Funding for this research was provided by:
Narodowe Centrum Nauki (2012/07/B/NZ7/01178, 2013/09/B/NZ5/02794, 2013/11/B/NZ1/00091, 2013/09/D/ST5/03909, 2016/23/B/NZ5/00573)
Article History
Received: 1 August 2017
Accepted: 20 February 2018
First Online: 26 February 2018
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The study was approved by the Bioethics Commission at the Poznan University of Medical Sciences (Approval no. 08/11).
: Written informed consent was obtained from all individuals participating in the study. Written informed consent was also obtained from the parents of all participants under the age of 16.