Kułaga, Zbigniew http://orcid.org/0000-0003-0509-1004
Świąder-Leśniak, Anna http://orcid.org/0000-0001-5935-4442
Kotowska, Aneta http://orcid.org/0000-0003-3289-2878
Litwin, Mieczysław http://orcid.org/0000-0002-5241-2483
Article History
Received: 2 March 2023
Revised: 11 April 2023
Accepted: 22 April 2023
First Online: 4 May 2023
Declarations
:
: This study was performed in line with the principles of the Declaration of Helsinki. Approvals to conduct both studies were granted by the Children’s Memorial Health Institute Ethics Committee before the studies commenced (approval number: 104/KBE/2007 date: 2007-10-10 and 177/KBE/2008 date 2008-10-12).
: Informed consent in writing was obtained from a parent of each participating child under 18 years of age, and, in addition, written consent was also obtained from all subjects over 16 years of age.
: Not applicable.
: The authors declare no competing interests.