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Article History

Received: 6 December 2017

Accepted: 7 March 2019

First Online: 19 March 2019

Ethics approval and consent to participate

: Prior to the start of this study, ethical approval was obtained from the Research Ethics Committee of Sichuan University, China (registration number K2014022). Since more than half of the participants are illiterate, oral consent with a handprint on the informed consent form was approved by the Research Ethics Committee. Participants received detailed explanations of the study’s objectives, procedures, risks, and benefits before interviews began. Participation in the survey was completely voluntary and the respondents were informed that they had the right to refuse to answer any questions or stop the interview at any point. All participants gave oral consent with a handprint on the informed consent form prior to participating in the study.

: Not applicable.

: The authors declare that they have no competing interests.

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