Received: 1 February 2018
Accepted: 9 July 2018
First Online: 16 July 2018
Ethics approval and consent to participate
: All participants were voluntary and anonymous, and written informed consent was provided. The study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the Committee on Human Experimentation of China Medical University.
: Not applicable.
: The author(s) declare that they have no competing interests.
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