Funding for this research was provided by:
Japan Society for the Promotion of Science (16H06322 and 17H00991)
Received: 25 September 2017
Accepted: 19 February 2018
First Online: 23 February 2018
Ethics approval and consent to participate
: Data that were obtained from the Longitudinal Survey of Middle-Aged and Older Adults, a 9-year panel survey, that was conducted by the Japanese Ministry of Health, Labour and Welfare (WHLW) each year between 2005 and 2014, were used. This survey was approved by the Japan’s Statistics Act, which required it to be reviewed from statistical, legal, ethical, and other viewpoints. Survey data were obtained from the MHLW with its official permission. Therefore, the current study did not require ethical approval. The need for written consent was waved in line with the Statistics Act.
: The survey data were obtained from the MHLW with its official permission. Therefore, the current study did not require consent for publication.
: The author declares that he has no competing interests.
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