title: Recent trends in the prevalence of Crohn's disease and ulcerative colitis in a commercially insured US population.
abstract: OBJECTIVE
  Most US inflammatory bowel disease (IBD) epidemiology studies conducted to date have sampled small, geographically restricted populations and have not examined time trends. The aim of our study was to determine the prevalence of Crohn's disease (CD) and ulcerative colitis (UC) in a commercially insured US population and compare prevalences across sociodemographic characteristics and time.
  
  
  METHODS
  Using claims data from approximately 12 million Americans, we performed three consecutive 2-year cross-sectional studies. Cases of CD and UC were identified using a previously described algorithm. Prevalence was estimated by dividing cases by individuals in the source population. Logistic regression was used to compare prevalences by region, age, and sex.
  
  
  RESULTS
  In 2009, the prevalences of CD and UC in children were 58 [95 % confidence interval (CI) 55-60] and 34 (95 % CI 32-36), respectively. In adults, the respective prevalences were 241 (95 % CI 238-245) and 263 (95 % CI 260-266). Data analysis revealed that IBD prevalences have slightly increased over time. Based on census data, an estimated 1,171,000 Americans have IBD (565,000 CD and 593,000 UC).
  
  
  CONCLUSIONS
  Analysis of the epidemiological data revealed an increasing burden of IBD in recent years, which may be used to inform policy.
authors.affiliation: Division of Pediatric Gastroenterology, Department of Pediatrics, University of North Carolina at Chapel Hill, 200 Mason Farm Road, Campus Box 7229, Chapel Hill, NC 27599, USA. michael_kappelman@med.unc.edu
authors.forename: Michael D
authors.initials: MD
authors.lastname: Kappelman
authors.forename: Kristen R
authors.initials: KR
authors.lastname: Moore
authors.forename: Jeffery K
authors.initials: JK
authors.lastname: Allen
authors.forename: Suzanne F
authors.initials: SF
authors.lastname: Cook
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000465:Algorithms; D002648:Child; D002675:Child, Preschool; D003093:Colitis, Ulcerative / Q000453:epidemiology*; D003424:Crohn Disease / Q000453:epidemiology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D014481:United States / Q000453:epidemiology; D055815:Young Adult