A population-based epidemiologic study of irritable bowel syndrome in South China: stratified randomized study by cluster sampling

Gender-specific insights into the irritable bowel syndrome pathophysiology. Focus on gut dysbiosis and permeability

Irritable bowel syndrome (IBS) is the most common functional gastrointestinal disorder involving the brain-gut interaction. IBS is characterized by persistent abdominal pain and changes in bowel habits. IBS exerts significant impacts on quality of life and imposes huge economic costs. Global epidemiological data reveal variations in IBS prevalence, both globally and between genders, necessitating comprehensive studies to uncover potential societal and cultural influences. While the exact pathophysiology of IBS remains incompletely understood, the mechanism involves a dysregulation of the brain-gut axis, leading to disturbed intestinal motility, local inflammation, altered intestinal permeability, visceral sensitivity, and gut microbiota composition. We reviewed several gender-related pathophysiological aspects of IBS pathophysiology, by focusing on gut dysbiosis and intestinal permeability. This perspective paves the way to personalized and multidimensional clinical management of individuals with IBS.

Multiomics Analysis Reveals Gut Virome-Bacteria-Metabolite Interactions and Their Associations with Symptoms in Patients with IBS-D

The gut microbiota is involved in the pathogenesis of diarrhea-predominant irritable bowel syndrome (IBS-D), but few studies have focused on the role of the gut virome in IBS-D. We aimed to explore the characteristics of the gut virome in patients with IBS-D, its interactions with bacteria and metabolites, and the associations between gut multiomics profiles and symptoms. This study enrolled twelve patients with IBS-D and eight healthy controls (HCs). The stool samples were subjected to metavirome sequencing, 16S rRNA gene sequencing, and untargeted metabolomic analysis. The participants completed relevant scales to assess the severity of their gastrointestinal symptoms, depression, and anxiety. The results revealed unique DNA and RNA virome profiles in patients with IBS-D with significant alterations in the abundance of contigs from Siphoviridae, Podoviridae, Microviridae, Picobirnaviridae, and Tombusviridae. Single-omics co-occurrence network analyses demonstrated distinct differences in the gut virus, bacteria, and metabolite network patterns between patients with IBS-D and HCs. Multiomics networks revealed that short-chain fatty acid-producing bacteria occupied more core positions in IBS-D networks, but had fewer links to viruses. Amino acids and their derivatives exhibit unique connectivity patterns and centrality features within the IBS-D network. The gastrointestinal and psychological symptom factors of patients with IBS-D were highly clustered in the symptom-multiomics network compared with those of HCs. Machine learning models based on multiomics data can distinguish IBS-D patients from HCs and predict the scores of gastrointestinal and psychological symptoms. This study provides insights into the interactions among gut viruses, bacteria, metabolites, and clinical symptoms in patients with IBS-D, indicating further classification and personalized treatment for IBS-D.

Using ultra-performance liquid chromatography with linear ion trap-electrostatic field orbitrap mass spectrometry, network pharmacology, and molecular docking to explore the constituent targets and action mechanisms of decoction of Angelica sinensis, Zingiberis Rhizoma Recens, and Mutton in the treatment of diarrhea-predominant irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a chronic intestinal disorder characterized by abdominal discomfort, stool characteristics, and changes in bowel habits. Among them, diarrhea-type (diarrhea-predominant irritable bowel syndrome, abbreviated as IBS-D) is the most common. Because its pathogenesis is not understood, symptomatic treatment is currently used in clinical practice, and its long-term effect is still unclear. Decoction of Angelica sinensis, Zingiberis Rhizoma Recens, and Mutton (DAZM) is a famous traditional Chinese medicine recipe created by Zhang Zhongjing, a famous doctor in the Eastern Han Dynasty 2000 years ago, and is still in use today. Our research team has previously investigated the clinical study of DAZM in the treatment of IBS-D and conducted animal experiment research, indicating that DAZM has a significant effect on improving IBS-D. Yet, there are few reports on the specific mechanism of action of DAZM in improving the treatment of IBS and related types. Most studies discuss and verify its efficacy and protection from a clinical perspective. For this reason, this research will explore the constituent targets and mechanisms of DAZM to improve the treatment of IBS-D, provide relevant scientific evidence, and also provide reference evidence for the efficacy of food therapy decoction in improving the treatment of diseases and mechanism to open up new experimental research ideas.

METHODS

Identification of drug ingredients and collection of targets for DAZM using ultra-performance liquid chromatography with linear ion trap-electrostatic field orbitrap mass spectrometry and the Bioinformatics Analysis Tool for Molecular Mechanisms of Traditional Chinese Medicine database, active ingredients were selected based on their oral bioavailability and drug-like properties. Obtained IBS-D targets using the GeneCards database, took the intersection of IBS-D targets and DAZM targets and obtained potential targets of DAZM for the treatment of IBS-D. Using Cytoscape software to draw a network diagram of "Food therapy decoction-ingredient-target-disease" and selected the ingredients with larger parameter values by topological analysis. Correlation analysis of the selected active and parametric ingredients with prominent symptoms of IBS-D using SymMap database, and selection of potential core ingredients. The construction of protein interaction networks from the String database and the selection of potential core targets. Gene Ontology functional and Kyoto Encyclopedia of Genes and Genomes signaling pathway enrichment analyses using the Metascape database, establishing the bioinformatic processes and signaling pathways involved. Molecular docking of core ingredients and potential core targets was performed using AutoDock Vina, and the results were visualized using Python molecule (PyMOL) and LigPlus+. Finally, based on the results of this research combined with previous literature reports, the discussion section of this paper summarizes in detail the key core ingredients, targets, and signaling pathways of DAZM in improving IBS-D.

RESULTS

DAZM may act on eight potential core targets (threonine kinase 1, insulin, tumour necrosis factor, tumour protein p53, interleukin 6, epidermal growth factor receptor, connexin β1, and interleukin 1β) through eight core ingredients (Zingiberone, Shyobunone, Palmitic acid, Sebiferic acid, β-Bisabolene, β-Sitosterol, Stigmasterol, and Oleic acid). inhibit pro-inflammatory factors through Advanced Glycation End Products-Receptor (AGE-RAGE) signaling pathway, Cyclic Adenosine Monophosphate (cAMP) signaling pathway, MAPK signaling pathway, IL-17 signaling pathway, Calmodulin (CaM) signaling pathway, and other pathways. It can alleviate the inflammatory response, enhance the intestinal mucosal barrier and regulate intestinal motility, and play a role in the treatment and improvement of IBS-D.

CONCLUSIONS

This research mainly found the mechanism of DAZM on IBS-D, which may involve multiple ingredients, multiple targets, and multiple pathways. DAZM with medicinal and edible functions can effectively improve the treatment of IBS-D. This kind of dietary therapy is suitable for long-term treatment and is worthy of promotion.

Gender differences in gastrointestinal, biopsychosocial and healthcare-seeking behaviors in Chinese patients with irritable bowel syndrome predominant with diarrhea

BACKGROUND

Evidences of comparison of sex difference in Chinese irritable bowel syndrome (IBS) patients were few. We aim to compare gender difference in the biopsychosocial characteristics of Chinese patients of IBS predominant with diarrhea (IBS-D).

METHODS

IBS-D patients meeting Rome III criteria were enrolled. We administered IBS symptom questionnaires, evaluation of psychological status (HAMD and HAMA scales) and IBS quality of life (IBS-QOL), dietary habits, healthcare seeking behaviors, and compared biopsychosocial characteristics between male and female patients.

RESULTS

Four hundred and ninety patients were enrolled including 299 males and 191 females. More female patients reported abdominal pain associated with defecation (84.3% vs. 74.9%, P = 0.014) while males reported more abdominal discomfort (39.8% vs. 26.7%, P = 0.003). Females had higher IBS symptom score (9.7 ± 1.7 vs. 9.4 ± 1.4, P = 0.025) and more of females had severe abdominal pain/discomfort (17.8% vs. 12.4%, P = 0.013) while there were no significant differences of other bowel symptoms. Females reported higher incidence of comorbid anxiety state (64.9% vs. 52.8%, P = 0.008) and depression state (35.6% vs. 19.7%, P < 0.001) than males. Female patients also had lower IBS-QOL score (70.2 ± 20.4 vs. 75.1 ± 16.8, P = 0.028) and more frequent consultations, as well as less response for dietary modification than males.

CONCLUSIONS

Chinese female patients with IBS-D had more prominent psychosocial disorders compared to male patients and their abdominal symptoms had minor differences.

Risk Factors of Developing Postinfectious Irritable Bowel Syndrome in Shigellosis Patients, 5 Years After Hospitalization During the Outbreak

Background

Irritable bowel syndrome (IBS) can be triggered by bacterial dysentery. This study aimed to investigate postinfectious IBS and its risk factors after the shigellosis outbreak in hospitalized patients.

Methods

This retrospective study was conducted in 2020-2021 in referral hospitals for Shigella gastroenteritis during the 2014 shigellosis outbreak in Isfahan. The Shigella-infected group included hospitalized shigellosis patients with clinical symptoms and positive stool culture. The control group included patients matched pairwise on age and sex to the Shigella-infected group, admitted to the same hospitals in the same period with diagnoses other than shigellosis. Both groups had no history of diagnosed IBS before the outbreak. The incidence of IBS (according to Rome-III criteria) and its related factors was compared between the 2 groups 5 years after infection.

Results

Of 619 participants, 220 (35.5%) were in the Shigella-infected group. The 5-year incidence of IBS was 31.8% and 5.7% in the Shigella-infected and control groups, respectively. Multivariate analysis showed that shigellosis was significantly associated with increased risk of IBS (odds ratio [OR], 17.18 [95% confidence interval {CI}, 9.37-31.48]). Multivariate analysis indicated education level (OR, 4.15 [95% CI, 1.47-11.73]), diarrhea lasting >4 days (OR, 1.69 [95% CI, 1.17-2.44]), and abdominal cramps during the infection (OR, 0.27 [95% CI, .77-.95]) associated with postinfectious IBS (P < .05).

Conclusions

Hospitalized patients with Shigella gastroenteritis are at increased risk of IBS within 5 years after infection. Factors such as higher education level and the absence of abdominal cramps and diarrhea persisting for >5 days during hospitalization can further increase this risk.

Cognition of abdominal pain and abdominal discomfort in Chinese patients with irritable bowel syndrome with diarrhea

BACKGROUND

In Asia, the proportion of patients with irritable bowel syndrome (IBS) with abdominal discomfort alone is significantly higher than that in western countries. The purposes of this study are to understand the cognition of abdominal pain and abdominal discomfort in Chinese patients with IBS and to compare the clinical characteristics of patients with abdominal pain alone and with abdominal discomfort alone.

METHODS

Patients with IBS with diarrhea (IBS-D) who met the Rome III diagnostic criteria and had episodes of at least one day/week were consecutively enrolled. The cognition of abdominal pain and abdominal discomfort were investigated through face-to-face unstructured interview. Patients were divided into a pain group and a discomfort group according to the cognition interviews, then the characteristics and severity of symptoms (IBS symptom severity scale, IBS-SSS), IBS quality of life (IBS-QOL) and psychological state were compared between groups.

RESULTS

A total of 88 patients with IBS-D were enrolled. Most of the patients with self-reported abdominal pain described their pain as spasm/cramping; patients with self-reported abdominal discomfort had as many as 24 different descriptions of discomfort. Most patients having abdominal pain and discomfort could accurately distinguish the two symptoms. The degree of abdominal pain in the pain group was higher than abdominal discomfort in the discomfort group (P = 0.002). There was no significant difference in IBS-SSS, extra-intestinal pain, IBS-QOL, and psychological state between the two groups.

CONCLUSIONS

For Chinese patients with IBS-D, abdominal pain and abdominal discomfort are two different symptoms, but they have similar clinical features.

TRIAL REGISTRATION

ChiCTR, ChiCTR1900028082. Registered 11 December 2019 - Retrospectively registered, http://www.chictr.org.cn .

Patients' perspectives on irritable bowel syndrome: a qualitative analysis based on social media in China

AIM

To explore the perspectives, experience, and concerns of patients with irritable bowel syndrome (IBS) in China.

METHODS

We used data mining to investigate posts shared in Baidu Tieba concerned with IBS; we collected the data through the crawler code, and mined the cleaned data's themes based on Latent Dirichlet allocation (LDA) and the Grounded theory.

RESULTS

We found 5746 network posts related to IBS. LDA analysis generated 20 topics, and grounded theory analysis established eight topics. Combining the two methods, we finally arranged the topics according to five concepts: difficulty in obtaining disease information; serious psychosocial problems; dissatisfied with the treatment; lack of social support; and low quality of life.

CONCLUSION

Social media research improved patient-centric understanding of patients' experiences and perceptions. Our study may facilitate doctor-patient communication and assist in the formulation of medical policies.

Golden bifid might improve diarrhea-predominant irritable bowel syndrome via microbiota modulation

Objective

Gut microbiota might play a crucial role in the pathogenesis of irritable bowel syndrome (IBS), and probiotics supplement may be an effective treatment option. This study aims to explore the therapeutic effects of Golden bifid on the diarrhea-predominant IBS (IBS-D).

Methods

Twenty-one consecutive IBS-D patients were recruited based on Rome IV criteria. All patients took 2000 mg Golden bifid triple daily for 4 weeks. Gastrointestinal (GI) symptoms, psychological symptoms, small intestine bacterial overgrowth (SIBO) and fecal microbiota characteristics were evaluated in IBS-D patients before and after treatment.

Results

After 4-week treatment of Golden bifid, the GI symptoms such as abdominal pain (2.90 ± 1.04 vs. 1.90 ± 1.26, P = 0.002), abdominal distension (2.00 ± 1.34 vs. 1.29 ± 1.31, P = 0.007), diarrhea (3.24 ± 1.37 vs. 1.81 ± 1.21, P = 0.001), defecatory urgency (3.48 ± 1.03 vs. 2.33 ± 1.35, P = 0.000) and incomplete evacuation (2.71 ± 1.15 vs. 1.76 ± 1.26, P = 0.003) were significantly alleviated in IBS-D patients. The Self-Rating Depression Scale (SDS) decreased significantly (46.19 ± 11.36 vs. 43.33 ± 9.65, P = 0.041), and SIBO could be eradicated in 25% (4/16) of IBS-D patients with SIBO. Meanwhile, the abundance of Unclassified Lachnospiraceae and Dorea in genus level and Unclassified Lachnospiraceae, Bacterium Dorea, Bacterium Butyricicoccus and Dorea formicigenerans ATCC 27755 in species level were increased in fecal microbiota (P < 0.05).

Conclusions

Golden bifid could improve most of GI symptoms and depressive symptoms in IBS-D patients and eradicate a small proportion of SIBO in those IBS-D patients with SIBO. What's more, Golden bifid could also modulate the fecal microbiota in IBS-D patients, which implied that the Golden bifid might improve IBS-D via microbiota modulation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41043-022-00302-0.

Gut microbiota plays a role in irritable bowel syndrome by regulating 5-HT metabolism

Irritable bowel syndrome (IBS) is a common chronic functional gastrointestinal disorder. Brain-gut-microbiota axis dysfunction is an important pathogenic factor for IBS, in which neurotransmitters and gut microbes play key roles. The gastrointestinal tract contains large amounts of serotonin (5-hydroxytryptamine, 5-HT), a neurotransmitter that has been strongly linked to IBS-related symptoms. More than 90% of serotonin is synthesized in the gut by enterochromaffin cells (ECs), and certain intestinal flora can affect the occurrence and development of IBS by regulating 5-HT and its metabolism. In this review, we will discuss the role of gut microbiota in IBS by regulating 5-HT.

Are bowel symptoms and psychosocial features different in irritable bowel syndrome patients with abdominal discomfort compared to abdominal pain?

BACKGROUND

The Rome IV criteria eliminated abdominal discomfort for irritable bowel syndrome (IBS), which was previously included in Rome III. There are questions as to whether IBS patients with abdominal discomfort (seen in Rome III but not Rome IV) are different from those with abdominal pain (Rome IV).

AIM

To compare bowel symptoms and psychosocial features in IBS patients diagnosed with Rome III criteria with abdominal discomfort, abdominal pain, and pain & discomfort.

METHODS

We studied IBS patients meeting Rome III criteria. We administered the IBS symptom questionnaire, psychological status, and IBS quality of life. Patients were classified according to the predominant abdominal symptom associated with defecation into an only pain group, only discomfort group, and pain & discomfort group. We compared bowel symptoms, extraintestinal symptoms, IBS quality of life, psychological status and healthcare-seeking behaviors, and efficacy among the three groups. Finally, we tested risk factors for symptom reporting in IBS patients.

RESULTS

Of the 367 Rome III IBS patients enrolled, 33.8% (124 cases) failed to meet Rome IV criteria for an IBS diagnosis. There were no meaningful differences between the pain group (n = 233) and the discomfort group (n = 83) for the following: (1) Frequency of defecatory abdominal pain or discomfort; (2) Bowel habits; (3) Coexisting extragastrointestinal pain; (4) Comorbid anxiety and depression; and (5) IBS quality of life scores except more patients in the discomfort group reported mild symptom than the pain group (22.9% vs 9.0%). There is a significant tendency for patients to report their defecatory and non-defecatory abdominal symptom as pain alone, or discomfort alone, or pain & discomfort (all P < 0.001).

CONCLUSION

IBS patients with abdominal discomfort have similar bowel symptoms and psychosocial features to those with abdominal pain. IBS symptoms manifesting abdominal pain or discomfort may primarily be due to different sensation and reporting experience.

Responses to faecal microbiota transplantation in female and male patients with irritable bowel syndrome

BACKGROUND

Faecal microbiota transplantation (FMT) seems to be a promising treatment for irritable bowel syndrome (IBS) patients. In Western countries (United States and Europe), there is a female predominance in IBS. A sex difference in the response to FMT has been reported recently in IBS patients.

AIM

To investigate whether there was a sex difference in the response to FMT in the IBS patients who were included in our previous randomized controlled trial of the efficacy of FMT.

METHODS

The study included 164 IBS patients who participated in our previous randomized controlled trial. These patients had moderate-to-severe IBS symptoms belonging to the IBS-D (diarrhoea-predominant), IBS-C (constipation-predominant) and IBS-M (mixed) subtypes, and had not responded to the National Institute for Health and Care Excellence (NICE)-modified diet. They belonged in three groups: placebo (own faeces), and active treated group (30-g or 60-g superdonor faeces). The patients completed the IBS severity scoring system (IBS-SSS), Fatigue Assessment Scale (FAS) and the IBS quality of life scale (IBS-QoL) questionnaires at the baseline and 2 wk, 1 mo and 3 mo after FMT. They also provided faecal samples at the baseline and 1 mo after FMT. The faecal bacteria profile and dysbiosis were determined using the 16S rRNA gene polymerase chain reaction DNA amplification covering V3-V9; probe labelling by single nucleotide extension and signal detection. The levels of short-chain fatty acids (SCFAs) were determined by gas chromatography and flame ionization.

RESULTS

There was no sex difference in the response to FMT either in the placebo group or active treated group. There was no difference between females and males in either the placebo group or actively treated groups in the total score on the IBS-SSS, FAS or IBS-QoL, in dysbiosis, or in the faecal bacteria or SCFA level. However, the response rate was significantly higher in females with diarrhoea-predominant (IBS-D) than that of males at 1 mo, and 3 mo after FMT. Moreover, IBS-SSS total score was significantly lower in female patients with IBS-D than that of male patients both 1 mo and 3 mo after FMT.

CONCLUSION

There was no sex difference in the response to FMT among IBS patients with moderate-to-severe symptoms who had previously not responded to NICE-modified diet. However, female patients with IBS-D respond better and have higher reduction of symptoms than males after FMT.

Alterations in short-chain fatty acids and serotonin in irritable bowel syndrome: a systematic review and meta-analysis

BACKGROUND

Short-chain fatty acids (SCFAs) and serotonin (5-hydroxytryptamine, 5-HT) may be associated with the pathogenesis of irritable bowel syndrome (IBS). There are some reports of alterations in SCFAs and 5-HT in IBS, but their results are inconsistent. We aimed to perform a meta-analysis to assess alterations in SCFAs and 5-HT in IBS patients and their potential role in the abnormal brain-gut-microbiota (BGM) axis.

METHODS

Case-control studies detecting SCFAs and 5-HT in IBS patients were identified from PubMed, Web of Science, Cochrane Library, and Scopus databases to identify relevant articles up to September 2018. The standardized mean differences (SMDs) with 95% confidence intervals (CIs) of SCFAs and 5-HT were calculated by REVIEW MANAGER 5.3 to evaluate the alterations of 5-HT and SCFAs in IBS.

RESULTS

Five studies on SCFAs and 5 on 5-HT in IBS patients were included. As compared to healthy controls (HCs), the SMDs of 5-HT in IBS patients was 2.35 (95% CI 0.46-4.24) and the SMDs of total SCFAs, acetic acid, propionic acid, and butyric acid in IBS patients were - 0.01 (95% CI - 0.57-0.55), - 0.04 (95% CI - 0.55-0.47), 0.07 (95% CI - 0.45-0.60), and - 0.00 (95% CI - 0.49-0.49), respectively.

CONCLUSIONS

There was an increase in 5-HT in blood of IBS patients, indicating the increased 5-HT in blood may be involved in IBS pathogenesis. However, there were no significant differences in SCFAs in feces between IBS patients and HCs. But the study did not differentiate between subgroups of IBS. These findings might provide insight for future studies of the BGM axis in the pathogenesis of IBS. Mei Luo and Xiaojun Zhuang contributed equally to the writing of this article.

The role of diet in the pathophysiology and management of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a chronic gastrointestinal (GI) disorder that reportedly affects 5% to 20% of the world population. The etiology of IBS is not completely understood, but diet appears to play an important role in its pathophysiology. Asian diets differ considerably from those in Western countries, which might explain differences in the prevalence, sex, and clinical presentation seen between patients with IBS in Asian and Western countries. Dietary regimes such as a low-fermentable oligo-, di-, monosaccharides, and polyols (FODMAP) diet and the modified National Institute for Health and Care Excellence (NICE) diet improve both symptoms and the quality of life in a considerable proportion of IBS patients. It has been speculated that diet is a prebiotic for the intestinal microbiota and favors the growth of certain bacteria. These bacteria ferment the dietary components, and the products of fermentation act upon intestinal stem cells to influence their differentiation into enteroendocrine cells. The resulting low density of enteroendocrine cells accompanied by low levels of certain hormones gives rise to intestinal dysmotility, visceral hypersensitivity, and abnormal secretion. This hypothesis is supported by the finding that changing to a low-FODMAP diet restores the density of GI cells to the levels in healthy subjects. These changes in gut endocrine cells caused by low-FODMAP diet are also accompanied by improvements in symptoms and the quality of life.

A Randomized, Double-Blind, Placebo Controlled, Parallel-Group, Comparative Clinical Study to Evaluate the Efficacy and Safety of OLNP-06 versus Placebo in Subjects with Functional Dyspepsia

OLNP-06 is ginger extract product standardized to higher amount of total gingerols formulated with proprietary Aqueosome technology. The safety and efficacy of OLNP-06 were evaluated in a randomized, double blind, placebo controlled, parallel group comparative clinical study in subjects with functional dyspepsia (FD). Significant improvements in clinical endpoints were observed during the trial along with excellent safety profile. Fifty subjects aged between 18 and 55 years suffering from FD as per ROME III criteria were enrolled into the study. They were randomized into two treatment groups, one group received OLNP-06, 200 mg twice daily and other group received placebo 200 mg twice daily. The primary efficacy end point was global assessment of overall treatment efficacy (OTE). Secondary efficacy endpoints were elimination rate of three major symptoms (postprandial fullness, upper abdominal bloating and early satiation) and elimination rate for each individual symptom scores. Biochemical and hematological parameters including urine analysis were performed to evaluate the safety of OLNP-06. Out of 50 subjects, 48subjects completed the study. Total 79% of the subjects receiving OLNP-06 and 21% of the subjects receiving placebo (p < .05) were classified as responders according to the assessment of OTE. Elimination rate (score 0) of postprandial fullness, upper abdominal bloating and early satiation was 64% in subjects receiving ONLP-06 compared with 13% in the placebo group (p < .05). OLNP-06 was found to be safe and well tolerated as there was no incidence of treatment-related AE's. Supplementation of OLNP-06 for 4 weeks significantly reduced dyspeptic symptoms in subjects suffering from FD.Trial Registration: Clinical Trial Registry-India, CTRI/2019/09/021019, Registered on 2 Sep 2019.

Global burden of irritable bowel syndrome: trends, predictions and risk factors

Irritable bowel syndrome (IBS) is one of the most common disorders of gut-brain interaction worldwide, defined according to patterns of gastrointestinal symptoms as described by the Rome diagnostic criteria. However, these criteria, developed with reference to research conducted largely in Western populations, might be limited in their applicability to other countries and cultures. Epidemiological data show a wide variation in the prevalence of IBS globally and more rigorous studies are needed to accurately determine any differences that might exist between countries as well as the potential explanations. The effects of IBS on the individual, in terms of their quality of life, and on health-care delivery and society, in terms of economic costs, are considerable. Although the magnitude of these effects seems to be comparable between nations, their precise nature can vary based on the existence of societal and cultural differences. The pathophysiology of IBS is complex and incompletely understood; genetics, diet and the gut microbiome are all recognized risk factors, but the part they play might be influenced by geography and culture, and hence their relative importance might vary between countries. This Review aims to provide an overview of the burden of IBS in a global context, to discuss future implications for the care of people with IBS worldwide, and to identify key areas for further research.

Short-course Rifaximin therapy efficacy and lactulose hydrogen breath test in Chinese patients with diarrhea-predominant irritable bowel syndrome

Background

Gut microbiota alterations including small intestinal bacterial overgrowth (SIBO) might play a role in pathogenesis of irritable bowel syndrome (IBS). Rifaximin could effectively and safely improve IBS symptoms. The aim of this study was to investigate the effect of rifaximin on Gastrointestinal (GI) symptoms, quality of life (QOL) and SIBO eradication in Chinese IBS-D patients.

Methods

This study included 78 IBS-D patients defined by the Rome IV criteria. Patients received 400 mg rifaximin twice daily for 2 weeks and 10-week follow-up. GI symptoms were assessed at week 0, 2, 4, 8 and 12. QOL and lactulose hydrogen breath test (LHBT) results were estimated at week 0 and 4.

Results

All participants showed significant improvements in GI symptom subdomains after rifaximin treatment (all P < 0.05), which could maintain at least 10 weeks of follow-up. Additionally, QOL scores were increased with concomitant improvement of clinical symptoms (all P < 0.05). The 45 rifaximin-responsive patients (57.7%) achieved significantly greater GI-symptom improvement than non-responders (all P < 0.05). No GI symptoms were associated with SIBO (all P > 0.05). SIBO normalization after rifaximin treatment measured by LHBT was found in 44.4% (20/45) of patients with SIBO before treatment.

Conclusion

A short course (2 weeks) of rifaximin improved GI symptoms and QOL in Chinese IBS-D patients whether they had SIBO or not. However, the efficacy of rifaximin could not be explained by the successful eradication of SIBO. Further studies on the therapeutic mechanisms of rifaximin in IBS are urgently needed.

Overlapping of irritable bowel syndrome with erosive esophagitis and the performance of Rome criteria in diagnosing IBS in a clinical setting

Irritable bowel syndrome (IBS) and gastroesophageal reflux disease (GERD) overlap. It is not clear whether GERD is caused by non-erosive esophagitis, or erosive esophagitis. The Rome criteria are not widely used for the diagnosis of IBS in the clinic. In total, 1,489 IBS patients without red flags were included in the present retrospective study. They comprised of 1,331 females and 158 males with a mean age of 51 years. The diagnosis of IBS was verified by endoscopic and histopathological examinations. Whereas erosive esophagitis occurred in 97% of patients, only 66% had GERD symptoms. Endoscopy and histopathological examinations revealed that 1.4% of the IBS patients with diarrhea as the predominant symptom had other organic gastrointestinal diseases: 0.3% with celiac disease, 0.2% with Crohn's disease, 0.07% with ulcerative colitis, 0.6% with microscopic colitis, and 0.2% with colon cancer. Applying the Rome III criteria produced a sensitivity of 100% [95% confidence intervals (CI)=99.8–100.0%] a specificity of 98.7% (95% CI=98.0–99.2%), a positive likelihood ratio of 76.9%, and a negative likelihood ratio of 0%. IBS is associated with erosive esophagitis. Applying Rome III criteria without red flags and history, was effective in diagnosing IBS. Celiac disease and microscopic colitis should be considered as alternative diagnoses.

Fecal Microbiota Alterations Associated With Diarrhea-Predominant Irritable Bowel Syndrome

Altered gut microbiota are assumed to be involved in the pathogenesis of irritable bowel syndrome (IBS). However, gut microbiota alterations reported in different studies are divergent and sometimes even contradictory. To better elucidate the relationship between altered gut microbiota and IBS, we characterized fecal microbiota of diarrhea-predominant IBS (IBS-D) patients and further explored the effect of rifaximin on gut microbiota using bacterial 16S rRNA gene-targeted pyrosequencing. In our study, IBS-D patients defined by Rome III criteria and age-and-gender matched healthy controls (HC) were enrolled to investigate the fecal microbiota alterations. These IBS-D patients were then treated with rifaximin for 2 weeks and followed up for 10 weeks. Fecal microbiota alterations, small intestine bacterial overgrowth (SIBO) and gastrointestinal (GI) symptoms of IBS-D patients were analyzed before and after treatment. Our results showed fecal microbiota richness but not diversity was decreased in IBS-D patients as compared to HC and there were alterations of fecal microbiota at different taxonomy levels. The abundant phyla Firmicutes was significantly decreased and Bacteroidetes was increased in IBS-D patients. Moreover, the alterations of predominant fermenting bacteria such as Bacteroidales and Clostridiales might be involved in the pathophysiology of IBS-D. In addition, rifaximin was effective in terms of SIBO eradication and even GI symptoms of IBS-D patients achieved at least 10-week improvement after treatment. Furthermore, rifaximin induced alterations of some special bacteria rather than affected the overall composition of microbiota in IBS-D patients. Meanwhile, a potential decrease in propanoate and butanoate metabolism was found in these IBS-D patients after rifaximin treatment. Taken together, there were alterations of gut microbiota in IBS-D patients as compared to HC. Rifaximin could relieve GI symptoms, modify gut microbiota in IBS-D patients and eradicate SIBO in those patients with SIBO, suggesting an additional therapeutic mechanism of rifaximin in the treatment of IBS-D. Our findings of compositional gut microbiota alterations in IBS-D and the effect of rifaximin on the gut microbiota implied that altered gut microbiota were associated with the pathogenesis of IBS.

A Comprehensive Look at Irritable Bowel Syndrome and its Associated Factors Considering the Rome IV Criteria: A Penalized Smoothly Clipped Absolute Deviation Regression Approach in the Pars Cohort Study

BACKGROUND

After the introduction of the Rome IV criteria for the diagnosis of irritable bowel syndrome (IBS), studies on the clinical significance of the new criteria in the settings of a large study has been scarce.

Objective: Herein we used the infrastructures provided by one the largest cohort studies in Iran to evaluate the epidemiological features related to IBS.

METHODS

A total of 9264 participants, were enrolled in the initial registry. Diagnosis of IBS was done using the Rome IV criteria. Individuals with IBS were compared with a control group. Since the study included a large sample size of patients, we used the penalized smoothly clipped absolute deviation (SCAD) regression analysis to construct a model for the evaluation of factors associated with IBS.

RESULTS

Overall, data of 9163 participants entered the final analysis. In total, 1067 (11.6%) individuals were diagnosed with IBS, among which 57 (5.3%) were diarrhea dominant (IBS-D), 380 (35.6%) were constipation dominant (IBS-C), and 630 (59%) did not mention having any of the two (IBS-U). In the regression model, back pain/arthralgia (OR: 1.98, 95% CI: 1.65 - 2.40), insomnia (OR: 1.65, 95% CI: 1.40 - 1.93), depression (OR: 1.64, 95% CI: 1.38 - 1.95), female sex (OR: 1.58, 95% CI: 1.27 - 1.96), anxiety (OR: 1.43, 95% CI: 1.21 - 1.69), and being married (OR: 1.23, 95% CI: 1.03 - 1.48), were associated with higher rates of IBS. We found that IBS prevalence displays a peak at the age of 41 years for both men and women.

CONCLUSION

The present study provides a background for follow-up studies to be conducted in order to evaluate causality between IBS and some major diseases such as liver disease. We also found that opium use, although not statistically significant, in addition to sex, education, back/joint pain, depression, insomnia, anxiety, and marital status might be a contributing factor in IBS.

Prevalence of celiac disease in adult Chinese patients with diarrhea-predominant irritable bowel syndrome: A prospective, controlled, cohort study

OBJECTIVE

Celiac disease is a chronic inflammatory enteropathy with a symptom spectrum similar to that of irritable bowel syndrome (IBS). It is a common but largely undiagnosed condition in the Western countries. However, it is extremely rare among Chinese individuals, and few studies have investigated its prevalence in China. The aim was to determine the prevalence of celiac disease in patients with IBS who were diagnosed using the Rome III criteria in a single center of northern China.

METHODS

This was a single-center, prospective, controlled cohort study performed in Qilu Hospital involving 246 patients with IBS and 246 healthy controls. Blood samples were drawn to assess serum tissue transglutaminase immunoglobulin A (tTg-IgA). Patients with a positive or equivocal tTg-IgA (≥15 U/mL) were subjected to probe-based confocal laser endomicroscopy (pCLE) and duodenal biopsy to confirm celiac disease.

RESULTS

Altogether 12 (4.9%) patients with IBS and two (0.8%) healthy controls were positive or equivocal for serum tTg-IgA. Of these, five patients with IBS underwent pCLE and a targeted biopsy; all were histopathologically found to have celiac disease, although one was eventually diagnosed with lymphoma. After implementation of a gluten-free diet, seven patients serologically positive for IBS showed clinical improvement, thus our study illustrated a minimum prevalence of 2.85% of celiac disease among patients with IBS in our center.

CONCLUSIONS

Celiac disease is not rare in Chinese individuals, particularly among those with IBS. Therefore, it should receive higher attention in clinical practice in China.

Effect of Lactobacillus rhamnosus GG supernatant on serotonin transporter expression in rats with post-infectious irritable bowel syndrome

AIM

To evaluate the effect of Lactobacillus rhamnosus GG supernatant (LGG-s) on the expression of serotonin transporter (SERT) in rats with post-infectious irritable bowel syndrome (PI-IBS).

METHODS

Campylobacter jejuni 81-176 (10¹⁰ CFU/mL) was used to induce intestinal infection to develop a PI-IBS model. After evaluation of the post-infectious phase by biochemical tests, DNA agarose gel electrophoresis, abdominal withdrawal reflex (AWR) test, and the intestinal motility test, four PI-IBS groups received different concentrations of LGG-s for 4 wk. The treatments were maintained for 1.0, 2.0, 3.0 or 4.0 wk during the experiment, and the colons and brains were removed for later use each week. SERT mRNA and protein levels were detected by real-time PCR and Western blot, respectively.

RESULTS

The levels of SERT mRNA and protein in intestinal tissue were higher in rats treated with LGG-s than in control rats and PI-IBS rats gavaged with PBS during the whole study. Undiluted LGG-s up-regulated SERT mRNA level by 2.67 times compared with the control group by week 2, and SERT mRNA expression kept increasing later. Double-diluted LGG-s was similar to undiluted-LGG-s, resulting in high levels of SERT mRNA. Triple-diluted LGG-s up-regulated SERT mRNA expression level by 6.9-times compared with the control group, but SERT mRNA expression decreased rapidly at the end of the second week. At the first week, SERT protein levels were basically comparable in rats treated with undiluted LGG-s, double-diluted LGG-s, and triple-diluted LGG-s, which were higher than those in the control group and PBS-treated PI-IBS group. SERT protein levels in the intestine were also comparable in rats treated with undiluted LGG-s, double-diluted LGG-s, and triple-diluted LGG-s by the second and third weeks. SERT mRNA and protein levels in the brain had no statistical difference in the groups during the experiment.

CONCLUSION

LGG-s can up-regulate SERT mRNA and protein levels in intestinal tissue but has no influence in brain tissue in rats with PI-IBS.

Irritable bowel syndrome in Asia: Pathogenesis, natural history, epidemiology, and management

Historically, the epidemiology of gastrointestinal diseases in Asia was different from that in Western countries. Early studies suggested a low prevalence of irritable bowel syndrome (IBS) in Asia. As the diagnosis of IBS is symptom-based and as symptom perception, expression, and interpretation are influenced by sociocultural perspectives including language, the presentation of IBS is expected to vary in different communities. Furthermore, the pathogenesis is multifactorial with psychosocial (stress, illness, behavior, and diet) and biological (infection, gut microbiota, and immune activation) variables interacting, and so, the present study can anticipate that the development of IBS will vary in different environments. In recognition of this aspect of functional gastrointestinal disorders, the recently published Rome IV documents have provided greater focus on cross-cultural factors. In this review, the present study seeks to highlight Asian perspectives by identifying historical trends and recent publications from the region and comparing these with the observations from Western societies.

Irritable bowel syndrome: prevalence, risk factors in an adult Lebanese population

Background

Very few studies report on the prevalence of irritable bowel syndrome (IBS) and its correlates in the Middle East. This study investigated Irritable Bowel Syndrome (IBS) prevalence in a sample of Lebanese adult individuals and associated demographic and behavioral lifestyle factors.

Methods

This is an observational population-based study. The target population is working Lebanese adults, eighteen-to-sixty five years old. The sample was selected from a convenience population of bank employees in different geographical areas in Lebanon. The study participants completed an anonymous self-administered questionnaire, to collect data on their socio-demographic, behavioral and life style characteristics, and diagnostic questions following Rome III criteria to assess IBS occurrence. The difference in IBS prevalence by socio-demographic characteristics, smoking, alcohol consumption, and physical activity was assessed by using the Chi-square test. Logistic regression adjusted odds ratios were used to investigate the association between risk factors and IBS.

Results

Data was collected from 553 individuals and consisted of 52.8% females (mean age 35.9 years, SD = 11.9) and 47.2% males (mean age = 36.1 years, SD = 10.3). The prevalence of IBS in the study population according to Rome III criteria was 20.1%. The bivariate analysis indicated that being younger than 30 years old, a female, an ever water pipe smoker, an ever alcohol consumer are significantly associated with a higher prevalence of IBS. Educational level, cigarettes smoking and physical exercise were not significantly associated with IBS occurrence. The logistic regression adjusted odds ratio showed that females were 1.67 times more likely to have IBS than males (P˂ 0.05). The participants aged less than 30 years old were at a higher risk of having IBS (P˂ 0.01). Those who ever smoked waterpipe were 1.63 times more likely to have IBS than those who never smoked waterpipe (P˂ 0.05). Those who were ever alcohol drinkers were twice as likely to have IBS than never-drinkers (P˂ 0.01).

Conclusion

New data on the high prevalence of IBS in an adult population in Lebanon has been reported. This is also the first study to investigate and show an association of waterpipe smoking and IBS. Further longitudinal studies are warranted to determine whether this association is causal.

Electronic supplementary material

The online version of this article (10.1186/s12876-017-0698-2) contains supplementary material, which is available to authorized users.

Enteroendocrine, Musashi 1 and neurogenin 3 cells in the large intestine of Thai and Norwegian patients with irritable bowel syndrome

OBJECTIVES

The prevalence, gender distribution and clinical presentation of IBS differ between Asian and Western countries. This study aimed at studying and comparing enteroendocrine, Musashi 1 (Msi 1) and neurogenin 3 (neurog 3) cells in Thai and Norwegian IBS patients.

MATERIAL AND METHODS

Thirty Thai and 61 Norwegian IBS patients as well as 20 Thai and 24 Norwegian controls were included. Biopsy samples were taken from each of the sigmoid colon and the rectum during a standard colonoscopy. The samples were immunostained for serotonin, peptide YY, oxyntomodulin, pancreatic polypeptide, somatostatin, Msi 1 and neurog 3. The densities of immunoreactive cells were determined with computerized image analysis.

RESULTS

The densities of several enteroendocrine cell types were altered in both the colon and rectum of both Thai and Norwegian IBS patients. Some of these changes were similar in Thai and Norwegian IBS patients, while others differed.

CONCLUSIONS

The findings of abnormal densities of the enteroendocrine cells in Thai patients support the notion that enteroendocrine cells are involved in the pathophysiology of IBS. The present observations highlight that IBS differs in Asian and Western countries, and show that the changes in large-intestine enteroendocrine cells in Thai and Norwegian IBS patients might be caused by different mechanisms.

Prevalence of lactose intolerance in patients with diarrhea-predominant irritable bowel syndrome: data from a tertiary center in southern China

BACKGROUND

Symptoms associated with lactose intolerance (LI) and diarrhea-predominant irritable bowel syndrome (IBS-D) are almost the same. These disease entities are difficult to differentiate clinically. In practice, differential diagnosis depends on self-reported patient milk intolerance. However, there is limited data on the prevalence of LI in China. The aim of this study was to investigate the prevalence of LI in IBS-D patients and asymptomatic healthy controls.

METHODS

Lactose malabsorption (LM) was diagnosed by a lactose hydrogen breath test (HBT) and was defined by peak breath H₂ excretion over the baseline level of ≥ 20 ppm. LI-related symptoms were monitored for 8 h following lactose administration. LI was defined in LM patients with positive symptoms during the observation time. Patients with IBS-D were additionally asked if they were intolerant to milk.

RESULTS

A total of 109 eligible IBS-D patients (Rome III criteria) and 50 healthy controls were enrolled in this study. Except for hydrogen non-producers, the prevalence of LM did not differ between IBS-D patients and the control group (85%, 82/96 vs 72%, 34/47; P = 0.061). There was, however, a higher LI prevalence in IBS patients than in healthy subjects (45%, 43/96 vs 17%, 8/47; P = 0.002). Sensitivity, specificity, and positive and negative predictive values of self-reported milk intolerance for detecting LI were 58, 58, 53, and 63%, respectively.

CONCLUSIONS

Prevalence of LI is significantly higher in IBS-D patients than in healthy subjects. Self-reported milk intolerance is a poor diagnostic predictor of LI.

Mind-Body Interventions for Irritable Bowel Syndrome Patients in the Chinese Population: a Systematic Review and Meta-Analysis

PURPOSE

The aim of this study is to identify and assess evidence related to the efficacy of mind-body interventions on irritable bowel syndrome (IBS) in the Chinese population.

METHOD

Drawn from Chinese databases, nine RCTs and three Q-E studies were included in the systematic review. The methodological quality of RCTs was evaluated based on the following criteria: adequate sequence generation, allocation concealment, blinding, completeness of outcome data, selective reporting, and other potential biases. For continuous variables, the effect size (ES) was determined by calculating the standardized mean difference between groups. For dichotomous variables, the ES was determined by calculating the risk ratio (RR) between groups. Given the heterogeneity between the trials and the small number of studies included, both random effects and fixed effects models were used. The inverse variance method was used for pooling. Statistical analyses were performed using Review Manager version 5.0.

RESULTS

The total number of papers identified was 710: 462 from English language databases and 248 from Chinese language databases. Twelve studies met our eligibility criteria. Among the studies selected, three were Q-E studies the rest RCTs. Two studies described the randomization process. None of the studies reported allocation concealment nor blinding. Seven studies reported no dropouts. One of the studies mentioned the total amount of dropouts; though the reason for dropping out was not referenced. The other four studies did not clearly report dropouts. With the exception of three studies, there was inadequate information to determine biased reporting for the majority; the level of risk for bias in these studies is unclear. Finally, six meta-analyses were performed. One was conducted with four randomized controlled trials (RCTs) that used cure rate as outcome measures to evaluate gastrointestinal (GI) symptoms, which suggested that mind-body interventions were effective in improving GI symptoms (random effects model: RR = 1.08; 95 % CI 1.01 to 1.17; fixed effects model: RR = 1.07; 95 % CI 1.01 to 1.12). The remaining five were conducted in three RCTs, which suggested that mind-body interventions were effective in improving several aspects of quality of life, including interference with activity (random effects and fixed effects models: SMD = 0.64; 95 % CI 0.41 to 0.86), body image (random effects model: SMD = 0.36; 95 % CI 0.06 to 0.67; fixed effects model: SMD = 0.33; 95 % CI 0.11 to 0.55), health worry (random effects and fixed effects models: SMD = 0.67; 95 % CI 0.44 to 0.90), food avoidance (random effects and fixed effects models: SMD = 0.45; 95 % CI 0.23 to 0.68), and social reaction (random effects model: SMD = 0.79; 95 % CI 0.47 to 1.12; fixed effects model: SMD = 0.78; 95 % CI 0.55 to 1.01), as measured by Irritable Bowel Syndrome Quality of Life Questionnaire ( IBS-QOL).

CONCLUSION

Mind-body interventions may have the potential to improve GI symptoms in Chinese patients with IBS. The improvement of GI symptoms was also accompanied with the improvement of various outcomes, including depression, anxiety, and quality of life, just to mention a few. However, the published studies generally had significant methodological limitations. Future clinical trials with rigorous research design are needed in this field. More studies focusing on the mind-body interventions originated in China, such as tai chi and qi gong should be encouraged.

Chromogranin A cell density in the large intestine of Asian and European patients with irritable bowel syndrome

OBJECTIVE

Patients with irritable bowel syndrome (IBS) in Asia show distinctive differences from those in the western world. The gastrointestinal endocrine cells appear to play an important role in the pathophysiology of IBS. The present study aimed at studying the density of chromogranin A (CgA) cells in the large intestine of Thai and Norwegian IBS patients.

METHODS

Thirty Thai IBS patients and 20 control subjects, and 47 Norwegian IBS patients and 20 control subjects were included. A standard colonoscopy was performed in both the patients and controls, and biopsy samples were taken from the colon and the rectum. The biopsy samples were stained with hematoxylin-eosin and immunostained for CgA. The density of CgA cells was determined by computerized image analysis.

RESULTS

In the colon and rectum, the CgA cell densities were far higher in both IBS and healthy Thai subjects than in Norwegians. The colonic CgA cell density was lower in Norwegian IBS patients than in controls, but did not differ between Thai IBS patients and controls. In the rectum, the CgA cell densities in both Thai and Norwegian patients did not differ from those of controls.

CONCLUSIONS

The higher densities of CgA cells in Thai subjects than Norwegians may be explained by a higher exposure to infections at childhood and the development of a broad immune tolerance, by differences in the intestinal microbiota, and/or differing diet habits. The normal CgA cell density in Thai IBS patients in contrast to that of Norwegians may be due to differences in pathophysiology.

Cross-cultural and psychological issues in irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal disorders encountered by gastroenterologists worldwide. Of all the etiological factors that had been postulated to explain the pathophysiology of IBS, cultural and psychological factors are unique and difficult to understand. Culture plays an important role in coloring the presentation of IBS, and many a times, it has a significant role in several treatment aspects too. Psychological aspects like personality profiles, family relationships, societal myths, and abuse in any form are equally important in the management perspectives of IBS. In this brief review, we had tried to specifically focus on these aspects in IBS and have explained the evidences in favor of these factors. Knowledge about various cross-cultural aspects and psychological factors in patients with IBS is essential for taking an appropriate history and for undertaking a holistic approach for the management of the same. A collaborative team effort by psychiatrists and gastroenterologists could help in reducing the burden of this difficult to treat functional bowel disorder.

The global prevalence of IBS in adults remains elusive due to the heterogeneity of studies: a Rome Foundation working team literature review

OBJECTIVES

The global prevalence of IBS is difficult to ascertain, particularly in light of the heterogeneity of published epidemiological studies. The aim was to conduct a literature review, by experts from around the world, of community-based studies on IBS prevalence.

DESIGN

Searches were conducted using predetermined search terms and eligibility criteria, including papers in all languages. Pooled prevalence rates were calculated by combining separate population survey prevalence estimates to generate an overall combined meta-prevalence estimate. The heterogeneity of studies was assessed.

RESULTS

1451 papers were returned and 83, including 288 103 participants in 41 countries, met inclusion criteria. The mean prevalence among individual countries ranged from 1.1% in France and Iran to 35.5% in Mexico. There was significant variance in pooled regional prevalence rates ranging from 17.5% (95% CI 16.9% to 18.2%) in Latin America, 9.6% (9.5% to 9.8%) in Asia, 7.1% (8.0% to 8.3%) in North America/Europe/Australia/New Zealand, to 5.8% (5.6% to 6.0%) in the Middle East and Africa. There was a significant degree of heterogeneity with the percentage of residual variation due to heterogeneity at 99.9%.

CONCLUSIONS

The main finding is the extent of methodological variance in the studies reviewed and the degree of heterogeneity among them. Based on this, we concluded that publication of a single pooled global prevalence rate, which is easily calculated, would not be appropriate or contributory. Furthermore, we believe that future studies should focus on regional and cross-cultural differences that are more likely to shed light on pathophysiology.

Randomised clinical trial: rifaximin versus placebo for the treatment of functional dyspepsia

BACKGROUND

Gut dysbiosis may contribute to pain and bloating in patients with functional gastrointestinal disease.

AIMS

To determine if treatment with rifaximin would improve the symptoms of functional dyspepsia in Chinese patients in a double-blinded, randomised, placebo-controlled trial.

METHODS

Consecutive subjects with a diagnosis of functional dyspepsia as per the Rome III criteria were randomised to receive rifaximin 400 mg or placebo, all taken three times daily for 2 weeks. The investigators and study subjects were blinded to the treatment allocation. Subjects were followed up for 8 weeks. The primary end point was adequate relief of global dyspeptic symptoms (GDS). Secondary endpoints were relief of individual dyspeptic symptoms.

RESULTS

Eighty-six subjects were recruited. At week 8, there were significantly more subjects in the rifaximin than in the placebo group who experienced adequate relief of GDS (78% vs. 52%, P = 0.02). A trend favouring rifaximin group was also noted in the preceding 4 weeks. Rifaximin was also superior to placebo in providing adequate relief of belching and post-prandial fullness/bloating (PPF) in subjects at week 4. Subgroup analysis revealed that female subjects had more significant response to rifaximin treatment (adequate relief of GDS at week 4: 76% vs. 42%, P = 0.006; week 8: 79% vs. 47%, P = 0.008), as well as improvements in their belching and PPF at week 4. The incidences of adverse effects were similar in both groups.

CONCLUSIONS

Treatment with 2 weeks of rifaximin led to adequate relief of global dyspeptic symptoms, belching and post-prandial fullness/bloating in subjects with functional dyspepsia. The difference was more marked in females. (clinicaltrials.org NCT01643083).

The possible role of gastrointestinal endocrine cells in the pathophysiology of irritable bowel syndrome

The etiology of irritable bowel syndrome (IBS) is unknown, but several factors appear to play a role in its pathophysiology, including abnormalities of the gastrointestinal endocrine cells. The present review illuminates the possible role of gastrointestinal hormones in the pathophysiology of IBS and the possibility of utilizing the current knowledge in treating the disease. Areas covered: Research into the intestinal endocrine cells and their possible role in the pathophysiology of IBS is discussed. Furthermore, the mechanisms underlying the abnormalities in the gastrointestinal endocrine cells in IBS patients are revealed. Expert commentary: The abnormalities observed in the gastrointestinal endocrine cells in IBS patients explains their visceral hypersensitivity, gastrointestinal dysmotility, and abnormal intestinal secretion, as well as the interchangeability of symptoms over time. Clarifying the role of the intestinal stem cells in the pathophysiology of IBS may lead to new treatment methods for IBS.

Increased expression of nerve growth factor correlates with visceral hypersensitivity and impaired gut barrier function in diarrhoea-predominant irritable bowel syndrome: a preliminary explorative study

BACKGROUND

Neural-immune-endocrine network mechanism has attracted increased attention in diarrhoea-predominant irritable bowel syndrome (IBS-D). Pre-clinical evidence indicates that nerve growth factor (NGF) mediates visceral hypersensitivity and gut barrier dysfunction, via interactions with mast cells and sensory nerve fibres.

AIM

To explore the role of nerve growth factor, as well as mast cell-nerve growth factor-nerve interaction in IBS-D pathophysiology.

METHODS

In this cross-sectional study, IBS-D patients and healthy controls first underwent clinical and psychological assessments. Visceral sensitivity to rectal distension was tested. As gut barrier function markers, serum diamine oxidase and d-lactate were detected. Rectosigmoid biopsies were taken for the analyses of nerve growth factor expression, mast cell count and activation, and sensory nerve fibres expressing transient receptor potential vanilloid 1 and calcitonin gene-related peptide. Correlations between these parameters were examined in patients.

RESULTS

Thirty-eight IBS-D patients (28 males, 10 females; average age 30.2 years) and 20 healthy controls (12 males, 8 females; average age 26.8 years) participated in the study. The patients presented increased psychological symptoms, visceral hypersensitivity and impaired gut barrier function. NGF gene expression, mast cell count and sensory nerve fibres were significantly increased in the patients (P < 0.05). In correlation analysis, NGF expression was positively correlated with the disease severity, anxiety and serum diamine oxidase; visceral sensitivity thresholds were negatively associated with NGF expression (Bonferroni corrected P < 0.0029).

CONCLUSIONS

Elevated mucosal NGF may interact with mast cells and sensory nerve fibres, contributing to visceral hypersensitivity and impaired gut barrier function in IBS-D.

Alterations of gut microbiota in patients with irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND AND AIMS

Alterations of gut microbiota were assumed to be the etiology and pathogenesis of irritable bowel syndrome (IBS) in some studies. However, alterations of gut microbiota in IBS patients had not been systematically assessed with a meta-analysis. We performed a mate-analysis to explore and compare the alterations of gut microbiota in IBS patients from China and other regions around the world.

METHODS

Case-control studies detecting gut microbiota in IBS patients were identified through English and Chinese databases. The standardized mean difference (SMD) with 95% confidence interval (CI) of bacterial counts was calculated.

RESULTS

Ten studies from China and seven studies from other regions around the world were included in our study. As compared with healthy controls, the SMDs of Bifidobacteria, Lactobacillus, Escherichia Coli, and Enterobacter in Chinese IBS patients were -1.42 (CI: -2.10, -0.75), -0.91 (95% CI: -1.31, -0.52), 0.83 (95% CI: 0.26, 1.40), and 0.57 (95% CI: 0.33, 0.82), respectively. But the SMDs of Bacteroides and Enterococcus were found no significant differences in Chinese IBS patients. However, the SMDs of Bifidobacteria and Bacteroides in IBS patients from other regions were -0.76 (CI: -1.43, -0.09) and 1.17 (CI: 0.00, 2.35), while the SMDs of Lactobacillus, E. Coli, Enterobacter, and Enterococcus were found no significant differences.

CONCLUSIONS

There were alterations of gut microbiota in IBS patients, and it implied that alterations of gut microbiota might be involved in the pathogenesis of IBS. However, the species-specific alterations of gut microbiota were different between IBS patients from China and other regions.

Prevalence and risk factors for functional bowel disorders in South China: a population based study using the Rome III criteria

BACKGROUND

Functional bowel disorders (FBDs) such as irritable bowel syndrome (IBS) impact on quality of life and health care resources. It is uncertain whether patients with functional digestive symptoms have similar characteristics in different populations. This population-based study assessed the prevalence and identified risk factors for these disorders in South-East China.

METHODS

Five communities were selected at random and invitations distributed to a representative sample (block randomization). Questionnaires were completely supervised by investigators. Demographic and medical data with FBD symptoms (Rome III criteria), psychological condition, life event stress, and quality of life were collected.

KEY RESULTS

Functional bowel disorder prevalence was 41.6% in 1999/2115 (94.5%) completed questionnaires: 9.9% functional constipation (FC), 6.8% bloating (FB), 6.5% diarrhea (FD), 5.9% IBS (IBS-D 47.1%, IBS-M 23.9%, IBS-C 12.8%, IBS-U 16.2%), and 12.6% unspecified. Similar numbers of men and women had FBDs or IBS (overall; 51.3% male vs 48.7% female, P=.796); however, there was female predominance in FC (62.1%, P<.001) and FB (58.5%, P=.038). FBDs were associated with greater anxiety, depression, life event stress, and a lower quality of life compared with those without symptoms (all, P<.0001). Logistic regression identified medical co-morbidity, anxiety/depression, and life event stress as independent risk factors for these disorders.

CONCLUSIONS & INFERENCES

Functional bowel disorders are as common in South China as in western populations. A similar number of men and women report FBDs and IBS. Only FC and FB are more prevalent in females. Independent risk factors associated with FBDs included physical and psychosocial stressors.

Electroacupuncture for patients with diarrhea-predominant irritable bowel syndrome or functional diarrhea: A randomized controlled trial

Diarrhea-predominant irritable bowel syndrome (IBS-D) and functional diarrhea (FD) are highly prevalent, and the effectiveness of acupuncture for managing IBS-D and FD is still unknown.The aim of this study was to compare the effectiveness of electroacupuncture with loperamide.It was a prospective, randomized, parallel group controlled trial.A total of 448 participants were randomly assigned to He electroacupuncture group (n = 113), Shu-Mu electroacupuncture group (n = 111), He-Shu-Mu electroacupuncture group (n = 112), or loperamide group (n = 112). Participants in the 3 acupuncture groups received 16 sessions of electroacupuncture during a 4-week treatment phase, whereas participants in the loperamide group received oral loperamide 2 mg thrice daily. The primary outcome was the change from baseline in stool frequency at the end of the 4-weeks treatment. The secondary outcomes were the Bristol scale, the MOS 36-item short form health survey (SF-36), the weekly average number of days with normal defecations and the proportion of adverse events.Stool frequency was significantly reduced at the end of the 4-week treatment in the 4 groups (mean change from baseline, 5.35 times/week). No significant difference was found between the 3 electroacupuncture groups and the loperamide group in the primary outcome (He vs. loperamide group [mean difference 0.6, 95% CI, -1.2 to 2.4]; Shu-Mu vs. loperamide group [0.4, 95% CI, -1.4 to 2.3]; He-Shu-Mu vs. loperamide group [0.0, 95% CI, -1.8 to 1.8]). Both electroacupuncture and loperamide significantly improved the mean score of Bristol scale and increased the weekly average number of days with normal defecations and the mean scores of SF-36; they were equivalent in these outcomes. However, the participants in electroacupuncture groups did not report fewer adverse events than those in the loperamide group. Similar results were found in a subgroup analysis of separating patients with IBS-D and FD patients.Electroacupuncture is equivalent to loperamide for reducing stool frequency in IBS-D and FD patients. Further studies on cost effectiveness of acupuncture are warranted.

A cross-cultural investigation of attachment style, catastrophizing, negative pain beliefs, and symptom severity in irritable bowel syndrome

BACKGROUND

Little information exists regarding whether psychosocial variables in irritable bowel syndrome (IBS) vary by geographic location. Adult attachment is an important psychological concept rooted in childhood relationship experience that has not been previously studied in IBS. Catastrophizing and negative pain beliefs have been described in IBS and may be affected by attachment.

AIMS

In this cross-cultural study, we determined: (i) whether attachment differs between IBS patients and controls, (ii) whether geographic location has a significant effect on attachment style, catastrophizing and negative pain beliefs, and (iii) how all three variables correlate with IBS symptom severity.

METHODS

463 IBS patients, with moderate to severe symptom scores, and 192 healthy controls completed validated questionnaires about attachment, catastrophizing, negative pain beliefs and IBS-SSS in nine locations, USA (New York, Los Angeles), Mexico, Italy (Rome, Bari), Romania, Iran, India, and China.

KEY RESULTS

Attachment anxiety and avoidance scores were significantly higher in IBS patients than in controls (p < 0.001). This was particularly true for the fearful-avoidant attachment category, especially in China and Romania. Path analysis showed that attachment anxiety and avoidance had indirect effects on IBS-SSS through catastrophizing (p < 0.0001) and negative pain beliefs (p = 0.005). All three psychosocial measures varied significantly depending on location.

CONCLUSIONS & INFERENCES

In the IBS population studied, attachment style was significantly different in IBS compared to a control population. Geographic differences in attachment, catastrophizing and negative pain beliefs were documented and their correlation with symptom severity and thus, research of psychosocial variables in IBS should take into account the location of the population studied.

The spectra, symptom profiles and overlap of Rome III functional gastrointestinal disorders in a tertiary center in South China

OBJECTIVE

Most previous studies exploring the overlap of functional gastrointestinal disorders (FGID) focus on the overlap between functional dyspepsia (FD) and irritable bowel syndrome (IBS). In this study, we aimed to explore the spectra, symptom profiles and overlap of all FGID using the validated Chinese version of the Rome III questionnaire.

METHODS

Consecutive newly diagnosed FGID patients who were admitted to the Outpatient Gastroenterology Clinic from 10 May to 10 September 2012 were recruited in the study. All the patients complained of gastrointestinal (GI) symptoms for at least 3 months with a symptom onset of at least 6 months before diagnosis after excluded organic diseases. Patients who met the inclusion criteria were asked to complete the scoring algorithm for the Rome III integrated questionnaire.

RESULTS

Among 350 eligible patients, 302 (86.3%) returned completed questionnaires. A total of six major domains including 17 disorders were diagnosed. The four most prevalent FGID were FD (54.6%), IBS (40.7%), unspecified functional bowel disorder (13.9%) and functional constipation (12.6%). The three most prevalent symptoms in FGID were abdominal pain (66.2%), loose stool (58.3%) and abdominal bloating/distension (56.3%). Of the 302 patients, 152 (50.3%) had one to five overlapping FGID. Only functional bloating had no overlap. Six patients had five overlapping FGID simultaneously. In all, 63 patients had overlapping FD and IBS.

CONCLUSIONS

This study provided the detailed spectra and symptom profiles for all FGID. Overlapping FGID are common in China.

Cognitive-behavioral therapy for irritable bowel syndrome: a meta-analysis

OBJECTIVE

To establish whether cognitive behavioral therapy (CBT) improves the bowel symptoms, quality of life (QOL) and psychological states of irritable bowel syndrome (IBS) patients.

METHODS

Randomized controlled trials (RCTs) of CBT for adult patients with IBS were searched by using PubMed, Scopus and Web of Science. The standardized mean difference (SMD) with 95% confidence intervals (CIs) of the evidence-based outcome measures of the IBS bowel symptoms, QOL and psychological states at post-treatment and follow-up was calculated. Prespecified subgroup analysis was performed.

RESULTS

Eighteen RCTs satisfied our inclusion criteria. In the subgroup analyses, CBT was more effective in reducing IBS bowel symptoms, QOL and psychological states than waiting list controls at the end of the intervention and short-term follow-up. When compared with controls of basic support and medical treatment, the effect sizes were found to favor CBT for the improvement of IBS bowel symptoms at post-treatment and short-term follow-up, but CBT was not superior to controls in improving QOL and psychological states. When comparing CBT with other psychological controls, the effect sizes were almost non-significant.

CONCLUSIONS

For IBS patients, CBT was superior to waiting list, basic support or medical treatment at the end of treatment but not superior to other psychological treatments. The meta-analysis might be limited by the heterogeneities and small sample sizes of the included studies.

Irritable bowel syndrome: recent developments in diagnosis, pathophysiology, and treatment

The diagnosis of irritable bowel syndrome (IBS) remains a diagnosis of exclusion, whereby an extensive investigation is performed to exclude other organic diseases that may explain the symptoms of patients. Attempts to have a positive diagnosis based on symptom assessments failed to achieve widely use in clinical practice. Abnormalities in the gastrointestinal endocrine cells in IBS patients have been reported recently, providing evidence that IBS is an organic disorder, and opening the door to the use of these abnormalities as markers for a positive diagnosis of IBS. New and promising drugs for the treatment of IBS with constipation as the predominant symptom are currently on the market, and the treatment results have been satisfactory thus far.

The epidemiology of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a functional condition of the bowel that is diagnosed using clinical criteria. This paper discusses the nature of the diagnostic process for IBS and how this impacts epidemiological measurements. Depending on the diagnostic criteria employed, IBS affects around 11% of the population globally. Around 30% of people who experience the symptoms of IBS will consult physicians for their IBS symptoms. These people do not have significantly different abdominal symptoms to those who do not consult, but they do have greater levels of anxiety and lower quality of life. Internationally, there is a female predominance in the prevalence of IBS. There is 25% less IBS diagnosed in those over 50 years and there is no association with socioeconomic status. IBS aggregates within families and the genetic and sociological factors potentially underlying this are reviewed. Patients diagnosed with IBS are highly likely to have other functional disease and have more surgery than the general population. There is no evidence that IBS is associated with an increased mortality risk. The epidemiological evidence surrounding these aspects of the natural history is discussed.

Is irritable bowel syndrome an organic disorder?

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder that is generally considered to be functional because there appears to be no associated anatomical defect. Stress and psychological factors are thought to play an important role in IBS. The gut neuroendocrine system (NES), which regulates all functions of the gastrointestinal tract, consists of endocrine cells that are scattered among the epithelial cells of the mucosa, and the enteric nervous system. Although it is capable of operating independently from the central nervous system (CNS), the gut NES is connected to and modulated by the CNS. This review presents evidence for the presence of an anatomical defect in IBS patients, namely in the gastrointestinal endocrine cells. These cells have specialized microvilli that project into the lumen and function as sensors for the luminal content and respond to luminal stimuli by releasing hormones into the lamina propria, which starts a chain reaction that progresses throughout the entire NES. The changes in the gastrointestinal endocrine cells observed in IBS patients are highly consistent with the other abnormalities reported in IBS patients, such as visceral hypersensitivity, dysmotility, and abnormal secretion.

Irritable bowel syndrome and migraine: bystanders or partners?

Irritable bowel syndrome (IBS) and migraine are distinct clinical disorders. Apart from the characteristics of chronic and recurrent pain in nature, these pain-related disorders apparently share many similarities. For example, IBS is female predominant with community prevalence about 5-10%, whereas that of migraine is 1-3% also showing female predominance. They are often associated with many somatic and psychiatric comorbidities in terms of fibromyaglia, chronic fatigue syndrome, interstitial cystitis, insomnia and depression etc., even the IBS subjects may have coexisted migraine with an estimated odds ratio of 2.66. They similarly reduce the quality of life of victims leading to the social, medical and economic burdens. Their pathogeneses have been somewhat addressed in relation to biopsychosocial dysfunction, heredity, genetic polymorphism, central/visceral hypersensitivity, somatic/cutaneous allodynia, neurolimbic pain network, gonadal hormones and abuses etc. Both disorders are diagnosed according to the symptomatically based criteria. Multidisciplinary managements such as receptor target new drugs, melantonin, antispasmodics, and psychological drugs and measures, complementary and alternatives etc. are recommended to treat them although the used agents may not be necessarily the same. Finally, the prognosis of IBS is pretty good, whereas that of migraine is less fair since suicide attempt and stroke are at risk. In conclusion, both distinct chronic pain disorders to share many similarities among various aspects probably suggest that they may locate within the same spectrum of a pain-centered disorder such as central sensitization syndromes. The true pathogenesis to involve these disorders remains to be clarified in the future.

Effects of demographic factors, body mass index, alcohol drinking and smoking habits on irritable bowel syndrome: a case control study

BACKGROUND

Irritable Bowel Syndrome (IBS) is a common functional gastrointestinal disorder.

AIMS

To identify demographic factors in patients with IBS.

SUBJECTS AND METHODS

One-hundred and fifty three IBS patients seen at Taleghani Hospital Gastroenterology Clinic and met the Rome III criteria and 163 peoples who did not meet IBS criteria were consecutively enrolled. Both groups were asked to complete a self-rating questionnaire containing information, which included questions about age, sex, monthly income, education level, marital status, height, weight, alcohol drinking and smoking habits. Student's t-test, Pearson's Chi-square and logistic regression were used to statistical analysis.

RESULTS

The mean (SD) age for IBS patients 36.3 (13.5) years and 33.1 (9.9) years in non-IBS group (P < 0.001). Frequency of IBS defined by Rome III criteria was higher in females and younger individuals. Univariate analysis showed that IBS in males was associated with a lower monthly income and educational level and in females younger age, single, lower monthly income and educational level, body mass index (BMI), and unemployment status. Multivariate logistic regression identified a low level of education in males (Odds ratio [OR] = 3.6, 95% Confidence interval [CI]: 1.4-9.6) and in females, lower education level (OR = 2.4, 95% CI: 1.1-5.2), lower BMI (OR = 0.94, 95% CI: 0.89-0.99), unemployed (OR = 0.31, 95% CI: 0.11-0.85) and smoking (OR = 6.2, 95% CI: 1.03-37.2).

CONCLUSION

We identified demographic factors in IBS patients. Being single and having a lower educational level, income, lower BMI and being unemployed were the most important factors associated with IBS, particularly in females.

A school-based study with Rome III criteria on the prevalence of functional gastrointestinal disorders in Chinese college and university students

BACKGROUND

Functional gastrointestinal disorders, including functional dyspepsia, irritable bowel syndrome and functional constipation are very common worldwide.

OBJECTIVE

This research aims to estimate the prevalence and associated factors involved in functional gastrointestinal disorders in Chinese college and university students using the Rome III criteria.

METHODS

A total of 5000 students from Shandong University in China were asked in January-May 2012 to complete questionnaires, including the Rome III questionnaire, hospital anxiety and depression scale, and negative life events scale.

RESULTS

Based on the 4638 students who completed the questionnaire, the prevalence of functional dyspepsia, irritable bowel syndrome and functional constipation in college and university students of North China worked out to be 9.25%, 8.34% and 5.45% respectively. They were more frequent in female students. The factors of anxiety (OR 1.07; 95% CI 0.99 to 1.16, P=0.002<0.05) and depression (OR 0.55; 95% CI 0.15 to 1.05, P=0.045<0.05) indicated a high risk of causing irritable bowel syndrome.

CONCLUSION

Functional dyspepsia, irritable bowel syndrome and functional constipation were common in college and university students of North China. Psychological disorders such as anxiety and depression provide significant risk factors for irritable bowel syndrome patients.

Irritable bowel syndrome: Diagnosis and pathogenesis

Irritable bowel syndrome (IBS) is a common gastrointestinal (GI) disorder that considerably reduces the quality of life. It further represents an economic burden on society due to the high consumption of healthcare resources and the non-productivity of IBS patients. The diagnosis of IBS is based on symptom assessment and the Rome III criteria. A combination of the Rome III criteria, a physical examination, blood tests, gastroscopy and colonoscopy with biopsies is believed to be necessary for diagnosis. Duodenal chromogranin A cell density is a promising biomarker for the diagnosis of IBS. The pathogenesis of IBS seems to be multifactorial, with the following factors playing a central role in the pathogenesis of IBS: heritability and genetics, dietary/intestinal microbiota, low-grade inflammation, and disturbances in the neuroendocrine system (NES) of the gut. One hypothesis proposes that the cause of IBS is an altered NES, which would cause abnormal GI motility, secretions and sensation. All of these abnormalities are characteristic of IBS. Alterations in the NES could be the result of one or more of the following: genetic factors, dietary intake, intestinal flora, or low-grade inflammation. Post-infectious IBS (PI-IBS) and inflammatory bowel disease-associated IBS (IBD-IBS) represent a considerable subset of IBS cases. Patients with PI- and IBD-IBS exhibit low-grade mucosal inflammation, as well as abnormalities in the NES of the gut.

Efficacy and safety of selective serotonin reuptake inhibitor antidepressants in patients with irritable bowel syndrome: A systematic review

AIM: To systematically assess the efficacy and safety of selective serotonin reuptake inhibitor (SSRI) antidepressants (SSRIs) for irritable bowel syndrome (IBS).

METHODS: PubMed, Embase, the Cochrane Central Register of Controlled Trials, Chinese Biomedical Literature Database, and China Journal Full-text Database were searched for randomized controlled trials investigating the efficacy of SSRIs in the management of IBS. The Revman 5.0 software provided by the Cochrane Collaboration was used for assessment.

RESULTS: Five placebo-controlled, double-blind, randomized trials including 300 patients were involved in this analysis. SSRIs used in these studies included citalopram, fluoxetine and paroxetine. Compared to placebo, SSRIs were not associated with a statistically significant global symptom relief [RR = 2.09, 95%CI = (0.97, 4.47), P < 0.05]. There was no significant difference in the incidence of serious adverse events between the SSRIs and placebo groups[RR = 1.38, 95%CI = (0.68, 2.82), P > 0.05].

CONCLUSION: There are no significant differences in IBS symptom improvement and incidence of side effects between SSRI and placebo groups.

The value of eliminating foods according to food-specific immunoglobulin G antibodies in irritable bowel syndrome with diarrhoea

OBJECTIVE

This study investigated the role of food intolerance in irritable bowel syndrome with diarrhoea (D-IBS).

METHODS

Specific immunoglobulin G (IgG) antibodies against 14 common food antigens in the serum were measured in 77 patients with D-IBS and 26 healthy controls. Food-specific IgG antibodies were identified in 39 (50.65%) patients with D-IBS patients compared with four (15.38%) controls. For 12 weeks following the serological testing, 35 patients with D-IBS and food intolerance consumed diets that excluded the identified food. Changes in the main symptoms of D-IBS were evaluated before treatment and regularly during treatment in these patients.

RESULTS

After 4 weeks' dietary therapy, most symptoms of D-IBS had improved. By 12 weeks, all symptom scores had decreased significantly compared with the baseline scores.

CONCLUSIONS

The 12-week specific-food exclusion diets resulted in significant improvements in abdominal pain (bloating level and frequency), diarrhoea frequency, abdominal distension, stool shape, general feelings of distress and total symptom score compared with baseline in patients with D-IBS.

Global prevalence of and risk factors for irritable bowel syndrome: a meta-analysis

BACKGROUND & AIMS

Many cross-sectional surveys have reported the prevalence of irritable bowel syndrome (IBS), but there have been no recent systematic review of data from all studies to determine its global prevalence and risk factors.

METHODS

MEDLINE, EMBASE, and EMBASE Classic were searched (until October 2011) to identify population-based studies that reported the prevalence of IBS in adults (≥15 years old); IBS was defined by using specific symptom-based criteria or questionnaires. The prevalence of IBS was extracted for all studies and based on the criteria used to define it. Pooled prevalence, according to study location and certain other characteristics, odds ratios (ORs), and 95% confidence intervals (CIs) were calculated.

RESULTS

Of the 390 citations evaluated, 81 reported the prevalence of IBS in 80 separate study populations containing 260,960 subjects. Pooled prevalence in all studies was 11.2% (95% CI, 9.8%-12.8%). The prevalence varied according to country (from 1.1% to 45.0%) and criteria used to define IBS. The greatest prevalence values were calculated when ≥3 Manning criteria were used (14%; 95% CI, 10.0%-17.0%); by using the Rome I and Rome II criteria, prevalence values were 8.8% (95% CI, 6.8%-11.2%) and 9.4% (95% CI, 7.8%-11.1%), respectively. The prevalence was higher for women than men (OR, 1.67; 95% CI, 1.53-1.82) and lower for individuals older than 50 years, compared with those younger than 50 (OR, 0.75; 95% CI, 0.62-0.92). There was no effect of socioeconomic status, but only 4 studies reported these data.

CONCLUSIONS

The prevalence of IBS varies among countries, as well as criteria used to define its presence. Women are at slightly higher risk for IBS than men. The effects of socioeconomic status have not been well described.