Funding for this research was provided by:
National Natural Science Foundation of China (81401606, 81400862, 81701880)
Key Project in the Science & Technology Program of Sichuan Province (2019YFS0322)
Science Foundation for The Excellent Youth Scholars of Sichuan University (2015SU04A15)
Text and Data Mining valid from 2019-08-01
Received: 12 April 2019
Accepted: 22 July 2019
First Online: 1 August 2019
Ethics approval and consent to participate
: Ethical approval for the study was provided by Ethics Committee of the West China Hospital of Sichuan University. Written informed consent was obtained from all parents or their surrogates of studied children.
: Not applicable.
: The authors declare that they have no competing interests.