Funding for this research was provided by:
National Natural Science Foundation of China (81871655)
Health and Family Planning Commission of Shenzhen Municipality Foundation of China (SZGW2017018)
Text and Data Mining valid from 2019-07-03
Received: 18 January 2019
Accepted: 23 June 2019
First Online: 3 July 2019
Ethics approval and consent to participate
: This study was approved by the ethics committee of the Shenzhen Blood Centre, China (Approval number: 2017002). All participants provided written informed consent. All methods were carried out in accordance with the principles of the Declaration of Helsinki. To guarantee donor confidentiality, donors were anonymized via de-identification (through the use of codes). The process of delinking donor identities and donation units was undertaken exclusively by a data specialist from Shenzhen Blood Centre.
: Not applicable.
: The authors declare that they have no competing interests.