Text and Data Mining valid from 2019-08-09
Received: 7 January 2019
Accepted: 31 July 2019
First Online: 9 August 2019
Ethics approval and consent to participate
: All participants were provided written informed consent. The study protocol was approved by the Committee on Medical Ethics of the Peking University. The number of ethics approval is IRB00001052–17107.
: Not applicable.
: The authors declare that they have no competing interests.