[1] Capital Med Univ, Beijing Childrens Hosp, Natl Ctr Childrens Hlth, Dept Otolaryngol Head & Neck Surg, Beijing, Peoples R China
[2] Capital Med Univ, Beijing Childrens Hosp, Natl Ctr Childrens Hlth, Beijing Pediat Res Inst,Beijing Key Lab Pediat Di, Beijing, Peoples R China
[3] Capital Med Univ, Beijing Childrens Hosp, Ctr Clin Epidemiol & Evidence Based Med, Natl Ctr Childrens Hlth, Beijing, Peoples R China
[4] Capital Med Univ, Beijing Childrens Hosp, Natl Ctr Childrens Hlth, Dept Resp Med, Beijing, Peoples R China
[5] Childrens Hosp, Capital Inst Pediat, Beijing, Peoples R China
[6] Lanzhou Univ, Evidence Based Med Ctr, Sch Basic Med Sci, Lanzhou, Peoples R China