Funding for this research was provided by:
China Medical Board (15-277, 16-262)
National Natural Science Foundation of China (71874137)
Shaanxi Social Science Foundation (2017S024)
Received: 26 May 2020
Accepted: 9 December 2020
First Online: 6 January 2021
Ethics approval and consent to participate
: In this study, we obtained verbal informed consent from each participant. The Health Department of Shaanxi Province has issued a document in which the guidance staff of the sample counties will contact each participant who agrees to be interviewed and make an appointment with them. The investigators then went to the participants’ homes, which meant that if we had questionnaires for the participants, we had the consent of the participants. This study is classified as a risk-free investigation because the study adopted literature research techniques and methods, with no intervention or intentional modification of the clinical, biometric or social data of the participants participating in the study. Informed consent in our study was approved by the Ethics Committee of Xi’an Jiaotong University Health Science Center because the research we conducted is classified as a risk-free investigation (No. 2015–644), and it was conducted under the ethics guidelines of the Declaration of Helsinki. The participants consented to the use of the information for investigative purposes, and the data was anonymized when analyzed and do not contain information that might lead to the identification of them.
: Not applicable.
: The authors declare that they have no other competing interests.