title: Seasonal Variation in Flares of Intestinal Behçet's Disease.
abstract: BACKGROUND
  There have been numerous investigations into the seasonality of several autoimmune diseases and inflammatory bowel disease in an effort to better understand the epidemiology and pathogenesis of these conditions. However, the relationship between the season and disease activity of intestinal Behçet's disease has not been investigated.
  
  
  OBJECTIVE
  This study aimed to evaluate the seasonal pattern of exacerbations of intestinal Behçet's disease.
  
  
  METHODS
  We evaluated 268 consecutive patients with intestinal Behçet's disease who were diagnosed and treated between November 1990 and March 2010 at Severance Hospital, Yonsei University, Seoul, Korea. Patient demographics, onset of symptoms, total number of relapses, and the month of each relapse were recorded. The relationship between the season and flares of intestinal Behçet's disease was analyzed.
  
  
  RESULTS
  A total of 339 relapses occurred in 142 patients (53 %). The median age at diagnosis was 39 (10-73) years; the median follow-up duration was 74 (7-372) months. The peak seasons for relapse were spring and autumn, especially the months of May and September (p value <0.001). Compared with winter, spring and autumn had higher rates of flares (HR 1.92 and 1.91, respectively, p value <0.001).
  
  
  CONCLUSIONS
  In this study, intestinal Behçet's disease demonstrated a biphasic pattern (peaks in spring and autumn) in exacerbations of disease, suggesting that seasonal or exogenous factors may be involved in the flares of intestinal Behçet's disease.
authors.affiliation: Department of Internal Medicine and Institute of Gastroenterology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Korea.
authors.forename: Jin Ha
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine and Institute of Gastroenterology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Korea. geniushee@yuhs.ac.
authors.forename: Jae Hee
authors.initials: JH
authors.lastname: Cheon
authors.affiliation: Department of Internal Medicine and Institute of Gastroenterology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Korea.
authors.forename: Sung Pil
authors.initials: SP
authors.lastname: Hong
authors.affiliation: Department of Internal Medicine and Institute of Gastroenterology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Korea.
authors.forename: Tae Il
authors.initials: TI
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine and Institute of Gastroenterology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Korea.
authors.forename: Won Ho
authors.initials: WH
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001528:Behcet Syndrome / Q000175:diagnosis / Q000453:epidemiology*; D002648:Child; D018450:Disease Progression; D005260:Female; D005767:Gastrointestinal Diseases / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D012621:Seasons; D013997:Time Factors; D055815:Young Adult
keywords: Disease activity; Intestinal Behçet’s disease; Seasonality