Fine particulate matter exposure and initial Pseudomonas aeruginosa acquisition in cystic fibrosis

Rationale: Increasing evidence suggests that exposure to ambient air pollution contributes to the severity of cystic fibrosis (CF) respiratory disease in school-age children and adults; however, the effects of air pollution on young children with CF are poorly understood. Objectives: To investigate the association of exposure to fine particulate matter less than 2.5 mmin aerodynamic diameter (PM_2.5) and initial Pseudomonas aeruginosa acquisition in young children with CF. Methods: Retrospective analysis of initial Pseudomonas acquisition in children 6 years of age or younger, using Cystic Fibrosis Foundation National Patient Registry data from 2003 to 2009. PM_2.5 exposure was estimated by inverse distance weighting methods based on air pollution monitors within 30 miles of place of residence, for the year before the patient's birth. Multivariable Weibull regression with interval-censored outcomes was done to evaluate the association of time to initial Pseudomonas acquisition and PM_2.5 concentrations. Measurements and Main Results: A total of 3,575 children met inclusion criteria and 48% (n = 1,711) acquired Pseudomonas at a median age of 15 months (25th-75th percentiles, 9-25 mo). An increase in PM_2.5 exposure of 10 mg/m³ was associated with a 24% increased risk of Pseudomonas acquisition (95% confidence interval, 1-51%) during follow-up. Results were generally consistent across exposure metrics. Conclusions: These results suggest that increased PM_2.5 exposure is associated with earlier Pseudomonas acquisition in young children with CF and may play an important, previously unrecognized, role in the etiology of initial Pseudomonas infection.