title: Differences in inflammatory bowel disease phenotype between South Asians and Northern Europeans living in North West London, UK.
abstract: OBJECTIVE
  The incidence and prevalence of inflammatory bowel disease (IBD) is increasing throughout Asia. Since the 1950s, there has been substantial migration from South Asia (India, Pakistan, and Bangladesh) to the United Kingdom. The aim of this study was to define the clinical phenotype of IBD in UK South Asians living in North West London, and to compare the results with a white Northern European IBD cohort.
  
  
  METHODS
  The phenotypic details of 367 South Asian IBD patients (273 ulcerative colitis (UC) and 94 Crohn's disease (CD)), undergoing active follow-up in five North West London hospitals, were compared with those of 403 consecutively collected white Northern European IBD patients (188 UC and 215 CD).
  
  
  RESULTS
  The phenotype of IBD differed significantly between the two populations. 63.0% of South Asian UC patients had extensive colitis compared with 42.5% of the Northern European cohort (P < 0.0001). Proctitis was uncommon in South Asian UC patients (9.9 vs. 26.1% in Northern European patients, P<0.0001). In the South Asian CD cohort, disease location was predominantly colonic (46.8%). CD behavior differed significantly between the groups, with less penetrating disease compared with Northern Europeans (P=0.01) and a reduced need for surgery (P=0.003).
  
  
  CONCLUSIONS
  The phenotype of IBD in South Asians living in North West London is significantly different from that of a white Northern European IBD cohort. Knowledge of ethnic variations in disease phenotype may help to identify key genetic, environmental, and behavioral factors contributing to the development of IBD.
authors.affiliation: Department of Medicine, Imperial College London, London, UK. david.walker1@imperial.ac.uk
authors.forename: David G
authors.initials: DG
authors.lastname: Walker
authors.forename: Horace R T
authors.initials: HR
authors.lastname: Williams
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Kane
authors.forename: Joel E
authors.initials: JE
authors.lastname: Mawdsley
authors.forename: Jayantha
authors.initials: J
authors.lastname: Arnold
authors.forename: Ian
authors.initials: I
authors.lastname: McNeil
authors.forename: Huw J W
authors.initials: HJ
authors.lastname: Thomas
authors.forename: Julian P
authors.initials: JP
authors.lastname: Teare
authors.forename: Ailsa L
authors.initials: AL
authors.lastname: Hart
authors.forename: Maxton C L
authors.initials: MC
authors.lastname: Pitcher
authors.forename: Julian R F
authors.initials: JR
authors.lastname: Walters
authors.forename: Sara E
authors.initials: SE
authors.lastname: Marshall
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Orchard
mesh_terms: D000293:Adolescent; D000328:Adult; D044466:Asian People; D001459:Bangladesh / Q000208:ethnology; D003082:Colectomy; D003093:Colitis, Ulcerative / Q000150:complications / Q000208:ethnology* / Q000473:pathology / Q000601:surgery; D003106:Colon / Q000473:pathology; D003424:Crohn Disease / Q000150:complications / Q000208:ethnology* / Q000473:pathology / Q000601:surgery; D004777:Environment; D005260:Female; D006801:Humans; D007082:Ileum / Q000473:pathology; D007194:India / Q000208:ethnology; D008131:London / Q000453:epidemiology; D008297:Male; D010154:Pakistan / Q000208:ethnology; D010641:Phenotype; D015995:Prevalence; D011349:Proctitis / Q000208:ethnology; D013997:Time Factors; D044465:White People; D055815:Young Adult