Assessment of irritable bowel syndrome

Using a validated self-administered modified Rome III questionnaire, different gastrointestinal disorders including symptoms related to IBS were assessed [1]. Since during the face validity evaluation of our study, we found that most participants found it difficult to discriminate the descriptors used in the original Rome III (never, less than one day a month, one day a month, two to three days a month, one day a week, more than one day a week, every day), we modified the rating scale into 4 descriptors (i.e. never or rarely, sometimes, often, always). We also asked whether each symptom was present in the past three months. In the current study, on the basis of the Rome III diagnostic criteria for functional gastrointestinal disorders, we defined IBS as having recurrent abdominal pain or discomfort at least “sometime” in the last 3 months associated with two or more of these criteria: improvement with defecation at least “sometimes” and onset associated with change in frequency or form (appearance) of stool at least “sometimes”. The Persian version of the Rome III questionnaire for Iranian population was validated previously [20].