Received: 14 March 2019
Accepted: 7 June 2019
First Online: 20 June 2019
Ethics approval and consent to participate
: Signed consent was obtained from all participants before interviews and after explaining the study focus and answering the participants’ enquiries. Ethical approval was obtained from the Survey and Behavioral Research Ethics Committee of the Chinese University of Hong Kong on 31st March 2016.
: Not applicable.
: The authors declare that they have no competing interests.