Funding for this research was provided by:
National Science Foundation of Sri Lanka (RG/2014/HS/09)
Received: 7 July 2020
Accepted: 15 December 2020
First Online: 6 January 2021
Ethics approval and consent to participate
: Ethics approval was obtained from the ethics committees of the Faculty of the Medicine University of Colombo (EC-14-168), Sri Lanka and the Lady Ridgeway Hospital, Sri Lanka. Approvals were obtained from the Ministry of Education and the Principals of Schools. All participants were recruited after obtaining informed written consent from them and their parents.
: Not applicable.
: The authors declare that they have no competing interests.