Funding for this research was provided by:
Research and Development Support Agency (APVV-15-0012)
Scientific Grant Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic and the Slovak Academy of Sciences (1/0981/15)
Internal Grant Agency of Czech Ministry of Health (IGA_CMTF_2018_006)
Text and Data Mining valid from 2018-11-22
Received: 2 May 2018
Revised: 23 October 2018
Accepted: 3 November 2018
First Online: 22 November 2018
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: All procedures performed in the study were in accordance with the 1964 Declaration of Helsinki 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 (No: 9/2012). Parents were informed about the study via the school administration and could opt out if they disagreed with their child’s participation. Participation in the study was fully voluntary and anonymous, with no explicit incentives provided for participation.