Received: 18 March 2020
Accepted: 23 July 2020
First Online: 17 August 2020
Ethical approval and consent to participate
: This study was approved by the Ethics review board of the Canton of Zurich (EK-16/2009; update PB_2017–00402) and all participants gave informed written consent.
: Not applicable.
: The authors declare no competing interests.