Funding for this research was provided by:
Ministry of Health, Labor and Welfare of Japan (20230601)
Text and Data Mining valid from 2018-03-29
Received: 12 December 2017
Accepted: 21 March 2018
First Online: 29 March 2018
Compliance with ethical standards
: All the authors have declared no competing interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee at which the studies were conducted (IRB approval number 1485 and 13085-3 at Fukushima Medical University and Osaka University Hospital, respectively) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: Informed consent was not obtained from participants, because all data were anonymized, according to Japanese Ethical Guidelines for Medical and Health Research Involving Human Subjects.