Funding for this research was provided by:
Polish Ministry of Science & Higher Education, Polish Mother’s Memorial Hospital – Research Institute - Internal Grant (2015/III/27-SZB)
Received: 12 February 2020
Accepted: 11 June 2020
First Online: 16 June 2020
Ethics approval and consent to participate
: The study was approved by the local Bioethics Committee of the Polish Mothers Memorial Hospital-Research Institute (PMMH-RI 39/2015). Parents and children ≥16 years old provided written informed consent before participation.
: Not applicable.
: The authors declare that they have no competing interests.