Lastly, genetic factors may play a role. Such were also considered when a higher TD incidence rate among British travelers was found.21 Three kinds of selection bias might limit our study: Travelers consulting for pre-travel health advice might have been either somewhat hypochondriac or represent a subpopulation with special health literacy skills, as 51.3% of our customers reported a university degree. The latter would result in an underestimation of the IBS risk when compared to travelers with

a different educational background, whereas for the former higher TD rates as well as a higher rate of IBS would be expected. Actually, we found learn more a higher TD incidence rate when compared with the nonresponders’ TD rate, which might indicate an overestimation of our IBS incidence rate. Third, although attracting millions of visitors, some popular tourist destinations, such as Turkey, North Africa, and the Caribbean were underrepresented as travelers to those countries rarely consult for pre-travel health advice.28 Diarrhea is a risk factor for IBS whether it occurred at home or abroad. Evidence shows that an infectious agent may trigger new onset MK-1775 of IBS and of other long-term sequelae,

such as, eg, reactive arthritis.29,30 Thereby, the severity and duration of IBS illness are important risk factors23; however, it remains unknown whether the type of the pathogen, the inoculum, and the time interval between diarrheal attacks play a role.31 Notably, it appears that multiple diarrheal episodes would raise the IBS risk. This might support the hypothesis of IBS being associated with increased epithelial barrier permeability and/or altered gut flora.4 The results of the sensitivity analyses validate

our risk estimates. For a more detailed subgroup analysis a different study design would be more appropriate. Such data would be needed to assess factors and syndromes associated with other low-grade inflammatory and immunological processes, such as, eg, atopy32 or antibiotic Quisqualic acid treatment14 which were supposed to be associated with IBS. The reported threefold increased IBS risk following the experience of a recent adverse life event corresponds to the relative risk of 2.0 found previously for IBS.33 Contrary to some reports, female gender and smoking were not found to be significant independent risk factors for IBS. IBS patients are often reluctant to request thorough medical evaluation. Accordingly, most of our IBS patients managed their symptoms themselves. The consulting physicians rated the severity of IBS as “mild.” At the beginning of the symptoms the Rome III-based case definition seemed to be prone to misclassification. In about one third of our IBS cases, who had visited a physician, the medical doctors’ diagnosis did not confirm the IBS assessment to full extent because another diagnosis was found.