Meng-Ting Lin, Medical School of Ningbo University, Ningbo 315000, Zhejiang Province, China
Hao-Jun Song, Xiao-Yun Ding, Gastroenterology Department, Ningbo First Hospital, Ningbo 315000, Zhejiang Province, China
Author contributions: Lin MT wrote the paper; Song HJ and Ding XY revised this manuscript; all of the authors gave their approval of the final version.
Supported by the Natural Science Foundation of Ningbo, No. 2014A610226 and No.2016A610158; the Scientific Benefit for People Project of Ningbo, No. 2014C51001.
Conflict-of-interest statement: Authors declare no conflict of interests for this article.
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: Xiao-Yun Ding, MD, PhD, Chief Doctor, Occupational Physician, Gastroenterology Department, Ningbo First Hospital, No. 59 Liu Ting Street, Haishu District, Ningbo 315000, Zhejiang Province, China. email@example.com
Telephone: +86-574-87085588 Fax: +86-574-87291583
Received: April 25, 2018
Peer-review started: April 25, 2018
First decision: May 16, 2018
Revised: May 22, 2018
Accepted: June 27, 2018
Article in press: June 27, 2018
Published online: September 7, 2018