Received: 24 September 2019
Accepted: 7 January 2021
First Online: 1 February 2021
Ethics approval and consent to participate
: We complied with the World Medical Association Declaration of Helsinki regarding ethical guidelines involving human subjects. The study protocol had been approved by the Ethics Committee of the Medical University of Warsaw (KB/292/2013), Warsaw, Poland. All participants gave written informed consent prior to their inclusion in the study.
: Not applicable.
: The authors declare that they have no competing interests.