Funding for this research was provided by:
National Institute of Environmental Health Sciences, National Health Research Institutes, Taiwan.
Received: 26 January 2019
Accepted: 18 December 2019
First Online: 30 December 2019
Ethics approval and consent to participate
: All information allowing a specific patient to be identified has been encrypted. The confidentiality of the data abides by the data regulations of the Bureau of National Health Insurance. The Institutional Review Board (IRB) of Taiwan National Health Research Institutes approved this study (IRB No.: NHRI-107-EMSP02).
: Not applicable.
: The authors declare that they have no competing interests.