Funding for this research was provided by:
National Health and Family Planning Commission of the People's Republic of China (250000118)
Received: 8 December 2018
Accepted: 12 June 2019
First Online: 28 June 2019
Change Date: 9 August 2019
Change Type: Correction
Change Details: An error occurred during the publication of a number of articles <i>Global Health Research and Policy</i>. Several articles were published in volume 4 with a duplicate citation number.
Ethics approval and consent to participate
: We declare that the study was conducted after securing ethical clearance from the Medical Ethics Committee of Wuhan University School of Medicine, and obtaining consent from study participants.
: Not applicable.
: We declare no competing interests.