Funding for this research was provided by:
Received: 23 March 2020
Accepted: 17 December 2020
First Online: 13 January 2021
Ethics approval and consent to participate
: Ethical approval was given by the institutional review board at the University of Lübeck (vote reference number 17-008). The study was conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from each subject before enrolment.
: Not applicable.
: The authors declare that they have no competing interests.