title: Effects of Birth Cohorts on the Irritable Bowel Syndrome Support Early-Life Risk Factors.
abstract: BACKGROUND
  Irritable bowel syndrome (IBS) is common with prevalence reported between 10 and 20 %. IBS clusters in families but it is unknown whether this is explained by a common environment, genes, or both. If early-life factors are important, IBS might be expected to demonstrate a birth cohort phenomenon.
  
  
  OBJECTIVE
  To investigate whether there is a birth cohort phenomenon for subjects with IBS.
  
  
  METHODS
  Validated questionnaires were sent to a random sample of Olmsted County, Minnesota, residents who recorded gastrointestinal symptoms; IBS diagnosis was based on the modified Rome criteria. Birth cohorts were chosen a priori based on historical national trends in birth weights using 10-year increments. Logistic regression was used to develop odds ratios to assess the association of IBS with calendar period, birth cohort, age, gender, and somatic symptom score.
  
  
  RESULTS
  A total of 4,893 surveys were completed with an overall survey response rate of 58 %. The survey responders were between 25 and 94 years of age and 53 % were female. The overall prevalence of IBS was 16.2 % (95 % CI 15.3-17.4). The univariate association of IBS with birth cohort was significant (p < 0.001) as was the association adjusted for age and gender. The prevalence of IBS was highest for the birth cohort 1963-1972 with an odds ratio of 2.6 (95 % CI 0.97-7.0, p = 0.058).
  
  
  CONCLUSIONS
  Population-based data support a possible birth cohort phenomenon in IBS. If correct, early-life risk factors likely play a key role in the development of IBS.
authors: Department of Internal Medicine, Mayo Clinic, Rochester, MN, USA.
authors: Neil R
authors: NR
authors: Brummond
authors: G Richard
authors: GR
authors: Locke
authors: Rok Seon
authors: RS
authors: Choung
authors: Joseph Y
authors: JY
authors: Chang
authors: Cathy D
authors: CD
authors: Schleck
authors: Alan R
authors: AR
authors: Zinsmeister
authors: Nicholas J
authors: NJ
authors: Talley
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging; D015988:Cohort Effect; D003625:Data Collection; D005260:Female; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D008910:Minnesota; D016017:Odds Ratio; D015995:Prevalence; D012307:Risk Factors; D011795:Surveys and Questionnaires