, but the associations were not significant in the Canadian cohort. PM2.5, sulfate, nitrate, and ammonium were associated with accelerated FEV1, FVC, and DlCO decline in the U.S. cohort. Conclusions: PM2.5 was associated with worse pulmonary disease severity and progression in a higher-exposure cohort, highlighting the importance of exposure disparities in this population.