1. Medical School of Chinese PLA, Chinese PLA General Hospital, Beijing, China
2. Department of Geriatrics, The Second Medical Center and National Clinical Research Center for Geriatric Diseases, Chinese PLA General Hospital, Beijing, China
3. Health Division of Guard Bureau, Joint Staff of the Central Military Commission, Beijing, China
4. Department of Geriatric Cardiology, The Second Medical Center, Chinese PLA General Hospital, Beijing, China
5. Department of Outpatient, The First Medical Center, Chinese PLA General Hospital, Beijing, China