Funding for this research was provided by:
National Institute on Aging (OGHA 04034785; YA1323-08-CN-0020; Y1-AG-1005-01)
Shanghai Municipal Health Bureau (15GWZK0801;GWIV-22)
Received: 4 December 2017
Accepted: 1 June 2018
First Online: 20 June 2018
Ethics approval and consent to participate
: WHO’s Ethical Review Committee approved SAGE (RPC146), and each country obtained local ethical approval to conduct the study. Written informed consent was obtained from each respondent.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.