ME/CFS linked to 7-fold higher odds of irritable bowel syndrome in meta-analysisPeople with chronic fatigue syndrome often have irritable bowel issues

BackgroundIrritable bowel syndrome (IBS) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are chronic, debilitating disorders characterized by substantial symptom burden, impaired quality of life, and high healthcare utilization. IBS is a disorder of gut–brain interaction with a global prevalence ranging from 3.8% to 9.2%, while ME/CFS is defined by persistent, exertion-intolerant fatigue and multisystem dysfunction. Growing evidence suggests frequent co-occurrence of these conditions, implicating shared mechanisms such as immune dysregulation, autonomic imbalance, and altered gut–brain signaling. However, the magnitude of their association has not been comprehensively quantified.MethodsWe conducted a systematic review and meta-analysis by searching Embase, PubMed, Scopus, and Google Scholar databases from inception through February 2026. Eligible observational studies reporting associations or prevalence between IBS and ME/CFS were included. Random-effects meta-analyses were performed to pool odds ratios (ORs) and prevalence estimates. Heterogeneity was assessed using I2 statistics. We evaluated for publication bias and assessed for risk of bias.ResultsTwenty-two studies were included in the systematic review and 18 in the meta-analysis. Individuals with ME/CFS had significantly higher odds of IBS compared with controls (OR = 7.20; 95% CI: 2.77–18.76; I2 = 72.1%). The pooled prevalence of IBS among individuals with ME/CFS was 37% (95% CI: 23–54%), with substantial heterogeneity (I2 = 99.5%). Subgroup analysis revealed that diagnostic criteria significantly influenced prevalence (p