Examining the Association Between Overweight, Obesity, and Irritable Bowel Syndrome: A Systematic Review and...

Irritable bowel syndrome (IBS) is a common yet debilitating disorder of gut-brain interaction, characterized by gut-brain axis dysregulation, visceral hypersensitivity, and other comorbidities. Obesity has been hypothesized to be a risk factor linked to IBS, albeit evidence remains conflicting. Given the growing global prevalence of obesity and IBS, we performed a meta-analysis examining their purported association.

Embase, MEDLINE, and the Cochrane Library were searched to identify studies reporting the prevalence and odds ratios (ORs) of IBS according to BMI categories. Random effects meta-analyses were used for the primary analysis.

From 1713 articles, 27 studies were included. Our findings showed that using study-defined categories for overweight, obese, and normal BMI, the odds of the diagnosis of IBS were not associated with overweight (OR 1.02; 95% CI 0.89 to 1.17; p = 0.772) or obese BMI (OR 1.11; 95% CI 0.91 to 1.37; p = 0.309). The meta-analysis of study-reported adjusted odds ratios of IBS among individuals living with overweight or obesity also did not yield significant results. Further sensitivity analysis by the Rome criteria demonstrated a statistically significant association between obese BMI and IBS in studies using the Rome IV criteria (OR 1.59; 95% CI 1.13 to 2.23; p < 0.01), with significant subgroup difference between studies using the Rome II, Rome III, and Rome IV criteria. Further sensitivity analysis using the different cut-off values and subgroup analysis by geographical territory did not yield significant associations.

In summary, excess body weight may not be a primary driver of IBS risk. Future research should focus on longitudinal studies that account for changes in weight and other lifestyle factors, as well as detailed mechanistic investigations.