Identification of early environmental risk factors for irritable bowel syndrome and dyspepsia

The Developmental Origins of Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis

OBJECTIVES

The Developmental Origins of Health and Disease (DOHaD) framework contends that chronic diseases are attributable to behavioral and environmental risks encountered during vital periods of fetal and childhood development. Clinical research investigating irritable bowel syndrome (IBS) largely focuses on adult risk factors, with emerging evidence of epigenetic contributions. Limited work considers potential childhood exposures. This paper applies a life course approach to the study of IBS, exploring the available evidence to ascertain the potential developmental origins of IBS.

METHODS

A systematic literature review was conducted adhering to MOOSE and PRISMA protocols, identifying papers from 1970 through April 2024 examining all IBS risk factors during the prenatal, postnatal, childhood, and adolescent periods. Data were extracted from screened papers and analyzed via meta-analysis using a random effects model.

RESULTS

A total of 27 case-control, cohort, and cross-sectional studies were identified for analysis. The meta-analysis revealed significant childhood risk factors for adult IBS, including family history (pooled OR 2.17, 95% CI 1.89-2.49, p < 0.0001, n = 11) and the occurrence of any childhood trauma event (pooled OR 1.61, 95% CI 1.29-2.01, p < 0.0001, n = 6). Physical and sexual trauma were the strongest trauma predictors. Factors including breastfeeding and Cesarean section were not significant.

CONCLUSIONS

This study found IBS is strongly predicted by traumatic childhood experiences, as well as having an immediate family member with IBS. These demonstrated environmental and genetic components indicate a potential gene-environment interaction during childhood, suggesting a need for primary research to better understand the developmental origins of IBS.

A multifaceted ecological approach to explore links between environmental factors and the epidemiology of disorders of gut-brain interaction

BACKGROUND

Disorders of gut-brain interaction (DGBI) are characterized by debilitating symptoms not explained by structural or biochemical abnormalities. While functional conditions present with complex, likely heterogeneous pathophysiology, we aimed to investigate if proxy measures of sociocultural and environmental factors are associated with the prevalence of various DGBI in populations across the world.

METHODS

We performed an ecological study utilizing peer-reviewed published datasets reporting for 26 countries prevalence rates of DGBI (Rome Foundation Global Epidemiology Study, RFGES), with six independent variables: Helicobacter pylori prevalence and household size as proxy measures for orofecal infections, gross domestic product per capita (GDP), and median age as a proxy measures for socioeconomic development, density of fast food outlets (FFO) per 100,000 population as proxy measure for processed food exposure, and suicide mortality rate per 100,000 people, and world happiness scores were used as a proxy for psychological stress. The data were retrieved from publicly accessible datasets (United Nations, CIA World Factbook, World Bank, World Happiness Report, commercial/financial reports of a global FFO chain). We used linear regression to assess variables in univariate and multivariate analysis and report standardized β coefficients with 95% confidence intervals (CI).

KEY RESULTS

The regression model revealed that the overall prevalence of DGBI was inversely associated with both GDP per capita (β = -0.57, 95% CI: -0.92, -0.22, p = 0.002) and happiness scores (β = -0.433 95% CI: 0.821, -0.065, p = 0.023), while being positively associated with H. pylori prevalence (β = 0.40, 95% CI: 0.008, 0.81, p = 0.046). The prevalence of functional constipation (FC) was also inversely associated with GDP per capita (β = -0.50, 95% CI: -0.86, -0.13, p = 0.01) and happiness scores (β = -0.497, 95% CI: -0.863, -0.132, p = 0.01), while being positively associated with H. pylori prevalence (β = 0.53, 95% CI: 0.16, 0.91, p = 0.007). The Multivariate model analysis revealed that combining the factors of H. pylori prevalence, suicide rate, household size and happiness scores showed statistically significant association with FC (p = 0.039). Household size (β = -0.43, 95% CI: -0.82, 0.038, p = 0.033) and suicide rates (β = 0.55, 95% CI: 0.19, 0.90, p = 0.004) were statistically significantly associated with functional diarrhea. Irritable bowel syndrome (IBS) was associated with GDP per capita (β = -0.40, 95% CI: -0.79, -0.014, p = 0.043) and happiness scores (β = -0.390, 95% CI: -0.778, -0.003, p = 0.049).

CONCLUSIONS & INFERENCES

Utilizing publicly available data, the prevalence of DGBI across diverse countries is linked to various socio-cultural and environmental factors. Collectively, the data suggests that the prevalence of DGBI is increased in less prosperous regions of the world.

A Minority of Childhood Disorders of Gut-Brain Interaction Persist Into Adulthood: A Risk-Factor Analysis

INTRODUCTION

Disorders of gut-brain interaction (DGBIs) may originate in childhood. There are currently limited data on persistence of DGBI into adulthood and risk factors for persistence. Furthermore, there are no data on this question from general practice, where the majority of DGBIs are diagnosed and managed. This study documents the proportion of childhood-diagnosed DGBIs that persisted into adulthood and what factors were associated with persistence.

METHODS

General practice records were obtained for more than 60,000 patients whose medical record spanned both childhood and adulthood years. Patients with diagnosed organic gastrointestinal disorder were excluded. Medical records were also interrogated for potential risk factors.

RESULTS

Eleven percent of patients with irritable bowel syndrome (IBS) and 20% of patients with functional dyspepsia (FD) diagnosed in childhood had repeat diagnoses of the same condition in adulthood. Female sex (odds ratio [OR] 2.02) was associated with persistence for IBS, while a childhood diagnosis of gastritis (OR 0.46) was risk-protective. Childhood non-steroidal anti-inflammatory drug use (OR 1.31, 95% confidence interval [CI] 1.09-1.56) was a risk factor for persistence in IBS. For FD, a childhood diagnosis of asthma (OR 1.30, 95% CI 1.00-1.70) was a risk factor, as was anxiety for both IBS (OR 1.24, 95% CI 1.00-1.54) and FD (OR 1.48 95% CI 1.11-1.97) with a similar finding for depression for IBS (OR 1.34, 95% CI 1.11-1.62) and FD (OR 1.88 95% CI 1.47-2.42).

DISCUSSION

Childhood DGBIs persist into adulthood in 10%-20% of patients, suggesting that management monitoring should continue into adulthood. Those diagnosed with anxiety or mood disorders in childhood should receive particular attention, and prescription of non-steroidal anti-inflammatory drugs in children should be made judiciously.

A systematic review of the association between environmental risk factors and the development of irritable bowel syndrome

BACKGROUND AND AIM

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder with roots in genetic, immune, psychological, and dietary factors. Recently, the potential correlation between environmental exposures, such as air pollution, and IBS has gained attention. This review aimed to systematically examine existing studies on environmental factors associated with IBS, elucidating this interplay and guiding future research.

METHODS

A literature search was conducted in Medline, EMBASE, Scopus, and Cochrane databases from database inception to October 10, 2023, using the keywords "Irritable Bowel" or IBS or "Irritable Colon" or "Mucous Colitis" or "Spastic Colitis" or "Spastic Colon" AND "environment* exposure*". Studies were included if they were original, published in English, described defined environmental exposure(s), and had documented diagnosis of IBS. For the purposes of this review, articles reporting physical (e.g. radiation and climate change), biological (e.g. bacteria and viruses), and chemical (e.g. harmful gases) exposures were included while psychological and dietary factors, which have been reviewed in detail elsewhere, are outside of the scope.

RESULTS

A total of seven studies focusing on air quality, microbial exposure, and other environmental factors were reviewed. Studies highlighted a potential association between air pollutants and increased IBS incidence. Microbial exposure, post-natural disaster or due to poor sanitation, was linked to IBS development and gut dysbiosis. Other exposures, such as early pet ownership, were also associated with IBS risk.

CONCLUSION

Existing research demonstrates an epidemiologic relationship between environmental exposures and the development of IBS. Further research is needed to understand these associations.

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.

Global prevalence of functional dyspepsia according to Rome criteria, 1990-2020: a systematic review and meta-analysis

Although functional dyspepsia (FD) is a common functional gastroduodenal disorder with a high socioeconomic burden, little is known about its global prevalence. Thus, we performed a comprehensive study to estimate long-term trends in the prevalence of FD. We searched PubMed/MEDLINE, Embase, and Google Scholar from 1990 to 2022 for population-based studies that reported the prevalence of FD in adults (≥ 18 years old) according to Rome I, II, III, or IV criteria. The prevalence of FD was extracted from included studies to obtain pooled prevalence with 95% confidence intervals (CI) and 95% prediction intervals. Subgroup analysis was performed according to certain characteristics, including geographic region. A total of 44 studies met the eligibility criteria, including 256,915 participants from 40 countries across six continents. The overall global pooled prevalence of FD was 8.4% (95% CI 7.4-.9.5). The prevalence was the highest in Rome I (11.9%; 95% CI 5.1-25.4) and lowest in Rome IV (6.8%; 95% CI 5.8-7.9). Developing countries showed a higher prevalence than developed countries (9.1% versus 8.0%), and prevalence was higher in women, irrespective of the definition used (9.0% versus 7.0%). The pooled prevalence gradually decreased from 1990 to 2020 (12.4% [8.2-18.3] in 1990-2002 versus 7.3% [6.1-8.7] in 2013-2020). The prevalence of FD differs by country, economic status, geographical region, and sex, and the global prevalence has been gradually declining. Despite the heterogeneity of sample population, our study estimates the current global burden of FD and provides information to heath care policy decisions.

Evolutionary medicine approaches to chronic disease: The case of irritable bowel syndrome

Irritable bowel syndrome (IBS), a gastrointestinal disease, is a global phenomenon correlated with industrialization. We propose that an evolutionary medicine approach is useful to understand this disease from an ultimate perspective and conducted a scoping literature review to synthesize the IBS literature within this framework. Our review suggests five potential evolutionary hypotheses for the cause of IBS, including (a) a dietary mismatch accompanying a nutritional transition, (b) an early hygienic life environment leading to the immune system and microbiotic changes, (c) an outcome of decreased physical activity, (d) a response to changes in environmental light-dark cycles, and (e) an artifact of an evolved fight or flight response. We find key limitations in the available data needed to understand early life, nutritional, and socioeconomic experiences that would allow us to understand evolutionarily relevant risk factors and identify a need for further empirical research to distinguish potential causes and test evolutionary hypotheses.

Early life adverse exposures in irritable bowel syndrome: new insights and opportunities

Irritable bowel syndrome (IBS) is a prevalent functional gastrointestinal disorder worldwide. Extensive research has identified multiple factors contributing to its development, including genetic predisposition, chronic infection, gut dysbiosis, aberrant serotonin metabolism, and brain dysfunction. Recent studies have emphasized the critical role of the early life stage as a susceptibility window for IBS. Current evidence suggests that diet can heighten the risk of IBS in offspring by influencing the microbiota composition, intestinal epithelium structure, gene expression, and brain-gut axis. The use of antibiotics during pregnancy and the neonatal period disrupts the normal gut microbiota structure, aligning it with the characteristics observed in IBS patients. Additionally, early life stress impacts susceptibility to IBS by modulating TLR4, NK1, and the hypothalamic-pituitary-adrenal (HPA) axis while compromising the offspring's immune system. Formula feeding facilitates the colonization of pathogenic bacteria in the intestines, concurrently reducing the presence of probiotics. This disruption of the Th1 and Th2 cell balance in the immune system weakens the intestinal epithelial barrier. Furthermore, studies suggest that delivery mode influences the occurrence of IBS by altering the composition of gut microbes. This review aims to provide a comprehensive summary of the existing evidence regarding the impact of adverse early life exposures on IBS during pregnancy, intrapartum, and neonatal period. By consolidating this knowledge, the review enhances our understanding of the direct and indirect mechanisms underlying early life-related IBS and offers new insights and research directions from childhood to adulthood.

Clinical Implications of Low-grade Duodenal Eosinophilia in Functional Dyspepsia: A Prospective Real-life Study

BACKGROUND

Functional dyspepsia (FD) is a multifactorial disorder with no targeted therapy. Duodenal eosinophilia and low-grade inflammation are potential pathogenic mechanisms. However, the impact of duodenal eosinophils (D-EO) histologic evaluation in real-life clinical practice was not explored.

AIM

To evaluate the clinical utility of D-EO and low-grade inflammation in FD in real-life practice.

MATERIALS AND METHODS

A multicenter prospective study was conducted. A total of 636 patients who meet Rome-III criteria were selected before upper endoscopy and 516 patients were included after normal endoscopy were assessed. Clinical parameters, Helicobacter pylori ( H. pylori), and duodenal histology were evaluated.

RESULTS

FD subtypes were 231 (45%) patients who had epigastric pain syndrome (EPS), 168 (33%) postprandial distress syndrome (PDS), and 117 (22%) EPS/PDS overlap. Two hundred fifty-nine (50.3%) patients were H. pylori+ . Histologic duodenal grading of chronic inflammation and intraepithelial lymphocytes showed no difference between FD subtypes. Increased in D-EO densities (>10 per high power field) was significant in PDS compared with EPS and EPS/PDS overlap subtypes. The odds ratio of PDS in subjects with duodenal eosinophilia densities was 2.28 (95% CI, 1.66-3.14; P <0.0001), adjusting for age, gender, H. pylori and nonsteroidal anti-inflammatory drug the odds ratio was 3.6 (95% CI, 2.45-5.28; P <0.0001). receiver operating characteristic curve analysis further demonstrated that low-grade duodenal eosinophilia, in particular H. pylori- , was highly accurate for PDS with the area under the curve 0.731 compared with H. pylori+ area under the curve 0.598. Furthermore, low-grade duodenal eosinophilia was significantly correlated with treatment response under 4 to 6 weeks of proton pump inhibitor therapy.

CONCLUSION

Our findings suggest that low-grade duodenal eosinophilia is associated with PDS subtype non- H. pylori FD patients and could be a useful marker of treatment response.

Irritable Bowel Syndrome and the Gut Microbiome: A Comprehensive Review

Irritable Bowel Syndrome (IBS) is a functional disorder of the gastrointestinal tract characterized by abdominal pain and altered bowel habits. It has a prevalence of 10 to 25% in the United States and has a high disease burden, as evidenced by reduced quality of life, decreased work productivity and increased healthcare utilization and costs. IBS has been associated with several intra-intestinal and extra-intestinal conditions, including psychiatric comorbidities. Although the pathophysiology of IBS has not been fully elucidated, it involves dysregulation of communication between the brain and gut (brain–gut axis) which is associated with alterations in intestinal motility, gut permeability, visceral hypersensitivity and gut microbiota composition. The purpose of this article is to review the role the gut microbiota plays in the pathophysiology of IBS, understand factors that affect the gut microbiome and explore the microbiome as a target of treatment.

Low-grade duodenal eosinophilia is associated with cagA in Helicobacter pylori-related dyspepsia

BACKGROUND AND AIM

Functional dyspepsia (FD) is a multifactorial disorder. Helicobacter pylori (H. pylori)-related dyspepsia (HpD) may be considered a separate entity. Duodenal eosinophilia is a potential pathogenic mechanism in FD. However, the impact of duodenal eosinophilia and H. pylori virulence genes in HpD was not explored. We aim to evaluate the association of H. pylori virulence genes and low-grade duodenal eosinophilia in HpD.

METHODS

A multi-center cross-sectional study was conducted. A total of 301 patients who meet Rome-III criteria were selected before upper endoscopy, and 95 patients were included after normal endoscopy and positive H. pylori in gastric biopsies were assessed. Clinical parameters, H. pylori virulence genes (cagA, oipA, and vacA) and duodenal histology were evaluated.

RESULTS

Sixty-nine (72%) patients had epigastric pain syndrome (EPS), 17 (18%) post-prandial distress syndrome (PDS) and 9 (10%) EPS/PDS overlap. FD syndromes were not associated with cagA or oipA strains. A significantly trend of vacA s1/m1 (78%) and s1/m2 (80%) positive strains in EPS was observed. Histological duodenal grading of chronic inflammation, low-grade duodenal eosinophilia and intra-epithelial lymphocytes showed no difference in oipA and vacA strains. Low-grade duodenal eosinophilia was significant in cagA positive strain, and the OR for low-grade duodenal eosinophilia with H. pylori cagA positive strain was 4.2 (95% CI, 1.78-9.93). Adjusting for age, gender, smoking, diabetes, alcohol, PPI, and NSAID, the OR was 5.44 (1.989-14.902).

CONCLUSION

Our findings suggest that low-grade duodenal eosinophilia is significantly associated with cagA strain in HpD.

Prevalence and Risk Factors of Functional Gastrointestinal Disorders: A Cross-Sectional Study in Italian Infants and Young Children

OBJECTIVES

Reports of prevalence of functional gastrointestinal disorders (FGIDs) in infants/toddlers are widely variable. Reasons for this variability are not yet fully understood. The objective of this study is to estimate the prevalence of FGIDs according to Rome IV criteria and to evaluate associated factors, in Italian infants and toddlers.

METHODS

Subjects aged 0-48 months were enrolled by general pediatricians from 3 Italian regions. Parents or legal guardians were administered questionnaires including information about the child, the family, and GI symptoms according to Rome IV criteria.

RESULTS

Five hundred eight infants aged 0-12 months [mean age 4.4 ± 3.4 months; females (F) 40.9%], and 268 children aged 13-48 months (mean age 30.8 ± 10.7 months; F 44.4%) were included. In infants, prevalence of FGIDs was 21.1%, and the most prevalent FGID was infant colic (9.3%). In toddlers, prevalence of FGIDs was 19.6%, with functional constipation being the most frequent disorder (16.1%). In infants, multivariable analysis found that being older, being the only child, and living in a rural environment were associated with a lower rate of FGIDs. Prevalence was, in contrast, higher in infants fed with formula.

CONCLUSIONS

One out of 5 Italian infants and young children is affected by at least 1 FGID. The most frequent FGID in infants is infant colic, while in toddlers this is functional constipation. In infants, prevalence of FGIDs is lower if the subject has no siblings, and in children living in a rural environment, while formula feeding represents a risk factor for FGIDs occurrence.

Overlap of heartburn, functional dyspepsia, and irritable bowel syndrome in a population sample: Prevalence, temporal stability, and associated comorbidities

BACKGROUND

Co-occurring (overlapping) irritable bowel syndrome (IBS), functional dyspepsia (FD), and heartburn has been observed. However, whether it is a distinct entity has not been established, nor what clinical, demographic, lifestyle, and psychological traits are associated with it. This study sought to estimate the prevalence and temporal stability of this overlap and to identify features specific to it in order to gain some insights into the potential etiopathogenesis.

METHODS

Two waves of a survey to a population-representative sample were conducted 3 years apart, recruiting 1312 individuals for this study. The chance-expected probability of complete overlap (CO) was calculated and compared with the observed CO. A range of demographic, lifestyle factors, medical diagnoses, sleep quality, and psychological distress were tested to identify predictors of overlap using logistic regression.

KEY RESULTS

CO was observed in 2.1% (95% confidence interval 1.9, 3.7) of the sample and was closely replicated in wave 2 at 2.0%. The observed CO was greater than expected by chance (0.2%) to a statistically significant extent (p < 0.001). Overlap between IBS subtypes, FD subtypes, and heartburn was also elevated above chance expectation. Individuals with CO were separately differentiated from others with respect to elevated rates of self-reported medically diagnosed asthma, elevated psychological distress score, and elevated impact on sleep quality. The discrimination provided by these factors was further independent of age and sex.

CONCLUSIONS AND INFERENCES

Overlap between IBS, FD, and heartburn (GERD) appears to be a distinct entity that has a profile including psychological morbidity, sleep disturbance, and elevated rates of atopy.

Effects of Intestinal Flora on Irritable Bowel Syndrome and Therapeutic Significance of Polysaccharides

In recent years, the relevant research on intestinal flora has been in full swing, and it has become an extremely important research direction in clinical medicine and life science. Irritable bowel syndrome (IBS) is a common disease characterized by changes in intestinal function and accompanied by comorbid anxiety. At present, the pathogenic mechanism of IBS is not yet clear. The gut-brain axis (GBA), as a two-way information exchange system between the gut and the brain, has an important influence on the prevention of IBS. Present studies have shown that polysaccharides are important for maintaining the steady status of intestinal micro-environment. This review summarized the relationship between intestinal flora, GBA and immune activation, and provided a new idea for the preventive treatment of IBS from the perspective of polysaccharides.

[Duodenal Microbiome and Its Clinical Implications in Functional Dyspepsia]

Functional dyspepsia is one of the most common functional gastrointestinal disorders with chronic bothersome epigastric pain or postprandial fullness without a definite organic cause. Despite its high clinical burden, the treatment modalities for modulating impaired motor dysfunction and visceral hypersensitivity have been unsatisfactory. Recently, studies demonstrating low-grade inflammation and dysbiosis of the duodenal mucosa as potential triggers of the disease have attracted attention. Observations, such as an increase in the proportion of oral commensal bacteria in the duodenal mucosa, such as Streptococcus species, highlight the importance of bacterial ecology in developing symptoms of functional dyspepsia. In the near future, anti-inflammatory drugs and probiotics that modulate the host-microbiome interaction are expected to emerge to treat functional dyspepsia.

Antibiotic use but not gastrointestinal infection frequently precedes first diagnosis of functional gastrointestinal disorders

INTRODUCTION

While the etiopathogenesis of functional gastrointestinal disorders (FGIDs) is not completely understood, alterations of the intestinal microbiome have been observed. Antibiotics can induce dysbiosis, but whether antibiotics are a risk factor for the onset of FGIDs is uncertain. Antibiotics have been reported as both a risk factor for new onset FGID but also as a therapy for existing FGID. This study aimed to estimate the fraction of cases where antibiotics provoked the onset of FGID.

METHOD

Electronic medical records were obtained from general practices (primary care) in the United Kingdom. Dates of antibiotic prescription (AP) were compared with first date of FGID diagnosis and contrasted across three prevalent FGIDs and controls without gastrointestinal disorders.

RESULTS

There were 10,926 GI healthy controls, 4326 IBS alone, 3477 FD alone, 340 chronic constipation and 4402 with overlap of multiple conditions. Both the prevalence of AP and rate were higher in FGID patients and increased with diagnosis of multiple FGIDs. 7%-14% of FGID patients were prescribed their first recorded antibiotic in the 12 months prior to their first FGID diagnosis and 20%-33% were prescribed an antibiotic in the same period. Differences between FGID groups were not accounted for by social deprivation and only rate of AP was moderated by social deprivation. In contrast, only 5%-10% of patients ever had a gastrointestinal infection recorded and only 1.5%-3.5% prior to their first FGID diagnosis.

CONCLUSION

These data indicate that antibiotics are prescribed prior to FGID diagnosis in a significant minority of care-seeking FGID patients, opening the potential for this medication to contribute to the pathophysiology. APs appears to mostly be for non-gastrointestinal conditions.

Role of smoking in functional dyspepsia and irritable bowel syndrome: three random population-based studies

BACKGROUND

It is uncertain if functional dyspepsia (FD) or irritable bowel syndrome (IBS) are linked to smoking, and smoking cessation is not part of the routine advice provided to these patients.

AIM

To assess if smoking is an independent risk factor for FD and IBS.

METHODS

Three population-based endoscopy studies in Sweden with 2560 community individuals in total (mean age 51.5 years, 46% male). IBS (14.9%), FD (33.5%), and associated symptoms were assessed using the validated abdominal symptom questionnaire, and smoking (17.9%) was obtained from standardised questions during a clinic visit. The effect of smoking on symptom status was analysed in an individual person data meta-analysis using mixed effect logistic regression, adjusted for snuffing, age and sex.

RESULTS

Individuals smoking cigarettes reported significantly higher odds of postprandial distress syndrome (FD-PDS) (OR 10-19 cig/day = 1.42, 95% CI 1.04-1.98 P = 0.027, OR ≥20 cig/day = 2.16, 95% CI 1.38-3.38, P = 0.001) but not epigastric pain. Individuals smoking 20 or more cigarettes per day reported significantly higher odds of IBS-diarrhoea (OR = 2.40, 95% CI 1.12-5.16, P = 0.025), diarrhoea (OR = 2.01, 95%CI 1.28-3.16, P = 0.003), urgency (OR = 2.21, 95%CI 1.41-3.47, P = 0.001) and flatus (OR = 1.77, 95%CI 1.14-2.76, P = 0.012) than non-smokers. Smoking was not associated with IBS-constipation or IBS-mixed.

CONCLUSION

Smoking is an important environmental risk factor for postprandial distress syndrome, the most common FD subgroup, with over a twofold increased odds of PDS in heavy smokers. The role of smoking in IBS-diarrhoea, but not constipation, is also likely important.

Early Life Modifiable Exposures and Their Association With Owner Reported Inflammatory Bowel Disease Symptoms in Adult Dogs

Background: Inflammatory bowel disease (IBD) is an idiopathic multifactorial disease in humans and dogs, usually assigned to the interactions between genes, gut microbiota, diet, environment, and the immune system. We aimed to investigate the modifiable early life exposures associated with IBD in dogs.

Materials and Methods: The study data was extracted from the validated owner-reported DogRisk food frequency questionnaire. This was a cross-sectional questionnaire-based study that tested 21 different early life dietary and environmental, demographic and genetic variables for their association with IBD or not, in adult dogs. A total of 7,015 dogs participated in this study. The study covered early life periods; prenatal, neonatal, early, and late postnatal periods. Two feeding patterns, a non-processed meat-based diet (NPMD) and an ultra-processed carbohydrate-based diet (UPCD) were studied. Data was analyzed using logistic regression analysis with a backward stepwise deletion.

Results: From the final models we found that the NPMD during early and late postnatal periods were significantly associated with lower IBD risk later in life. The UPCD during the same periods was associated with a higher risk of IBD incidence. Also, the maternal diet during the neonatal period showed a non-significant trend of lower IBD risk in the offspring with the NPMD and a higher IBD risk with the UPCD. Additionally, the normal body weight of puppies during the first 6 months of age was associated with a lower risk of IBD in adulthood while, slim puppies associated significantly with IBD in adulthood. From the non-modifiable background variables, we identified the maternal history of IBD as the strongest risk factor for later incidence of IBD. Furthermore, male dogs were twice as likely to develop IBD as female dogs were.

Conclusions: It is reassuring for owners to know that they themselves can have an impact on their dog's health. A high-fat, low-carbohydrate NPMD exposure during early life, and a normal body condition in puppyhood were significantly associated with less IBD in adult dogs. The opposite was true for UPCD exposure and abnormal body condition score in 6 month old puppies.

Gastroparesis and functional dyspepsia: different diseases or different ends of the spectrum?

PURPOSE OF REVIEW

This review assesses the relationship between gastroparesis and functional dyspepsia, in light of recent research assessing cause, pathophysiology and treatment.

RECENT FINDINGS

The Gastroparesis Cardinal Symptom Index (GCSI) lacks the ability to readily distinguish functional dyspepsia from gastroparesis based on symptoms. Although prior studies found that the extent of delay in gastric emptying did not accurately predict severity of symptoms, when optimally measured, delayed gastric emptying may in fact correlate with gastroparesis symptoms. Enteric dysmotility may be an important risk factor for gastroparesis. Altered central processing may play a role in symptom generation for both gastroparesis and functional dyspepsia based on functional brain MRI. Treatment directed towards reducing low-grade inflammation and improving mucosal barrier function in the duodenum may represent a novel therapeutic target for functional dyspepsia, whereas gastric peroral endoscopy myotomy (G-POEM) remains a promising intervention for refractory gastroparesis.

SUMMARY

Abnormalities on functional MRI of the brain have been identified in patients with functional dyspepsia and gastroparesis. Small bowel dysmotility and duodenal barrier dysfunction have been implicated in the pathophysiology of gastroparesis and functional dyspepsia, respectively. New treatments for functional dyspepsia may target low-grade duodenal inflammation and barrier dysfunction. The pylorus remains a target in gastroparesis.

Pediatric Acute Lymphoblastic Leukemia Patients Exhibit Distinctive Alterations in the Gut Microbiota

Previous studies have shown that gut microbiota can affect human immune system in many ways. Our aim was to investigate quantitative differences in fecal bacterial compositions of childhood acute lymphoblastic leukemia (ALL) patients compared to those of healthy children, so as to identify individual bacterial species that are related to the etiology of ALL. We recruited 81 subjects, including 58 patients with ALL and 23 healthy controls. Fecal samples were collected and examined by 16S rRNA quantitative arrays and bioinformatics analysis. Both Principal Coordinates Analysis (PCoA) and Non-metric Multidimensional scaling (NMDS) demonstrated that the microbial composition of ALL patients deviated from the tight cluster of healthy controls. Multiple bacterial species exhibited significant changes (e.g., Roseburia faecis, Edwardsiella tarda, and Fusobacterium naviforme) in the ALL samples. Some of the differentially abundant taxa were correlated with the level of interleukin-10. The ALL cases could be efficiently distinguished from healthy controls by the random forest model based on differential species (area under ROC curve = 0.843). Taken together, the composition of gut microbiota differed from healthy controls to pediatric ALL patients. Our study identified a series of ALL-related species in the gut microbiota, providing a new direction for future studies aiming to understand the host-gut microbiota interplay in ALL pathogenesis.

Parental, Perinatal, and Childhood Risk Factors for Development of Irritable Bowel Syndrome: A Systematic Review

Background/Aims

Adverse early life experiences are associated with the development of stroke, cancer, diabetes, and chronic respiratory and ischemic heart diseases. These negative experiences may also play a role in the development of irritable bowel syndrome (IBS)--a functional gastrointestinal disease. This review discusses the research to date on the parental, perinatal, and childhood risk and protective factors associated with the development of IBS.

Methods

A literature search was completed for studies published between 1966 and 2018 that investigated premorbid factors occurring during the perinatal and childhood periods as well as parental factors that were associated with the development of IBS.

Results

Twenty-seven studies fulfilled the review criteria. Risk factors that appeared in more than one study included: (1) parental IBS, substance abuse, parental punishment, and rejection as parental risk factors; (2) low birth weight as a perinatal risk factor; and (3) crowded living conditions in low-income families, childhood anxiety, depression, or child abuse as childhood risk factors. Protective factors for IBS were emotional warmth from the parents and being born to an older mother.

Conclusions

More effort is needed to identify what fetal and maternal factors are associated with low birth weight and IBS. A well-executed prospective birth cohort with a collection of bio-samples and functional data will provide a better understanding of how adversity and the interplay between genetics, epigenetics, and numerous risk factors affect the development of IBS.

Systematic review with meta-analysis: global prevalence of uninvestigated dyspepsia according to the Rome criteria

BACKGROUND

Prevalence of uninvestigated dyspepsia varies across cross-sectional surveys. This may be due to differences in definitions used or study methodology, rather than global variability.

AIM

To determine the global prevalence of uninvestigated dyspepsia according to Rome criteria.

METHODS

MEDLINE and EMBASE were searched to identify population-based studies reporting prevalence of uninvestigated dyspepsia in adults (≥18 years old) according to Rome I, II, III or IV criteria. Prevalence of uninvestigated dyspepsia was extracted, according to criteria used to define it. Pooled prevalence, according to study location and certain other characteristics, odds ratios (OR), and 95% confidence intervals (CIs) were calculated.

RESULTS

Of 2133 citations evaluated, 67 studies fulfilled eligibility criteria, representing 98 separate populations, comprising 338 383 subjects. Pooled prevalence ranged from 17.6% (95% CI 9.8%-27.1%) in studies defining uninvestigated dyspepsia according to Rome I criteria, to 6.9% (95% CI 5.7%-8.2%) in those using Rome IV criteria. Postprandial distress syndrome was the commonest subtype, occurring in 46.2% of participants using Rome III criteria, and 62.8% with Rome IV. Prevalence of uninvestigated dyspepsia was up to 1.5-fold higher in women, irrespective of the definition used. There was significant heterogeneity between studies in all our analyses, which persisted even when the same criteria were applied and similar methodology was used.

CONCLUSIONS

Even when uniform symptom-based criteria are used to define the presence of uninvestigated dyspepsia, prevalence varies between countries. This suggests that there are environmental, cultural, ethnic, dietary or genetic influences determining symptoms.

Global prevalence of irritable bowel syndrome according to Rome III or IV criteria: a systematic review and meta-analysis

BACKGROUND

Irritable bowel syndrome (IBS) is one of the most common functional bowel disorders, but community prevalence appears to vary widely between different countries. This variation might be due to the fact that previous cross-sectional surveys have neither applied uniform diagnostic criteria nor used identical methodology, rather than being due to true global variability. We aimed to determine the global prevalence of IBS.

METHODS

We did a systematic review and meta-analysis of data from all population-based studies using relatively uniform methodology and using only the most recent iterations of the Rome criteria (Rome III and IV). We searched MEDLINE, Embase, and Embase Classic (from Jan 1, 2006, to April 30, 2020) to identify cross-sectional surveys reporting the prevalence of IBS in adults (≥90% of participants aged ≥18 years) according to the Rome III or Rome IV criteria. We also hand-searched a selection of conference proceedings for relevant abstracts published between 2006 and 2019. We extracted prevalence data for all studies, according to the criteria used to define the presence of IBS. We did a meta-analysis to estimate pooled prevalence rates, according to study location and certain other characteristics (eg, sex and IBS subtype).

FINDINGS

We identified 4143 citations, of which 184 studies appeared relevant. 57 of these studies were eligible, and represented 92 separate adult populations, comprising 423 362 participants. The pooled prevalence of IBS in 53 studies that used the Rome III criteria, from 38 countries and comprising 395 385 participants, was 9·2% (95% CI 7·6-10·8; I²=99·7%). By contrast, pooled IBS prevalence among six studies that used the Rome IV criteria, from 34 countries and comprising 82 476 individuals, was 3·8% (95% CI 3·1-4·5; I²=96·6%). IBS with mixed bowel habit (IBS-M) was the most common subtype with the Rome III criteria, reported by 33·8% (95% CI 27·8-40·0; I²=98·1%) of people fulfilling criteria for IBS (ie, 3·7% [2·6-4·9] of all included participants had IBS-M), but IBS with diarrhoea (IBS-D) was the most common subtype with the Rome IV criteria (reported by 31·5% [95% CI 23·2-40·5; I²=98·1% 61·6%] of people with IBS, corresponding to 1·4% [0·9-1·9] of all included participants having IBS-D). The prevalence of IBS was higher in women than in men (12·0% [95% CI 9·3-15·0] vs 8·6% [6·3-11·2]; odds ratio 1·46 [95% CI 1·33-1·59]). Prevalence varied substantially between individual countries, and this variability persisted even when the same diagnostic criteria were applied and identical methodology was used in studies.

INTERPRETATION

Even when uniform symptom-based criteria are applied, based on identical methodology, to define the presence of IBS, prevalence varies substantially between countries. Prevalence was substantially lower with the Rome IV criteria, suggesting that these more restrictive criteria might be less suitable than Rome III for population-based epidemiological surveys.

FUNDING

None.

Atopic Patients Who Fulfilled Rome III Criteria for Irritable Bowel Syndrome Had Higher Animal Danders Sensitization

Background/Aims

The relationship between animal exposure and irritable bowel syndrome (IBS) is debated. Epidemiological studies have shown that atopy is more prevalent in IBS patients and vice versa. We set out to examine the association between animal danders sensitization and IBS-like symptoms in atopic patients.

Methods

We recruited 69 consecutive atopic patients from the allergy clinic of a tertiary hospital. Subjects completed validated bowel questionnaires, underwent skin prick test, blood was collected for serum total immunoglobulin E, and ImmunoCAP immune solid-phase allergen chip (ISAC) IgE multiplex assay.

Results

Twenty-eight (41.0%) atopic patients fulfilled the Rome III IBS criteria (atopy-IBS). There were no differences in gender, age, pet ownership, total serum IgE, or food allergen sensitization between atopy-IBS group and atopy-non-IBS group. We found that atopy-IBS group had significantly higher number of positive skin prick test for cat dander (64.3% vs 24.4%, P < 0.001), dog dander (64.3% vs 41.5%, P = 0.015) and weed pollens (32.1% vs 14.6%, P = 0.050) compared to atopy-non-IBS group. Out of 112 components from 51 allergen sources (both aeroallergen and food allergens), only Fel d1 (a major cat dander antigen) IgE is significantly higher in atopy-IBS group than atopy-non-IBS group (21.4% vs 2.4%, P = 0.029). Majority of atopy-IBS patients had mixed-type IBS.

Conclusions

We demonstrated an association between animal danders sensitization, in particular cat dander sensitization, and IBS-like symptoms in atopic patients. Future studies are needed to explore the relationship between aeroallergen and functional gastrointestinal disorders. Sensitization may be related to the pathophysiology of IBS or it could be that we are missing aeroallergen-induced gut allergy.

Novel concepts in the pathophysiology and treatment of functional dyspepsia

Emerging data increasingly point towards the duodenum as a key region underlying the pathophysiology of functional dyspepsia (FD), one of the most prevalent functional GI disorders. The duodenum plays a major role in the control and coordination of gastroduodenal function. Impaired duodenal mucosal integrity and low-grade inflammation have been associated with altered neuronal signalling and systemic immune activation, and these alterations may ultimately lead to dyspeptic symptoms. Likely luminal candidates inducing the duodenal barrier defect include acid, bile, the microbiota and food antigens although no causal association with symptoms has been convincingly demonstrated. Recognition of duodenal pathology in FD will hopefully lead to the discovery of new biomarkers and therapeutic targets, allowing biologically targeted rather than symptom-based therapy. In this review, we summarise the recent advances in the diagnosis and treatment of FD with a focus on the duodenum.

Abdominal Pain in Children Develops With Age and Increases With Psychosocial Factors

BACKGROUND & AIMS

Functional gastrointestinal disorders are highly prevalent, cause significant suffering, and are costly to society. Pain is a central feature of 2 of the most common functional gastrointestinal disorders: irritable bowel syndrome and functional dyspepsia. Although these disorders have been well studied in adults, their etiology is poorly understood. We sought to identify early life factors associated with the development of abdominal pain in children (age, 2-12 y).

METHODS

We collected data from the All Babies in Southeast Sweden study of 1781 children, born from October 1, 1997, through October 31, 1999, whose families answered questions about abdominal pain and risk factors at birth, 1 year, 2.5 years, 5 years, 8 years, and 10 to 12 years. We used latent growth curve models to evaluate risk factors for development of abdominal pain. The primary outcomes were prevalence of abdominal pain and associated factors.

RESULTS

The prevalence of abdominal pain increased linearly with age in the study cohort, increasing by approximately 6% per year. Psychosocial variables associated with slope of the growth curve included lower emotional control at age 2 years (P = .005), parental concern for the child at age 2 years (P = .02), and measures of parental stress (P = .004). Nonvaginal birth was associated with a reduced slope of the growth curve (P = .03).

CONCLUSIONS

In a study of children in Sweden, we found early psychosocial environment and mode of delivery at birth was associated with development of childhood abdominal pain. Factors associated with development of the early immune system, identified in previous recall-based research, were not supported by data from this study. These findings have important implications for the prevention of abdominal pain in children and later in life.

Epigenetic Mechanisms in Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a brain-gut axis disorder characterized by abdominal pain and altered bowel habits. IBS is a multifactorial, stress-sensitive disorder with evidence for familial clustering attributed to genetic or shared environmental factors. However, there are weak genetic associations reported with IBS and a lack of evidence to suggest that major genetic factor(s) contribute to IBS pathophysiology. Studies on animal models of stress, including early life stress, suggest a role for environmental factors, specifically, stress associated with dysregulation of corticotropin releasing factor and hypothalamus-pituitary-adrenal (HPA) axis pathways in the pathophysiology of IBS. Recent evidence suggests that epigenetic mechanisms, which constitute molecular changes not driven by a change in gene sequence, can mediate environmental effects on central and peripheral function. Epigenetic alterations including DNA methylation changes, histone modifications, and differential expression of non-coding RNAs (microRNA [miRNA] and long non-coding RNA) have been associated with several diseases. The objective of this review is to elucidate the molecular factors in the pathophysiology of IBS with an emphasis on epigenetic mechanisms. Emerging evidence for epigenetic changes in IBS includes changes in DNA methylation in animal models of IBS and patients with IBS, and various miRNAs that have been associated with IBS and endophenotypes, such as increased visceral sensitivity and intestinal permeability. DNA methylation, in particular, is an emerging field in the realm of complex diseases and a promising mechanism which can provide important insights into IBS pathogenesis and identify potential targets for treatment.

What Causes Functional Gastrointestinal Disorders? A Proposed Disease Model

Chronic unexplained gastrointestinal symptoms impact more than 1 in 5 Americans and their families; these disorders include the irritable bowel syndrome (IBS) and functional dyspepsia (FD), currently classified by Rome IV as functional gastrointestinal disorders. By definition, IBS and FD have no established pathology, but emerging evidence suggests this paradigm may need revision. Immune activation and, in subsets, subtle intestinal pathology have been identified in FD (most notably, postprandial distress syndrome) and IBS-diarrhea. A disease model is proposed that accounts for all of the intestinal and extraintestinal symptoms, relationship to food and infection, and the overlap with gastroesophageal reflux disease. It is speculated that antigen presentation to the mucosa (e.g., microbial antigens or food proteins after acute gastroenteritis) induces, in a genetically primed host, immune activation of the intestine with low-grade intestinal inflammation and subsequently neuronal structural and functional alterations, producing regional intestinal hypersensitivity and motor dysfunction. Immune activation may explain the female predominance and fluctuations in immune activity for symptom variability over time. In the future, as further evidence accumulates, the management paradigm may potentially shift to objective pathology-based subtyping based on serological, microbiological, and clinical assessments to identify when targeted therapies should be deployed in subsets. Potential targeted interventions may include therapies to dampen down immune activation or block release of key mediators such as histamine, specific microbial targeted treatments that may reverse disease, and dietary advice to eliminate relevant food antigens after objective in vivo testing. Only by identifying causation can we eventually anticipate cure, and as the true pathology unravels in subsets, this may become a reality.

Association between Irritable Bowel Syndrome and Allergic Diseases: To Make a Case for Aeroallergen

Irritable bowel syndrome (IBS) is a functional gastrointestinal disease and the most common cause of prolonged abdominal pain and bowel disturbances in the developed world. While initially thought to be functional or psychosomatic in nature, IBS is now recognized as a heterogeneous group of conditions. A subset of IBS patients and patients with allergic diseases share some characteristic inflammatory features. In fact, atopic children show an increased likelihood of developing IBS as adults. Given these findings, a subset of IBS may be suffering from allergy-related gut diseases. In this review, we present the allergy-related comorbidities of IBS, including genetic, environmental, and immunologic factors. We discuss studies demonstrating an increased sensitization of IBS patients to aeroallergens compared to food allergens. We then postulate potential pathophysiological mechanisms underlying both IBS and aeroallergens in the gut, followed by potential implications in the screening and treatment of allergies in IBS patients.

Tangible pathologies in functional dyspepsia

Functional dyspepsia (FD) is a common, costly and complex disease, currently defined by symptoms, directed by the Rome consensus on functional bowel disorders, which has evolved over the past two decades. Symptoms include abdominal pain, are often meal related and there are two major subtypes, postprandial distress syndrome and epigastric pain syndrome, not attributed to pathology. Increasingly it is recognised that tangible pathologies occur in FD, for example Helicobacter pylori and other pathophysiological changes, most notably duodenal pathology, namely duodenal eosinophilia, permeability alterations, structural neuronal changes and microbial duodenal dysbiosis. This has led to the idea that FD is a true disease entity and triggers of this condition based on epidemiology studies point towards allergy, immune disorders and infection. Anxiety and depression may precede or follow FD, (brain-gut/gut-brain disorders). Currently most therapies for FD are inadequate but underlying pathology may lead to targeted treatment success as an attainable goal.

Exploring early life events including diet in cats presenting for gastrointestinal signs in later life

Our study aimed to determine if certain early life events were more prevalent in cats presenting to veterinary practices specifically for gastrointestinal signs on at least two occasions between six months and 30 months of age. Data from an owner-completed questionnaire for 1212 cats before 16 weeks of age and subsequent questionnaires for the same cats between six months and 30 months of age were reviewed. Of the 1212 cats included, 30 visited a veterinary practice for gastrointestinal signs on two or more occasions. Of the early life events recorded, cats reported with vomiting, diarrhoea or both, and/or those not exclusively fed commercial diet(s) that meets the World Small Animal Veterinary Association (WSAVA) Global Nutrition Committee (GNC) guidelines before 16 weeks of age were more likely to visit veterinary practices specifically for gastrointestinal signs on at least two occasions between six months and 30 months of age (P<0.001, odds ratio (OR)=2.64, 95 per cent confidence interval (CI)=1.66-4.22 and P=0.030, OR=1.51, 95 per cent CI=1.04-2.22, respectively). Ensuring cats exclusively consume commercial diet(s) that meets the WSAVA GNC guidelines and further studies identifying specific aetiologies for vomiting and diarrhoea before 16 weeks of age to enable prevention may reduce the number of cats subsequently presenting to primary care veterinary practices for repeated gastrointestinal signs.

Population based study: atopy and autoimmune diseases are associated with functional dyspepsia and irritable bowel syndrome, independent of psychological distress

BACKGROUND

The pathogenesis of functional GI disorders (FGIDs) is uncertain. However, underlying immune activation and psychological distress has been documented in irritable bowel syndrome (IBS) and functional dyspepsia (FD). Epidemiological data from the UK suggest that FGIDs are linked to atopy and certain autoimmune diseases but this has not been confirmed.

AIM

To test if allergic or autoimmune diseases are independently associated with FGIDs, irrespective of psychological distress in a large population based study.

METHODS

A total of 3542 people (mean age 57.9 years and 52.7% females) randomly selected from the Australian population, returned a mail survey (response rate = 43%). The survey asked about a physician diagnosis of autoimmune disease (scleroderma, psoriasis, rheumatoid arthritis and diabetes mellitus) or allergic conditions (asthma, food, pollen and/or animal allergy). The questionnaire assessed psychological distress and Rome III criteria for FD and IBS.

RESULTS

Asthma, food, pollen and animal allergies, psoriasis and rheumatoid arthritis were univariately significantly associated with IBS and FD. Food allergy (OR = 1.66; 95% CI = 1.15-2.40, P = 0.007), psoriasis (OR = 1.81; 95% CI = 1.19-2.74, P = 0.006) and rheumatoid arthritis (OR = 1.68; 95% CI = 1.15-2.4, P = 0.007) were independent risk factors for IBS, controlling for age, gender and psychological distress. In FD, asthma (OR = 1.32; 95% CI = 1.04-1.68, P = 0.025) and food allergy (OR = 1.78; 95% CI = 1.28-2.49, P = 0.001) were independent predictors, controlling for age, sex and psychological distress.

CONCLUSIONS

There is evidence that both atopic and autoimmune diseases are risk factors for FGIDs, independent of psychological distress, differing in IBS and FD. This provides evidence that different peripheral pathways may be involved in the pathogenesis of certain FGIDs.

Pre- and perinatal stress and irritable bowel syndrome in young adults - A nationwide register-based cohort study

BACKGROUND

The etiology of irritable bowel syndrome (IBS) is poorly understood. Animal and human data suggest that early life stress may induce long-term changes in the nociceptive circuitry, but conclusive studies are lacking.

METHODS

We identified all Swedish children born between 1973 and 1992 in the Swedish Medical Birth Register. We had access to all diagnostic codes for specialized (nonprimary care) outpatient visits 2001-2009 (the National Patient Register) and identified individuals who were diagnosed with IBS (ICD-10 code: K58) after 18 years of age. We compared incidence of IBS in individuals with and without pre- and perinatal stress using multivariable logistic regression.

KEY RESULTS

2 056 430 children were included in the study. After turning 18 years, 14 382 of them were diagnosed with IBS in specialized outpatient care. Neither high, nor low birth weight was a risk factor for IBS in young adults. Preterm birth was associated with lower occurrence of IBS (adjusted OR 0.82 [0.75-0.90]) and vaginal instrumental delivery and Cesarean delivery were associated with slightly increased odds of IBS (adjusted OR 1.14 [1.06-1.24] and 1.09 [1.03-1.16] respectively). Neonatal distress and respiratory distress were not associated with future IBS. Female gender was by far the strongest risk factor for IBS in young adults (adjusted OR 3.48 [3.34-3.63]).

CONCLUSIONS & INFERENCES

In this large population-based study, we found that mode of delivery was associated with an increased risk for IBS in young adulthood, while other proxies for pre- and perinatal stress were not. Female gender remains the most important risk factor for IBS.

Wheat Intolerance and Chronic Gastrointestinal Symptoms in an Australian Population-based Study: Association Between Wheat Sensitivity, Celiac Disease and Functional Gastrointestinal Disorders

OBJECTIVES

Wheat avoidance in the absence of celiac disease (CD) is common but occurrence of concurrent functional gastrointestinal disorders (FGIDs) in this group is uncertain. The aims of this study were to determine the prevalence of self-reported wheat or gluten sensitivity and doctor diagnosed CD in an Australian population, define the associated gastrointestinal (GI) symptoms and FGIDs, and determine the relationship between self-reported wheat sensitivity, demographic and medical factors.

METHODS

A total of 3542 people randomly selected from the Australian population returned a mail survey which contained questions on wheat avoidance, GI symptoms, demographic, medical, and lifestyle factors. We defined self-reported wheat sensitivity as people who reported gastrointestinal symptoms on ingestion of wheat based foods, but did not suffer from celiac disease, inflammatory bowel disease or colorectal cancer. Functional dyspepsia (FD) and irritable bowel syndrome (IBS) were diagnosed by Rome III criteria. CD status was self-reported.

RESULTS

The prevalence of self-reported wheat sensitivity in this cohort was 14.9% (95% CI 13.7-16.2). The prevalence of CD was 1.2% (95%CI 0.8-1.6). Doctor diagnosed CD was significantly associated with a diagnosis of FD (OR 3.35, 95%CI 1.72-6.52) and IBS (OR 2.28, 95%CI 1.08-4.81). Those with self-reported wheat sensitivity were more likely to report multiple abdominal symptoms (of the 18 assessed) than those without (3.9 symptoms with self-reported wheat sensitivity vs. 1.6 without, p = 0.0001). In a multivariate analysis, self-reported wheat sensitivity was independently associated with IBS (OR 3.55, 95%CI 2.71-4.65) and FD (1.48, 95%CI 1.13-1.94).

CONCLUSIONS

Self-reported wheat sensitivity is common, with a prevalence of 14.9% in this cohort. There is a strong association between both celiac disease and self-reported wheat sensitivity, and chronic gastrointestinal symptoms, as well as a diagnosis of FD and IBS.

Perinatal and familial risk factors for irritable bowel syndrome in a Swedish national cohort

OBJECTIVE

Studies of the importance of perinatal factors for the development of irritable bowel syndrome (IBS) are sparse. We conducted a large national cohort study to examine perinatal and familial risk factors for IBS.

MATERIAL AND METHODS

A national cohort of 1,963,685 persons who were born in Sweden in 1973-1992 (identified from the Swedish Birth Registry) were followed up for adult (18 years and older) IBS incidence in the Swedish Patient Register through 2010 (maximum age 38 years). There were 24,633 IBS cases in 46,784,296 person-years of follow-up.

RESULTS

After adjusting for potential confounders, significant risk factors for IBS included caesarean (HR = 1.10, 95% confidence interval [CI] 1.05-1.11, p < .001), low birth weight (<2500g) (HR = 1.11, 95%CI 1.01-1.22, p = .02), being second in birth order (HR = 1.04, 95%CI 1.01-1.08, p = .01), foetal growth ≥1 SD (HR = 1.06, 95%CI 1.00-1.11, p = .05), young maternal age (<20 years) (HR= 1.09, 95%CI 1.02-1.17, p = .02), maternal marital status (divorced/widowed) (HR = 1.12, 95%CI 1.08-1.17, p < .001), maternal education of 10-11 years (HR = 1.04, 95%CI 1.01-1.08, p = .01), maternal education of 12-14 years (HR = 1.06, 95%CI 1.01-1.11, p = .03), parental history of IBS (HR = 1.54, 95%CI 1.42-1.66, p < .001), parental history of anxiety (HR = 1.21, 95%CI 1.17-1.26, p < .001) and parental history of depression (HR = 1.09, 95%CI 1.02-1.17, p = .02). Protective factors were male sex (HR = 0.36, 95%CI 0.35-0.37, p < .001) and old maternal at delivery (≥35 years) (HR = 0.95, 95%CI 0.90-1.00, p = .03).

CONCLUSIONS

In this large cohort study, several perinatal and familial factors were associated with an increased risk of IBS independently, suggesting that perinatal and familial factors may play an important long-term role in the aetiology of IBS.

Functional Dyspepsia: Advances in Diagnosis and Therapy

Functional dyspepsia (FD) is a common but under-recognized syndrome comprising bothersome recurrent postprandial fullness, early satiety, or epigastric pain/burning. Epidemiologically, there are two clinically distinct FD syndromes (although these often overlap clinically): postprandial distress syndrome (PDS; comprising early satiety or meal-related fullness) and epigastric pain syndrome. Symptoms of gastroesophageal reflux disease overlap with FD more than expected by chance; a subset has pathological acid reflux. The pre-test probability of FD in a patient who presents with classical FD symptoms and no alarm features is high, approximately 0.7. Coexistent heartburn should not lead to the exclusion of FD as a diagnosis. One of the most exciting observations in FD has been the consistent finding of increased duodenal eosinophilia, notably in PDS. Small bowel homing T cells, signaling intestinal inflammation, and increased cytokines have been detected in the circulation, and elevated tumor necrosis factor-α levels have been significantly correlated with increased anxiety. Postinfectious gastroenteritis is a risk factor for FD. Therapeutic options remain limited and provide only symptomatic benefit in most cases. Only one therapy is known to change the natural history of FD–Helicobacter pylori eradication. Treatment of duodenal eosinophilia is under investigation.

The Role of Bacteria, Probiotics and Diet in Irritable Bowel Syndrome

Irritable bowel syndrome is a highly prevalent gastrointestinal disorder that threatens the quality of life of millions and poses a substantial financial burden on healthcare systems around the world. Intense research into the human microbiome has led to fascinating discoveries which directly and indirectly implicate the diversity and function of this occult organ in irritable bowel syndrome (IBS) pathophysiology. The benefit of manipulating the gastrointestinal microbiota with diet and probiotics to improve symptoms has been demonstrated in a wealth of both animal and human studies. The positive and negative mechanistic roles bacteria play in IBS will be explored and practical probiotic and dietary choices offered.

Functional dyspepsia and duodenal eosinophilia: A new model

Functional dyspepsia (FD) is a highly prevalent disorder that affects more than 10% of the population. In the past decade, the theoretical underpinning of the concept of FD has begun to change, in light of new data on the underlying pathophysiological mechanisms of this disorder, with a focus on the duodenum. The Rome IV criteria, published in 2016, note that gastroesophageal reflux disease and irritable bowel syndrome overlap with FD more than expected by chance, suggesting that they may be part of the same disease spectrum. Infection by Helicobacter pylori (H. pylori) may explain a minority of cases of FD and in the Rome IV criteria H. pylori-associated dyspepsia (defined as symptom relief after eradication therapy) is considered a separate entity. Duodenal inflammation characterized by increased eosinophils and in some cases mast cells, may impair the intestinal barrier. Post-infectious gastroenteritis is now an established risk factor for FD. Other risk factors may include atopy, owning herbivore pets and exposure to antibiotics, together with gastroduodenal microbiome disturbances. Small bowel homing T cells and increased cytokines in the circulation occur in FD, correlating with slow gastric emptying, and a possible association with autoimmune rheumatological disease supports background immune system activation. A genetic predisposition is possible. FD has been linked to psychological disorders, but in some cases psychological distress may be driven by gut mechanisms. Therapeutic options are limited and, aside from responders to H. pylori eradication, provide only modest and temporary relief. Advances in understanding FD may alter clinical practice, and the treatment of duodenal inflammation or microbiome alterations may lead to a cure for a subset of these patients in the future.

Functional dyspepsia

Functional dyspepsia is one of the most prevalent functional gastrointestinal disorders. Functional dyspepsia comprises three subtypes with presumed different pathophysiology and aetiology: postprandial distress syndrome (PDS), epigastric pain syndrome (EPS) and a subtype with overlapping PDS and EPS features. Functional dyspepsia symptoms can be caused by disturbed gastric motility (for example, inadequate fundic accommodation or delayed gastric emptying), gastric sensation (for example, sensations associated with hypersensitivity to gas and bloating) or gastric and duodenal inflammation. A genetic predisposition is probable but less evident than in other functional gastrointestinal disorders, such as irritable bowel syndrome (IBS). Psychiatric comorbidity and psychopathological state and trait characteristics could also play a part, although they are not specific to functional dyspepsia and are less pronounced than in IBS. Possible differential diagnoses include Helicobacter pylori infection and peptic ulceration. Pharmacological therapy is mostly based on the subtype of functional dyspepsia, such as prokinetic and fundus-relaxing drugs for PDS and acid-suppressive drugs for EPS, whereas centrally active neuromodulators and herbal drugs play a minor part. Psychotherapy is effective only in a small subset of patients, whereas quality of life can be severely affected in nearly all patients. Future therapies might include novel compounds that attempt to treat the underlying gastric and duodenal inflammation.

Irritable bowel syndrome: a gut microbiota-related disorder?

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal (GI) disorders. Despite its prevalence, the pathophysiology of IBS is not well understood although multiple peripheral and central factors are implicated. Recent studies suggest a role for alterations in gut microbiota in IBS. Significant advances in next-generation sequencing technology and bioinformatics and the declining cost have now allowed us to better investigate the role of gut microbiota in IBS. In the following review, we propose gut microbiota as a unifying factor in the pathophysiology of IBS. We first describe how gut microbiota can be influenced by factors predisposing individuals to IBS such as host genetics, stress, diet, antibiotics, and early life experiences. We then highlight the known effects of gut microbiota on mechanisms implicated in the pathophysiology of IBS including disrupted gut brain axis (GBA), visceral hypersensitivity (VH), altered GI motility, epithelial barrier dysfunction, and immune activation. While there are several gaps in the field that preclude us from connecting the dots to establish causation, we hope this overview will allow us to identify and fill in the voids.

Functional dyspepsia

PURPOSE OF REVIEW

Functional dyspepsia affects 10% of the population. Emerging data are beginning to unravel the pathogenesis of this heterogeneous disorder, and new data on treatment are helping to guide evidence-based practice. In this review, the latest advances are summarized and discussed.

RECENT FINDINGS

The Rome IV criteria were published in 2016 and are similar to Rome III but further emphasize the subtypes (postprandial distress syndrome and epigastric pain syndrome) rather than focussing on the syndrome as a whole, and conclude that gastroesophageal reflux disease and irritable bowel syndrome are part of the functional dyspepsia spectrum. Environment is dominant in the pathogenesis. New data implicate herbivore pets and antibiotic exposure for a nongastrointestinal infection but require confirmation. Further experimental data suggest duodenal eosinophils and mast cells can alter enteric neuronal structure and function in functional dyspepsia.

SUMMARY

Advances in our understanding of functional dyspepsia are changing clinical practice.

Prevalence of Irritable Bowel Syndrome in Singapore and Its Association with Dietary, Lifestyle, and Environmental Factors

Background/Aims

The prevalence of irritable bowel syndrome (IBS) has risen considerably over the past decade in Singapore. We aim to explore the contribution of changes in diet, lifestyle and habits that may contribute to the increased prevalence and development of IBS.

Methods

This is a survey-based cross-sectional population study aimed to gather demographic, socio-economical, lifestyle, dietary, antibiotic usage and other related information. Subjects were adult male or female Singaporeans aged 21 years or above. Association of the factors gathered with the presence or absence of IBS (by Rome III criteria) was assessed using chi-square or Fisher's exact test. Variables with a level of statistical significance of 0.1 or less in the univariate analysis were entered into a stepwise logistic regression model.

Results

A total of 297 subjects participated in the study (female 60.3%). Overall, 20.9% subjects fulfilled the Rome III IBS criteria. Univariate analysis showed that IBS was associated with pet ownership, antibiotic usage, late dinner, (> 9 PM) and consumption of Western meals, coffee, and bread. The multivariate logistic regression analyses showed that IBS was independently associated with being a pet owner (P = 0.008; OR, 2.5; 95% CI, 1.278-5.037).

Conclusions

The prevalence of IBS was 20.9% using the Rome III criteria in our study. The association between IBS and pet ownership will need further investigation.

Inflammation, Genetics, Dysbiosis, and the Environment: New Paradigms for Diagnosis in Complex Chronic Gut Syndromes

Chronic and complex gut syndromes are complex to diagnose and manage, but good clinicopathologic correlation, recognition of new entities, understanding (and understanding the limits) of genetic susceptibility and the importance of the microbiome, dysbiosis and influence of the environmental allows development of new models for diagnosis. An awareness of overlap in chronic gut syndromes has been clarified by the realization that inflammatory pathways involved in chronic gut disease can arise through variable gene expression that is influenced by the environment in susceptible individuals. Recent advances in diagnosis of inflammatory bowel disease and diverticular disease may be aided by genetic tests but at present, pathology and some simple biomarkers such as C-reactive protein and fecal calprotectin are still mainstream investigative measures. When made aware of the importance of these recent developments in chronic gut disease, histopathologists can easily recognize colonic spirochetosis and microscopic colitis. The role of the microbiome alongside interaction with the environment, are now recognized as key players in complex diseases. Integration of appropriate and cost-effective tests into new paradigms will surely advance patients' well-being and allow development of curative-targeted therapies rather than current treatments which, in many cases, merely alleviate symptoms.

Irritable bowel syndrome and the perinatal period: lower birth weight increases the risk

BACKGROUND

Early life events have been found to be associated with irritable bowel syndrome (IBS) suggesting a role in development of functional disorders. The study aim was to identify potential perinatal risk factors for adult IBS.

METHODS

Utilizing a population-based nested case-control design, cases who met modified Rome III criteria for IBS and age- and-gender matched controls were identified using responses from prior mailed surveys to a random sample of Olmsted County residents. Medical records of eligible respondents were reviewed for perinatal events of interest. The association of early life events with subsequent case status was assessed using conditional logistic regression.

KEY RESULTS

Of 3 417 respondents, 513 were born in Olmsted County and 108 met criteria for IBS. Due to missing records, 89 pairs were included in the final analyses. Logistic regression revealed only birth weight as a predictor of IBS. Lower birth weight increased the odds for IBS (OR = 1.54 [95% CI = (1.12, 2.08), p = 0.008]). Median birth weight was 3.35 kg (range: 1.96-5.24) and 3.57 kg (range: 2.18-4.59) for cases and controls, respectively. Maternal age, delivery method, and antibiotic exposure were not associated with IBS status but this study was only powered to detect large odds ratios.

CONCLUSIONS AND INFERENCES

Lower birth weight was observed as a risk factor for IBS. It is not clear if in utero developmental delays directly lead to IBS or if low birth weight is a prospective marker for subsequent early life problems leading to IBS.