Received: 6 June 2019
Accepted: 5 November 2019
First Online: 2 December 2019
Ethics approval and consent to participate
: Approval for this cross-sectional prospective study was obtained from the Research Ethics Committee of Alexandria Faculty of Medicine (Ethics committee’s reference number: 020814, IRB no: 00012098, FWA no: 00018699). All study procedures were carried out in accordance with the Declaration of Helsinki regarding research involving human subjects. Written informed consent was obtained from the parents of each child.
: Written informed consent for publication of this data was given by the parents or legal guardians of the included children.
: The authors declare that they have no competing interests.