Received: 26 February 2019
Accepted: 6 September 2019
First Online: 29 October 2019
Ethics approval and consent to participate
: At the beginning of this study, an informed consent was obtained from all parents of children, including an agreement of the children to participate as volunteers. This study is confirmed by the ethical committee of Baqiyatallah University of Medical Sciences in November 2017 with Ethics code: IR.BMSU.REC.1396.526.
: Not applicable
: The authors declare that they have no competing interests.