Links between celiac disease and small intestinal bacterial overgrowth: A systematic review and meta-analysis

J Gastroenterol Hepatol. 2022 Oct;37(10):1844-1852. doi: 10.1111/jgh.15920. Epub 2022 Jul 1.

Abstract

Background and aim: Symptoms of small intestinal bacterial overgrowth (SIBO) and celiac disease (CeD) often overlap, and studies suggest a link between SIBO and CeD. We thus conducted a systematic review and meta-analysis to compare SIBO prevalence in CeD patients and controls and assessed effects of antimicrobial therapy on gastrointestinal symptoms in SIBO positive CeD patients.

Methods: Electronic databases were searched until February 2022 for studies reporting SIBO prevalence in CeD. Prevalence rates, odds ratio (OR), and 95% confidence intervals (CI) of SIBO in CeD and controls were calculated.

Results: We included 14 studies, with 742 CeD patients and 178 controls. The pooled prevalence of SIBO in CeD was 18.3% (95% CI: 11.4-28.1), with substantial heterogeneity. Including case-control studies with healthy controls, SIBO prevalence in CeD patients was significantly increased (OR 5.1, 95% CI: 2.1-12.4, P = 0.0001), with minimal heterogeneity. Utilizing breath tests, SIBO prevalence in CeD patients was 20.8% (95% CI: 11.9-33.7), almost two-fold higher compared with culture-based methods at 12.6% (95% CI: 5.1-28.0), with substantial heterogeneity in both analyses. SIBO prevalence in CeD patients nonresponsive to a gluten free diet (GFD) was not statistically higher as compared with those responsive to GFD (OR 1.5, 95% CI: 0.4-5.0, P = 0.511). Antibiotic therapy of SIBO positive CeD patients resulted in improvement in gastrointestinal symptoms in 95.6% (95% CI: 78.0-99.9) and normalization of breath tests.

Conclusions: This study suggests a link between SIBO and CeD. While SIBO could explain nonresponse to a GFD in CeD, SIBO prevalence is not statistically higher in CeD patients non-responsive to GFD. The overall quality of the evidence is low, mainly due to substantial "clinical heterogeneity" and the limited sensitivity/specificity of the available diagnostic tests.

Keywords: bacterial overgrowth; breath tests; celiac disease; gluten sensitive enteropathy; prevalence; small intestinal bacterial overgrowth.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Anti-Bacterial Agents / therapeutic use
  • Breath Tests
  • Case-Control Studies
  • Celiac Disease* / complications
  • Celiac Disease* / epidemiology
  • Celiac Disease* / microbiology
  • Humans
  • Intestine, Small / microbiology
  • Prevalence

Substances

  • Anti-Bacterial Agents