Small Intestinal Bacterial Overgrowth Is Associated with Non- Alcoholic Fatty Liver Disease

Abstract

Background: Changes in gut bacteria play a role in type 2 diabetes mellitus (DM) and hepatic steatosis. There is a lack of studies evaluating the frequency and risk factors for non-alcoholic fatty liver disease (NAFLD) in patients tested for small intestinal bacterial overgrowth (SIBO). Aim: To evaluate the frequency of NAFLD and associated risk factors in patients tested for SIBO.
 Methods: In this case-control study, 372 eligible patients submitted to glucose hydrogen/methane breath test for SIBO who also had an abdominal imaging study were included. Patients were divided into SIBO-positive and SIBO-negative groups. Clinical, demographic and laboratory variables were evaluated in addition to the presence of NAFLD on abdominal imaging.
 Results: Of the 372 eligible patients, 141 (37.9%) were tested positive for SIBO (study group) and 231 (62.1%) were negative for it (control group). NAFLD occurred in 45.4% (64/141) of the study group compared to 17.3% (40/231) of the control group (p<0.001). Patients in the study group were found to have higher rates of elevated aspartate aminotransferase (AST) (20.6% vs. 11.3%; p=0.034) and alanine aminotransferase (ALT) levels (56.0% vs. 40.7%; p= 0.039), type 2 diabetes (23.4% vs. 13.9%; p=0.041), hypertension (54.6% vs. 40.3%; p=0.046) and metabolic syndrome (78.0% vs. 60.2%; p=0.020). In the multivariate analysis, SIBO (odds ratio [OR]: 1.95; 95% confidence interval [CI]: 1.14-3.31; p=0.014), type 2 DM (OR: 3.04; 95%CI: 1.57-5.90; p=0.001) and obesity (OR: 3.58; 95%CI: 1.70-7.54; p=0.001) remained associated with NAFLD.Conclusion: Patients with SIBO have an increased risk for hepatic steatosis and may benefit from aggressive control of the risk factors for NAFLD including metabolic syndrome.
 Abbreviations: ALT: alanine aminotransferase; AST: aspartate aminotransferase; BMI: body mass index; CTE: computed tomography enterography; DM: diabetes mellitus; ETOH: ethanol; IL: interleukin; LPS: lipopolysaccharide; NAFLD: non-alcoholic fatty liver disease; NASH: non-alcoholic steatohepatitis; PPI: proton pump inhibitor; SIBO: small intestinal bacterial overgrowth; TLR-4: toll-like receptor 4; TMAO: trimethylamine-N-oxide (TMAO); TNF-α: tumor necrosis factor alpha.

Gut Microbiota’s Relationship with Liver Disease and Role in Hepatoprotection by Dietary Natural Products and Probiotics

“…Additionally, gut microbiota alteration could independently indicate the severity of NAFLD, namely, Streptococcaceae [ 46 ] and Bacteroides increase for NASH, and Ruminococcus increase for significant fibrosis, providing predictive effects on chronic liver diseases as well as the possible targets of treatment [ 47 ]. Furthermore, a positive association was found between small intestinal bacterial overgrowth and the frequency of NAFLD [ 48 ].…”

Treatment efficacy of a probiotic preparation for non‐alcoholic steatohepatitis: A pilot trial

“…The composition of the gastrointestinal (GI) microbial community has recently emerged as a new component in the pathogenesis of NASH . The conventional view is that bacteria are either destroyed by the gastric acid and phospholipase‐containing pancreatic juice or released with stool.…”

Ассоциация Синдрома Избыточного Бактериального Роста И Неалкогольной Жировой Болезни Печени У Детей

“…Thus, SIBO was diagnosed in 70 % of patients with NAFLD, at the same time, 70 % of obese/overweight children with SIBO were diagnosed with NAFLD. According to literature sources, the prevalence of SIBO with NAFLD ranges from 50 to 77.8 % [3,9,20].…”

“…Most of the works investigating SIBO effect on NAFLD development was performed in adult patients [9,10,14,16,18,20]. Frequently, for the diagnosis of SIBO, glucose hydrogen breath test is used, data on the presence of lactosedependent SIBO in such patients are limited.…”