[1] Gansu Prov Hosp, Dept Resp Med, Lanzhou, Peoples R China
[2] Karolinska Inst, Ctr Mol Med, Dept Med Solna, Resp Med Unit, Stockholm, Sweden
[3] Univ Helsinki, Dept Pulm Dis, Helsinki, Finland
[4] Helsinki Univ Hosp, Helsinki, Finland
[5] Tsinghua Univ, Vanke Sch Publ Hlth, Beijing, Peoples R China
[6] Northwest Agr & Forestry Univ, Coll Nat Resources & Environm, Yangling, Peoples R China
[7] Karolinska Univ Hosp, Dept Resp Med & Allergy, Stockholm, Sweden
[8] Gansu Univ Chinese Med, Sch Clin Med 1, Lanzhou, Peoples R China
[9] Gansu Prov Hosp, Dept Gen Surg, Lanzhou, Peoples R China
[10] Tsinghua Univ, Inst Hlth China, Beijing, Peoples R China