title: Effects of family history on inflammatory bowel disease characteristics in Japanese patients.
abstract: BACKGROUND
  Although the prevalence of inflammatory bowel disease (IBD) is reported to have reached a plateau in Western countries, it is increasing in Asia. The etiology of IBD is still under investigation. We performed an epidemiological study to clarify the characteristics of IBD in Japan, focusing on patients' family history.
  
  
  METHODS
  We obtained clinical data on ulcerative colitis (UC) (46,114 cases) and Crohn's disease (CD) (11,305 cases) in 2007 from an electronic database maintained under the Japanese Ministry of Health, Labour and Welfare's nationwide registry system, and analyzed the differences in disease characteristics between patients with IBD who had a family history of the disease and those who did not.
  
  
  RESULTS
  A total of 2.7% of the patients with UC and 2.6% of those with CD had a family history. The present age and age at disease onset were lower among the patients with UC who had a family history than among those without (present age: p < 0.001; age at disease onset: p < 0.001; Mann-Whitney U-test), but no similar trend was observed in the patients with CD. Disease severity was worse among both the UC and CD patients with a family history. The clinical course of patients with UC was not affected by family history. Levels of independence in daily life were associated with family history among CD patients, whereas age was associated with levels of independence in daily life among UC patients.
  
  
  CONCLUSIONS
  Disease characteristics of IBD vary in some aspects according to the presence or absence of a family history.
authors.affiliation: Department of Preventive Medicine and Public Health, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. erika_yano@mail.goo.ne.jp
authors.forename: Erika
authors.initials: E
authors.lastname: Kuwahara
authors.forename: Keiko
authors.initials: K
authors.lastname: Asakura
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nishiwaki
authors.forename: Nagamu
authors.initials: N
authors.lastname: Inoue
authors.forename: Mamoru
authors.initials: M
authors.lastname: Watanabe
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Hibi
authors.forename: Toru
authors.initials: T
authors.lastname: Takebayashi
mesh_terms: D000203:Activities of Daily Living; D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003093:Colitis, Ulcerative / Q000453:epidemiology* / Q000235:genetics; D003424:Crohn Disease / Q000453:epidemiology* / Q000235:genetics; D005192:Family Health; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D055815:Young Adult