Funding for this research was provided by:
The Support Program of Science and Technology in Hebei province (H2018206310)
Shenzhen Science and Technology Project (JCYJ20170816170527583)
Received: 28 May 2020
Accepted: 17 November 2020
First Online: 25 November 2020
Ethics approval and consent to participate
: This study was approved by the Ethics Committee of the Third Hospoital of Hebei Medical University under approval number: 2010–009-1. All procedures performed in this study was in accordance with the ethical standards of the institutional and/or national research committee, as well as the 1964 Helsinki declaration and its subsequent amendments or comparable ethical standard. The guardians of enrolled infants gave written informed consents to participate this research project.
: Not applicable.
: We declare no financial interests or conflicts.