Funding for this research was provided by:
Health and Medical Research Fund (12130651)
Received: 10 May 2018
Accepted: 4 November 2019
First Online: 21 November 2019
Ethics approval and consent to participate
: Ethical approval was obtained for this study from the Ethics Committee in the Hong Kong Hospital Authority and Department of Health. Written consent was obtained from each study participant after a clear explanation of the study objectives and to ensure data confidentiality.
: Not applicable
: The authors declare that they have no competing interests.