Risk factors for inflammatory bowel disease in the general population

Shenling Baizhu Decoction treats ulcerative colitis of spleen-deficiency and dampness obstruction types by targeting 'gut microbiota and galactose metabolism-bone marrow' axis

ETHNOPHARMACOLOGICAL RELEVANCE

Shenlin Baizhu Decoction (SLBZD), which comes from 'Taiping Huimin Heji Ju Fang', belongs to a classical prescription for treating spleen deficiency and dampness obstruction (SQDDS)-type ulcerative colitis (UC) in traditional Chinese medicine. However, the mechanism of SLBZD in treating UC with SQDDS remains unclear.

AIM OF THE STUDY

This study aims to investigate the mechanism of SLBZD against SQDDS-type UC of based on the "gut microbiota and metabolism - bone marrow" axis to induce endogenous bone marrow mesenchymal stem cells (BMSCs) homing.

MATERIALS AND METHODS

Ultra-performance liquid chromatography-mass spectrometry was used to analysis of SLBZD qualitatively. The efficacy of SLBZD in SQDDS-type UC was evaluated based on the following indicators: the body weight, colon length, disease activity index (DAI) score, Haemotoxylin and Eosin (H&E) pathological sections, and intestinal permeability proteins (occluding and ZO-1). 16S rRNA gene sequencing and non-target metabolomics were performed to identify gut microbiota changes and its metabolites in feces, respectively. BMSCs in each group was collected, cultured, and analyzed. Optimal passaged BMSCs were injected by tail vein into UC rats of SQDDS types. BMSCs homing to the colonic mucosal tissue was observed by immunofluorescent. Finally, the repairing effect of BMSCs homing to the colonic mucosal tissue after SLBZD treatment was analyzed by transmission electron microscopy, qRT-PCR, and immunohistochemistry.

RESULTS

SLBZD effectively improved the colonic length and the body weight, reduced DAI and H&E scores, and increased the expression of the intestinal permeability proteins, including occluding and ZO-1, to treat SQDDS-type UC. After SLBZD treatment, the α-diversity and β-diversity of the gut microbiota were improved. The differential microbiota was screened as Aeromonadaceae, Lactobacillaceae, and Clostridiaceae at the family level, and Aeromonas, Lactobacillus, Clostridium_sensu_stricto_1 at the genus level. Meanwhile, the main metabolic pathway was the galactose metabolism pathway. SLBZD treatment timely corrected the aberrant levels of β-galactose in peripheral blood and bone marrow, senescence-associate-β-galactosidase in BMSCs, and galactose kinase-2, galactose mutase, and galactosidase beta-1 in peripheral blood to further elevate the expression levels of senescence-associated (SA) proteins (p16, p53, p21, and p27) in BMSCs. The Spearman's correlation analysis demonstrated the relationship between microbiota and metabolism, and the relationship between the galactose metabolism pathway and SA proteins. After BMSCs in each group injection via the tail vein, the pharmacodynamic effects were consistent with those of SLBZD in SQDDS-type UC rats. Furthermore, BMSCs have been homing to colonic mucosal tissue. BMSCs from the SLBZD treatment group had stronger restorative effects on intestinal permeability function due to increasing protein and mRNA expressions of occludin and ZO-1, and decreasing the proteins and mRNA expressions of SDF-1 and CXCR4 in colon.

CONCLUSIONS

SLBZD alleviated the damaged structure of gut microbiota and regulated their metabolism, specifically the galactose metabolism, to treat UC of SDDOS types. SLBZD treatment promotes endogenous BMSCs homing to colonic mucosal tissue to repaire the intestinal permeability. The current exploration revealed an underlying mechanism wherein SLBZD activates endogenous BMSCs by targeting 'the gut microbiota and its metabolism-bone marrow' axis and repairs colonic mucosal damage to treat SDDOS-type UC.

The Potential Role of Female Sex Hormones in Patients With Inflammatory Bowel Disease: A 2-Sample Mendelian Randomization Study

INTRODUCTION

An association between female sex hormones and inflammatory bowel disease (IBD) has been reported in epidemiological studies. However, a solid causal relationship has not been established. Therefore, we performed a 2-sample Mendelian randomization (MR) study to explore the causal association between genetically predicted female sex hormone exposure, especially estrogen, and IBD.

METHODS

Genetic variants for female sex hormone exposure (ovulatory function, reproductive function, oral contraceptive pills, and hormone replacement therapy) were obtained from genome-wide association studies. Summary statistics for IBD were derived from the International Inflammatory Bowel Disease Genetics Consortium. We applied inverse variance weighted (IVW), MR-Egger, and weighted median (WM) methods in this MR study. Heterogeneity, horizontal pleiotropy, and sensitivity analyses were conducted to confirm the accuracy and robustness of our results.

RESULTS

Our study found that genetically predicted age at menarche was associated with an increased risk of Crohn's disease (odds ratio [OR] IVW 1.235, 95% confidence interval [CI] 1.028-1.484, P = 0.024), genetically predicted age of the last used hormone replacement therapy was associated with an increased risk of ulcerative colitis (OR WM 1.636, 95% CI 1.011-2.648, P = 0.045), and genetically predicted number of live births was related to a decreased risk of Crohn's disease (OR IVW 0.583, 95% CI 0.373-0.912, P = 0.018).

DISCUSSION

This study provided evidence for a link between female sex hormone exposure, especially estrogen, and IBD. Further investigations are needed to explore the causal effect of estrogen on IBD activity and the underlying mechanism of estrogen in IBD.

Inflammatory bowel disease and breast cancer: A two-sample bidirectional Mendelian randomization study

There is a correlation between IBD and breast cancer according to previous observational studies. However, so far there is no evidence to support if there is a causal relationship between these 2 diseases. We acquired comprehensive Genome-Wide Association Study (GWAS) summary data on IBD (including ulcerative colitis [UC] and Crohn disease [CD]) as well as breast cancer of completely European descent from the IEU GWAS database. The estimation of bidirectional causality between IBD (including UC and CD) and breast cancer was achieved through the utilization of 2-sample Mendelian randomization (MR). The MR results were also assessed for any potential bias caused by heterogeneity and pleiotropy through sensitivity analyses. Our study found a bidirectional causal effect between IBD and breast cancer. Genetic susceptibility to IBD was associated with an increased risk of breast cancer (OR = 1.053, 95% CI: 1.016-1.090, P = .004). Similarly, the presence of breast cancer may increase the risk of IBD (OR = 1.111, 95% CI: 1.035-1.194, P = .004). Moreover, the bidirectional causal effect between IBD and breast cancer can be confirmed by another GWAS of IBD. Subtype analysis showed that CD was associated with breast cancer (OR = 1.050, 95% CI: 1.020-1.080, P < .001), but not UC and breast cancer. There was a suggestive association between breast cancer and UC (OR = 1.106, 95% CI: 1.011-1.209, P = .028), but not with CD. This study supports a bidirectional causal effect between IBD and breast cancer. There appear to be considerable differences in the specific associations of UC and CD with AD. Understanding that IBD including its specific subtypes and breast cancer constitute common risk factors can contribute to the clinical management of both diseases.

Association of Depression With Incident Inflammatory Bowel Diseases: A Systematic Review and Meta-Analysis

BACKGROUND

Individuals with a history of depression/depressive symptoms are suspected to be at increased risk of incident inflammatory bowel diseases (IBDs).

METHODS

We systematically searched MEDLINE/PubMed, Embase, and Scopus databases for longitudinal studies examining the association between depression/depressive symptoms and subsequent new-onset IBD (ie, Crohn's disease and ulcerative colitis). We included studies in which the exposure was a confirmed diagnosis of depression/depressive symptoms measured through a validated scale. To limit concerns of diagnostic bias and reverse causality, and support temporality between exposure and outcomes, we synthesized estimates corresponding to the longest time lag reported. Two authors extracted study data independently and assessed each study's risk of bias. Maximally adjusted relative risk (RR) estimates were synthesized using random- and fixed-effects models.

RESULTS

Of 5307 records, 13 studies (8 cohort and 5 nested case-control studies; 9 million individuals) fulfilled the eligibility criteria. Depression was significantly associated with incident Crohn's disease (RRrandom, 1.17; 95% confidence interval, 1.02-1.34; 7 studies, 17 676 cases) and ulcerative colitis (RRrandom, 1.21; 95% confidence interval, 1.10-1.33; 6 studies, 28 165 cases). The primary studies considered pertinent confounders. Several years, on average, separated exposure and outcomes. No evidence of important heterogeneity or publication bias was found. Summary estimates were at low risk of bias, and results were confirmed in multiple sensitivity analyses. No firm conclusions could be drawn regarding a dilution of the association over time.

CONCLUSIONS

Individuals with a history of depression may show small-to-moderate increased risk of IBD even when depression is diagnosed several years before new-onset IBD. Further epidemiological and mechanistic studies should clarify whether these associations are causal.

Association between prior appendectomy and the risk and course of Crohn's disease: A systematic review and meta-analysis

BACKGROUND AND AIMS

The appendix has an important immune function in both health and disease, and appendectomy may influence microbial ecology and immune function. This meta-analysis aims to assess the association between appendectomy and the risk and course of Crohn's disease (CD).

METHODS

PubMed, EMBASE, and the Cochrane Library were used to identify all studies published until June 2022. Data from studies evaluating the association between appendectomy and CD were reviewed.

RESULTS

A total of 28 studies were included in the final analysis, comprising 22 case-control and 6 cohort studies. A positive relationship between prior appendectomy and the risk of developing CD was observed in both case-control studies (odds ratio [OR]: 1.59, 95% confidence interval [CI]: 1.22-2.08) and cohort studies (relative risk [RR]: 2.28, 95% CI: 1.66-3.14). The elevated risk of CD persisted 5 years post-appendectomy (RR = 1.24, 95% CI: 1.12-1.36). The risk of developing CD was similarly elevated regardless of the presence (RR = 1.64, 95% CI: 1.17-2.31) or absence (RR = 2.77, 95% CI: 1.84-4.16) of appendicitis in patients. Moreover, significant differences were found in the proportion of terminal ileum lesions (OR = 1.63; 95% CI: 1.38-1.93) and colon lesions (OR = 0.70; 95% CI: 0.5-0.84) between CD patients with appendectomy and those without appendectomy.

CONCLUSIONS

The risk of developing CD following an appendectomy is significant and persists 5 years postoperatively. Moreover, the elevated risk of CD may mainly occur in the terminal ileum.

Proton pump inhibitors and the risk of inflammatory bowel disease: population-based cohort study

OBJECTIVE

To determine whether the use of proton pump inhibitors (PPIs) compared with the use of histamine-2 receptor antagonists (H2RAs) is associated with an increased risk of inflammatory bowel disease (IBD).

DESIGN

Population-based cohort study designed to address the impact of protopathic bias.

SETTING

General practices contributing data to the UK Clinical Practice Research Datalink GOLD.

PARTICIPANTS

1 498 416 initiators of PPIs and 322 474 initiators of H2RAs from 1 January 1990 to 31 December 2018, with follow-up until 31 December 2019. Patients were analysed according to the timing of the IBD diagnosis after treatment initiation (early vs late).

MAIN OUTCOME MEASURES

Standardised morbidity ratio weighted Cox proportional hazards models were used to estimate marginal HRs and 95% CIs. In the early-event analysis, IBD diagnoses were assessed within the first 2 years of treatment initiation, an analysis subject to potential protopathic bias. In the late-event analysis, all exposures were lagged by 2 years to account for latency and minimise protopathic bias.

RESULTS

In the early-event analysis, the use of PPIs was associated with an increased risk of IBD within the first 2 years of treatment initiation, compared with H2RAs (HR 1.39, 95% CI 1.14 to 1.69). In contrast, the use of PPIs was not associated with an increased risk of IBD in the late-event analysis (HR 1.05, 95% CI 0.90 to 1.22). The results remained consistent in several sensitivity analyses.

CONCLUSIONS

Compared with H2RAs, PPIs were not associated with an increased risk of IBD, after accounting for protopathic bias.

Methotrexate showed efficacy both in Crohn’s disease and ulcerative colitis, predictors of surgery were identified in patients initially treated with methotrexate monotherapy

Objective: This study aimed to evaluate methotrexate efficacy in patients with Crohn’s disease (CD) and ulcerative colitis (UC), and identify predictors of surgery for patients who were initially treated with methotrexate monotherapy.

Design: We performed a retrospective analysis of 34,860 patients with inflammatory bowel disease (IBD) in the IBD Bioresource (United Kingdom) prior to 9 November 2021. Logistic regression was used to identify factors associated with methotrexate efficacy. The data were randomly stratified into training and testing sets (7:3). Nomograms were developed based on Cox regression analysis outcomes. The predictive accuracy and discriminative ability were determined using the concordance index (C-index) and calibration curves.

Results: Overall, 1,042 patients (CD: 791, UC: 251) were included. Independent factors associated with effective methotrexate monotherapy were younger age at diagnosis, latest therapy period, exclusive upper gastrointestinal tract disease (for CD), and longer duration between diagnosis and methotrexate initiation (for UC). For CD, predictors in the nomogram were gender, treatment era, tolerance, lesion site, perianal involvement, disease behaviour, and biologics requirements (C-index: 0.711 and 0.732 for training and validation cohorts, respectively). For UC, the factors were age at diagnosis and sex (C-index: 0.784 and 0.690 for training and validation cohorts, respectively). Calibration curves demonstrated good agreement between predictions and actual observations.

A Comparative Analysis of Drug Therapy, Disease Phenotype, and Health Care Outcomes for Men and Women with Inflammatory Bowel Disease

BACKGROUND

Sex and gender refer to biological and social differences between men and women. While well-evaluated in other disciplines, their roles in inflammatory bowel disease (IBD) are not well-defined. This study aimed to characterize differences in healthcare outcomes in men and women with IBD.

METHODS

A retrospective single-centre cohort study was conducted to evaluate differences between men and women receiving care for Crohn's disease (CD) and ulcerative colitis (UC) at the Western University Personalized Medicine Clinic from March 2012 to September 2019. The primary endpoint was the proportion of IBD drugs used for all drug classes. Additional outcomes in healthcare utilization and disease phenotype were assessed. Student's t test and Fisher's exact test were used to assess differences RESULTS: A total of 1015 participants were included (CD = 656; UC = 359). In UC and CD, 47.9% and 59.0% were women, respectively. Overall, women were more likely prescribed budesonide than men (23.6% vs. 13.4%; p < 0.0001), while more men were exposed to prednisone for IBD management (73.5% vs. 67.4%; p = 0.04). Immunomodulator use was higher in men with CD versus women (86.6% vs. 78.3%; p = 0.008) and of those exposed, women more commonly experienced ADRs (29.5% vs. 21.2%; p = 0.01). Though no sex-related difference was identified, age was a predictor of biologic exposure in women with CD and men with UC, with those > 55 being less likely to receive biologics.

CONCLUSIONS

These findings highlight differences in disease course and treatment approaches between men and women with IBD and support the consideration of sex and gender when researching disease outcomes.

Modulating Effect of Paeonol on Piglets With Ulcerative Colitis

Piglet enteritis is a major problem that needs to be solved urgently in modern pig production. Paeonol (Pae) has been used as a novel treatment option due to its good medicinal value. This study purported to elucidate the regulatory mechanism of Pae on dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) in weaned piglets. A total of 36 crossbred (Duroc × Landrace × Yorkshire) weaned piglets were stochastically split into six groups: the control group, DSS group, 0.2% Pae group, 0.4% Pae group, 0.8% Pae group, and mesalazine group. The control and DSS groups were fed with a basic diet, the three Pae and mesalazine groups were fed with 0.2, 0.4, 0.8%, and 2 g mesalazine per kilogram of basic diet throughout the study. On the 15th day of the test period, the control group was gavaged with 10 ml of normal saline, while the remaining five groups were gavaged with 10 ml 5% DSS solution for 13 days. The study lasted for 27 days. The results showed that the 0.8% Pae group significantly increased the average daily feed intake (ADFI) and Occludin mRNA expression in the colon of piglets (P < 0.05). The 0.2% Pae group markedly increased the average daily gain (ADG) and zonula occludens-1 (ZO-1) mRNA expression (P < 0.05). In the 0.2% and 0.4% Pae groups, the feed-to-gain ratio (F/G) was significantly reduced and the mRNA expression levels of Caspase-8, respectively, markedly enhanced the mRNA expression levels of transforming growth factor-β (TGF-β) and interleukins-4 (IL-4) (P < 0.05). In the 0.8% Pae group, the relative abundance of Campilobacterota was significantly reduced (P < 0.05). In the 0.4% Pae group, the relative abundance of Firmicutes was notably increased (P < 0.05). In the 0.2 and 0.8% Pae groups, the relative abundance of Prevotella was markedly increased (P < 0.05). In the 0.2% Pae group, the contents of propionic acid, butyric acid, and valerate acid were markedly higher (P < 0.05). Thus, it is speculated that Pae may regulate the balance of anti-inflammatory/pro-inflammatory factors, improve intestinal tight junction expression, reduce apoptosis, and improve intestinal microflora structure and growth performance of piglets, thereby restoring intestinal barrier function and alleviating DSS-induced UC in piglets.

The role of diosgenin in crohn’s disease

Inflammatory bowel disease (IBD) is a chronic idiopathic inflammation that can grossly affect the entire gastrointestinal tract (GIT) from the mouth to the anus. Crohn’s disease is the most known type of IBD and has been the focus of attention due to its increase in prevalence worldwide. Although the etiology is yet to be elucidated, recent studies have pointed out Crohn’s disease to arise from a complex interaction between environmental influences, genetic predisposition, and altered gut microbiota, resulting in dysregulated adaptive and innate responses. The presenting hallmarks of Crohn’s disease may include weight loss, nausea, vomiting, abdominal pain, diarrhea, fever, or chills. Treatment is usually done with many approved immunosuppressive drugs and surgery. However, a promising avenue from natural compounds is a safer therapy due to its safe natural active ingredients and the strong activity it shows in the treatment and management of diseases. Diosgenin, “a major biologically active natural steroidal sapogenin found in Chinese yam,” has been widely reported as a therapeutic agent in the treatment of various classes of disorders such as hyperlipidemia, inflammation, diabetes, cancer, infection, and immunoregulation. In this review, an analysis of literature data on diosgenin employed as a therapeutic agent for the treatment of Crohn’s disease is approached, to strengthen the scientific database and curtail the dreadful impact of Crohn’s disease.

Ethnic Differences in the Smoking-related Risk of Inflammatory Bowel Disease: A Systematic Review and Meta-analysis

BACKGROUND AND AIMS

The association between smoking and inflammatory bowel disease [IBD] relies on old meta-analyses including exclusively non-Jewish White populations. Uncertainty persists regarding the role of smoking in other ethnicities.

METHODS

We systematically searched Medline/PubMed, Embase, and Scopus for studies examining tobacco smoking and the risk of developing IBD, ie, Crohn's disease [CD] or ulcerative colitis [UC]. Two authors independently extracted study data and assessed each study's risk of bias. We examined heterogeneity and small-study effect, and calculated summary estimates using random-effects models. Stratified analyses and meta-regression were employed to study the association between study-level characteristics and effect estimates. The strength of epidemiological evidence was assessed through prespecified criteria.

RESULTS

We synthesised 57 studies examining the smoking-related risk of developing CD and UC. Non-Jewish White smokers were at increased risk of CD (29 studies; relative risk [RR]: 1.95, 95% confidence interval [CI]: 1.69‒2.24; moderate evidence). No association was observed in Asian, Jewish. and Latin-American populations [11 studies; RR: 0.97; 95% CI: 0.83-1.13], with no evidence of heterogeneity across these ethnicities. Smokers were at reduced risk of UC [51 studies; RR: 0.55, 95% CI: 0.48-0.64; weak evidence] irrespectively of ethnicity; however, cohort studies, large studies, and those recently published showed attenuated associations.

CONCLUSIONS

This meta-analysis did not identify any increased risk of CD in smokers in ethnicities other than non-Jewish Whites, and confirmed the protective effect of smoking on UC occurrence. Future research should characterise the genetic background of CD patients across different ethnicities to improve our understanding of the role of smoking in CD pathogenesis.

Acute Gastroenteritis in the Etiology of Inflammatory Bowel Disease: Systematic Review and Meta-analysis

Background

Inflammatory bowel disease (IBD) consists of a spectrum of disorders including ulcerative colitis and Crohn's disease, with a rising incidence worldwide. However, despite this prevalence the etiology of IBD remains uncertain. It has been suggested that an episode of gastroenteritis may precipitate IBD.

Methods

Studies were identified using a literature search of Pubmed/Medline and Embase/Ovid. This review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The primary outcome was incidence of new-onset IBD after gastroenteritis. Secondary outcomes included incidence of IBD after bacterial, viral, and parasitic gastrointestinal infections.

Results

Eleven studies (n = 923 608 patients) were included. Four studies assessed patients with gastroenteritis, subsequently developing IBD as the primary outcome. Patients with gastroenteritis had a higher incidence of subsequent IBD but this did not reach statistical significance (odds ratio [OR] 3.81, 95% CI 0.52-27.85, P = .19). Seven studies examined the incidence of antecedent gastroenteritis (primary outcome) in patients with a confirmed diagnosis of IBD, compared to the controlled population. There was no difference between incidence of antecedent gastroenteritis across the 2 population groups (OR 1.07, 95% CI 0.55-2.08, P = .85). There was no association between IBD and bacterial, viral, or parasitic infections.

Conclusions

In summary, our meta-analysis has shown that there is considerable heterogeneity in the literature regarding the role of gastroenteritis in the development of IBD. Further higher quality studies need to be performed to ascertain the true nature of this.

Hormonally Active Contraceptives, Part II: Sociological, Environmental, and Economic Impact

To investigate the sociological, environmental, and economic impact of hormonally active contraceptives, a series of comprehensive literature surveys were employed. Sociological effects are discussed including abortion, exploitation of women, a weakening of marriage, and an increase in divorce with deleterious effects on children such as child poverty, poorer health, lower educational achievement, suicide risks, drug and alcohol abuse, criminality, and incarceration, among others. The environmental impact is discussed briefly and includes the feminization and trans-gendering of male fish downstream from the effluent of city wastewater treatment plants with declining fish populations. The potential economic impact of most of these side effects is estimated based on epidemiologic data and published estimates of costs of caring for the diseases which are linked to the use of hormonally active contraceptives. Hormonally active contraceptives appear to have a deleterious impact on multiple aspects of women's health as well as negative economic and environmental impacts. These risks can be avoided through the use of nonhormonal methods and need to be more clearly conveyed to the public.

SUMMARY

Hormonal contraceptives have wide-ranging effects.  The potential economic impact of the medical side effects is estimated. Sociological effects are discussed including abortion, exploitation of women, a weakening of marriage and an increase in divorce with negative effects on children such as child poverty, poorer health, lower educational achievement, suicide risks, drug and alcohol abuse, criminality and incarceration among others. The environmental impact includes hormonal effects on fish with declining fish populations. Women seeking birth control have a right to know about how to avoid these risks by using effective hormone-free methods like Fertility Awareness Methods.

The incidence and prevalence of inflammatory bowel disease in UK primary care: a retrospective cohort study of the IQVIA Medical Research Database

BACKGROUND

Our knowledge of the incidence and prevalence of inflammatory bowel disease (IBD) is uncertain. Recent studies reported an increase in prevalence. However, they excluded a high proportion of ambiguous cases from general practice. Estimates are needed to inform health care providers who plan the provision of services for IBD patients. We aimed to estimate the IBD incidence and prevalence in UK general practice.

METHODS

We undertook a retrospective cohort study of routine electronic health records from the IQVIA Medical Research Database covering 14 million patients. Adult patients from 2006 to 2016 were included. IBD was defined as an IBD related Read code or record of IBD specific medication. Annual incidence and 12-month period prevalence were calculated.

RESULTS

The prevalence of IBD increased between 2006 and 2016 from 106.2 (95% CI 105.2-107.3) to 142.1 (95% CI 140.7-143.5) IBD cases per 10,000 patients which is a 33.8% increase. Incidence varied across the years. The incidence across the full study period was 69.5 (95% CI 68.6-70.4) per 100,000 person years.

CONCLUSIONS

In this large study we found higher estimates of IBD incidence and prevalence than previously reported. Estimates are highly dependent on definitions of disease and previously may have been underestimated.

Prognostic tools for identification of high risk in people with Crohn's disease: systematic review and cost-effectiveness study

BACKGROUND

Crohn's disease is a lifelong condition that can affect any segment of the gastrointestinal tract. Some people with Crohn's disease may be at higher risk of following a severe course of disease than others and being able to identify the level of risk a patient has could lead to personalised management.

OBJECTIVE

To assess the prognostic test accuracy, clinical impact and cost-effectiveness of two tools for the stratification of people with a diagnosis of Crohn's disease by risk of following a severe course of disease.

DATA SOURCES

The data sources MEDLINE, EMBASE, the Cochrane Database of Systematic Reviews and the Cochrane Central Register of Controlled Trials were searched to inform the systematic reviews on prognostic accuracy, clinical impact of the prognostic tools, and economic evaluations. Additional data sources to inform the review of economic evaluations were NHS Economic Evaluation Database, Database of Abstracts of Reviews of Effects and the Health Technology Assessment Database.

REVIEW METHODS

Systematic reviews of electronic databases were carried out from inception to June 2019 for studies assessing the prognostic accuracy and clinical impact of the IBDX® (Crohn's disease Prognosis Test; Glycominds Ltd, Lod, Israel) biomarker stratification tool and the PredictSURE-IBD™ (PredictImmune Ltd, Cambridge, UK) tool. Systematic reviews of studies reporting on the cost-effectiveness of treatments for Crohn's disease were run from inception to July 2019. Two reviewers independently agreed on studies for inclusion, assessed the quality of included studies and validated the data extracted from studies. Clinical and methodological heterogeneity across studies precluded the synthesis of data for prognostic accuracy. A de novo economic model was developed to compare the costs and consequences of two treatment approaches - the 'top-down' and 'step-up' strategies, with step-up considered standard care - in people at high risk of following a severe course of Crohn's disease. The model comprised a decision tree and a Markov cohort model.

RESULTS

Sixteen publications, including eight original studies (n = 1478), were deemed relevant to the review of prognostic accuracy. Documents supplied by the companies marketing the prognostic tools were also reviewed. No study meeting the eligibility criteria reported on the sensitivity or specificity of the IBDX biomarker stratification tool, whereas one study provided estimates of sensitivity, specificity and negative predictive value for the PredictSURE-IBD tool. All identified studies were observational and were considered to provide weak evidence on the effectiveness of the tools. Owing to the paucity of data on the two tools, in the base-case analysis the accuracy of PredictSURE-IBD was assumed to be 100%. Accuracy of IBDX was assumed to be 100% in a scenario analysis, with the cost of the tests being the only difference between the analyses. The incremental analysis of cost-effectiveness demonstrated that top-down (via the use of PredictSURE-IBD in the model) is more expensive and generates fewer quality-adjusted life-years than step-up (via the standard care arm of the model).

LIMITATIONS

Despite extensive systematic searches of the literature, no robust evidence was identified of the prognostic accuracy of the biomarker stratification tools IBDX and PredictSURE-IBD.

CONCLUSIONS

Although the model indicates that standard care dominates the tests, the lack of evidence of prognostic accuracy of the two tests and the uncertainty around the benefits of the top-down and step-up treatment approaches mean that the results should be interpreted as indicative rather than definitive.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42019138737.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Evidence Synthesis programme and will be published in full in Health Technology Assessment; Vol. 25, No. 23. See the NIHR Journals Library website for further project information.

The recording and prevalence of Inflammatory bowel disease in girls' primary care medical Spanish records

PURPOSE

Inflammatory bowel disease (IBD) recording validation among girls in the Spanish Primary Care Database For Pharmacoepidemiological Research (BIFAP).

METHODS

In this observational study, girls aged 9 to 18 years registered in BIFAP between 2002 and 2016, were followed up until there was a recorded IBD diagnosis or a referral to specialist indicating IBD. Anonymized profiles were reviewed to retrieve diagnosis confirmation (a positive colonoscopy or biopsy, specialist, or physician's comments mentioning the IBD diagnosis) or discarding (negative procedure results, alternative diagnosis, or family history). "possible" IBD were profiles missing that evidence, or had suspected IBD. The prescriptions of intestinal anti-inflammatory agents, azatioprine, and mercaptopurine were collected. The prevalence of IBD was estimated after review.

RESULTS

Out of 480 634 girls, 323 had a first ever recorded IBD, of which, 37.8% (N = 122) were "confirmed" incident IBD diagnosis, 19.8% (N = 64) discarded and 38.7% (N = 125) "possible" IBD. Additionally, 12 IBD records (3.7%) referred to prevalent IBD. Prescriptions were recorded in 94.3% (confirmed), 63.2% (possible), 83.3% (prevalent), and 3.1% (discarded) IBD cases. Prevalence was 52.83 "confirmed" or 93.58/10⁵ girls when "possible" IBD were added.

CONCLUSIONS

For a third of the girls, the first recorded IBD included evidence confirming the diagnosis while most of those with missing evidence had treatment indicated for IBD. For research focused in sensitivity, an algorithm including "possible" plus "confirmed" episodes is recommended, whereas only "confirmed" to guarantee higher predictive value. Prevalence suggests that IBD is not a rare disease among girls.

Primary Humoral Immune Deficiencies: Overlooked Mimickers of Chronic Immune-Mediated Gastrointestinal Diseases in Adults

In recent years, the incidence of immune-mediated gastrointestinal disorders, including celiac disease (CeD) and inflammatory bowel disease (IBD), is increasingly growing worldwide. This generates a need to elucidate the conditions that may compromise the diagnosis and treatment of such gastrointestinal disorders. It is well established that primary immunodeficiencies (PIDs) exhibit gastrointestinal manifestations and mimic other diseases, including CeD and IBD. PIDs are often considered pediatric ailments, whereas between 25 and 45% of PIDs are diagnosed in adults. The most common PIDs in adults are the selective immunoglobulin A deficiency (SIgAD) and the common variable immunodeficiency (CVID). A trend to autoimmunity occurs, while gastrointestinal disorders are common in both diseases. Besides, the occurrence of CeD and IBD in SIgAD/CVID patients is significantly higher than in the general population. However, some differences concerning diagnostics and management between enteropathy/colitis in PIDs, as compared to idiopathic forms of CeD/IBD, have been described. There is an ongoing discussion whether CeD and IBD in CVID patients should be considered a true CeD and IBD or just CeD-like and IBD-like diseases. This review addresses the current state of the art of the most common primary immunodeficiencies in adults and co-occurring CeD and IBD.

Incidence and prevalence of inflammatory bowel disease in Devon, UK

BACKGROUND AND AIMS

We sought to define temporal changes in prevalence of inflammatory bowel disease (IBD) in East Devon, UK, in order to facilitate service planning over the next 5 years.

METHODS

Multiple primary and secondary care databases were used to identify and verify cases. Point prevalence and incidence of IBD were reported in April 2017 and from 2008 to 2016, respectively. Future prevalence and healthcare activity requirements were estimated by linear regression.

RESULTS

Prevalence of ulcerative colitis (UC), Crohn's disease (CD) and inflammatory bowel disease unclassified (IBDU) were 479.72, 265.94 and 35.34 per 100 000 persons, respectively. In 2016, the incidence rates of UC, CD and IBDU were 15.4, 10.7 and 1.4 per 100 000 persons per year, respectively. There were no significant changes in the incidence of CD (p=0.49, R=0.26) or UC (p=0.80, R=0.10). IBD prevalence has increased by 39.9% (95% CI 28.2 to 53.7) in the last 10 years without differences in the rate of change between UC and CD. Overall, 27% of patients were managed in primary care, a quarter of whom were eligible but not receiving endoscopic surveillance. Outpatient clinics, MRI and biologic use, but not helpline calls, admissions, or surgeries increased over and above the change in IBD prevalence.

CONCLUSIONS

We report one of the highest prevalence and incidence rates of IBD from Northern Europe. Overall, IBD incidence is static, but prevalence is increasing. We estimate that 1% of our population will live with IBD between 2025 and 2030.

Changing patterns in the epidemiology and outcomes of inflammatory bowel disease in the United Kingdom: 2000-2018

BACKGROUND

Data regarding incidence, prevalence and long-term outcomes of inflammatory bowel diseases in the UK are limited or outdated.

AIMS

To investigate incidence and prevalence of Crohn's disease and ulcerative colitis and risk of colorectal cancer and all-cause mortality in these diseases.

METHODS

Inflammatory bowel disease cases between 2000 and 2018 were identified from a national primary care database. Inflammatory bowel disease prevalence was forecast until 2025. The association between inflammatory bowel disease and colorectal cancer and all-cause mortality was investigated using age/sex-matched retrospective cohort studies. Hazard ratios were adjusted for age, sex, deprivation, comorbidity, smoking status and body mass index.

RESULTS

Ulcerative colitis prevalence increased from 390 to 570 per 100 000 population from 2000 to 2017. Prevalence of Crohn's disease increased from 220 to 400 per 100 000. In 2017 male Crohn's disease prevalence was 0.35% (95% confidence interval 0.34-0.36); female prevalence was 0.44% (0.43-0.45). Prevalence of inflammatory bowel disease is predicted to be 1.1% by 2025. Incidence of ulcerative colitis and Crohn's disease was 23.2 (22.8-23.6) and 14.3 (14.0-14.7) per 100 000 person-years respectively. Subjects with ulcerative colitis were more likely to develop colorectal cancer than controls (adjusted Hazard Ratio 1.40 [1.23-1.59]). Colorectal cancer rates remained stable in inflammatory bowel diseases over time. Ulcerative colitis and Crohn's disease were associated with increased risk of all-cause mortality (1.17 [1.14-1.21] and 1.42 [1.36-1.48] respectively).

CONCLUSIONS

The UK prevalence of inflammatory bowel disease is greater than previous reports suggest and we predict an 11% increase in prevalence by the year 2025. Mortality risk in inflammatory bowel disease and colorectal cancer risk in ulcerative colitis are increased compared to matched controls.

Associations between an MDM2 gene polymorphism and ulcerative colitis by ARMS-PCR

Ulcerative colitis is a form of inflammatory bowel disease characterized by chronic inflammation of the colon and rectum. The abnormal lesions in the digestive system caused by ulcerative colitis and intermittent colitis are of major clinical importance. MDM2 is a phospho-protein that functions as a ubiquitin ligase for p53. Recently, a T>G substitution in the promoter of the MDM2 gene (rs309) has been identified. In this case-control study, 174 ulcerative colitis biopsy samples and 82 control samples were collected from colonoscopy centers, hospitals, and clinics in Mazandaran and Gilan Provinces in Iran from October 2014 to May 2015. This MDM2 polymorphism was investigated in DNA samples (extracted from biopsy samples) by amplification-refractory mutation system polymerase chain reaction. The mean age of patients with ulcerative colitis was 46.5 years (range, 28 to 69 years) and that of control individuals was 45.3 years (range, 26 to 71 years). Seventy-eight patients (44.82%) were men and 96 (55.18%) were women. The distribution of the TT, TG, and GG genotypes was 17.93%, 27.59%, and 34.48%, respectively, in the ulcerative colitis patients and 31.70%, 24.40%, and 43.90%, respectively, in the control individuals (odds ratio of GG for ulcerative colitis, 7.142; 95% confidence interval, 2.400 to 9.542; p = 0.001). It was found that a single-nucleotide polymorphism at rs309 in the MDM2 gene was associated with ulcerative colitis. A direct relationship was found between age and ulcerative colitis, while no relationship was found with sex. This finding is of note because the occurrence of intestinal inflammation and subsequent ulcers can precede the development of cancer.

An approach to acute severe ulcerative colitis

Introduction: Despite the introduction of novel therapies and treatment strategies for ulcerative colitis (UC), many patients develop acute, severe episodes, warranting prompt care and aggressive management. There is a significant unmet need to improve outcomes in these patients. Clinicians must be able to identify those that will have worse prognosis and plan an aggressive therapy with an early/proactive adjustments in management if needed.Areas covered: The aim of this review is to evaluate the most recent evidence on the assessment and management of patients with acute severe ulcerative colitis. We searched the mainstream literature search engines for the most recent evidence on diagnosis and management of acute UC.Expert Opinion: The approach to patients with severe UC includes clinical and endoscopic assessment of disease severity and ruling out over-infections. While intravenous corticosteroids remain the first line therapy for acute severe colitis, many patients do not respond and require escalation to calcineurin inhibitors or infliximab, and may ultimately require colectomy. Even though several novel therapies are available or in development, their role in acute severe episodes of colitis is unknown.

Global smoking trends in inflammatory bowel disease: A systematic review of inception cohorts

Background and aims

The effect of smoking on the risk of developing inflammatory bowel diseases (IBD) may be heterogeneous across ethnicity and geography. Although trends in smoking for the general population are well described, it is unknown whether these can be extrapolated to the IBD cohort. Smoking prevalence trends specific to the global IBD cohort over time have not been previously reported. This is a systematic review of smoking prevalence specific to the IBD cohort across geography.

Methods

A systematic literature search was conducted on Medline and Embase from January 1^st 1946 to April 5^th 2018 to identify population-based studies assessing the prevalence of smoking at diagnosis in inception cohorts of Crohn’s disease(CD) or ulcerative colitis(UC). Studies that did not report smoking data from time of diagnosis or the year of IBD diagnosis were excluded. Prevalence of smoking in IBD was stratified by geography and across time.

Results

We identified 56 studies that were eligible for inclusion. Smoking prevalence data at diagnosis of CD and UC was collected from twenty and twenty-five countries respectively. Never-smokers in the newly diagnosed CD population in the West has increased over the last two decades, especially in the United Kingdom and Sweden; +26.6% and +11.2% respectively. Never-smokers at CD diagnosis in newly industrialised nations have decreased over the 1990s and 2000s; China (-19.36%). Never-smokers at UC diagnosis also decreased in China; -15.4%. The former-smoker population at UC diagnosis in China is expanding; 11%(1990–2006) to 34%(2011–2013).

Conclusion

There has been a reduction in the prevalence of smoking in the IBD cohort in the West. This is not consistent globally. Although, smoking prevalence has decreased in the general population of newly industrialised nations, this remains an important risk factor with longer term outcomes awaiting translation in both UC and CD.

Prior Appendectomy and the Onset and Course of Crohn's Disease in Chinese Patients

Background and Aim

The relationship between prior appendectomy and Crohn's disease (CD) has previously revealed conflicting findings. The present study investigates the relationship between prior appendectomy and CD development in Chinese patients.

Methods

A retrospective case-control study was performed to compare prior appendectomy rate between CD patients and age- and gender-matched controls at two Chinese hospitals. The clinical course of CD was determined in patients who underwent and did not undergo appendectomies before CD diagnosis.

Results

A total of 617 CD patients and 617 controls were included. The appendectomy rate before CD diagnosis in patients was higher, when compared to controls (6.65% versus 3.73%, P = 0.033). Appendectomy was a risk factor for the onset of CD independent of smoking in the multivariate analysis (OR: 1.878; 95% CI: 1.111–3.174; P = 0.019). Appendectomies were performed closer to the date of CD diagnosis in the trend test (P = 0.039). The rate of appendectomy within one year or 1-5 years before CD diagnosis was higher in patients when compared to that in controls (0.97% versus 0%, P = 0.031; 1.13% versus 0.32%, P = 0.180). However, the rate of appendectomy over five years before CD diagnosis was close to controls (4.54% versus 3.40%, P = 0.392). No significant differences in disease location, behavior, medication, and intestinal resection between appendectomy and nonappendectomy CD patients were found, even in the subgroup analysis by age of appendectomy.

Conclusion

Prior appendectomy is a risk factor for the onset of CD. However, the appendectomy rate only increased for a short duration before CD diagnosis, likely reflecting a diagnostic bias. Prior appendectomy did not influence the features or course of CD.

Ulcerative Colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease that can involve any aspect of the colon starting with mucosal inflammation in the rectum and extending proximally in a continuous fashion. Typical symptoms on presentation are bloody diarrhea, abdominal pain, fecal urgency, and tenesmus. In some patients, extraintestinal manifestations may predate the onset of gastrointestinal symptoms. A diagnosis of UC is made on the basis of presenting symptoms consistent with UC as well as endoscopic evidence showing continuous and diffuse colonic inflammation that starts in the rectum. Biopsies of the colon documenting chronic inflammation confirm the diagnosis of UC. Most cases are treated with pharmacological therapy to first induce remission and then to maintain a corticosteroid-free remission. There are multiple classes of drugs used to treat the disease. For mild to moderate UC, oral and rectal 5-aminosalycilates are typically used. In moderate to severe colitis, medication classes include thiopurines, biological agents targeting tumor necrosis factor and integrins, and the small-molecule Janus kinase inhibitors. However, in up to 15% of cases, patients in whom medical therapy fails or who have development of dysplasia secondary to their long-standing colitis will require surgical treatment. Finally, to minimize the complications of UC and adverse events from medications, a working collaboration between primary care physicians and gastroenterologists is necessary to make sure that vaccinations are optimized and that patients are screened for colon cancer, skin cancer, bone loss, depression, and other treatable and preventable complications.

Sex- and Age-Related Estrogen Signaling Alteration in Inflammatory Bowel Diseases: Modulatory Role of Estrogen Receptors

The pathogenesis of inflammatory bowel diseases (IBD) seems to be associated with alterations of immunoregulation. Several lines of evidence suggest that estrogens play a role in the modulation of immune responses and may be related to the etiology of IBD. The purpose of this work was to examine the involvement of G protein-coupled estrogen receptor (GPER), estrogen receptor α (ERα), estrogen receptor β (ERβ) and ERα spliced variants ERα36 and ERα46 in Crohn's disease (CD) and ulcerative colitis (UC). The studied group included 73 patients with IBD and 31 sex and age-related controls. No differences in serum levels of 17β-estradiol nor of CYP1A1 and SULT1E1 enzymes involved in estrogen catabolism were stated. The expression pattern of estrogen receptors in tissue samples was quantified using real-time PCR and Western blotting. Statistically significant up-regulation of GPER and ERα in both CD and UC as well as down-regulation of ERβ in CD patients was found. However, differences in the expression of estrogen receptors in CD and UC have been identified, depending on the sex and age of patients. In men, up-regulation of GPER, ERα and ERα46 expression was shown in CD and UC patients. In women under 50 years of age, GPER protein level increased in UC whereas ERβ expression tended to decrease in CD and UC patients. In turn, in women over 50 the protein level of ERα increased in UC while ERβ expression decreased in CD patients. Dysregulation of estrogen receptors in the intestinal mucosa of patients with CD and UC indicates that estrogen signaling may play a role in the local immune response and maintain epithelial homeostasis in a gender- and age-dependent manner.

G protein-coupled estrogen receptor mediates anti-inflammatory action in Crohn's disease

Estrogens exert immunomodulatory action in many autoimmune diseases. Accumulating evidence highlights the meaningful impact of estrogen receptors in physiology and pathophysiology of the colon. However, the significance of G protein-coupled estrogen receptor (GPER) on Crohn's disease (CD), one of the inflammatory bowel disease (IBD) types, is still elusive. Our study revealed GPER overexpression at the mRNA and protein levels in patients with CD. To evaluate the effects of GPER activation/inhibition on colitis development, a murine 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced model of CD was used. We showed that activation of GPER reduces mortality, improves macroscopic and microscopic scores and lowers C-reactive protein (CRP) level. The impact of estrogen signaling on the suppression of the intestinal inflammation was proved by immunohistochemistry. It was demonstrated that GPER activation is accompanied by modulation of extracellular-signal regulated kinase (ERK) signaling pathway and expression level of genes involved in signal transmission and immune response as well as the expression of some microRNAs (miR-145, miR-148-5p and miR-592). Our study revealed that the membrane-bound estrogen receptor GPER mediates anti-inflammatory action and seems to be a potent therapeutic target in maintaining remission in CD.

The association between new generation oral contraceptive pill and the development of inflammatory bowel diseases

Background/Aims

To examine the association between use of oral contraceptive pills (OCPs) and the risk of developing inflammatory bowel diseases (IBD), in a modern cohort.

Methods

A prospective nested case-control study across sites in the Asia-Pacific region was conducted; involving female IBD cases and asymptomatic controls. Subjects completed a questionnaire addressing questions related to OCP use. Primary outcome was the risk of development of IBD of those exposed to OCP versus non-exposure. Secondary outcomes were development of Crohn's disease (CD) versus ulcerative colitis (UC), and whether age of first use of OCP use may be associated with risk of IBD.

Results

Three hundred and forty-eight female IBD cases (41% CD, median age: 43 years) and 590 female age-matched controls were recruited. No significant association was found between OCP use and the risk of IBD (odds ratio [OR], 1.65; 95% confidence interval, 0.77-3.13; P=0.22), CD (OR, 1.55) or UC (OR, 1.01). The lack of association persisted when results were adjusted for age and smoking. IBD cases commenced OCP use at a younger age than controls (18 years vs. 20 years, P=0.049).

Conclusions

In this large cohort of subjects from the Asia-Pacific region, we found a modest but not significantly increased risk of developing IBD amongst OCP users.

Development and validation of novel algorithms to identify patients with inflammatory bowel diseases in Israel: an epi-IIRN group study

Background

Before embarking on administrative research, validated case ascertainment algorithms must be developed. We aimed at developing algorithms for identifying inflammatory bowel disease (IBD) patients, date of disease onset, and IBD type (Crohn's disease [CD] vs ulcerative colitis [UC]) in the databases of the four Israeli Health Maintenance Organizations (HMOs) covering 98% of the population.

Methods

Algorithms were developed on 5,131 IBD patients and 2,072 controls, following independent chart review (60% CD and 39% UC). We reviewed 942 different combinations of clinical parameters aided by mathematical modeling. The algorithms were validated on an independent cohort of 160,000 random subjects.

Results

The combination of the following variables achieved the highest diagnostic accuracy: IBD-related codes, alone if more than five to six codes or combined with purchases of IBD-related medications (at least three purchases or ≥3 months from the first to last purchase) (sensitivity 89%, specificity 99%, positive predictive value [PPV] 92%, negative predictive value [NPV] 99%). A look-back period of 2-5 years (depending on the HMO) without IBD-related codes or medications best determined the date of diagnosis (sensitivity 83%, specificity 68%, PPV 82%, NPV 70%). IBD type was determined by the majority of CD/UC codes of the three recent contacts or the most recent when less than three contacts were recorded (sensitivity 92%, specificity 97%, PPV 97%, NPV 92%). Applying these algorithms, a total of 38,291 IBD patients were residing in Israel, corresponding to a prevalence rate of 459/100,000 (0.46%).

Conclusion

The application of the validated algorithms to Israel's administrative databases will now create a large and accurate ongoing population-based cohort of IBD patients for future administrative studies.

Bariatric surgery is associated with increased risk of new-onset inflammatory bowel disease: case series and national database study

BACKGROUND

Case series suggest a possible association between bariatric surgery and incident IBD.

AIM

The aim of this study was to evaluate the association between bariatric surgery and new-onset IBD.

METHODS

We first conducted a multi-institutional case series of patients with a history of IBD and bariatric surgery. We next conducted a matched case-control study using medical and pharmacy claims from 2008 to 2012 in a US national database from Source Healthcare Analytics LLC. Bariatric surgery was defined by ICD-9 or CPT code. Bariatric surgery was evaluated as recent (code in database timeframe), past (past history V code) or no history. Conditional logistic regression was used to estimate odds ratios (OR) and 95% CI for new-onset IBD, CD and UC.

RESULTS

A total of 15 cases of IBD (10 CD, 4 UC, 1 IBD, type unclassified) with a prior history of bariatric surgery were identified. Most cases were women, had Roux-en-Y surgery years prior to diagnosis and few IBD-related complications. A total of 8980 cases and 43 059 controls were included in our database analysis. Adjusting for confounders, a past history of bariatric surgery was associated with an increased risk of new-onset IBD (OR 1.93, 95% CI 1.34-2.79). However, patients who had recent bariatric surgery did not appear to be at shorter term risk of IBD (OR 0.94, 95% CI 0.58-1.52).

CONCLUSION

New-onset IBD was significantly associated with a past history of bariatric surgery. This potential association needs to be confirmed in future prospective studies.

Dipeptidyl peptidase-4 inhibitors and incidence of inflammatory bowel disease among patients with type 2 diabetes: population based cohort study

OBJECTIVE

To assess whether the use of dipeptidyl peptidase-4 inhibitors is associated with the incidence of inflammatory bowel disease in patients with type 2 diabetes.

DESIGN

Population based cohort study.

SETTING

More than 700 general practices contributing data to the United Kingdom Clinical Practice Research Datalink.

PARTICIPANTS

A cohort of 141 170 patients, at least 18 years of age, starting antidiabetic drugs between 1 January 2007 and 31 December 2016, with follow-up until 30 June 2017.

MAIN OUTCOME MEASURES

Adjusted hazard ratios for incident inflammatory bowel disease associated with use of dipeptidyl peptidase-4 inhibitors overall, by cumulative duration of use, and by time since initiation, estimated using time dependent Cox proportional hazards models. Use of dipeptidyl peptidase-4 inhibitors was modelled as a time varying variable and compared with use of other antidiabetic drugs, with exposures lagged by six months to account for latency and diagnostic delays.

RESULTS

During 552 413 person years of follow-up, 208 incident inflammatory bowel disease events occurred (crude incidence rate of 37.7 (95% confidence interval 32.7 to 43.1) per 100 000 person years). Overall, use of dipeptidyl peptidase-4 inhibitors was associated with an increased risk of inflammatory bowel disease (53.4 v 34.5 per 100 000 person years; hazard ratio 1.75, 95% confidence interval 1.22 to 2.49). Hazard ratios gradually increased with longer durations of use, reaching a peak after three to four years of use (hazard ratio 2.90, 1.31 to 6.41) and decreasing after more than four years of use (1.45, 0.44 to 4.76). A similar pattern was observed with time since starting dipeptidyl peptidase-4 inhibitors. These findings remained consistent in several sensitivity analyses.

CONCLUSIONS

In this first population based study, the use of dipeptidyl peptidase-4 inhibitors was associated with an increased risk of inflammatory bowel disease. Although these findings need to be replicated, physicians should be aware of this possible association.

Effects of Estrogen on the Gastrointestinal Tract

Estrogen is a kind of steroid compound that has extensive biologic activities. The effect of estrogen is pleiotropic, affecting multiple systems in the body. There is accumulating evidence that estrogen has important effects on the gastrointestinal tract. Longer exposure to estrogen may decrease the risk of gastric cancer. Use of the anti-estrogen drug tamoxifen might increase the risk of gastric adenocarcinoma. Estrogen receptor β may serve as a target for colorectal cancer prevention. In addition, estrogen has been reported to be closely related to the mucosal barrier, gastrointestinal function and intestinal inflammation. However, the role of estrogen in the gastrointestinal tract has not been systematically summarized. In this review, we aim to provide an overview of the role of estrogen in the gastrointestinal tract and evaluate it from various aspects, including estrogen receptors, the mucosal barrier, intestinal inflammation and gastrointestinal tract tumors, which may provide the basis for the development of therapeutic strategies to manage gastrointestinal diseases.

Smoking is associated with risk for developing inflammatory bowel disease including late onset ulcerative colitis: a prospective study

OBJECTIVES

Life style factors have been associated with inflammatory bowel disease (IBD) but there is a lack of data on the exposure of life styles factors before the onset of IBD. Our aim was to study the association between lifestyle factors and the development of IBD in a prospective setting.

MATERIALS AND METHODS

We performed a case control study of 72 patients who later developed ulcerative colitis (UC), 26 patients who developed Crohn's disease (CD) and 427 healthy controls from the Västerbotten intervention project matched for gender, age, year of health survey and area of residence. At recruitment, participants completed validated lifestyle questionnaires including data on alcohol intake. Information from this was used to assess the connection between lifestyle factors and later developing IBD.

RESULTS

For CD and UC, the median age at diagnosis was 53 and 52 years and median time of survey was 4 and 6 years before diagnosis, respectively. Multivariate odds ratio (OR) showed an association between never smoking and not developing IBD, including both UC and CD, OR (95% CI) 0.341 (0.136-0.853) and 0.473 (0.259-0.864), respectively. Marital status, educational level, alcohol consumption, reported physical activity and use of moist smokeless tobacco (snus) did not differ between patients and controls.

CONCLUSIONS

Smoking proves to be a risk factor for both CD and UC in this prospective case-control study. No association was seen for snus users, implying a non-nicotine pathogenic mechanism from combusted tobacco.

Inflammatory Bowel Diseases: Review of Known Environmental Protective and Risk Factors Involved

Inflammatory bowel diseases consisting of Crohn's disease and ulcerative colitis are chronic inflammatory diseases of the gastrointestinal tract. In addition to genetic susceptibility and disturbances of the microbiome, environmental exposures forming the exposome play an important role. Starting at birth, the cumulative effect of different environmental exposures combined with a predetermined genetic susceptibility is thought to cause inflammatory bowel disease. All these environmental factors are part of a Western lifestyle, suiting the high incidence rates in Europe and the United States. Whereas receiving breastfeeding, evidence of a Helicobacter pylori infection and vitamin D are important protective factors in Crohn's disease as well as ulcerative colitis, increased hygiene, experiencing a bacterial gastroenteritis in the past, urban living surroundings, air pollution, the use of antibiotics, nonsteroidal anti-inflammatory drugs, and oral contraceptives are likely to be the most important risk factors for both diseases. Current cigarette smoking yields a divergent effect by protecting against ulcerative colitis but increasing risk of Crohn's disease, whereas former smoking increases chances of both diseases. This review gives a clear overview of the current state of knowledge concerning the exposome. Future studies should focus on measuring this exposome yielding the possibility of combining all involved factors to one exposome risk score and our knowledge on genetic susceptibility.

Exposure to oral contraceptives increases the risk for development of inflammatory bowel disease: a meta-analysis of case-controlled and cohort studies

BACKGROUND

The oral contraceptive pill (OCP) is a widely used method of contraception. There have been conflicting studies linking the use of OCPs to the development of inflammatory bowel disease (IBD). The intent of this meta-analysis is to better define the association between OCP exposure and the risk for development of IBD.

METHODS

A thorough search of multiple databases, including Scopus, Cochrane, MEDLINE/PubMed, and CINAHL, and abstracts from major gastroenterology meetings was performed (October, 2016). Studies reporting the development of IBD in patients with or without previous exposure to OCP, compared with healthy controls, were included. A meta-analysis was completed using the Mantel-Haenszel model to evaluate the risk of developing IBD in the setting of previous OCP exposure.

RESULTS

In a complete analysis of 20 studies, there appeared to be over a 30% increased risk for the development of IBD in patients exposed to OCP compared with patients not exposed to OCP [odds ratio (OR): 1.32, 95% confidence interval (CI): 1.17-1.49, P<0.001, I=14%]. More specifically, there was a 24% higher risk for developing Crohn's disease (OR: 1.24, 95% CI: 1.09-1.40, P<0.001; I=38%) and a 30% higher risk for developing ulcerative colitis (OR: 1.30, 95% CI: 1.13-1.49, I=26%) in patients exposed to OCP compared with those not exposed to the medication.

CONCLUSION

The use of OCP is associated with an increased risk for development of Crohn's disease and ulcerative colitis in the genetically susceptible host. The total duration, dose of OCP exposure, and the risk for development of IBD need to be better characterized.

Crohn’s disease environmental factors in the developing world: A case-control study in a statewide catchment area in Brazil

AIM

To identify environmental risk factors associated with the development of Crohn’s disease (CD) in order to re-assess the hygiene hypothesis.

METHODS

A hospital-based, case-control study was carried out with CD patients (n = 145) and controls (n = 163) representing a socioeconomically diverse statewide catchment area in Brazil. Controls were recruited from caregivers of patients seen in different outpatient clinics at the same hospital. A multi-item survey with 94 questions regarding family history of CD, perinatal and childhood circumstances, living conditions, tobacco use and familial socioeconomic status was carried out by interviewers.

RESULTS

On the univariate analysis, predictive variables for CD included being male, under age of 40, a high education level, urban dweller, smaller family size, exposure to enteric pathogens and user of treated water (P < 0.005). On the multivariate analysis, variables significantly associated with CD were male gender (OR = 2.09), under age 40 (OR = 3.10), white (OR = 2.32), from a small family in childhood (OR = 2.34) and adulthood (OR = 3.02), absence of viral infections in childhood (OR = 2.23), exposure to enteric pathogens (OR = 2.41), having had an appendectomy (OR = 2.47) and prior or current smoker (OR = 2.83/1.12).

CONCLUSION

Most variables supporting the “hygiene hypothesis” are associated with the development of CD but are not independent predictors of the diagnosis.

Genetic Factors Interact With Tobacco Smoke to Modify Risk for Inflammatory Bowel Disease in Humans and Mice

BACKGROUND & AIMS

The role of tobacco smoke in the etiology of inflammatory bowel disease (IBD) is unclear. We investigated interactions between genes and smoking (gene-smoking interactions) that affect risk for Crohn's disease (CD) and ulcerative colitis (UC) in a case-only study of patients and in mouse models of IBD.

METHODS

We used 55 Immunochip-wide datasets that included 19,735 IBD cases (10,856 CD cases and 8879 UC cases) of known smoking status. We performed 3 meta-analyses each for CD, UC, and IBD (CD and UC combined), comparing data for never vs ever smokers, never vs current smokers, and never vs former smokers. We studied the effects of exposure to cigarette smoke in Il10^-/- and Nod2^-/- mice, as well as in Balb/c mice without disruption of these genes (wild-type mice). Mice were exposed to the smoke of 5 cigarettes per day, 5 days a week, for 8 weeks, in a ventilated smoking chamber, or ambient air (controls). Intestines were collected and analyzed histologically and by reverse transcription polymerase chain reaction.

RESULTS

We identified 64 single nucleotide polymorphisms (SNPs) for which the association between the SNP and IBD were modified by smoking behavior (meta-analysis Wald test P < 5.0 × 10^-5; heterogeneity Cochrane Q test P > .05). Twenty of these variants were located within the HLA region at 6p21. Analysis of classical HLA alleles (imputed from SNP genotypes) revealed an interaction with smoking. We replicated the interaction of a variant in NOD2 with current smoking in relation to the risk for CD (frameshift variant fs1007insC; rs5743293). We identified 2 variants in the same genomic region (rs2270368 and rs17221417) that interact with smoking in relation to CD risk. Approximately 45% of the SNPs that interact with smoking were in close vicinity (≤1 Mb) to SNPs previously associated with IBD; many were located near or within genes that regulate mucosal barrier function and immune tolerance. Smoking modified the disease risk of some variants in opposite directions for CD vs UC. Exposure of Interleukin 10 (il10)-deficient mice to cigarette smoke accelerated development of colitis and increased expression of interferon gamma in the small intestine compared to wild-type mice exposed to smoke. NOD2-deficient mice exposed to cigarette smoke developed ileitis, characterized by increased expression of interferon gamma, compared to wild-type mice exposed to smoke.

CONCLUSIONS

In an analysis of 55 Immunochip-wide datasets, we identified 64 SNPs whose association with risk for IBD is modified by tobacco smoking. Gene-smoking interactions were confirmed in mice with disruption of Il10 and Nod2-variants of these genes have been associated with risk for IBD. Our findings from mice and humans revealed that the effects of smoking on risk for IBD depend on genetic variants.

Crohn Disease: Epidemiology, Diagnosis, and Management

Crohn disease is a chronic idiopathic inflammatory bowel disease condition characterized by skip lesions and transmural inflammation that can affect the entire gastrointestinal tract from the mouth to the anus. For this review article, we performed a review of articles in PubMed through February 1, 2017, by using the following Medical Subject Heading terms: crohns disease, crohn's disease, crohn disease, inflammatory bowel disease, and inflammatory bowel diseases. Presenting symptoms are often variable and may include diarrhea, abdominal pain, weight loss, nausea, vomiting, and in certain cases fevers or chills. There are 3 main disease phenotypes: inflammatory, structuring, and penetrating. In addition to the underlying disease phenotype, up to a third of patients will develop perianal involvement of their disease. In addition, in some cases, extraintestinal manifestations may develop. The diagnosis is typically made with endoscopic and/or radiologic findings. Disease management is usually with pharmacologic therapy, which is determined on the basis of disease severity and underlying disease phenotype. Although the goal of management is to control the inflammation and induce a clinical remission with pharmacologic therapy, most patients will eventually require surgery for their disease. Unfortunately, surgery is not curative and patients still require ongoing therapy even after surgery for disease recurrence. Importantly, given the risks of complications from both Crohn disease and the medications used to treat the disease process, primary care physicians play an important role in optimizing the preventative care management to reduce the risk of complications.

Modifiable Environmental Factors in Inflammatory Bowel Disease

PURPOSE OF REVIEW

Environmental factors may influence predisposition to develop inflammatory bowel diseases (Crohn's disease, ulcerative colitis) or alter its natural history by modification of both the host immune response and intestinal microbial composition. The purpose of this review is to translate such evidence into clinical practice by a focus on interventional studies that have modified such environmental influences to improve disease outcomes.

RECENT FINDINGS

Several environmental influences have been identified in the recent literature including tobacco use, diet, antibiotics, vitamin D deficiency, stress, appendectomy, and oral contraceptive use. Some risk factors have similar influences on both Crohn's disease and ulcerative colitis while others are disease-specific or have divergent effects. Emerging epidemiologic evidence has confirmed the association of many of these factors with incident disease using prospective data. In addition, laboratory data has supported their mechanistic plausibility and relevance to intestinal inflammation.

Epidemiology of inflammatory bowel disease among participants of the Millennium Cohort: incidence, deployment-related risk factors, and antecedent episodes of infectious gastroenteritis

BACKGROUND

Crohn's disease (CD) and ulcerative colitis (UC) are two pathotypes of inflammatory bowel disease (IBD) with unique pathology, risk factors and significant morbidity.

AIM

To estimate incidence and identify IBD risk factors in a US military population, a healthy subset of the US population, using information from the Millennium Cohort Study.

METHODS

Incident IBD was identified from medical encounters from 2001 to 2009 or by self-report. Our primary risk factor of interest, infectious gastroenteritis, was identified from medical encounters and self-reported post-deployment health assessments. Other potential risk factors were assessed using self-reported survey responses and military personnel files. Hazard ratios were estimated using Cox proportional hazards analysis.

RESULTS

We estimated 23.2 and 21.9 diagnoses per 100 000 person-years, respectively, for CD and UC. For CD, significant risk factors included [adjusted hazard ratio (aHR), 95% confidence interval]: current smoking (aHR: 2.7, 1.4-5.1), two life stressors (aHR: 2.8, 1.4-5.6) and prior irritable bowel syndrome (aHR: 4.7, 1.5-15.2). There was no significant association with prior infectious gastroenteritis. There was an apparent dose-response relationship between UC risk and an increasing number of life stressors. In addition, antecedent infectious gastroenteritis was associated with almost a three-fold increase in UC risk (aHR: 2.9, 1.4-6.0). Moderate alcohol consumption (aHR: 0.4, 0.2-0.6) was associated with lower UC risk.

CONCLUSIONS

Stressful conditions and the high risk of infectious gastroenteritis in deployment operations may play a role in the development of IBD in military populations. However, observed differences in risk factors for UC and CD warrant further investigation.

Statins Associated With Decreased Risk of New Onset Inflammatory Bowel Disease

OBJECTIVES

Prior studies suggest that medication exposures may be associated with new onset inflammatory bowel disease (IBD). The aim of this study was to determine the effect of statins on the risk of new onset IBD in a large United States health claims database.

METHODS

We conducted a retrospective matched case-control study with a national medical claims and pharmacy database from Source Healthcare Analytics LLC. We included any patient aged 18 or older with ICD-9 code 555.x for Crohn's disease (CD) or 556.x for ulcerative colitis (UC) between January 2008 and December 2012. IBD patients diagnosed in 2012 were compared with the age group, gender, race, and geographically matched controls. Controls had no ICD-9 codes for CD, UC, or IBD-associated diseases and no prescriptions for IBD-related medications. New onset IBD patients were defined as having at least three separate CD or UC ICD-9 codes and no IBD-related ICD-9 or prescription before first IBD ICD-9. Statin exposure was assessed by Uniform System of Classification level 5 code. To account for diagnostic delay, exposures within 6 months of first ICD-9 were excluded. Exposures within 12 and 24 months were excluded in sensitivity analyses. Conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for new onset IBD, CD, and UC.

RESULTS

A total of 9,617 cases and 46,665 controls were included in the analysis. Any statin exposure was associated with a significantly decreased risk of IBD (OR 0.68, 95% CI 0.64-0.72), CD (0.64, 95% CI 0.59-0.71), and UC (OR 0.70, 95% CI 0.65-0.76). This effect was similar for most specific statins and regardless of intensity of therapy. The protective effect against new onset CD was strongest among older patients. Statins' association with a lower risk of IBD was similar after adjusting for antibiotics, hormone replacement therapy, oral contraceptives, comorbidities, and cardiovascular medications.

CONCLUSIONS

Statins may have a protective effect against new onset IBD, CD, and UC. This decreased risk is similar across most statins and appears to be stronger among older patients, particularly in CD.

Androgen Deprivation Therapy and the Incidence of Inflammatory Bowel Disease in Patients With Prostate Cancer

Androgen deprivation therapy (ADT) is the mainstay treatment for advanced prostate cancer. By lowering androgen levels, ADT inhibits the progression of prostate cancer, but it may also affect gut autoimmunity. We investigated the association between ADT and the incidence of inflammatory bowel disease using a cohort of 31,842 men newly diagnosed with prostate cancer between 1988 and 2014, identified in the United Kingdom Clinical Practice Research Datalink. Exposure to ADT was treated as a time-varying variable and lagged by 1 year to account for diagnostic delays, with nonuse as the reference category. During 133,018 person-years of follow-up, 48 men were newly diagnosed with ulcerative colitis (incidence rate (IR) = 36/100,000 person-years (PY)) and 12 were diagnosed with Crohn's disease (IR = 9/100,000 PY). In Cox proportional hazards models, ADT was associated with a decreased risk of ulcerative colitis (IR = 24/100,000 PY vs. IR = 50/100,000 PY; hazard ratio = 0.52, 95% confidence interval: 0.28, 0.99) and a nonsignificant decreased risk of Crohn's disease (hazard ratio = 0.38, 95% confidence interval: 0.11, 1.37). These findings indicate that the use of ADT may be associated with intestinal autoimmunity. Further research is warranted to replicate these findings and assess their clinical significance.

Risk of Inflammatory Bowel Disease with Oral Contraceptives and Menopausal Hormone Therapy: Current Evidence and Future Directions

Crohn's disease (CD) and ulcerative colitis (UC), collectively known as inflammatory bowel diseases, are archetypical inflammatory disorders of the gastrointestinal tract with rising incidence worldwide. Although the role of genetic factors in disease development has been highlighted by genome-wide association studies, environmental risk factors likely play a pivotal role in development of CD and UC. Prior observational studies have suggested a link between exogenous hormone use and risk of CD and UC. Specifically, studies have shown an association between oral contraceptive use and risk of CD and menopausal hormone therapy and risk of UC. Although the exact mechanism of these associations is largely unknown, a number of hypotheses have been proposed. First, oral estrogen has been shown to modify intestinal permeability, a critical step in the pathophysiology of inflammatory bowel disease. Second, exogenous hormone use through its effect on endogenous levels of hormones may enhance the development of Th1- and Th2-mediated inflammatory diseases. Lastly, recent data have linked modification in the gut microbiome to endogenous levels of androgens, which are also known to be altered with exogenous hormone use and influence the development of autoimmune diseases. This supports the intriguing hypothesis that the gut microbiome lies at the crossroads of pathways linking exogenous hormone use with innate and adaptive immunity. Future studies should therefore focus on bridging these epidemiologic findings to disease pathogenesis through comprehensive understanding of the complex interaction between exogenous hormone use, sex steroid biomarkers, genetic risk loci, and alterations in the intestinal microbial environment in the etiology of CD and UC.

Identification of Clinical and Genetic Parameters Associated with Hidradenitis Suppurativa in Inflammatory Bowel Disease

BACKGROUND

Hidradenitis suppurativa (HS) has recently been associated with inflammatory bowel disease (IBD). The objective of this study is to investigate the prevalence of HS in IBD and to identify clinical and genetic parameters associated with HS in IBD.

METHODS

A questionnaire, validated for HS, was sent to 1969 patients suffering from IBD.

RESULTS

The prevalence of HS in our IBD cohort (1260 participating patients) was significantly higher than in the general population (6.8%-10.6% versus 1%-2%). IBD patients with HS were affected by IBD significantly earlier and more often treated with anti-TNF-α therapy and surgical resection compared to IBD without HS. Female gender, smoking, a higher body mass index, and younger age were independent associated parameters for HS. Within cases allelic association analysis was performed for 59 cases (IBD with HS) and 293 controls (IBD without HS). We observed 2 promising new associations in genomic regions harboring ELOVL7 (rsnumber 10057395 P = 7.15 × 10, odds ratio = 0.4), and in the intergenic region between SULT1B1 and SULT1E1 (rsnumber 2014777 P = 7.48 × 10, odds ratio = 2.3).

CONCLUSIONS

HS is present in 6.8% to 10.6% of IBD patients. Co-morbid HS is associated with an early onset of IBD in which anti-tumor necrosis factor-α therapy and surgical resections are often needed. We identified a suggestive protective association with ELOVL7 and suggestive risk association with the genes SULT1B1 and SULT1E1 for HS, in the context of IBD. These genetic associations need further exploration and replication in additional independent cohorts.

Variations in inflammatory genes as molecular markers for prediction of inflammatory bowel disease occurrence

OBJECTIVE

Research on inflammatory bowel disease (IBD) has highlighted genes involved in the regulation of inflammatory responses as contributors to disease pathogenesis. This study aimed to evaluate the associations between IBD and variations in NOD2, TLR4, TNF-α, IL-6, IL-1β and IL-1RN genes, and to use the genetic data obtained in predictive modeling.

METHODS

A total of 167 IBD patients and 101 healthy controls were genotyped by polymerase chain reaction-restriction fragment length polymorphism. Using the genotype data attained as the input to various classification algorithms, IBD prediction models were designed. The area under the receiver operating characteristic curve (AUROC) was used to measure their performance.

RESULTS

Significant associations were found between Crohn's disease (CD) and minor NOD2 variants, as well as TLR4 299Gly, TNF-α G-308A, IL-6 G-174C and IL-1RN VNTR A2 variants, while ulcerative colitis (UC) was associated only with IL-1RN VNTR A2 variants. CD and UC showed highly significant difference in the allelic distribution of TNF-α G-308A, where the A allele was found to be related to CD, and the G allele to UC. A combined effect of patients' gender and TLR4 variants was observed among CD patients. When all analyzed genotype and gender data were used, prediction performance achieved a maximum AUROC of 0.690 for CD and 0.601 for UC dataset.

CONCLUSION

Variations in the genes involved in immune regulation are genetic factors of importance in IBD susceptibility that could potentially be used as predictors of disease development.

Inflammatory Bowel Disease in Juvenile Idiopathic Arthritis Patients Treated with Biologics

Objective.

Evolving inflammatory bowel disease (IBD) is a matter of interest in patients with juvenile idiopathic arthritis (JIA) and might be associated with JIA therapy.

Methods.

Data from the German biologics registry (Biologika in der Kinderrheumatologie; BiKeR) from 2001 to 2013 were analyzed.

Results.

There were 3071 patients with 8389 patient-years (PY) of observation followed. IBD was diagnosed in 11 patients, 8 with Crohn disease and 3 with ulcerative colitis. IBD incidence in patients with JIA was 1.31/1000 PY and higher than published IBD incidences in pediatric populations. Compared with the total BiKeR cohort, patients with IBD more commonly had enthesitis-related arthritis, extended oligoarthritis, psoriatic arthritis, and also rheumatoid factor (RF)-negative polyarthritis. No IBD occurred in patients with systemic JIA or RF-positive polyarthritis. In patients treated with methotrexate (MTX), the IBD incidence was significantly lower compared with patients not treated with MTX. Etanercept (ETN) monotherapy, but not the combination of ETN and MTX, was associated with an increased incidence of IBD.

Conclusion.

Incidence of IBD in patients with JIA is higher than in the population. MTX turned out to be protective, even in combination with ETN.

Neutrophil Extracellular Traps in Ulcerative Colitis: A Proteome Analysis of Intestinal Biopsies

BACKGROUND

The etiology of the inflammatory bowel diseases, including ulcerative colitis (UC), remains incompletely explained. We hypothesized that an analysis of the UC colon proteome could reveal novel insights into the disease etiology.

METHODS

Mucosal colon biopsies were taken by endoscopy from noninflamed tissue of 10 patients with UC and 10 controls. The biopsies were either snap-frozen for protein analysis or prepared for histology. The protein content of the biopsies was characterized by high-throughput gel-free quantitative proteomics, and biopsy histology was analyzed by light microscopy and confocal microscopy.

RESULTS

We identified and quantified 5711 different proteins with proteomics. The abundance of the proteins calprotectin and lactotransferrin in the tissue correlated with the degree of tissue inflammation as determined by histology. However, fecal calprotectin did not correlate. Forty-six proteins were measured with a statistically significant differences in abundances between the UC colon tissue and controls. Eleven of the proteins with increased abundances in the UC biopsies were associated with neutrophils and neutrophil extracellular traps. The findings were validated by microscopy, where an increased abundance of neutrophils and the presence of neutrophil extracellular traps by extracellular DNA present in the UC colon tissue were confirmed.

CONCLUSIONS

Neutrophils, induced neutrophil extracellular traps, and several proteins that play a part in innate immunity are all increased in abundance in the morphologically normal colon mucosa from patients with UC. The increased abundance of these antimicrobial compounds points to the stimulation of the innate immune system in the etiology of UC.

Autophagy and inflammatory bowel disease: Association between variants of the autophagy-related IRGM gene and susceptibility to Crohn's disease

BACKGROUND

Crohn's disease and ulcerative colitis are inflammatory bowel diseases involving a genetically determined inappropriate mucosal immune response towards luminal antigens, including resident bacterial flora. Recent studies identified susceptibility genes involved in autophagy.

AIMS

We analyzed known autophagic loci (IRGM, ULK1 and AMBRA1) previously described as associated with inflammatory bowel diseases or with other autoimmune and/or inflammatory disorders in a sample of Italian inflammatory bowel diseases patients in order to confirm their possible involvement and relative contribution in the disease.

METHODS

We performed a case-control association study, a sub-phenotype correlation and a haplotype analysis. The analysis included 263 Crohn's disease, 206 ulcerative colitis patients and 245 matched healthy controls. Five polymorphisms were genotyped by allelic discrimination assays.

RESULTS

IRGM was the most strongly associated with Crohn's disease susceptibility [rs13361189: P=0.011, OR=1.66 [95% CI: (1.12-2.45)]; rs4958847: P=0.05, OR=1.43 [95% CI: (1-2.03)]. The SNP rs13361189 was also found to increase the risk of Crohn's disease clinical sub-phenotype (fibrostricturing behaviour, ileal disease, perianal disease, intestinal resection). These findings suggest that IRGM variants may modulate clinical characteristics of Crohn's disease.

CONCLUSIONS

Our study confirms IRGM rs13361189 and rs4958847 polymorphisms to be important for Crohn's disease susceptibility and phenotype modulation, in accordance with previous findings.