Factors associated with the development of post-infectious functional gastrointestinal diseases: does smoking play a role?

Predictors of abdominal pain severity in patients with constipation-prevalent irritable bowel syndrome

BACKGROUND

Symptoms of irritable bowel syndrome (IBS) have been associated to altered colonic motility and sensation. Smoking affects pain perception and is a risk factor in the development of post-infectious IBS, but its effect on abdominal pain and colonic transit remains to be elucidated in IBS.

METHODS

Forty patients with IBS-C and 28 with IBS-M were selected based on Rome IV criteria. Colonic transit time was studied and smoking habit was recorded. Presence of mild or severe abdominal pain and the prevalent pain characteristics (diffuse or localized, chronic or acute, with cramps or gradually distending) were recorded. Data were analyzed by univariate and stepwise multiple logistic regression analysis to verify the risk association between pain and all other variables.

RESULTS

IBS-C patients had a longer transit time in the right colon and scored more chronic pain than IBS-M patients. When severity of abdominal pain was used as discriminating factor, a significant number of subjects reporting severe pain were males and smokers (16/30 vs. 4/38 and 20/30 vs. 4/38, both ƿ<0.001). Multivariate analysis confirmed that smoking was an independent factor associated with severe abdominal pain (OR 14.3, CI 2-99, p=0.007). Smoking was not associated with colonic transit times and colonic transit was not associated with IBS symptoms' severity (both ƿ=N.S.).

CONCLUSIONS

Smoking was the only factor independently associated with severe abdominal pain. As smoking does not seem to affect colonic transit time, we suggest that smoking may influence visceral perception and symptoms severity in IBS patients.

Postinfection Irritable Bowel Syndrome

Following acute gastroenteritis (AGE) due to bacteria, viruses, or protozoa, a subset of patients develop new onset Rome criteria positive irritable bowel syndrome (IBS), called postinfection IBS (PI-IBS). The pooled prevalence of PI-IBS following AGE was 11.5%. PI-IBS is the best natural model that suggests that a subset of patients with IBS may have an organic basis. Several factors are associated with a greater risk of development of PI-IBS following AGE including female sex, younger age, smoking, severity of AGE, abdominal pain, bleeding per rectum, treatment with antibiotics, anxiety, depression, somatization, neuroticism, recent adverse life events, hypochondriasis, extroversion, negative illness beliefs, history of stress, sleep disturbance, and family history of functional gastrointestinal disorders (FGIDs), currently called disorder of gut-brain interaction. Most patients with PI-IBS present with either diarrhea-predominant IBS or the mixed subtype of IBS, and overlap with other FGIDs, such as functional dyspepsia is common. The drugs used to treat non-constipation IBS may also be useful in PI-IBS treatment. Since randomized controlled trials on the efficacy of drugs to treat PI-IBS are rare, more studies are needed on this issue.

Relative risk of functional dyspepsia in patients with sleep disturbance: a population-based cohort study

Increased prevalence of sleep disorders has been found in patients with functional dyspepsia; however, direction of causality remains unclear. Our aim was to compare the risk of incident functional dyspepsia between patients with and without sleep disturbance from a large population-based sample. Utilizing a nation-wide health insurance administrative dataset, we assembled an 11-year historic cohort study to compare subsequent incidence of diagnosed functional dyspepsia between adult patients with any diagnosis of sleep disturbance and age- and gender-matched controls. Hazard ratios adjusted for other relevant comorbidities and medications were calculated using Cox regression models. 45,310 patients with sleep disorder and 90,620 controls were compared. Patients with sleep apnea had a 3.3-fold (95% confidence interval: 2.82 ~ 3.89) increased hazard of functional dyspepsia compared with controls. This increased risk persisted regardless of previously diagnosed depression coexisted. Sleep disturbance was associated with an increased risk of subsequent functional dyspepsia. Potential mechanisms are discussed.

Gastrointestinal Symptoms and Irritable Bowel Syndrome Are Associated With Female Sex and Smoking in the General Population and With Unemployment in Men

Background: The influence of daily life exposure on the gastrointestinal tract is not fully understood. This study aimed to examine associations between functional gastrointestinal symptoms and sociodemographic status and lifestyle habits in the general population. Methods: The Malmö Offspring Study (MOS) included 2,648 participants from the general population who had answered a questionnaire about sociodemographic status, lifestyle habits, medical health, and self-reported irritable bowel syndrome (IBS). The visual analog scale for IBS (VAS-IBS) was completed to assess gastrointestinal symptoms the past 2 weeks. Subjects with organic gastrointestinal diseases were excluded. Presence of self-reported IBS and gastrointestinal symptoms the past 2 weeks were used as dependent variables to study the associations with age, sex, body mass index, education, occupation, marital status, smoking, snuff using, alcohol drinking frequency, alcohol amount per drinking occasion, physical activity at work, and physical activity during leisure time, using logistic regression and generalized linear model. Results: Self-reported IBS was associated with gastrointestinal symptoms the past 2 weeks (p < 0.001). There was an association between IBS and female sex (p < 0.001), former smoking (p < 0.001), present smoking (p < 0.001), and an inverse association with drinking 3-4 standard glasses per occasion (p = 0.038). Gastrointestinal symptoms were associated with age 50-59 years (p = 0.009), ≥60 years (p = 0.004), female sex (p < 0.001), studying (p = 0.036), unemployment (p = 0.009), former smoking (p = 0.001), and present smoking (p = 0.012). In men, IBS was associated with middle-age and both IBS and gastrointestinal symptoms were associated with unemployment (p < 0.001 and p = 0.001, respectively). In women, IBS was associated with present smoking (p = 0.022), and gastrointestinal symptoms were associated with former smoking and inversely associated with higher age (p = 0.006) and intermediate physical activity at work (p = 0.008). No associations were found with BMI, education, marital status, or snuff using. Conclusion: Self-reported IBS in the general population shows strongest association with female sex and smoking, whereas gastrointestinal symptoms also are associated with unemployment and inversely associated with higher age. In men, both IBS and gastrointestinal symptoms are associated with unemployment. In women, both IBS and gastrointestinal symptoms are associated with smoking, whereas symptoms are inversely associated with higher age and intermediate physical activity.

Functional dyspepsia in depression: A population-based cohort study

BACKGROUND

Patients with functional dyspepsia (FD) are more likely to have persistent depression, yet whether depression and antidepressant treatments are associated with subsequent risk of FD remain unclear.

METHODS

Using population-based insurance administrative data of Taiwan, an 11-year historic cohort study was assembled, comparing cases aged 18 and above with the diagnosis of depressive disorder, to a propensity score-matched sample of adults without depression. Incident FD as a primary diagnosis was ascertained. Hazard ratios of FD were calculated using Cox regression models by age, gender, other comorbidities, nonsteroidal anti-inflammatory medications, antidepressants and antidiabetic agents.

RESULTS

A total of 20,197 people with depressive disorder and 20,197 propensity score-matched comparisons without depression were followed up. The incidence of FD was 1.7-fold greater in the depressive cohort than in comparisons (12.9 versus 7.57 per 1000 person-years), with an adjusted hazard ratio (aHR) of 2.16 (95% confidence interval (CI) 1.93~2.41). Increased risks were significant regardless of comorbidities or medication uses, the highest in the untreated depression group compared to the group without depression, with an aHR of 2.51(95% CI 2.15~2.93).

CONCLUSIONS

This population-based study showed that patients with depressive disorder are at elevated risk of FD. Antidepressant treatment could reduce the risk of FD.

Ileocolonic Histopathological and Microbial Alterations in the Irritable Bowel Syndrome: A Nested Community Case-Control Study

INTRODUCTION

Histopathological alterations in the ileum and colon in irritable bowel syndrome (IBS) are controversial, and normal values are poorly established. We hypothesized that changes in mucosal immune cells characterize IBS and key changes in immune composition are associated with the mucosa-associated microbiota (MaM).

METHODS

A nested case-control study (48 IBS and 106 controls included) from 745 colonoscopy participants in a random population sample. Intraepithelial lymphocytes (IELs)/100 enterocytes and eosinophils/5 nonoverlapping high-power fields counted; mast cells identified by immunocytochemistry (CD117)/5 high-power fields. Paneth cells quantified per 5 crypts. 16S rRNA gene amplicon sequencing performed on available sigmoid MaM, n = 55 and fecal microbiota, n = 20. Microbiota profiles compared between samples with high and low IEL counts.

RESULTS

IBS had increased IELs in the terminal ileum (relative risk ratio = 1.70, 95% confidence interval 1.08-2.76, P = 0.022 adjusted for age, sex, and smoking). Cecal IELs were increased in IBS-diarrhea (relative risk ratio = 2.03, 95% confidence interval 1.13-3.63, P = 0.017). No difference was observed in alpha diversity of MaM or fecal microbiota based on IEL count. There was no difference in beta diversity of the MaM according to IEL count in the terminal ileal (TI) (P = 0.079). High TI IEL counts associated with a significant expansion of the genus Blautia (P = 0.024) and unclassified Clostridiales (P = 0.036) in colon MaM.

DISCUSSION

A modest but significant increase in IELs was observed in IBS vs. controls in a population-based setting. Subtle TI and cecal inflammation may play a pathogenic role in IBS but needs confirmation. Modest but discernible differences in the colonic MaM were seen according to TI IEL count but not IBS status.

Is there a causal link between psychological disorders and functional gastrointestinal disorders?

INTRODUCTION

Psychological distress is associated with functional gastrointestinal disorders (FGIDs) including irritable bowel syndrome (IBS) and functional dyspepsia (FD) but only evidence from prospective longitudinal and treatment studies can indicate whether the link between FGIDs and psychological distress is causal. Emerging evidence suggests underlying biological mechanisms may explain the association of psychological distress with FGIDs.

AREAS COVERED

This review critically evaluates whether anxiety and/or depression and FGIDs are causally related including evidence for a temporal sequence, strength and specificity of the association, biological gradient, and biological plausibility.

EXPERT OPINION

Accumulating evidence suggests that psychological factors are causal for symptoms in a subset of FGID patients and not explained by health care seeking behavior (brain-gut disorder). In other cases, psychological factors may arise secondary to intestinal disease (gut-brain disorder). Prospective population-based studies are needed in FGIDs other than IBS and FD to determine if a similar brain-gut and gut-brain syndrome exists. Treatment studies have not phenotyped FGIDs according to brain-gut versus gut-brain origins which may be important in understanding true treatment efficacy. Future research needs to unravel biological mechanisms that may explain the link between psychological factors and FGIDs but promising data in the area of the brain-gut-immune-microbe axis is emerging.

Negative Events During Adulthood Are Associated With Symptom Severity and Altered Stress Response in Patients With Irritable Bowel Syndrome

BACKGROUND & AIMS

Irritable bowel syndrome (IBS) is a stress-sensitive disorder associated with dysregulation of the hypothalamic-pituitary-adrenal axis. We studied the cumulative effect of events during adulthood on this pathway in patients with IBS.

METHODS

We studied 129 patients with IBS, based on Rome III criteria (mean age 28.1 years, 66% women), and 108 healthy individuals (controls; mean age 29.8 years, 60% women) who completed the Life Experiences Survey from August 2013 to September 2017. Data were collected on the presence and effects of events since age 18, IBS severity scores, and IBS-related quality of life. For a subset of subjects, we measured serum cortisol and adrenocorticotropic hormone (ACTH) production in response to administration of corticotropin-releasing factor and ACTH.

RESULTS

Compared with controls, patients with IBS perceived more adulthood life events as negative and had a significantly higher negative life event impact score (14.17 ± 12.04 vs 10.83 ± 9.98; P=.022). In patients with IBS, the presence of more-negatively perceived adulthood life events was associated with worse IBS symptom severity (β = 1.53, 95% CI, 0.21-2.84; P = .025) and IBS-related quality of life (β = -0.70; 95% CI, -1.02 to -0.38; P < .001). Negatively perceived adulthood life events were associated with reduced production of ACTH in response to corticotropin-releasing factor in patients with IBS compared with controls (P < .05).

CONCLUSION

In a study of more than 200 subjects, we associated more-negatively perceived events during adulthood with an increased risk for IBS, worse symptom severity and quality of life, and a dysregulated stress response. Understanding the effects of events that cause stress in adults and their perceived effects on IBS may help guide disease management.

Systematic review with meta-analyses: does the pathogen matter in post-infectious irritable bowel syndrome?

Objective: Acute gastroenteritis (AGE) is a risk factor for post-infectious irritable bowel syndrome (PI-IBS). This systematic review evaluates the prevalence and risk-factors of PI-IBS after AGE by specific pathogens. Materials and methods: Medline (1966-2019) and Embase (1974-2019) were searched for studies evaluating PI-IBS minimum 3 months after AGE with Campylobacter spp., Salmonella spp., Shigella spp., Escherischia coli, Clostridium difficile, norovirus, rotavirus, Cryptosporidium spp. or Giardia intestinalis using validated criteria for IBS. Pooled prevalence (PP), odds ratios (OR) and risk factors were determined for single pathogens, groups of bacteria, viruses and parasites, and overall for AGE caused by any pathogen. Random-effect models were used for meta-analyses. Results: A total of 34 articles were included. PP of PI-IBS after Campylobacter spp. was 12% (confidence interval 95% [CI]: 10-15%), Salmonellosis 12% (CI: 9-15%), Shigellosis 11% (CI: 8-15%), C. difficile 14% (CI: 4-29%) and E. coli spp. 12% (CI: 5-20%). OR of PI-IBS after salmonellosis was 5.5 (CI: 2.3-12.8) and after shigellosis 13.8 (CI: 4.2-45.4). Bacterial AGE overall showed OR 5.8 (CI: 4.0-8.3) and AGE caused by any pathogen OR 4.9 (CI: 3.9-6.1). Few studies exist on viral and parasitic gastroenteritis. Conclusions: Current literature show similar risks for bacterial pathogens. Studies are limited for viral and parasitic pathogens. The evaluated risk-factors for PI-IBS varied among the included studies and the existing evidence is insufficient to identify pathogen-specific risk factors.

The role of smoking and alcohol behaviour in management of functional gastrointestinal disorders

Functional gastrointestinal disorders (FGIDs) are common disorders in the population. Lifestyle habits have been suspected to influence the presence and degree of symptoms, and many studies have examined the role of food components and physical activity on the disease development. The role of smoking and alcohol intake on FGID has been less thoroughly examined. This systematic literature review, of a large amount of studies from different countries around the world with different design and application of FGID criteria, shows that smoking seems to be associated with a significant 50% increased risk of FD for current compared with never smokers. The associations between smoking and other FGIDs are weak, if present at all. A moderate alcohol intake is not associated with FGIDs. On the other hand, a high alcohol intake may lead to development and aggravation of FGID symptoms, especially functional dyspepsia.

Post-Infectious Irritable Bowel Syndrome

PURPOSE OF REVIEW

Post-infectious irritable bowel syndrome (PI-IBS) is characterized by persistent abdominal pain and diarrhea, typically following an episode of infectious gastroenteritis. The mechanisms that underlie IBS-D remain elusive, but PI-IBS provides a mechanistic model of this disorder. This review provides an up-to-date appraisal of the pathophysiology, clinical features, and management approaches for PI-IBS.

RECENT FINDINGS

Disordered immune reactions and release of cytokines with resultant gut inflammation and dysfunction appear to be key features of PI-IBS. Disordered brain-gut-microbiota interactions, type of infecting agent, and host-genetic susceptibility are risk factors but also are reasons for the varying spectrum of clinical severity. Although prognosis is generally good, symptoms and inflammation may persist for a long time. Symptomatic relief with antidiarrheals, antispasmodics, 5HT₃ antagonists, mesalamine, probiotics, and low-dose antidepressants remain the primary approaches, but in some difficult cases, a combination of drugs that target the pathophysiology may be helpful. PI-IBS has many overlapping features with IBS-D and shares similar pathophysiology and management approaches.

Smoking in Irritable Bowel Syndrome: A Systematic Review

OBJECTIVE

The aim of this review was to examine (1) the prevalence of smoking in subjects with irritable bowel syndrome (IBS), (2) whether smoking prevalence significantly differs between subjects with and without IBS, and (3) whether smoking significantly predicts the presence or the development of IBS.

METHODS

Articles were retrieved by systematically searching the Scopus, Web of Science, and PubMed electronic databases from inception to July 2016, using the keywords "smoking" and "tobacco" combined with "irritable bowel syndrome." Reference lists of included articles were also searched. Articles were included if they (1) reported data on smoking prevalence in subjects with IBS and/or on the association (assessed by means of multivariate analyses) between smoking and IBS, (2) identified IBS according to Manning criteria or Rome I-III criteria, (3) were English-language articles, and (4) involved only adult subjects.

RESULTS

The electronic searches yielded a total of 1,637 records, and 42 articles met inclusion criteria. Another 13 articles were retrieved through manual search, leading to a total of 55 included articles. Smoking prevalence in subjects with IBS was assessed by 48 articles and ranged from 0% in university students to 47.1% in patients with microscopic colitis. Thirty-three articles compared smoking prevalence between subjects with and without IBS. In 25 articles no significant difference was found. In seven articles smoking was significantly more frequent in subjects with IBS compared to those without IBS, while one study found a significantly higher smoking prevalence in controls. Eighteen multivariate analyses assessing the association between smoking and IBS were presented in 16 articles. Only one study employed a prospective design. In 11 analyses, smoking was not significantly associated with IBS after adjusting for covariates. In seven studies smoking independently predicted the presence of IBS.

CONCLUSIONS

According to the selected articles, a significant association between smoking and IBS cannot be confirmed. However, different shortcomings may hinder generalizability and comparability of many studies. A dimensional assessment of smoking, a prospective design, the differentiation between IBS subgroups, and the recruitment of patients in clinical settings, especially in primary care, are necessary to clarify the role of smoking in IBS.

Post-infectious IBS, tropical sprue and small intestinal bacterial overgrowth: the missing link

Evidence is emerging that IBS, a hitherto enigmatic disorder thought to be predominantly related to psychological factors, has a microorganic basis in a subset of patients with the disease. Post-infectious IBS (PI-IBS), commonly of the diarrhoea-predominant subtype (defined as new development of IBS following acute infectious diarrhoea), is one such condition known to occur in up to 10-30% individuals after acute gastroenteritis. However, following acute infectious gastroenteritis, patients can also develop post-infectious malabsorption syndrome (PI-MAS), popularly known as tropical sprue. As no study on PI-IBS has rigorously excluded tropical sprue by appropriate investigations, including small intestinal biopsy, the frequency of tropical sprue among patients with PI-IBS is not known. Small intestinal bacterial overgrowth (SIBO) has been suggested to be associated with IBS in general, and in particular diarrhoea-predominant IBS, including PI-IBS. SIBO is also known to be associated with tropical sprue. As both IBS, particularly the subset probably associated with SIBO, and tropical sprue improve with antibiotic treatment, we provide evidence and an explanatory model to support a link among these disorders.

A systematic review with meta-analysis of the role of anxiety and depression in irritable bowel syndrome onset

BACKGROUND

It is well established that people with irritable bowel syndrome (IBS) have higher levels of anxiety and depression compared with controls. However, the role of these as risk factors is less clearly established. The aims of this systematic review were to investigate: (1) whether anxiety and/or depression predict IBS onset; (2) the size of the relative risk (RR) of anxiety versus depression in IBS onset. Subgroup analyses explored if methodological factors affected the overall findings.

METHOD

Prospective cohort or case-control studies were included if they: (1) focused on the development of IBS in population-based or gastroenteritis cohorts; (2) explored the effects of anxiety and/or depression at baseline as predictors of IBS onset at a future point. In all, 11 studies were included of which eight recruited participants with a gastrointestinal infection. Meta-analyses were conducted.

RESULTS

The risk of developing IBS was double for anxiety cases at baseline compared with those who were not [RR 2.38, 95% confidence interval (CI) 1.58-3.60]. Similar results were found for depression (RR 2.06, 95% CI 1.44-2.96). Anxiety and depression seemed to play a stronger role in IBS onset in individuals with a gastrointestinal infection although this could be attributed to other differences in methodology, such as use of diagnostic interviews rather than self-report.

CONCLUSIONS

The findings suggest that self-reported anxiety and depression provide a twofold risk for IBS onset. There is less support for the role of anxiety or depressive disorder diagnosed using clinical interview. These findings may have implications for the development of interventions focused on IBS prevention and treatment.

Smoking is associated with several functional gastrointestinal symptoms

BACKGROUND

The etiology behind functional gastrointestinal symptoms is not clear. Only a few studies have examined how lifestyle factors affect these symptoms, especially in middle-aged or elder subjects. The aim of the present study was to describe the prevalence of functional gastrointestinal symptoms in a Swedish population-based cohort of middle-aged to elder subjects, and to examine associations between symptoms and smoking and alcohol use.

METHODS AND MATERIALS

This study was conducted on a web-based baseline questionnaire from a part of the EpiHealth study. The cohort included 16,840 subjects between 45 and 75 years of age. Subjects with organic gastrointestinal diseases were excluded. Gastrointestinal symptoms were defined as functional abdominal pain, functional bloating, functional constipation, and functional diarrhea. Parameters regarding age, gender, educational level, occupation, civil status, physical activity, and body mass index (BMI) were described, and association between smoking and alcohol habits were calculated, adjusted for parameters with >5 percentage difference between cases and controls.

RESULTS

An association was found between former and current smoking and functional abdominal pain (OR: 1.15, 95% CI: 1.03-1.28 vs. OR: 1.30, 95% CI: 1.08-1.57). Former smoking was associated with functional bloating (OR: 1.18, 95% CI: 1.04-1.33) and functional constipation (OR: 1.28, 95% CI: 1.06-1.56). There was a trend of decreased functional abdominal pain, functional constipation, and functional diarrhea in subjects with a moderate alcohol intake.

CONCLUSION

Smoking is associated with functional abdominal pain, functional bloating, and functional constipation. A moderate alcohol intake tends to be associated with decreased risk of functional gastrointestinal symptoms.

Anxiety Is Linked to New-Onset Dyspepsia in the Swedish Population: A 10-Year Follow-up Study

BACKGROUND & AIMS

Functional dyspepsia (FD) is associated with anxiety but it is not clear if one causes the other. We investigated whether anxiety and depression precede the onset of FD (based on the modified Rome III criteria) and gastroesophageal reflux symptoms (GERS) in a population-based follow-up study.

METHODS

Participants from the Kalixanda study (n = 3000), randomly selected from the national population register of Sweden, were given the validated Abdominal Symptom Questionnaire 1998-2001; 1000 of these participants then were selected randomly to undergo esophagogastroduodenoscopy and were given the Abdominal Symptom Questionnaire along with the Hospital Anxiety and Depression Scale questionnaire. All eligible subjects who underwent endoscopy (n = 887) were invited to participate in a follow-up study in June-August 2010 and were given the same questionnaires. Data were analyzed by logistic regression.

RESULTS

Of the 703 subjects who completed the follow-up questionnaires (79.3%); 110 were found to have FD at baseline (15.6%) and 93 at the follow-up examination (13.3%); 48 of these were new cases of FD. GERS without organic disease was reported by 273 individuals (38.8%) at baseline and by 280 at follow-up examination (39.8%); 93 cases were new. Major anxiety was associated with FD at the follow-up evaluation (odds ratio [OR], 6.30; 99% confidence interval [CI], 1.64-24.16). Anxiety was associated with postprandial distress syndrome at baseline (OR, 4.83; 99% CI, 1.24-18.76) and at the follow-up examination (OR, 8.12; 99% CI, 2.13-30.85), but not with epigastric pain syndrome. Anxiety at baseline was associated with new-onset FD at the follow-up examination (OR, 7.61; 99% CI, 1.21-47.73), but not with GERS.

CONCLUSIONS

In a study of the Swedish population, anxiety at baseline, but not depression, increased the risk for development of FD by 7.6-fold in the next 10 years. Anxiety did not affect risk for GERS.

Staple foods consumption and irritable bowel syndrome in Japanese adults: a cross-sectional study

Background

Carbohydrates can cause gastrointestinal symptoms due to incomplete absorption in the small bowel. Thus, high-carbohydrate diets may induce symptoms of irritable bowel syndrome (IBS).

Objective

This observational and cross-sectional study assessed the association between consumption of several carbohydrate-enriched staple foods, such as rice, Japanese wheat noodles, Chinese noodles, bread, pasta, and buckwheat noodles, and the prevalence of IBS in Japanese adults.

Subjects and Methods

One thousand and eighty-two (837 men) Japanese adult employees aged 19-85 were included in this cross-sectional study conducted in 2011. IBS diagnosis was based on the Rome III criteria. Consumption of staple foods was assessed using a brief self-administered diet history questionnaire, and divided into three categories (low, middle, high) depending on their distribution.

Results

In the multivariate analysis, daily consumption of rice (odds ratios [ORs] and [95% confidence interval (CI)]: middle, 1.36 [0.93–1.99]; high, 1.67 [1.12–2.49]; P for trend = 0.01), bread (middle, 1.88 [1.28–2.75]; high, 1.63 [1.10–2.41]; P for trend = 0.01), pasta (middle, 1.47 [1.01–2.15]; high, 1.68 [1.12–2.52]; P for trend = 0.01), and buckwheat noodles (middle, 1.76 [1.18–2.61]; high, 1.98 [1.31–3.00]; P for trend = 0.001) were associated with higher prevalence of IBS after adjustment for socio-demographic, anthropometric, and lifestyle-related factors. Buckwheat noodles, but not other staple foods, retained an association with the prevalence of IBS even after adjustment for daily intake of carbohydrates or plant proteins.

Conclusions

This cross-sectional study demonstrated that the consumption of staple foods, such as rice, bread, pasta, and buckwheat noodles is associated with the prevalence of IBS. Of these, the consumption of buckwheat noodles, but not other staple foods, is associated with IBS independent of carbohydrate or plant protein contents.

New insights and challenges in microscopic colitis

Microscopic colitis (MC) is described as an inflammatory bowel disease characterized by chronic, bloodless diarrhea with normal or close to normal endoscopic findings. Histopathological examination reveals two subtypes: collagenous colitis (CC) and lymphocytic colitis (LC), which are indistinguishable clinically. The disease debuts typically in middle-aged patients, but can occur at all ages, including children. A female predominance is found in both CC and LC, but is not confirmed by others in LC. The etiology is unclear, but the disease has been assumed to be of autoimmune origin. However, several etiologies may render a microscopic inflammation in the mucosa; this is a common, universal reaction to a variety of irritants in contact with the intestinal lumen. Furthermore, some patients with a microscopic inflammation in their colonic mucosa have no symptoms, or are suffering from constipation or abdominal pain, rather than diarrhea. Recently, a discussion was initiated calling into question the overdiagnosing of symptoms and pointing out the danger of exacerbating people's perception of their ailments, of weakening their eligibility in health insurance, of overprescription of drugs, and thus the increasing cost to the society of health care. In the light of this discussion, this review will highlight histopathological and clinical features of MC, and discuss the diagnosis and management of this disease. Perhaps, the intestinal mucosa has no other mode by which to react than an inflammatory response, irrespective of the presence or absence of autoimmunity. Thus, to better identify and classify subgroups of MC, and to clarify and correctly handle the inflammatory changes, this field of research stands to benefit from a review of the results and experience gained to date.

Systematic review with meta-analysis: post-infectious functional dyspepsia

BACKGROUND

The prevalence of functional dyspepsia (FD) following infectious gastroenteritis has not been systematically reviewed.

AIM

To conduct a systematic review and calculate the summary odds ratio (OR) for the development of FD following infectious gastroenteritis, as compared to a control population.

METHODS

Published studies in PubMed, EmBASE, and Cochrane Database and abstracts from standard sources were screened for eligible studies. Data from studies meeting inclusion criteria were pooled for meta-analysis.

RESULTS

Nineteen studies were eligible for inclusion. The mean prevalence of FD following acute gastroenteritis (AGE) was 9.55% (FD, n = 909; AGE, n = 9517) in adult populations. The summary OR for the development of post-infectious FD was 2.54 (95% CI = 1.76-3.65) at more than 6 months after AGE, as compared to the prevalence in controls within the same population. This is compared with the summary OR (3.51; 95% CI = 2.05-6.00) for the development of post-infectious irritable bowel syndrome (IBS) in the same population at more than 6 months after AGE. There was significant statistical heterogeneity with an I(2) of 72.8% for the summary OR of post-infectious FD. Several pathogens, including Salmonella spp., Escherichia coli O157, Campylobacter jejuni, Giardia lamblia and Norovirus have been shown to be associated with post-infectious FD symptoms.

CONCLUSIONS

Infectious gastroenteritis is associated with an increased risk for subsequent dyspepsia as well as for irritable bowel syndrome. Post-infectious FD and post-infectious irritable bowel syndrome may represent different aspects of the same pathophysiology. Further studies will be needed to determine this.

Smoking- and alcohol habits in relation to the clinical picture of women with microscopic colitis compared to controls

Background

Microscopic colitis (MC) induces gastrointestinal symptoms, which are partly overlapping with irritable bowel syndrome (IBS), predominately in middle-aged and elderly women. The etiology is unknown, but association with smoking has been found. The aim of this study was to examine whether the increased risk for smokers to develop MC is a true association, or rather the result of confounding factors. Therefore, patients suffering from MC and population-based controls from the same geographic area were studied regarding smoking- and alcohol habits, and other simultaneous, lifestyle factors, concerning the clinical expression of the disease.

Methods

Women at the age of 73 years or younger, who had been treated for biopsy-verified MC at any of the Departments of Gastroenterology in Skåne, between 2002 and 2010, were invited to the study (240 patients). Women (737) from the population-based prospective cohort study, Malmö Diet and Cancer Study (MDCS), served as controls. A self-administered questionnaire about lifestyle factors, gastrointestinal symptoms, medical conditions and medication at the time for the study was sent by post.

Results

Altogether, 131 women with MC could be included after age-matching with controls (median age 56 years) and exclusion of secondary MC. Patients were divided into persistent MC (MC1) and transient MC (MC2). Past smoking was associated with increased risk to develop MC2 (OR = 2.67, 95 CI = 1.15–6.23), whereas current smoking was associated with increased risk to develop MC1 (OR = 3.18, 95 CI = 1.57–6.42). Concomitant symptoms of IBS were associated with smoking (OR = 4.24, 95 CI = 1.92–9.32). Alcohol drinking had no association with MC or IBS.

Conclusions

The results suggest that past smoking is associated with transient MC, whereas current smoking is associated with persistent MC. Smoking is associated with MC patients with concomitant IBS-like symptoms.

Relationship between infectious gastroenteritis and irritable bowel syndrome

A newly recognized causative factor in a subset of patients with irritable bowel syndrome (IBS) is called post-infectious IBS (PI-IBS). IBS symptoms frequently develop after an acute episode of infectious gastroenteritis. Several studies have been made in our understanding of the concept of PI-IBS. Recent studies suggest that transient or chronic gastrointestinal inflammation may play a role in IBS pathogenesis. PI-IBS can be regarded as a natural experiment model in which an insult in the form of an infective disease impacts on subjects with underlying genetic and psychosocial predispositions who then develop IBS. IBS is likely to be a complex trait wherein variability in clinical presentation is partially explained by heterogeneity in underlying genetic and environmental risk factors for PI-IBS. Further studies on PI-IBS are needed to understand the pathophysiology of functional gastrointestinal disorders and to develop new promising management for such patients.

Post-infectious sequelae of travelers' diarrhea

BACKGROUND

Travelers' diarrhea (TD) has generally been considered a self-limited disorder which resolves more quickly with expeditious and appropriate antibiotic therapy given bacteria are the most frequently identified cause. However, epidemiological, clinical, and basic science evidence identifying a number of chronic health conditions related to these infections has recently emerged which challenges this current paradigm. These include serious and potentially disabling enteric and extra-intestinal long-term complications. Among these are rheumatologic, neurologic, gastrointestinal, renal, and endocrine disorders. This review aims to examine and summarize the current literature pertaining to three of these post-infectious disorders: reactive arthritis, Guillain-Barré syndrome, and post-infectious irritable bowel syndrome and the relationship of these conditions to diarrhea associated with travel as well as to diarrhea associated with gastroenteritis which may not be specifically travel related but relevant by shared microbial pathogens. It is hoped this review will allow clinicians who see travelers to be aware of these post-infectious sequelae thus adding to our body of knowledge in travel medicine.

METHODS

Data for this article were identified by searches of PubMed and MEDLINE, and references from relevant articles using search terms "travelers' diarrhea" "reactive arthritis" "Guillain-Barré syndrome" "Post-Infectious Irritable Bowel Syndrome." Abstracts were included when related to previously published work.

RESULTS AND CONCLUSIONS

A review of the published literature reveals that potential consequences of travelers' diarrhea may extend beyond the acute illness and these post-infectious complications may be more common than currently recognized. In addition since TD is such a common occurrence it would be helpful to be able to identify those who might be at greater risk of post-infectious sequelae in order to target more aggressive prophylactic or therapeutic approaches to such individuals. It is hoped this review will allow clinicians who see travelers to be aware of these post-infectious sequelae thus adding to our body of knowledge in travel medicine.

Diarrhoea is not the only symptom that needs to be treated in patients with microscopic colitis

BACKGROUND

Many patients with microscopic colitis (MC) also suffer from symptoms of irritable bowel syndrome (IBS), but the only treatment given is corticosteroids for the diarrhoea. The aim of this study was to examine how social factors, life style factors and drug treatment affect symptoms and well-being in patients suffering from MC.

METHODS

Women, over the age of 73years, with biopsy-verified MC, at any Departments of Gastroenterology, Skåne, between 2002 and 2010 were invited. The questionnaires Gastrointestinal Symptom Rating Scale (GSRS) and Psychological General Well-being Index (PGWB) were sent by mail, along with questions about social and life style factors, and medical history.

RESULTS

Of 240 invited, 158 patients (66%) were included (median age 63years, range 27-73years). Only 26% had never smoked. Smoking and concomitant IBS were associated with both impaired gastrointestinal symptoms (OR=3.96, 95% CI=1.47-10.66 and OR=4.40, 95% CI=2.09-9.26, respectively) and impaired psychological well-being (OR=2.77, 95% CI=1.04-7.34 and OR=3.82, 95% CI=1.83-7.99, respectively). Treatment with proton pump inhibitors (PPI) was associated with increased gastrointestinal symptoms (OR=3.44, 95% CI=1.45-8.16). Age, social factors, and corticosteroids had no effect on symptoms or well-being. Smoking was the only risk factor associated with IBS (OR=2.68, 95% CI=1.115-6.26).

CONCLUSION

Smoking and IBS are associated with impaired gastrointestinal symptoms and psychological well-being in MC patients. PPI is associated with impaired gastrointestinal symptoms.

Chronic diarrhea in travelers

As a rule, travelers' diarrhea is a self-limited bacterial infection that affects approximately 40 % of travelers to developing countries. Health-care professionals who see returning travelers have noted that some travelers afflicted with diarrhea do not recover completely but, instead, develop chronic diarrhea or a persistent change in gastrointestinal function. Concurrent with this observation has been the recognition that in many patients with long-standing irritable bowel syndrome, an episode of traveler's diarrhea or gastroenteritis preceded the onset of symptoms. Before a diagnosis of postinfectious irritable bowel syndrome is considered, other diagnostic considerations must be excluded. This review will examine an approach to the patient with chronic diarrhea posttravel.

Irritable bowel syndrome with constipation: a European-focused systematic literature review of disease burden

OBJECTIVE

To conduct a systematic literature review to assess burden of disease and unmet medical needs in patients with irritable bowel syndrome (IBS) with constipation (IBS-C), with a focus on five European countries (France, Germany, Italy, Spain, UK).

METHODS

MEDLINE, EMBASE, and grey literature searches were carried out using terms for IBS and constipation, to identify studies reporting epidemiological, clinical, humanistic, or economic outcomes for IBS-C, published between 2000 and 2010.

RESULTS

Searches identified 885 unique abstracts and 33 supplementary articles, of which 100 publications and six grey literature sources met the inclusion criteria. Among patients with IBS, the prevalence estimates of IBS-C ranged from 1 to 44%. Co-morbid conditions, such as personality traits, psychological distress, and stress, were common. Patients with IBS-C had lower health-related quality-of-life (HRQoL) compared with the general population, and clinical trials suggested that effectively treating IBS-C improves HRQoL. The European societal cost of IBS-C is largely unknown, as no IBS-C-specific European cost-of-illness studies were identified. Two cost analyses demonstrated the substantial societal impact of IBS-C, including reduced productivity at work and work absenteeism. Guidelines offered similar recommendations for the diagnosis and management of IBS; however, recommendations specifically for IBS-C varied by country. Current IBS-C treatment options have limited efficacy and the risk:benefit profile of early 5-HT(4) agonists restricts clinical use.

CONCLUSIONS

This systematic review indicates a clear need for European-focused IBS-C burden-of-disease and cost-of-illness studies to address identified evidence gaps. There is a need for new therapies for IBS-C that are effective, well tolerated, and have a positive impact on HRQoL.

Intestinal microbiota, pathophysiology and translation to probiotic use in patients with irritable bowel syndrome

Probiotic agents have received growing attention in recent years as an alternative therapeutic tool in the management of irritable bowel syndrome. In this article, we will discuss the rationale that support this indication, including the role of intestinal microbiota in gastrointestinal function in both human and animal models, potential links between an impaired microbiota imbalance and the psycho-immunopathophysiology of irritable bowel syndrome, and the results of the available clinical trials to date.

The effects of lifestyle modification on symptoms and quality of life in patients with irritable bowel syndrome: a prospective observational study

Background/Aims

Although notably common, irritable bowel syndrome (IBS) has no specific cure. Lifestyle modification may be as important as medication; however, few studies support the effectiveness of such modifications. We performed this observational study of IBS patients to explore further the role of lifestyle changes in treatment.

Methods

This study included 831 men who enlisted in 2010 as armed surgeon cadets and 85 women who concurrently entered the Armed Forces Nursing Academy. Of these 916 participants, 89 were diagnosed with IBS using the Rome III criteria. Subjective changes in bowel habits, quality of life, pain, stress, stool frequency and stool consistency were surveyed before and after 9 weeks of army training. We evaluated the lifestyle risk factors that impacted improvement in IBS symptoms by comparing those who responded to lifestyle modification (the responding group) to those who did not respond (the nonresponding group).

Results

More than half of the participants (63%) reported that their symptoms improved after training. The quality of life and levels of pain and stress significantly improved after military training. Initial stress levels before military training and smoking history affected IBS symptom improvement.

Conclusions

Lifestyle modification may be effective in managing IBS patients.

[Post-infectious functional gastrointestinal disorders: from the acute episode to chronicity]

Functional gastrointestinal disorders (FGID) form a major part of gastroenterology practice. Several studies have reported the development of post-infectious irritable bowel syndrome (PI-IBS) after acute gastroenteritis (AGE). Non-gastrointestinal (GI) infections may increase the risk of developing IBS. There are also data showing that a GI infection may trigger functional dyspepsia (PI-FD). The possible development of PI-IBS or PI-FD depends on factors related to both the infection and the host. Microinflammation has been found in patients with post-infectious FGID. Studies performed in animal models show that infection and acute inflammation permanently change gastrointestinal motility and sensitivity. The role of AGE in the development of FGID is important not only because this entity provides an excellent natural model for pathogenic study but also because it provides an opportunity for preventive action.

Systematic review of animal models of post-infectious/post-inflammatory irritable bowel syndrome

AIMS

Post-infectious irritable bowel syndrome (PI-IBS) is a subset of IBS which occurs after an episode of acute gastrointestinal infections. The mechanisms of PI-IBS are not fully understood. Currently, numerous animal models have been used in the study of PI-IBS. This article reviews the strengths and weaknesses of these models.

METHODS

All relevant articles were identified by searching in Ovid SP from 1962, the year the term PI-IBS was coined, up to December 31, 2009. The types of model were categorized as either post-infectious or post-inflammatory, and the characteristics of each kind of model were listed.

RESULTS

Based on our literature search, 268 articles were identified. Of those articles, 50 were included in this review. The existing PI-IBS models include infection with bacteria (e.g., Campylobacter jejuni, Salmonella enterica, and Campylobacter rodentium), and infection with parasites (e.g., Trichinella spiralis, Nippostrongylus brasiliensis, and Cryptosporidium parvum). The post-inflammatory IBS models are commonly induced with chemical agents, such as acetic acid, deoxycholic acid, dextran sulfate sodium, mustard oil, zymosan, and trinitrobenzene sulfonic acid (TNBS). TNBS is the most commonly used agent for post-inflammatory IBS models, but the experimental protocol varies. These models have one or more aspects similar to IBS patients.

CONCLUSIONS

Different methods have been used for the development of post-infectious or post-inflammatory IBS models. Each model has its weaknesses and strengths. More studies are needed to establish post-infection IBS models using more common pathogens. A standard protocol in developing TNBS-induced post-inflammatory IBS model is needed.

Prevalence of uninvestigated dyspepsia 8 years after a large waterborne outbreak of bacterial dysentery: a cohort study

BACKGROUND & AIMS

Symptoms of dyspepsia may occur following an episode of acute gastroenteritis, but data are conflicting. We assessed prevalence of uninvestigated dyspepsia in a cohort of individuals, some of whom were exposed to bacterial dysentery in May 2000, as well as risk factors for dyspepsia in exposed individuals.

METHODS

This was a cohort study conducted in the town of Walkerton, Ontario, Canada. Involved individuals were recruited into the Walkerton Health Study between 2002 and 2003 and were attending for annual assessment in 2008. Exposed individuals were subdivided into those with self-reported gastroenteritis, with acute illness unconfirmed by health records, and those with clinically confirmed gastroenteritis, with substantiation of acute illness by health record review. Presence of dyspepsia at 8 years, according to a broad definition (any symptom referable to the upper gastrointestinal tract), and the Rome II criteria, was compared between exposed and nonexposed individuals.

RESULTS

Of 2597 subjects eligible, 1088 (41.9%) provided data for analysis, and 706 (64.9%) had reported acute gastroenteritis. Multivariate odd ratios for dyspepsia at 8 years in exposed individuals using a broad definition and the Rome II definition were 2.09 (95% confidence interval: 1.58-2.78) and 2.30 (95% confidence interval: 1.63-3.26), respectively. Prevalence of dyspepsia was higher in females; smokers; those with premorbid irritable bowel syndrome, anxiety, or depression; and those reporting >7 days of diarrhea or abdominal cramps during the acute illness.

CONCLUSIONS

Symptoms of dyspepsia 8 years after an outbreak of acute gastroenteritis were significantly more prevalent in exposed compared with nonexposed individuals.

Pathogenesis of IBS: role of inflammation, immunity and neuroimmune interactions

IBS is one of the most common functional gastrointestinal disorders worldwide and is thought to be the result of disturbed neural function along the brain-gut axis. The mechanisms behind this disturbance are not clear, but important roles for low-grade inflammation and immunological alterations in the development of symptoms compatible with IBS have become evident. The development of long-standing gastrointestinal symptoms after infectious gastroenteritis and patients with IBD in remission frequently having functional gastrointestinal symptoms support this hypothesis. An increased innate immune activity in the intestinal mucosa and in blood is found in subpopulations of patients with IBS. Mast cells and monocytes seem to be particularly important. In addition, studies have demonstrated that IBS may be associated with an activated adaptive immune response. Increased epithelial barrier permeability and an abnormal gut flora might lead to increased activation of the intestinal immune system. Functional and anatomical evidence for abnormal neuroimmune interactions has been found in patients with IBS. The link between immune alterations and severity of gastrointestinal symptoms and the positive effect of anti-inflammatory treatments in IBS further highlight the relevance of neuroimmune interactions in this condition.

Infection, inflammation, and the irritable bowel syndrome

Gastrointestinal infection is ubiquitous worldwide though the pattern of infection varies widely. Poor hygiene and lack of piped water is associated with a high incidence of childhood infection, both viral and bacterial. However in developed countries bacterial infection is commoner in young adults. Studies of bacterial infections in developed countries suggest 75% of adults fully recover, however around 25% have long lasting changes in bowel habit and a smaller number develop the irritable bowel syndrome (IBS). Whether the incidence is similar in developing countries is unknown. Post-infective IBS (PI-IBS) shares many features with unselected IBS but by having a defined onset allows better definition of risk factors. These are in order of importance: severity of initial illness, smoking, female gender and adverse psychological factors. Symptoms may last many years for reasons which are unclear. They are likely to include genetic factors controlling the immune response, alterations in serotonin signaling, low grade mucosal inflammation maintained by psychological stressors and alterations in gut microbiota. As yet there are no proven specific treatments, though 5HT(3) receptor antagonists, anti-inflammatory agents and probiotics are all logical treatments which should be examined in large well-designed randomised placebo controlled trials.

The clinical course of postinfectious irritable bowel syndrome: a five-year follow-up study

OBJECTIVES

Irritable bowel syndrome (IBS) is a common disorder seen in general practice. Bacterial gastroenteritis has been known to be a risk factor for IBS. We investigated the clinical course, risk factors, and prognosis of postinfectious IBS (PI-IBS) 5 years after Shigella infection.

METHODS

We recruited 153 individuals and used a questionnaire to investigate their current bowel habits. We also looked for the presence of other functional bowel disorders (FBDs). The Shigella-exposed group consisted of hospital employees and medical students who experienced abdominal pain, diarrhea, or fever during the shigellosis outbreak and whose stool culture revealed Shigella sonnei. The control group consisted of age-matched and sex-matched subjects who corresponded fairly well with patients, considering that they were enrolled from the same hospital and were not infected.

RESULTS

Complete data were obtained from 119 individuals who were divided into the Shigella-exposed group (59) and the control group (60). In the Shigella-exposed group, 3 patients had IBS before infection (previous IBS) and 6 out of 13 cases of PI-IBS after 3 years showed persistent IBS after 5 years. Five out of 11 PI-IBS patients (45.5%, 2 excluded), 3 out of 6 previous IBS patients (50%) in the Shigella-exposed group, and 7 out of 11 previous IBS patients (63.6%) in the control group recovered after 5 years (P>0.05). Five cases in the Shigella-exposed group and 3 in the control group developed new cases of IBS after 5 years. The prevalence of PI-IBS after 5 years in the previous FBD groups was 63.6%, whereas the prevalence of PI-IBS without a history of FBDs was 36.4% (P<0.05). There were no significant differences among the other risk factors in each group.

CONCLUSIONS

About half of PI-IBS and previous IBS patients with or without infection recover over 5 years. Previous IBS and FBDs are risk factors of PI-IBS after 5 years. We suggest that our results support the understanding of the clinical course and prognosis of PI-IBS.

Postinfectious irritable bowel syndrome

Approximately 1 in ten patients with irritable bowel syndrome (IBS) believe their IBS began with an infectious illness. Prospective studies have shown that 3% to 36% of enteric infections lead to persistent new IBS symptoms; the precise incidence depends on the infecting organism. Whereas viral gastroenteritis seems to have only short-term effects, bacterial enteritis and protozoan and helminth infections are followed by prolonged postinfective IBS (PI-IBS). Risk factors for developing PI-IBS include, in order of importance, prolonged duration of initial illness, toxicity of infecting bacterial strain, smoking, mucosal markers of inflammation, female gender, depression, hypochondriasis, and adverse life events in the preceding 3 months. Age older than 60 years might protect against PI-IBS, whereas treatment with antibiotics has been associated with increased risk. The mechanisms that cause PI-IBS are unknown but could include residual inflammation or persistent changes in mucosal immunocytes, enterochromaffin and mast cells, enteric nerves, and the gastrointestinal microbiota. Adverse psychological factors contribute to persistent low-grade inflammation. The prognosis for patients with PI-IBS is somewhat better than for those with unselected IBS, but PI-IBS can still take years to resolve. There are no specific treatments for PI-IBS; these should be tailored to the predominant bowel disturbance, which is most frequently diarrhea.

Postinfectious irritable bowel syndrome

After acute bacterial gastroenteritis, up to one-third of patients will have prolonged gastrointestinal complaints, and a portion of those affected will meet the diagnostic criteria for postinfectious irritable bowel syndrome. After resolution of the acute infection, patients with postinfectious irritable bowel syndrome appear to have chronic mucosal immunologic dysregulation with altered intestinal permeability and motility that can lead to persistent intestinal symptoms. Both host- and pathogen-related factors, such as preexisting psychological disorders and duration of initial infection, have been associated with an increased risk for the development of postinfectious irritable bowel syndrome. Current treatments for postinfectious irritable bowel syndrome are typically targeted at specific symptoms, although studies evaluating therapies directed at preventing or reducing the duration of the initial infection are ongoing.

Post-infectious irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common disorder associated with abdominal pain or discomfort and altered bowel habits. The majority of patients describe an insidious onset of symptoms; however, a subset report a fairly precise time of onset following an attack of acute gastroenteritis. Typically, the potential acute infectious symptoms, such as fever and vomiting, resolve after several days, but abdominal discomfort, bloating, and diarrhea persist. Although the underlying mechanism of post-infectious IBS (PI-IBS) has not been established, ongoing inflammation appears to play a role, with an increase in serotonin-containing enterochromaffin cells, T lymphocytes, mast cells, proinflammatory cytokines, and intestinal permeability. Psychiatric comorbidities are less common in PI-IBS, compared with IBS patients in general; however, the prevalence of psychological disorders is still higher compared with that in the general population and is associated with a poorer prognosis. Overall, patients with PI-IBS have a slightly improved prognosis compared with those with IBS without an infectious onset.

Systematic review and meta-analysis: The incidence and prognosis of post-infectious irritable bowel syndrome

BACKGROUND

Individual studies suggest that post-infectious irritable bowel syndrome is common, but symptoms gradually improve.

AIM

To review evidence for an association between intestinal infection and development of irritable bowel syndrome, assess the prognosis of post-infectious irritable bowel syndrome and explore factors that increase the risk.

METHODS

MEDLINE (1966-2007) and EMBASE (1980-2007) databases were searched to identify the studies of post-infectious irritable bowel syndrome epidemiology. Data were extracted by two independent reviewers. Pooled odds ratios (POR) and corresponding 95% CI for incidence of irritable bowel syndrome were estimated among the exposed and unexposed groups.

RESULTS

Eighteen of 26 studies identified were eligible for inclusion. Intestinal infection was associated with increased odds of developing irritable bowel syndrome at study end (POR = 5.86; 95% CI: 3.60-9.54). In subgroup analysis, the odds of developing irritable bowel syndrome was increased at 3 months (POR = 7.58; 95% CI: 4.27-13.45), 6 months (POR = 5.18; 95% CI: 3.24-8.26), 12 months (POR = 6.37; 95% CI: 2.63-15.40) and 24-36 months (POR = 3.85; 95% CI: 2.95-5.02). Among all studies (controlled and uncontrolled), the pooled incidence of irritable bowel syndrome at study conclusion was 10% (95% CI: 9.4-85.6). Subjects with post-infectious irritable bowel syndrome were younger and more anxious and depressed than those without post-infectious irritable bowel syndrome.

CONCLUSION

The odds of developing irritable bowel syndrome are increased sixfold after acute gastrointestinal infection. Young age, prolonged fever, anxiety and depression are risk factors for post-infectious irritable bowel syndrome.

Risk of irritable bowel syndrome after an episode of bacterial gastroenteritis in general practice: influence of comorbidities

BACKGROUND & AIMS

Given the discrepant estimates of incidence rates of irritable bowel syndrome (IBS) after gastroenteritis (GE), we performed a cohort study to quantify this risk in community subjects and to identify factors acting as modifiers of this effect.

METHODS

In a previous study, we identified patients aged 20-74 years with a first ever episode of bacterial GE during 1992-2001. We excluded patients with a history of bowel disease and cancer, resulting in a cohort of 5894 individuals with GE. From the same source population, a control group free of GE was sampled. We followed up the 2 cohorts to identify incident cases of IBS. A nested case-control analysis was performed to quantify the role of potential risk factors.

RESULTS

During a mean follow-up period of 4.1 years, 1105 patients developed IBS. The incidence rate of IBS after an episode of bacterial GE was 98.2 per 10,000 person-years, and 45.3 per 10,000 person-years in the comparison cohort. The adjusted relative risk of IBS associated with bacterial GE was 2.2 (1.5-2.9) compared with the control cohort. The nested case-control analysis adjusting for additional risk factors produced similar results (odds ratio, 1.8; 95% confidence interval, 1.5-2.1). The risk of IBS after GE was increased significantly in patients with depression, anxiety, stress or sleep disorders, prior gastrointestinal morbidity, or prolonged use of antibiotics.

CONCLUSIONS

The risk of IBS in community individuals after having bacterial GE was two fold greater in the general population. Pre-existing psychologic and gastrointestinal comorbidities independently increase this risk of developing IBS.

Postinfectious irritable bowel syndrome may occur after non-gastrointestinal and intestinal infection

Postinfectious functional gastrointestinal disorders (FGIDs) may not be specific to gastroenteritis. This pilot study aimed to ascertain the 3- and 6-month incidence of functional gut disorders in people with non-gastrointestinal (GI) infection, gastroenteritis and healthy controls. This was a prospective study of three cohorts recruited from hospital (non-GI infections) and the community (others). FGIDs were diagnosed using self-completed Rome II modular questionnaires administered at baseline, 3 and 6 months. Thirty-six subjects with non-GI infection, 219 healthy subjects and 108 with bacterial gastroenteritis participated. No difference in incidence of FGID was detected between the GI and non-GI infection cohorts. Any FGID was more frequent in people who had a non-GI infection than in controls at both 3 [odds ratio: 4.34 (95% CI: 3.60-16.45)] and 6 months [4.76 (4.42-27.92)]. Irritable bowel syndrome (IBS) alone was more frequent in people with non-GI infections than in controls at 3 months (6.12 [1.30-29.12]) but did not quite reach statistical significance at 6 months (4.58 [0.79-26.46]). Our findings were unexpected. Postinfectious FGIDs may be related to non-GI and GI infection, although not all potential biases were controlled in study design. Further studies need to explore these preliminary findings and, if confirmed, the underlying mechanisms.

Postinfectious irritable bowel syndrome--a meta-analysis

OBJECTIVES

Irritable bowel syndrome (IBS) is a heterogeneous disorder affecting 12% of the population worldwide. Several studies identify IBS as a sequela of infectious gastroenteritis (IGE) with reported prevalence ranging from 4% to 31% and relative risk from 2.5 to 11.9. This meta-analysis was conducted to explore the differences between reported rates and provide a pooled estimate of risk for postinfectious irritable bowel syndrome (PI-IBS).

DATA SOURCES

Electronic databases (MEDLINE, OLDMEDLINE, EMBASE, Cochrane database of clinical trials) and pertinent reference lists (including other review articles).

REVIEW METHODS

Data were abstracted from included studies by two independent investigators; study quality, heterogeneity, and publication bias were assessed; sensitivity analysis was performed; and a summative effect estimate was calculated for risk of PI-IBS.

RESULTS

Eight studies were included for analysis and all reported elevated risk of IBS following IGE. Median prevalence of IBS in the IGE groups was 9.8% (IQR 4.0-13.3) and 1.2% in control groups (IQR 0.4-1.8) (sign-rank test, p= 0.01). The pooled odds ratio was 7.3 (95% CI, 4.7-11.1) without significant heterogeneity (chi2 heterogeneity statistic, p= 0.41). Subgroup analysis revealed an association between PI-IBS risk and IGE definition used.

CONCLUSIONS

This study provides supporting evidence for PI-IBS as a sequela of IGE and a pooled risk estimate revealing a sevenfold increase in the odds of developing IBS following IGE. The results suggest that the long-term benefit of reduced PI-IBS may be gained from primary prevention of IGE.