1. Department of Breast and Thyroid Surgery, Binzhou Medical University Hospital, Binzhou, Shandong 256603, P.R. China
2. Department of Health Management, The People's Hospital of South District of Qingdao, Qingdao, Shandong 266000, P.R. China
3. Department of Respiratory Medicine, Binzhou Medical University Hospital, Binzhou, Shandong 256603, P.R. China