Received: 31 August 2019
Accepted: 31 December 2019
First Online: 6 January 2020
Ethics approval and consent to participate
: All participants were enrolled after informed consent was obtained from their parents or guardians in a written form. The study was approved by the Research Ethical Committee of Dr. Soetomo General Academic Hospital in Surabaya, Indonesia.
: Not applicable.
: The authors declare that they have no competing interests.