Funding for this research was provided by:
Health and Medical Research Fund, Hong Kong (06171706)
Received: 14 June 2019
Accepted: 7 May 2020
First Online: 20 May 2020
Ethics approval and consent to participate
: The research was approved by local institution ethics review board HKU/HA HKW IRB (No. UW 16–560). Written consent was waived as the research presented no additional risk or intervention to the participants.
: Not applicable.
: EL is the primary investigator of the Health and Medical Research Fund, Hong Kong (06171706), which partially supported this study. Other authors declare that they have no competing interests.