Funding for this research was provided by:
CRCG grant, the University of Hong Kong (201007176156)
General Research Fund, Research Grants Council of Hong Kong, China (HKU 783111M)
Article History
Received: 6 November 2018
Accepted: 12 February 2020
First Online: 17 February 2020
Ethics approval and consent to participate
: Ethical approval was obtained from the Institutional Review Board of the University of Hong Kong/Hospital Authority Hong Kong West Cluster (HKU/HA HKW IRB, Reference number: UW 09–230). Informed written consent from the parents and for their children was obtained before the data collection.
: Not applicable.
: The authors declare that they have no competing interests in this study. No financial or non-financial interests influenced the interpretation of the data or presentation of the information.