Association Between Systemic Interleukin-1β Levels and Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis IL-1β Levels and IBS

Abstract

Background: Abdominal pain or discomfort, inconsistent stools, and bloating are the hallmarks of irritable bowel syndrome (IBS), a functional bowel condition. Although interleukin-1β (IL-1β), a significant pro-inflammatory cytokine implicated in immunological activation and visceral hypersensitivity, has been thoroughly studied in IBS, published results are still conflicting.
Aim: To compare systemic IL-1β levels between patients with IBS and healthy controls
Patients and Methods: Using PubMed, Scopus, Cochrane, and Web of Science databases, a thorough literature search was carried out for articles published from inception to May 2026, with an emphasis on clinical studies comparing IBS patients with healthy controls. Pooled effect sizes and statistical significance were computed using meta-analytical techniques, and the methodological quality and risk of bias of the included observational studies were evaluated using the Newcastle–Ottawa Scale (NOS).
Results: The IBS group's serum IL-1β was noticeably higher than healthy control group's (MD= 0.77, 95% CI= 0.61:0.92, P value<0.001, I2=99) while a single study evaluating plasma IL-1β reported significantly lower levels in patients with IB.
Conclusion: Patients with IBS had considerably higher serum IL-1β levels than healthy controls, which may indicate a role for low-grade systemic immune activation in the pathophysiology of IBS. However, its current usefulness as a stand-alone biomarker is limited by the significant heterogeneity and contradictory plasma findings, which call for additional standardized research.