title: Persistent abdominal symptoms in US adults after short-term stay in Mexico.
abstract: BACKGROUND
  Postinfectious irritable bowel syndrome (PI-IBS) has been reported as a complication of bacterial diarrhea including travelers' diarrhea (TD). This study assessed the role of TD among US students in Mexico in triggering the onset of persistent abdominal symptoms (PAS) and IBS.
  
  
  METHODS
  We conducted a 6-month follow-up of a cohort of 817 US students in Mexico as short-term study to assess the frequency of PAS and IBS. Using Rome II criteria for IBS, groups of students with PAS were then categorized as PI-IBS if they met the symptom criteria for IBS or as suffering from functional abdominal disorder (FAD) if they did not meet the criteria.
  
  
  RESULTS
  FAD and IBS were commonly found in US students 6 months after leaving Mexico. Important variables in their development were younger adult age, longer stays in Mexico and occurrence of acute diarrhea while in Mexico. Diarrhea while in Mexico occurred more commonly for those later diagnosed with FAD, 101/196 (52%), relative risk (RR) = 1.5 [confidence interval (CI) 1.2-1.8; p = 0.001]; IBS, 20/32 (63%), RR = 2.5 (CI 1.2-5.0; p = 0.007); and PAS (FAD + IBS), 121/228 (53%), RR = 1.5 (CI 1.2-1.8; p < 0.001) compared with subjects who had experienced diarrhea while in Mexico but were not diagnosed with PAS at 6 months, 227/589 (39%). Diarrhea caused by heat-labile enterotoxin-producing enterotoxigenic Escherichia coli or Providencia ssp. demonstrated a greater risk of developing PAS.
  
  
  CONCLUSIONS
  PAS occurred commonly in a subset of younger adult travelers who stayed longer in Mexico and experienced acute diarrhea while there. Further studies with this cohort will focus on host genetic associations with the development of PAS.
authors.affiliation: Division of Epidemiology, Human Genetics and Environmental Sciences, Center for Infectious Disease, The University of Texas School of Public Health, Houston, TX, USA.
authors.forename: Parvathy
authors.initials: P
authors.lastname: Nair
authors.forename: Pablo C
authors.initials: PC
authors.lastname: Okhuysen
authors.forename: Zhi-Dong
authors.initials: ZD
authors.lastname: Jiang
authors.forename: Lily G
authors.initials: LG
authors.lastname: Carlin
authors.forename: Jaime
authors.initials: J
authors.lastname: Belkind-Gerson
authors.forename: Jose
authors.initials: J
authors.lastname: Flores
authors.forename: Mercedes
authors.initials: M
authors.lastname: Paredes
authors.forename: Herbert L
authors.initials: HL
authors.lastname: DuPont
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D003967:Diarrhea / Q000150:complications / Q000453:epidemiology / Q000382:microbiology / Q000503:physiopathology; D004926:Escherichia coli / Q000302:isolation & purification*; D005260:Female; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D008297:Male; D008800:Mexico / Q000453:epidemiology; D011532:Providencia / Q000302:isolation & purification*; D018570:Risk Assessment; D063189:Symptom Assessment; D013997:Time Factors; D014195:Travel / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology