Qin Zhou, Yan Li, Hua-Zhang Liu, Ying-Ru Liang, Guo-Zhen Lin, Department of Non-communicable Chronic Disease Control and Prevention, Guangzhou Center for Disease Control and Prevention, Guangzhou 510440, Guangdong Province, China
Author contributions: Zhou Q, Li Y, Liu HZ, and Lin GZ conceived of and designed the study; Zhou Q and Liang YR performed the data collection, statistical analyses, and data interpretation; Zhou Q drafted the manuscript; all authors read and approved the final manuscript.
Supported by the Natural Science Foundation of Guangdong Province, No. 2016A030313504; and Guangzhou Science and Technology Program Key Project, No. 201707010205.
Institutional review board statement: The study was reviewed and approved by the ethics committee of the Guangzhou Center of Disease Control and Prevention.
Informed consent statement: Written informed consent to participate in the study was obtained from all participants.
Conflict-of-interest statement: There are no conflicts of interest to report.
Data sharing statement: We declare that the datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Qin Zhou, MD, Occupational Physician, Research Scientist, Staff Physician, Statistical Worker, Technician, Department of Non-communicable Chronic Disease Control and Prevention, Guangzhou Center for Disease Control and Prevention, No. 1, Qide Road, Baiyun district, Guangzhou 510440, Guangdong Province, China. firstname.lastname@example.org
Telephone: +86-20-36055856 Fax: +86-20-37431722
Received: July 23, 2018
Peer-review started: July 23, 2018
First decision: August 27, 2018
Revised: September 1, 2018
Accepted: October 5, 2018
Article in press: October 5, 2018
Published online: November 7, 2018