Received: 17 February 2019
Accepted: 12 July 2019
First Online: 25 July 2019
Ethics approval and consent to participate
: This study was submitted to the local Ethics Committee of Universidade Federal de São Paulo, number:1.402.940. The principals/coordinators and the parents were informed about the study, and their participation was voluntary.
: Not applicable.
: The authors declare that they have no competing interests.