Funding for this research was provided by:
National Natural Science Foundation of China (81670903)
the Beijing Key Laboratory of Upper Airway Dysfunction-related Cardiovascular Diseases (BZ0377)
the Beijing Municipal Administration of Hospitals (DFL20150602)
the Beijing Municipal Administration of Hospitals Clinical Medicine Development of Special Funding Support (ZYLX201605)
the Beijing Natural Science Foundation (7152057)
Text and Data Mining valid from 2019-04-01
Received: 18 January 2019
Accepted: 26 March 2019
First Online: 1 April 2019
Compliance with ethical standards
: There are no financial disclosures of the authors.
: All the authors declare that they have no conflict of interest.
: This study was approved by the Ethics Committee of Beijing An Zhen Hospital, Capital Medical University, and had been performed in accordance with the ethical standards as laid down in the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants included in the study.