1. Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China
2. Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao, China
3. Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, Nanjing, China
4. Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA, USA