Received: 18 February 2021
Accepted: 24 May 2021
First Online: 4 June 2021
: The research ethics approval was obtained from the Social, Behavioural and Educational Research Ethics Committee of the National University of Singapore (NUS-IRB Reference Code: SSHSPH-032). All methods were performed in accordance with the relevant guidelines and regulations by the ethics committee. Informed consent was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.