Funding for this research was provided by:
Japan Society for the Promotion of Science (26242059)
Text and Data Mining valid from 2018-05-11
Received: 18 September 2017
Accepted: 11 April 2018
First Online: 11 May 2018
Ethics approval and consent to participate
: This study was approved by the ethics committee of the National Center for Geriatrics and Gerontology, Japan. All participants gave their informed consent.
: The authors declare that they have no competing interests.
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