Received: 3 August 2019
Accepted: 14 May 2020
First Online: 27 May 2020
Ethics approval and consent to participate
: The protocol for this cross-sectional study was approved by the Institutional Review Board of the University of Gondar on Dec. 15, 2018 (No 1556). All participants gave oral informed consent, and parental consent was obtained also in a written form for participants under 16 and this form of consent was approved from the ethics committee.
: The authors declare that they have no competing interests.