MIN, Kaiyuan
WANG, Jing
LIAO, Wei
Astell-Burt, Thomas
FENG, Xiaoqi
CAI, Shuya
LIU, Yang
ZHANG, Peiwen
SU, Fenghua
YANG, Kexin
SUN, Liang
ZHANG, Juan
WANG, Lianjun
LIU, Zechen
JIANG, Yu
Funding for this research was provided by:
Fundamental Research Funds for the Central Universities (3332019010)
Dongcheng Health and Family Planning Commission Research Project ([2018]-22)
Article History
Received: 2 September 2020
Accepted: 14 January 2021
First Online: 27 January 2021
Ethics approval and consent to participate
: This study was approved by the Ethics Committee of Dongcheng Center for Disease Control and Pre-vention (DCCDPCIRB-20180416-1). Prior to participation, all participants provided written informed consent. For the preschool children, written informed consent was obtained from their legal guardians.
: Not applicable.
: The authors declare that they have no competing interests.