Received: 2 August 2018
Accepted: 30 April 2019
First Online: 14 May 2019
Ethics approval and consent to participate
: The CHNS has been approved by institutional review boards at the University of North Carolina at Chapel Hill and the National Institute for Nutrition and Food Safety, China Centre for Disease Control and Prevention. All participants aged 16 and above provided written informed consent for their participation in the survey. For participants below the age of 16, their parents/ legal guardians provided written informed consent for participation of their behalf in the survey.
: Not applicable.
: The authors declare that they have no competing interests.
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