Received: 20 November 2019
Accepted: 7 July 2020
First Online: 27 August 2020
Ethics approval and consent to participate
: The present study was performed according to the protocol that was approved by the Epidemiological Research Ethics Review Committee of Hiroshima University (approval number E-1003). All the participants of this study gave their written informed consent to participate in this study.
: Not applicable.
: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.