Funding for this research was provided by:
National Health Research Institutes (98A1-EOSP03-014, 99A1-EOSP03-014, 00A1-EOSP03-014, and 01A1-EOSP03-014)
Institute of Occupational Safety and Health, Taiwan (IOSH98-M323, IOSH99-M323, IOSH100-M323, and IOSH101-M323)
Received: 27 June 2019
Accepted: 6 November 2019
First Online: 9 December 2019
Ethics approval and consent to participate
: This study has been approved by the institutional review board of the National Health Research Institutes of Taiwan (No. EC0971003-E).
: This study has not been published previously and is not under consideration for publication elsewhere. The corresponding author is responsible on behalf of all co-authors for all aspects of the research and writing process, and take final responsibility for this paper.
: The authors declare that they have no competing interests.