Funding for this research was provided by:
Japan Society for the Promotion of Science (16H06322 and 17H00991)
Received: 13 April 2018
Accepted: 15 August 2018
First Online: 22 August 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, conducted by the Japanese Ministry of Health, Labour and Welfare (MHLW) each year between 2005 and 2014, were used. This survey was approved by Japan’s Statistics Act, which required that it 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 waived, in line with the Statistics Act.
: Not applicable.
: The author declare he has no competing interests.
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