Mei-Yan Xu, Jian Yin, Department of Nutrition, Aerospace Center Hospital, Beijing 100049, China
Lan Liu, Bao-Shi Yuan, Department of Health Management, Aerospace Center Hospital, Beijing 100049, China
Qing-Bin Lu, School of Public Health, Peking University, Beijing 100191, China
Author contributions: Xu MY and Liu L contributed equally to this work; Xu MY, Liu L and Lu QB designed the study, analyzed the data and wrote the paper; Liu L, Yuan BS and Yin J collected the data; Yin J and Yuan BS revised the paper; all authors have read and approved the final version to be published.
Supported by the State Key Laboratory of Pathogen and Biosecurity (Academy of Military Medical Science), No. SKLPBS1442; and the Youth Talent Support Program of the School of Public Health, Peking University.
Institutional review board statement: This study was reviewed and approved by the Research Ethics Committee of Aerospace Center Hospital.
Informed consent statement: All study participants, or their legal guardian, provided informed written consent prior to study enrollment.
Conflict-of-interest statement: We have no financial relationships to disclose.
Data sharing statement: No additional data are available in this manuscript.
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: Qing-Bin Lu, MD, School of Public Health, Peking University, No. 38 Xue-Yuan Road, Haidian District, Beijing 100191, China. email@example.com
Telephone: +86-10-82805327 Fax: +86-10-82805327
Received: December 12, 2016
Peer-review started: December 14, 2016
First decision: December 29, 2016
Revised: January 17, 2017
Accepted: March 15, 2017
Article in press: March 15, 2017
Published online: April 21, 2017