Received: 18 September 2019
Accepted: 19 December 2019
First Online: 26 December 2019
Ethics approval and consent to participate
: The participation in the study was voluntary and all the subjects were not paid for. The work was carried out in accordance with the Helsinki Declaration of 1975, as revised in 2008, including, but not limited to, the absence of potential harm to participants, their guaranteed anonymity, and informed consent approved by the Ethics Committee of Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico of Milan, Italy. All the participants have provided a signed written consent to participate.
: The authors and the participants provided consent for publication.
: The authors declare that they have no competing interests.