There have been inconsistent findings on the association of obesity and non-constipation irritable bowel syndrome (IBS). Small intestinal bacterial overgrowth (SIBO) with hydrogen (H₂) gas forming-microflora causes non-constipation IBS. But, the effect of H₂ producing SIBO on obesity in non-constipation IBS patients has not been studied yet. The aim of this study was to investigate the association between obesity and SIBO in non-constipation IBS patients. We reviewed the charts of patients who showed IBS symptoms along with the documented results of their lactulose hydrogen breath test (LHBT) for SIBO. Multivariate models were used to assess the association between obesity and SIBO. Four-hundred fifty-eight patients were retrospectively included in the study. Of the 485 IBS patients, 158 (30.7%) subjects had positive results for LHBT. Subjects without SIBO showed significantly higher levels of body mass index (24.8 vs. 23.3; P < 0.001) and waist circumference (86.5 vs. 82.7; P < 0.001) as compared to subjects with SIBO. In multivariate analysis, the odds ratios of SIBO were 0.396 (P = 0.018) for obesity and 0.482 (P = 0.021) for abdominal obesity. This is the first human study to demonstrate that obesity is inversely related to SIBO with H2 gas production in non-constipation IBS patients.
Body Mass Index ; Breath Tests ; Humans ; Hydrogen ; Irritable Bowel Syndrome* ; Lactulose ; Multivariate Analysis ; Obesity* ; Obesity, Abdominal ; Odds Ratio ; Retrospective Studies ; Waist Circumference

OBJECTIVETo investigate the effects of lactulose on intestinal bacterial overgrowth (IBO), bacterial translocation (BT), intestinal transit and permeability in cirrhotic rats.

METHODSBT in all animals was assessed by bacterial culture of mesenteric lymph node (MLN), liver and spleen, and IBO was assessed by a jejunal bacterial count of the specific organism. Intestinal permeability was determined by the 24-hour urinary (99m)Tc-diethylenetriamine pentaacetatic acid ((99m)Tc-DTPA) excretion, and intestinal transit was determined by measuring the distribution of (51)Cr in the intestine.

RESULTSBT and IBO were found in 48% and 80% of the cirrhotic rats, respectively, while not in the control rats. Cirrhotic rats with IBO had significantly higher levels of intestinal endotoxin higher rates of bacterial translocation, shorter intestinal transit time and higher intestinal permeability than those without IBO. It was also found that BT were closely associated with IBO and injury of the intestinal barrier. Compared with the placebo group, lactulose-treated rats had lower rates of BT and IBO, which were closely associated with increased intestinal transit and improved intestinal permeability by lactulose.

CONCLUSIONSOur study indicate that endotoxin and bacterial translocation in cirrhotic rats may attribute to IBO and increased intestinal permeability. Lactulose that accelerates intestinal transit and improves intestinal permeability might be helpful in preventing intestinal bacterial and endotoxin translocation.

Animals ; Bacterial Translocation ; drug effects ; Endotoxins ; analysis ; Gastrointestinal Agents ; pharmacology ; Intestines ; metabolism ; microbiology ; Lactulose ; pharmacology ; Liver Cirrhosis, Experimental ; metabolism ; microbiology ; Male ; Rats ; Rats, Sprague-Dawley

Whether hydrogen and methane gas produced during lactulose breath test (LBT) are associated with symptoms of irritable bowel syndrome (IBS) is not determined. We aimed to investigate whether hydrogen and methane on LBT are associated with IBS symptoms. Sixty-eight IBS patients meeting the Rome III criteria for IBS, and 55 healthy controls, underwent LBT. The IBS subjects recorded their customary gastrointestinal symptoms on a questionnaire using visual analogue scales. LBT positivity was defined to be above 20 ppm rise of hydrogen or 10 ppm rise of methane within 90 min. Gas amounts produced during LBT were determined by calculating area under the curve of hydrogen and methane excretion. Symptom severity scores were not different between the LBT (+) IBS and LBT (-) IBS subjects and also between methane producers and non-methane producers. Gas amounts produced during LBT were not associated with IBS symptoms, except a weak correlation between total gas amounts and a few IBS symptoms such as bloating (r = 0.324, P = 0.039), flatulence (r = 0.314, P = 0.046) and abdominal pain (r = 0.364, P = 0.018) only in LBT (+) IBS. In conclusion, hydrogen and methane gas on LBT are not useful for predicting the customary symptoms and subtypes of IBS.
Abdominal Pain/etiology ; Adult ; Area Under Curve ; Breath Tests ; Female ; Flatulence/etiology ; Gases/analysis ; Humans ; Hydrogen/*analysis ; Irritable Bowel Syndrome/*diagnosis ; Lactulose/*metabolism ; Male ; Methane/*analysis ; Middle Aged ; ROC Curve ; Risk Factors

Small intestinal bacterial overgrowth (SIBO) can partly explain irritable bowel syndrome (IBS), and rifaximin has been observed to improve abdominal symptoms in nonconstipated IBS patients. However, there are few reports on the association of the rifaximin treatment periods with the results of a lactulose breath test (LBT). Therefore, we performed a retrospective review of patient charts to investigate the relation between the rifaximin treatment periods with LBT results in nonconstipated IBS patients. We also evaluated the time to achieve a symptomatic improvement in the IBS patients as compared to the changes in the LBT. We reviewed the charts for patients who showed IBS symptoms with documented positive results for LBT during their initial visit and who had a follow-up LBT after treatment with rifaximin. The LBT values were compared to the subjects' symptom scores. A total of 102 subjects had a follow-up LBT to assess LBT normalization. The subjects were divided into groups according to treatment periods of 4 weeks (n = 36), 8 weeks (n = 43), and 12 weeks (n = 23). The groups with a longer treatment exhibited an increase in the hydrogen gas value at 90 min and its sum during 90 min at the initial LBT. There were significant differences in hydrogen gas value at 90 min and in its sum during 90 min at the initial LBT between the groups treated for 4 and 12 weeks. The most significant treatment response was observed during the first 4 weeks for all treatment groups. Symptomatic improvement occurred earlier than LBT normalization in the treatment period over 4 weeks. The results indicate that different rifaximin treatment periods are needed in accordance with LBT levels to effectively eradicate SIBO.
Biomarkers/analysis ; Breath Tests/*methods ; Constipation ; Drug Administration Schedule ; Drug Monitoring/*methods ; Female ; Gastrointestinal Agents/administration & dosage ; Humans ; Irritable Bowel Syndrome/*diagnosis/*drug therapy ; Lactulose/*analysis ; Male ; Middle Aged ; Reproducibility of Results ; Rifamycins/*administration & dosage ; Sensitivity and Specificity ; Treatment Outcome