1. Otorhinolaryngological Department, Hiser Medical Center of Qingdao , Qingdao 266033, Shandong , China
2. Department of Geriatrics, Hiser Medical Center of Qingdao , Qingdao 266033, Shandong , China
3. Pneumology Department, Hiser Medical Center of Qingdao , Qingdao 266033, Shandong , China
4. Pneumology Department, Hiser Medical Center of Qingdao , No. 4 Renmin Road , Qingdao 266033, Shandong , China