1. School of Nursing, The University of Hong Kong, Hong Kong
2. Guangzhou No.12 Hospital, Guangdong Province, China
3. Institute of Geriatrics, Chinese PLA General Hospital, Beijing, China
4. Guangzhou Chest Hospital, Guangdong Province, China
5. Institute of Applied Health Research, University of Birmingham, UK
6. School of Public Health, The University of Hong Kong, Hong Kong