Peng, Zhekuan
Klomek, Anat Brunstein
Li, Liping
Su, Xuefen
Sillanmäki, Lauri
Chudal, Roshan
Sourander, Andre
Article History
Received: 13 November 2018
Accepted: 11 October 2019
First Online: 28 October 2019
Ethics approval and consent to participate
: The study was approved by the Ethics Committee of Shantou University Medical College and obtained permission from all the junior high schools. All the participants and their guardians agreed and provided signed, informed assent or consent on a voluntarily basis.
: Not applicable.
: The authors declare that they have no competing interests.