Funding for this research was provided by:
Fujian Provincial Department of Science and Technology (2018D0009)
Undergraduate program of basic innovation research fund of Xiamen University (2017XX0050, 2017Y0077)
Text and Data Mining valid from 2020-01-16
Received: 12 March 2019
Accepted: 4 September 2019
First Online: 16 January 2020
Compliance with ethical standards
: The study were approved by the ethics committee of School of Public health, Xiamen University. All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2000.
: The authors declare that they have no conflict of interest.
: Informed consent was obtained from all individual participants included in the study.