title: Letter: Role of bronchitis in mitigating coal-workers' pneumoconiosis.
mesh_terms: D001991:Bronchitis / Q000150:complications* / Q000503:physiopathology; D003032:Coal Mining; D004391:Dust / Q000032:analysis; D006801:Humans; D008168:Lung / Q000032:analysis / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011009:Pneumoconiosis / Q000150:complications* / Q000503:physiopathology
chemical_list: D004391:Dust