Funding for this research was provided by:
Shandong Medical and Health Science and Techology Development Plan (2014WS0130)
Received: 19 June 2018
Accepted: 24 October 2018
First Online: 14 November 2018
Ethics approval and consent to participate
: Permission of this study was granted by the Ethics Committee of Human Research at the Medical Examination Center, Shandong University Qilu Hospital, China (KYLL-2017031).
: All subjects gave their written informed consent to participate in this study.
: The authors declare that they have no competing interests.
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