Funding for this research was provided by:
Ministry of Education, Culture, Sports, Science and Technology (18K10082, 19H01074)
Ajinomoto Co., Inc.
Received: 18 January 2020
Accepted: 22 September 2020
First Online: 29 September 2020
Ethics approval and consent to participate
: Ethical approval for the study was granted by the ethics committee of The University of Tokyo (11964). Written informed consent was not required, as this study was a secondary analysis of anonymized data that is collected routinely by the MHLW. Data of GBD 2017 are also secondary, aggregated estimates by country, sex, and age groups.
: Not applicable.
: SN reports grants from Ajinomoto Co., Inc. and the Ministry of Education, Culture, Sports, Science and Technology of Japan. DY, SN, ST, and KS declare no competing interests. KN, HU, and NH declare that they are employed by Ajinomoto Co., Inc. and have no other competing interests. This does not alter the authors’ adherence to the journal policies on sharing data and materials. The study was approved by the appropriate ethics review board. We have read and understood your journal’s policies, and we believe that neither the manuscript nor the study violates any of these.