ABSTRACT:

Background: Irritable bowel syndrome (IBS) shows substantial geographic variability in symptom presentation, but regional differences in the clinical relevance of bloating remain poorly understood. We aimed to characterize regional differences in IBS phenotype, symptom burden, psychological and quality-of-life measures, and meal-related symptoms between Asian/Australian and European populations, with particular emphasis on the contribution of bloating to disease burden.

Methods: We performed a cross-sectional analysis of the multinational AEGIS survey including adults fulfilling Rome IV criteria for IBS from 11 centers across Asia/Australia and Europe. Participants completed validated assessments of IBS subtype, symptom severity, quality of life, psychological burden, and dietary triggers. Regional comparisons used nonparametric and chi-square tests.

Results: Among 1074 participants, 339 met Rome IV criteria for IBS. The proportion of IBS patients was lower in Asia/Australia than in Europe (20.9% vs. 40.9%, p = 0.039). IBS-D (57.1% vs. 35.9%, p < 0.001) predominated in Asia/Australia, whereas IBS-M (31.6% vs. 20.0%, p = 0.028) was more common in Europe. European patients demonstrated higher psychological burden and greater overall symptom severity despite comparable abdominal pain intensity. Bloating severity was significantly higher in European participants (p < 0.001) and showed a substantially stronger association with impaired quality of life than pain (r = -0.552, p < 0.001 vs. r = -0.260, p = 0.005). Postprandial symptoms were more common in Europe, whereas in Asia/Australia, they were associated with greater consumption of dairy products, gluten-containing foods, coffee, and carbonated beverages.

Conclusions: IBS phenotype and symptom burden differ across regions. Bloating, rather than abdominal pain, was more strongly associated with impaired quality of life, supporting symptom-centered and culturally tailored IBS management.

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