Ethics approval and consent to participate
This study was performed in accordance with the Declaration of Helsinki. This research was reviewed and approved by the ethical committees of both Hong Kong Polytechnic University (registration number: HSEARS20190824002) and Shandong University of Traditional Chinese Medicine affiliated hospital (registration number: (2019) 伦审 (044)号–KY). Written informed consent was obtained from all participants. Informed consent was obtained from all the parents of the participating children (aged from 4–7 years) before the commencement of intervention implementation.