Liu, Changsong
Liao, Yanfen
Zhu, Zongyuan
Yang, Lili
Zhang, Qin
Article History
Received: 18 November 2020
Accepted: 22 January 2021
First Online: 28 January 2021
Ethics approval and consent to participate
: All participants provided written informed consent (parental consent was obtained for those < 18 years) and NHANES was approved by the National Center for Health Statistics’ Ethics Review Board.
: Not applicable.
: The authors declare that they have no competing interests.