Ethics approval and consent to participate
Ethical approval for the study was obtained from the Human Subjects Ethics Review Committee of The Hong Kong Polytechnic University (application number: HSEARS20160114001). All methods were performed in accordance with the Declaration of Helsinki and relevant institutional guidelines and regulations. Permission to conduct the study was also sought from the person in charge of the community centres for older people. Written informed consent was obtained from each participant, to whom all aspects of the study had been explained, and questions answered prior to the commencement of the study.