Funding for this research was provided by:
Javna Agencija za Raziskovalno Dejavnost RS (ID P5-0142)
Received: 4 June 2020
Accepted: 25 January 2021
First Online: 4 February 2021
Ethics approval and consent to participate
: The study was approved by the Commission of the Republic of Slovenia for Medical Ethics (No. 138/05/13). One parent or legal guardian provided written, informed consent to include his/her child in the study.
: Not applicable.
: The authors declare that they have no competing interests.