Gallstone disease is associated with an increased risk of inflammatory bowel disease: results from three prospective cohort studies

INTRODUCTION: Gallstone diseases affect intestinal inflammation, bile flow, and gut microbiota, which in turn may increase the risk of inflammatory bowel disease (IBD). However, epidemiological studies exploring the associations between gallstone diseases and subsequent IBD risk have been limited. METHODS: This is a combined analysis of 3 prospective cohort studies (Nurses' Health Study, Nurses' Health Study II, and UK Biobank) and replicated in a case-control study (Chinese IBD Etiology Study). We evaluated the hazard ratios (HRs)/odds ratios (ORs) between gallstone diseases with IBD risk by Cox logistic regression or conditional logistic regression, adjusting for demographic characteristics, lifestyles, comorbidities, and medication usage. RESULTS: We identified 3,480 cases of IBD over 2,127,471 person-years of follow-up in the 3 cohort studies. The participants with gallstone disease had a 38% increase in the risk of IBD (HR 1.38, 95% confidence intervals [CI] 1.21–1.59), 68% increase in Crohn's disease (HR 1.68, 95% CI 1.38–2.06), and 24% increase in ulcerative colitis (HR 1.24, 95% CI 1.03–1.49). In Chinese IBD Etiology Study, we found even larger magnitude of effects between gallstone diseases and IBD risk (IBD: OR 3.03, 95% CI 2.32–3.97; Crohn's disease: OR 5.31; 95% CI 3.71–7.60; ulcerative colitis: OR 1.49; 95% CI 1.07–2.06). There were no major differences in the estimated associations between the presence of unremoved gallstones and prior cholecystectomy with IBD risk. DISCUSSION: Gallstone disease was linked to an increased risk of IBD and its subtypes, independent of traditional risk factors. Further research is needed to confirm these associations and clarify the underlying biological mechanisms.