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©2013 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Dec 21, 2013; 19(47): 9063-9068
Published online Dec 21, 2013. doi: 10.3748/wjg.v19.i47.9063
Published online Dec 21, 2013. doi: 10.3748/wjg.v19.i47.9063
Seasonal variations in the onset of ulcerative colitis in Japan
Shigeo Koido, Toshifumi Ohkusa, Kan Uchiyama, Hiroshi Arakawa, Hisao Tajiri, Division of Gastroenterology and Hepatology, Department of Internal Medicine, the Jikei University School of Medicine, Chiba 277-8567, Japan
Hiroaki Saito, Tomoyoshi Shibuya, Naoto Sakamoto, Taro Osada, Akihito Nagahara, Sumio Watanabe, Department of Gastroenterology, Juntendo University School of Medicine, Tokyo 113-8421, Japan
Tetsuji Yokoyama, Department of Health Promotion, National Institute of Public Health, Saitama 351-0197, Japan
Author contributions: Koido S, Ohkusa T, Saito H, Watanabe S, and Tajiri H designed the research; Koido S, Ohkusa T, Saito H, Yokoyama T, Shibuya T, Sakamoto N, Uchiyama K, Arakawa H, Osada T, and Nagahara A performed the research and analyzed the data; Koido S and Ohkusa T wrote the paper.
Supported by Grants in Aid for Scientific Research (C) from the Japanese Ministry of Education, Culture, Sports, Science, and Technology, No. 23501289
Correspondence to: Shigeo Koido, MD, Division of Gastroenterology and Hepatology, Department of Internal Medicine, the Jikei University School of Medicine, 8 Chome-3-1 Kokuryocho, Chiba 277-8564, Japan. shigeo_koido@jikei.ac.jp
Telephone: +81-4-71641111 Fax: +81-4-71633488.
Received: July 21, 2013
Revised: September 12, 2013
Accepted: September 29, 2013
Published online: December 21, 2013
Revised: September 12, 2013
Accepted: September 29, 2013
Published online: December 21, 2013
Core Tip
Core tip: Monthly seasonality in the symptomatic onset of ulcerative colitis (UC) during October and March was observed in Japan. The onset of symptoms frequently occurred during the winter, whereas relapse of UC particularly occurred in October. Upper respiratory inflammation was one of the main factors responsible for relapse. Therefore, environmental factors associated with winter and spring seasonality may be responsible for triggering the clinical onset of UC in Japan.