Funding for this research was provided by:
Agentúra na Podporu Výskumu a Vývoja (APVV-18-0070, APVV-17-0568, APVV-15-0012)
Received: 8 November 2019
Accepted: 4 August 2020
First Online: 20 August 2020
Ethics approval and consent to participate
: All procedures performed in the study were in accordance with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The study was approved by the Ethics Committee of the Medical Faculty at the P.J. Safarik University in Kosice (16 N/2017). Parents were informed about the study via the school administration and could opt out if they disagreed with their child’s participation. Then, written consent from study participants was obtained.
: Not applicable.
: The authors declare that they have no competing interests.