Introduction:The detrimental role of air pollution on idiopathic pulmonary fibrosis (IPF) has been shown in various studies. The adverse effects of pollution may be modulated by genetic background. The MUC5B polymorphism is associated with IPF incidence and also a good prognostic factor. The aim of this study was to investigate the impact of pollution on IPF survival according to MUC5B status.

Methods:Patients were selected from the French prospective multicentre IPF cohort (COhorte FIbrose, COFI). Exposure level to O3, NO2, PM2.5, PM10 came from the nearest air quality station of the patient's residence. Analysis of the MUC5B rs35705950 polymorphism was performed. A Cox model, adjusted for FVC and age, was used to estimate the impact of pollution on survival according to MUC5B status.

Results: Of the 236 patients included in COFI, 117 had MUC5B polymorphism analysis and pollution exposure data available. Thirty-eight (33%) patients had a GG allelic status, 63 (54%) GT and 16 (1%) TT. Mean exposure levels were comparable regardless of allelic status. Patients with at least one T allele had a better median survival (41 [35-72] months vs. 23 [20-36] months, HR: 0.51 IC95%[0.32-0.81] p=0.003). In the overall population only PM2.5 had a negative impact on survival (HR: 1.26 IC95% [1.11-1.44], p=0.0005, independent of age, FVC and MUC5B status). Finally, in patients with a T allele, exposure to PM2.5 also had a negative impact on survival (HR: 1.19 CI95% [1.04-1.36]).

Conclusion: The study confirms the link between MUC5B polymorphism and IPF survival, but this does not seem to influence the deleterious effects of fine particles.