Obesity and Risk of Small Intestine Bacterial Overgrowth: A Systematic Review and Meta-Analysis

  • Karn WijarnpreechaEmail author
  • Monia E. Werlang
  • Kanramon Watthanasuntorn
  • Panadeekarn Panjawatanan
  • Wisit Cheungpasitporn
  • Victoria Gomez
  • Frank J. Lukens
  • Patompong Ungprasert
Original Article



Recent studies have proposed that obesity may be associated with a higher risk of small intestine bacterial overgrowth (SIBO) although the results were inconsistent. The microbiome has a known metabolic role; its impact on obesity in animal models generated the hypothesis of an association between a dysfunctional microbiome and obesity. We performed this systematic review and meta-analysis to elucidate this possible association by summarizing all available data.


A literature search utilizing MEDLINE and EMBASE databases from inception until August 2019 was conducted. Eligible studies included either cohort studies or cross-sectional studies that consisted of two groups of participants, those with obesity and those without obesity, and compared the prevalence of SIBO between the groups. Adjusted odds ratios (OR) from each study were consolidated by the generic inverse variance method of DerSimonian and Laird.


A total of five studies with 515 patients fulfilled eligibility criteria and were included in this meta-analysis. The risk of SIBO among individuals with obesity was higher than in individuals without obesity but did not reach statistical significance with a pooled OR of 2.08 [95% confidence interval (CI) 0.82–5.31; p = 0.12; I2 84%]. Sensitivity analysis including only studies from Western countries increased the pooled OR to 3.41 and reached statistical significance (95% CI 1.21–9.59; p = 0.02; I2 62%).


This meta-analysis found that the risk of SIBO was about two times higher among individuals with obesity compared to individuals without obesity, although the result did not reach statistical significance. The risk increased to threefold and reached statistical significance when only studies from Western countries were included. These observations may suggest the role of obesity as a predisposing factor for SIBO although more studies are still needed to corroborate these preliminary results.


Obesity Overweight Bacterial overgrowth Meta-analysis 



We would like to thank Mr. Matthew Roslund, medical librarian at Bassett Medical Center in Cooperstown, New York, for his assistance with the development of the search strategy.

Author’s contribution

All authors had access to the data and a role in writing the manuscript.

Compliance with Ethical Standards

Conflict of interest

Victoria Gomez participates in consulting work for Olympus Corporation. All other authors do not have any financial or non-financial potential conflicts of interest.

Supplementary material

10620_2019_5887_MOESM1_ESM.docx (18 kb)
Supplementary material 1 (DOCX 17 kb)
10620_2019_5887_MOESM2_ESM.doc (64 kb)
Supplementary material 2 (DOC 64 kb)


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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  • Karn Wijarnpreecha
    • 1
    Email author
  • Monia E. Werlang
    • 1
  • Kanramon Watthanasuntorn
    • 2
  • Panadeekarn Panjawatanan
    • 2
  • Wisit Cheungpasitporn
    • 3
  • Victoria Gomez
    • 1
  • Frank J. Lukens
    • 1
  • Patompong Ungprasert
    • 4
  1. 1.Division of Gastroenterology and Hepatology, Mayo Clinic College of MedicineMayo ClinicJacksonvilleUSA
  2. 2.Department of Internal MedicineBassett Medical CenterCooperstownUSA
  3. 3.Division of Nephrology, Department of MedicineUniversity of Mississippi Medical CenterJacksonUSA
  4. 4.Clinical Epidemiology Unit, Department of Research and Development, Faculty of Medicine Siriraj HospitalMahidol UniversityBangkokThailand

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