Funding for this research was provided by:
Guangxi Medical and Health Self-funding Project (No Z2014379, No Z2016531, Z20170509, Z20180022)
Liuzhou Science and Technology Bureau Project (No 2014J030422; No. 2017BD20201;No.2018BJ10502;No.2018BJ10504)
Guangxi Nature Science Foundation (No. 2015GXSFBA139129)
Text and Data Mining valid from 2019-02-15
Received: 23 January 2018
Accepted: 8 February 2019
First Online: 15 February 2019
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of Liuzhou Maternity and Child Healthcare Hospital (No 2017003). A written informed consent was obtained from parents or legal guardians on behalf of the children involved in the study for collection of information and samples. The Ethics Committee also permitted the authors to use the patients records to write this article.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.