[1] Shanxi Med Univ, Dept Pulm & Crit Care Med, Hosp 1, Taiyuan, Peoples R China
[2] Shanxi Med Univ, Clin Med Coll 1, Taiyuan, Peoples R China
[3] Shanxi Key Lab Resp Dis, Taiyuan, Peoples R China
[4] NHC Key Lab Pneumoconiosis, Taiyuan, Peoples R China
[5] Shanxi Med Univ, Dept Resp & Crit Care Med, Hosp 1, Taiyuan 030001, Peoples R China