Funding for this research was provided by:
Meiji Yasuda Mental Health Foundation (2017-1-019)
Received: 24 October 2017
Accepted: 16 April 2018
First Online: 23 April 2018
Ethics approval and consent to participate
: The present study is a secondary analysis of freely available data. Since the ethics committee of the Panasonic Health Center does not regard de-identified secondary data analysis as research on human subjects, the ethics committee of the Panasonic Health Center waived the need for formal ethical approval and ruled that no formal approval was required for the present study.
: The authors declare that they have no competing interests.
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