Article History
Received: 19 September 2018
Accepted: 21 February 2019
First Online: 4 March 2019
Ethics approval and consent to participate
: The Ethics Committee of Collegium Medicum of Nicolaus Copernicus University approved this prospective longitudinal study (procedure nr KB257/2012), and all subjects signed written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.
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