Received: 6 February 2020
Accepted: 17 March 2020
First Online: 22 April 2020
Ethics approval and consent to participate
: All participants provided informed consent verbally. Study information was disseminated to participants both verbally and in written form. This study protocol was approved by the ethical committee of Osaka University (H26.E-36).
: All participants consented to the publication of their data through a written consent form obtained from the ethical committee of Osaka University.
: Motohiro Otsuki, Masahiro Wada, Masaya Yamaguchi, Shigetada Kawabata, Yoshinobu Maeda, and Kazunori Ikebe declare that they have no competing interests.