title: Prevalence of gastrointestinal diseases in two British national birth cohorts.
abstract: BACKGROUND
  Few studies have investigated the prevalence of multiple gastrointestinal diseases in the general British population.
  
  
  OBJECTIVE
  To examine the prevalence of Crohn's disease (CD), ulcerative colitis (UC), irritable bowel syndrome (IBS), gall stones (GS), and peptic ulcer disease (PUD).
  
  
  METHODS
  The 1970 British Cohort Study (BCS70) and the National Child Development Study (NCDS) are two one week national birth cohorts born in 1970 and 1958, respectively. All cohort members living in Great Britain were interviewed in 1999/2000.
  
  
  METHODS
  The prevalence rates of the five diseases were calculated, and associations with sex and childhood social class were investigated using logistic regression.
  
  
  RESULTS
  At age 30 years, the prevalence rates per 10,000 (95% confidence interval (CI)) in the 1970 and 1958 cohorts, respectively, were: CD 38 (26-49), 21 (13-30); UC 30 (20-41), 27 (18-37); IBS 826 (775-877), 290 (267-330); GS 88 (71-106), 78 (62-94); and PUD 244 (214-273), 229 (201-256). There was a significantly higher proportion with CD (p=0.023) and IBS (p=0.000) in the 1970 cohort compared with the 1958 cohort at age 30 years. Comparing the cohorts in the 1999/2000 sweep, UC, GS, and PUD were significantly (p=0.001, p=0.000, p=0.000) more common in the 1958 cohort. There was a statistically significant trend for a higher risk of GS with lower social class in both cohorts combined (p=0.027).
  
  
  CONCLUSIONS
  The study indicates an increasing temporal trend in the prevalence of CD and suggests a period effect in IBS, possibly due to adult life exposures or variation in recognition and diagnosis of IBS.
authors.affiliation: Enheten för Klinisk Epidemiologi, Institutionen för medicin vid Karolinska Sjukhuset, Karolinska Institutet, Stockholm, Sweden. Anna.Ehlin@medks.ki.se
authors.forename: A G C
authors.initials: AG
authors.lastname: Ehlin
authors.forename: S M
authors.initials: SM
authors.lastname: Montgomery
authors.forename: A
authors.initials: A
authors.lastname: Ekbom
authors.forename: R E
authors.initials: RE
authors.lastname: Pounder
authors.forename: A J
authors.initials: AJ
authors.lastname: Wakefield
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D017668:Age of Onset; D002769:Cholelithiasis / Q000453:epidemiology*; D015331:Cohort Studies; D003093:Colitis, Ulcerative / Q000453:epidemiology*; D003109:Colonic Diseases, Functional / Q000453:epidemiology*; D003424:Crohn Disease / Q000453:epidemiology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D010437:Peptic Ulcer / Q000453:epidemiology*; D015995:Prevalence; D012044:Regression Analysis; D006113:United Kingdom / Q000453:epidemiology