Funding for this research was provided by:
Japan Society for the Promotion of Science (25871166, 16K21379, and 19K10671)
National Center for Global Health and Medicine (28-Shi-1206)
Industrial Health Foundation (NA)
Industrial Disease Clinical Research Grants (170301-01)
Received: 5 July 2019
Accepted: 22 October 2019
First Online: 6 November 2019
Ethics approval and consent to participate
: The study protocol, including the consent procedure, was approved by the Ethics Committee of the National Center for Global Health and Medicine, Japan. Prior to the data collection, the conduct of the J-ECOH Study was announced in each participating companies using posters to explain the purpose and procedures of the study. Participants did not provide their verbal or written informed consent to join the study but were allowed to refuse their participation. This procedure conforms to the Japanese Ethical Guidelines for Epidemiological Research.
: Not applicable.
: The authors declare no conflict of interest. T.N., S.Y., T.H., and T.H. are occupational physicians in the participating company.