title: Prevalence of irritable bowel syndrome (IBS) in first-degree relatives of patients with inflammatory bowel disease (IBD).
abstract: BACKGROUND
  Epidemiological studies have shown a greater prevalence of irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) among first-degree relatives of patients diagnosed of these diseases. However, it is not known whether relatives of patients with IBD have a greater prevalence of IBS than the general population.
  
  
  OBJECTIVE
  To analyse the prevalence of IBS among first-degree relatives by consanguinity (parents, siblings and offspring) and affinity (spouses) of patients with IBD.
  
  
  METHODS
  A prevalence study was conducted identifying 490 relatives of 91 patients with IBD. Of these, 404 met inclusion criteria; and 360 (response rate: 89.1%) answered the questionnaires. Subjects were invited to participate in the study through index cases (patients with IBD). The following variables were collected: age, sex, history of digestive diseases, kinship and cohabitation with the index case. The relatives completed a questionnaire to identify those who met Rome I and Rome II criteria for IBS.
  
  
  RESULTS
  The overall prevalence of IBS among the first-degree relatives of patients with IBD was 49.4% and 10% according to Rome I and Rome II criteria respectively. IBS prevalence was higher in first-degree blood relatives than in spouses of patients (Rome I: 53.1% vs 29.1%, p=0.001; Rome II: 10.8% vs 5.4%, NS). No differences were found in IBS prevalence depending on whether relatives were living with the index case or not.
  
  
  CONCLUSIONS
  IBS prevalence in first-degree relatives of patients with IBD is elevated. It is significantly greater in blood relatives, which suggests involvement of genetic and psychological factors rather than environmental factors.
authors.affiliation: Gastroenterology Dept. La Fe University Hospital, Valencia, Spain. aguas_mar@gva.es
authors.forename: Mariam
authors.initials: M
authors.lastname: Aguas
authors.forename: Vicente
authors.initials: V
authors.lastname: Garrigues
authors.forename: Guillermo
authors.initials: G
authors.lastname: Bastida
authors.forename: Pilar
authors.initials: P
authors.lastname: Nos
authors.forename: Vicente
authors.initials: V
authors.lastname: Ortiz
authors.forename: Alberto
authors.initials: A
authors.lastname: Fernandez
authors.forename: Julio
authors.initials: J
authors.lastname: Ponce
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000453:epidemiology* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D010290:Parents; D010375:Pedigree; D015995:Prevalence; D035781:Siblings; D018454:Spouses; D055815:Young Adult