Funding for this research was provided by:
National Natural Science Foundation of China (71673169, 71974118)
NHC Key Laboratory of Health Economics and Policy Research (NHC-HEPR2019015)
Article History
Received: 23 February 2020
Accepted: 11 May 2020
First Online: 15 June 2020
Compliance with ethical standards
:
: The authors declare that there is no conflict of interests.
: Ethical approval was obtained from Shandong University Ethical Review Committee (No. 20170110). This study was performed in accordance with the ethical principles of the Declaration of Helsinki.
: Verbal informed consent for the collection and application of information was obtained from all participants.