Funding for this research was provided by:
National Medical Research Council (TCR12dec010, MOH-TA18may-0003, NMRC/STaR/014/2013, CNIG/1165/2017)
Received: 13 January 2020
Accepted: 28 May 2020
First Online: 5 June 2020
Ethics approval and consent to participate
: Ethics approval was obtained from the Singapore Health Services Centralised Institutional Review Board (CIRB) for the use of human participants in this study, and all participants provided informed written consent.
: All authors have approved of the manuscript and agree with its submission.
: The authors declare no competing interests.