Consent for publication
Ethics approval and consent to participate
The JECS protocol was approved by the Review Board of the Ministry of the Environment for epidemiological studies, and by the Ethics Committees of all participating institutions. The JECS is conducted in accordance with the Declaration of Helsinki and other nationally valid regulations, and written informed consent was obtained from all participants.
Availability of data and materials
The data used to derive our conclusions are unsuitable for public deposition due to ethical restrictions and specific legal framework in Japan. The Ethical Guidelines for Epidemiological Research enforced by the Japan Ministry of Education, Culture, Sports, Science, and Technology; and the Ministry of Health, Labor, and Welfare also restricts the open sharing of epidemiological data.
The authors declare that they have no competing interests.
JECS was funded by the Ministry of the Environment, Japan. The findings and conclusions of this article are solely the responsibility of the authors and do not represent the official views of government. The funding bodies had no role in the study design, collection and analysis of data, interpretation of results, writing of the manuscript, or decision to publish.
AT, KH, and HI designed the study. AT, KH, and HI analyzed and interpreted the data. AT and HI wrote the manuscript. All authors contributed to the critical revision of the manuscript. All authors read and approved the final manuscript.
We are grateful to all of the participants of the JECS and to all individuals involved in data collection.
Members of the JECS (principal investigator, Michihiro Kamijima) as of 2019: Shin Yamazaki (National Institute for Environmental Studies, Tsukuba, Japan), Yukihiro Ohya (National Center for Child Health and Development, Tokyo, Japan), Reiko Kishi (Hokkaido University, Sapporo, Japan), Nobuo Yaegashi (Tohoku University, Sendai, Japan), Koichi Hashimoto (Fukushima Medical University, Fukushima, Japan), Chisato Mori (Chiba University, Chiba, Japan), Shuichi Ito (Yokohama City University, Yokohama, Japan), Zentaro Yamagata (University of Yamanashi, Chuo, Japan), Hidekuni Inadera (University of Toyama, Toyama, Japan), Michihiro Kamijima (Nagoya City University, Nagoya, Japan), Takeo Nakayama (Kyoto University, Kyoto, Japan), Hiroyasu Iso (Osaka University, Suita, Japan), Masayuki Shima (Hyogo College of Medicine, Nishinomiya, Japan), Youichi Kurozawa (Tottori University, Yonago, Japan), Narufumi Suganuma (Kochi University, Nankoku, Japan), Koichi Kusuhara (University of Occupational and Environmental Health, Kitakyushu, Japan), and Takahiko Katoh (Kumamoto University, Kumamoto, Japan).