Funding for this research was provided by:
National Natural Science Foundation of China (81070493)
Received: 26 March 2019
Accepted: 17 June 2019
First Online: 1 July 2019
Ethics approval and consent to participate
: The study was approved by the Ethics Committee of Beijing Jishuitan Hospital (Permission no 201703–11), and written informed consent was obtained from each individual prior to recruitment.
: Not applicable.
: The authors declare that they have no competing interests.