Tian, Tian
Lei, Yunping
Chen, Yongyan
Guo, Yinnan
Jin, Lei
Finnell, Richard H.
Wang, Linlin
Ren, Aiguo
Funding for this research was provided by:
National Natural Science Foundation of China (81773441, 81472987)
the Ministry of Science and Technology of the People’s Republic of China (2016YFC1000501)
Article History
Received: 23 February 2020
Accepted: 21 April 2020
First Online: 9 May 2020
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.
: The study protocol was approved by the institutional review board of Peking University.
: Written informed consent was obtained from the mothers and fathers prior to questionnaire interview and sample collection.
: Not applicable