Received: 17 October 2018
Accepted: 23 August 2019
First Online: 11 September 2019
Ethics approval and consent to participate
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The study was approved by the institutional review board (Ethics Committee of the Juntendo University Hospital), and the consent to participate was obtained by the opt-out method through our hospital website.
: Not applicable.
: The authors declare that they have no competing interests.