Yang, Lili
Wang, Huan
Yang, Liu
Zhao, Min
Guo, Yajun
Bovet, Pascal
Funding for this research was provided by:
Youth Team of Humanistic and Social Science of Shandong University (20820IFYT1902)
Article History
Received: 12 September 2021
Accepted: 22 November 2021
First Online: 11 January 2022
Declarations
:
: The birth certificate data from the National Vital Statistics System are de-identified and do not include any protected health information. The data are publically available and exempt under the ethical board review of the corresponding author’s institution.
: Not applicable.
: The authors declare that they have no competing interests.