title: Decreasing incidence of inflammatory bowel disease in eastern Canada: a population database study.
abstract: BACKGROUND
  Nova Scotia has one of the highest incidences of inflammatory bowel disease (IBD) in the world. We wished to determine trends of IBD over time.
  
  
  METHODS
  All Provincial residents have government provided health insurance and all interactions with the hospital, and physician billing systems, are captured on an administrative database. We used a validated measure to define incident cases of Crohn's (CD), ulcerative colitis (UC) and undifferentiated IBD (IBDU). Incidence rates of these diseases for the years 1996-2009 were calculated.
  
  
  RESULTS
  Over the study period, 7,153 new cases of IBD were observed of which 3,046 cases were categorized as CD (42.6%), 2,960 as UC (41.4%) and 1,147 as IBDU (16.0%). Annual age standardized incidence rates were very high but have declined for CD from 27.4 to 17.7/100,000 population and for UC from 21.4 to 16.7/100,000. The decline was seen in all age groups and both genders. The decrease was not explained by a small increase in IBDU.
  
  
  CONCLUSIONS
  The incidence of CD and UC are decreasing in Nova Scotia. If replicated elsewhere this indicates a reversal after a long period of increasing occurrence of IBD. This has implications for both epidemiology and health planning.
authors.affiliation: Department of Medicine, Dalhousie University, 912 Victoria, Victoria General Hsopital, Halifax, NS B3H 2Y9, Canada. dleddin@Dal.Ca.
authors.forename: Desmond
authors.initials: D
authors.lastname: Leddin
authors.forename: Hala
authors.initials: H
authors.lastname: Tamim
authors.forename: Adrian R
authors.initials: AR
authors.lastname: Levy
mesh_terms: D000328:Adult; D003093:Colitis, Ulcerative / Q000453:epidemiology*; D003424:Crohn Disease / Q000453:epidemiology*; D016208:Databases, Factual; D005260:Female; D006801:Humans; D015994:Incidence; D015212:Inflammatory Bowel Diseases / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009674:Nova Scotia / Q000453:epidemiology; D055815:Young Adult
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