1. Department of Geriatrics, Qingdao Chengyang District People’s Hospital, Qingdao, Shandong, P.R. China
2. Department of Health Management, Qingdao Eighth People’s Hospital, Qingdao, Shandong, P.R. China
3. Department of Ophthalmology, Qingdao Eighth People’s Hospital, Qingdao, Shandong, P.R. China
4. The Third Department of Internal Medicine, Qingdao Women and Children’s Hospital, Qingdao University, Qingdao, Shandong, P.R. China