Epidemiological features of irritable bowel syndrome and its subtypes among Iranian adults

BACKGROUND The epidemiological features of irritable bowel syndrome (IBS) have not been properly investigated in Iran. Also, worldwide there is limited knowledge about the characteristics of IBS subtypes. The aim of the study was to explore the epidemiological features of IBS and its subtypes among Iranian adults. METHODS This is a cross-sectional study in Iranian adults living in Isfahan province. Demographic characteristics and common gastrointestinal symptoms were assessed using a self-administered modified Persian version of the Rome III questionnaire. RESULTS In 4763 subjects aged 19-70 years the overall prevalence of IBS was 21.5%. IBS was more prevalent in women than men (24.0 vs. 18.3%, P<0.001). In multivariate analysis, being married was associated with 27% increased odds of IBS (95% confidence interval: 1.03-1.57, P<0.05). However, IBS was not associated with age (P=0.71) or educational attainment (P=0.61). Constipation-predominant IBS (IBS-C) was the most prevalent subtype of IBS followed by mixed IBS (IBS-M), diarrhea-predominant IBS (IBS-D), and unsubtyped IBS. Female gender was associated with IBS-C while male gender was associated with IBS-D and IBS-M. CONCLUSION IBS is highly prevalent among Iranian adults, affecting particularly women in whom IBS-C is the most prevalent subtype.