Rong-Guang Zhang, Guang-Cai Duan, Shuai-Yin Chen, Department of Epidemiology and Biostatistics, College of Public Health, Zhengzhou University, Zhengzhou 450001, Henan Province, China
Qing-Tang Fan, Henan Key Laboratory of Molecular Medicine, Zhengzhou University, Zhengzhou 450001, Henan Province, China
Author contributions: Zhang RG performed the review and wrote the paper; Duan GC conducted the review and inspected the manuscript; Fan QT and Chen SY took part in literature retrieval and analysis of the reported research findings.
Supported by The China Postdoctoral Science Foundation, No. 200801273.
Conflict-of-interest statement: No conflict-of-interest exists.
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: Guang-Cai Duan, PhD, Department of Epidemiology and Biostatistics, College of Public Health, Zhengzhou University, 100 Kexue Avenue, Zhengzhou 450001, Henan Province, China. email@example.com
Telephone: +86-371-67781472 Fax: +86-371-66997182
Received: April 28, 2015
Peer-review started: May 5, 2015
First decision: July 27, 2015
Revised: September 18, 2015
Accepted: November 3, 2015
Article in press: November 4, 2015
Published online: February 15, 2016