First Online: 19 December 2019
Ethics approval and consent to participate
: The study was conducted in accordance with the Declaration of Helsinki, and was approved by the local (Peking Union Medical College Hospital) ethics committee. Informed consent to participate in the study was obtained from all participants. Data access was granted in the context of project National Key R&D Program of China (2017YFC0112000) and the National Science Foundation Program of China (81627803, 61501030, 61672099), where the authors’ institutions participate.
: Not applicable.
: The authors declare that they have no competing interests.