Funding for this research was provided by:
Young Scientists Fund (71603149)
Major Research Plan (71974114)
Natural Science Foundation of Shandong Province (ZR2016HQ01)
Shandong University (IFYT18033)
Article History
Received: 2 April 2020
Accepted: 30 October 2020
First Online: 16 November 2020
Compliance with ethical standards
:
: The authors declare that they have no competing interests.
: The institutional review board of Shandong University School of Public Health (ref.: 20181219) approved the study protocol before data collection. Informed consent was obtained from all the participants.