Funding for this research was provided by:
Mashhad University of Medical Sciences
Received: 15 July 2020
Accepted: 9 September 2020
First Online: 15 September 2020
Ethics approval and consent to participate
: This study was approved by the Ethics Committee of Mashhad University of Medical Sciences (Approval code was IR.MUMS.fm.REC.1396.732). The objectives of the study were fully explained to the children’s parents/guardians. Those who wished to participate in the study signed the written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.