Funding for this research was provided by:
University of Colombo (AP/3/2/2015/PG/07)
University Grants Commission - Sri Lanka (UGC/DRIC/PG/2015(i)/CMB/01)
Received: 12 October 2018
Accepted: 12 July 2019
First Online: 19 July 2019
Ethics approval and consent to participate
: Written, informed consent from all study participants and ethical clearance to conduct this study was obtained from the Ethics Review Committee, Faculty of Medicine, University of Colombo [EC-15-082].
: Not applicable.
: The authors declare that they have no competing interests.