Funding for this research was provided by:
National Natural Science Foundation of China (71673299)
Hunan Provincial Science and Technology Department (2019JJ40213)
Health Commission of Hunan Province (WTB201902)
Received: 12 September 2019
Accepted: 26 December 2019
First Online: 4 February 2020
Ethics approval and consent to participate
: The study was approved by Ethics Committee of The First Hospital of Hunan University of Chinese Medicine (HN-LL-KY-2019-18). All participants provided verbal consent prior to participation in the study. This method of obtaining consent was approved by the ethics committee as the study presented no more than minimal risk to the participants.
: Not Applicable.
: The authors declare that they have no competing interests.