Funding for this research was provided by:
Science and Technology Bureau of Xi'an city (201805098YX6SF32(1))
Chinese Center for Disease Control and Prevention (2015FYJ002)
The Health and Family Planning Bureau of Xi'an City (HX201549)
Key Science and Technology Program of Shaanxi Province (2019SF-100)
Received: 19 March 2019
Accepted: 20 September 2019
First Online: 21 October 2019
Ethics approval and consent to participate
: The Ethics Committee for the Science of Medical center, at the First Affiliated Hospital of the Xi’an Jiaotong University approved all study protocols on 13 October, 2017 (No: XJTU1AF2017LSK-45). The patient’s informed consent regarding the analysis of their medical records and the hospital’s permission were obtained. Written informed consent forms were obtained from the participants who took part in this survey.
: Not applicable.
: The authors declare that they have no competing interests.