Funding for this research was provided by:
National Natural Science Foundation of China (81500449)
Text and Data Mining valid from 2019-03-27
Received: 28 October 2018
Accepted: 5 March 2019
First Online: 27 March 2019
Ethics approval and consent to participate
: This study was carried out in accordance with the recommendations of the Declaration of Helsinki, World Medical Association. The protocol was approved by the Ethical Review Board of Xinhua Hospital. Written informed consent was obtained from parents or legal guardians of all children eligible for study enrollment.
: Not applicable.
: The authors declare that they have no competing interests.
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