Received: 3 April 2020
Accepted: 18 June 2020
First Online: 22 June 2020
Ethics approval and consent to participate
: This study was approved by the ethics review board of Osaka Medical College with notification for guaranteed withdrawal of participants on the website providing means of “opt-out” (No. 2194–01).
: Our manuscript does not contain any individual person’s data in any form (including individual details, images or videos).
: The authors declare that they have no competing interests.