Funding for this research was provided by:
National Natural Science Foundation of China (71673057)
Received: 13 November 2018
Accepted: 5 June 2019
First Online: 3 July 2019
Ethics approval and consent to participate
: The 2014 and 2015 Migrants Population Dynamic Monitoring Survey was approved by the National Health and Family Planning Commission Ethics Review Board, and all participants provided informed consent. All participants received a written informed consent form and an oral explanation of the purpose and content of the research. When minors (< 18 years old) are involved in research, consent was obtained from their parents or guardians. This second data analysis was approved by the School of Nursing, Fudan University (IRB#TYSA2016-3-1).
: Not applicable.
: The authors report no real or perceived interests that relate to this article that could be construed as a competing interest.