Funding for this research was provided by:
the National Health and Family Planning Commission of the People’s Republic of China (201202010)
Health and Family Planning Commission of Hangzhou Municipality (2012A060)
Received: 11 January 2017
Accepted: 31 January 2018
First Online: 7 February 2018
Ethics approval and consent to participate
: All aspects of the study were approved by the ethics committee of the School of Public Health at Soochow University and by the review boards in each of the participating cities. The details of the study were explained to all of the participants, and the participants or their guardians provided written informed consent prior to taking part in the study. The participants or their guardians completed the experiments individually at each SHSS center.
: Not applicable.
: The authors declare that they have no competing interests.
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