Age at onset is associated with the seasonal pattern of onset and exacerbation in inflammatory bowel disease.
BACKGROUND
Environmental factors are suggested to affect the pathogenesis of several diseases, including inflammatory bowel disease (IBD). The seasonality of disease onset and exacerbation in IBD, however, are not well established. We herein aimed to clarify the disease seasonality and to investigate the underlying characteristics in IBD patients exhibiting seasonality of the disease course.


METHODS
This was a multicenter observational study comprising 20 institutions (Osaka Gut Forum) in Japan. Data were collected from November 2013 to August 2014 using survey forms for physicians and questionnaires for patients. Multivariate analysis was performed to clarify the independent factors affecting disease seasonality.


RESULTS
A total of 1055 patients, including 298 patients with Crohn's disease (CD) and 757 patients with ulcerative colitis (UC), were enrolled. The proportion of CD patients with disease onset in the summer was significantly larger than that in the other seasons, while UC patients exhibited no seasonality of disease onset. More than half of the IBD patients (51.1%) experienced seasonal exacerbation of IBD, and winter was the most common season for disease exacerbation in both CD and UC patients. Seasonality of disease onset and exacerbation was observed in young-onset patients (≤40 years old), but not in elderly-onset patients. Age at onset was independently associated with the seasonality of both disease onset and exacerbation.


CONCLUSIONS
Seasonality of disease onset and exacerbation was observed especially in young-onset IBD patients. Underlying pathophysiologic triggers for disease initiation and exacerbation may be influenced by age at disease onset.
Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Manabu
M
Araki
Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Shinichiro
S
Shinzaki
Department of Gastroenterology, National Hospital Organization Osaka National Hospital, Osaka, Japan.
Takuya
T
Yamada
Kinshukai Infusion Clinic, Osaka, Japan.
Shoko
S
Arimitsu
Department of Gastroenterology, Osaka Rosai Hospital, Sakai, Japan.
Masato
M
Komori
Department of Gastroenterology, NTT-West Osaka Hospital, Osaka, Japan.
Narihiro
N
Shibukawa
Department of Gastroenterology, Sumitomo Hospital, Osaka, Japan.
Akira
A
Mukai
Department of Gastroenterology, Toyonaka Municipal Hospital, Toyonaka, Japan.
Sachiko
S
Nakajima
Department of Gastroenterology, Otemae Hospital, Osaka, Japan.
Kazuo
K
Kinoshita
Department of Gastroenterology, Sakai City Hospital, Sakai, Japan.
Shinji
S
Kitamura
Department of Gastroenterology and Hepatology, Itami City Hospital, Itami, Japan.
Yoko
Y
Murayama
Department of Gastroenterology, Nishinomiya Municipal Central Hospital, Nishinomiya, Japan.
Hiroyuki
H
Ogawa
Department of Gastroenterology, Hyogo Prefectural Nishinomiya Hospital, Nishinomiya, Japan.
Yuichi
Y
Yasunaga
Department of Internal Medicine, Osaka Police Hospital, Osaka, Japan.
Masahide
M
Oshita
Department of Gastroenterology, Yao Municipal Hospital, Yao, Japan.
Hiroyuki
H
Fukui
Department of Gastroenterology, National Hospital Organization Osaka-Minami National Hospital, Kawachinagano, Japan.
Eiji
E
Masuda
Department of Gastroenterology, Higashiosaka Municipal Hospital, Higashiosaka, Japan.
Masahiko
M
Tsujii
Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Satoshi
S
Hiyama
Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Takahiro
T
Inoue
Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan. hiijima@gh.med.osaka-u.ac.jp.
Hideki
H
Iijima
Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Tetsuo
T
Takehara
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D003093:Colitis, Ulcerative / Q000453:epidemiology* / Q000503:physiopathology; D003424:Crohn Disease / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012621:Seasons; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D055815:Young Adult
Age at onset; Inflammatory bowel disease; Seasonality