Text and Data Mining valid from 2019-06-13
Received: 26 March 2019
Accepted: 28 May 2019
First Online: 13 June 2019
Ethics approval and consent to participate
: The design and protocol of this study conformed with the Helsinki Declaration and was approved by the Institutional Ethics Committee (approval number: 869; Saitama Medical University, 2911; National Defense Medical College).
: Not applicable.
: The authors declare that they have no competing interests.