Early life exposures and the risk of inflammatory bowel disease: Systematic review and meta-analyses

The Rising Burden of Inflammatory Bowel Disease in Denmark Over Two Decades: A Nationwide Cohort Study

BACKGROUND & AIMS

Shifts in epidemiological stages of inflammatory bowel disease (IBD) carry implications toward understanding IBD etiology and managing clinical care. We conducted a temporal analysis of the epidemiology of IBD between 1995 and 2016 in the Danish nationwide cohort.

METHODS

We used the Danish registers to obtain data on demographics and IBD-related outpatient and inpatient contacts between 1995 and 2016. IBD diagnosis was defined as having ≥2 registrations related to Crohn's disease (CD) or ulcerative colitis (UC) within a 2-year period. We estimated overall and annual incidence rates and prevalence of CD and UC standardized with respect to age and sex.

RESULTS

A total of 47,830 individuals met the criteria for IBD diagnosis, of which 33% were diagnosed with CD and 67% with UC. Between 1995 and 2016, the incidence rate (95% confidence interval) per 100,000 person-years rose from 9.1 (8.3-10.0) to 17.8 (16.8-19.0) for CD, and from 21.0 (19.8-22.3) to 28.4 (27.0-29.8) for UC. The highest increase in CD and UC incidence rates occurred in children and young adults, respectively. The prevalence of IBD doubled from 1995 to 2016; the greatest increase (2.5-fold) was in UC prevalence among individuals aged >40 years. During this period, the median age of the IBD population increased by 6 to 7 years.

CONCLUSIONS

In Denmark, the incidence and prevalence of IBD have increased during the last 2 decades. The IBD population is shifting toward an older age. These findings have implications towards understanding environmental shifts as well as preparing health care systems for an aging IBD population.

Early-Life Mebendazole Exposure Increases the Risk of Adult-Onset Ulcerative Colitis: A Population-Based Cohort Study

INTRODUCTION

According to the hygiene hypothesis, exposure to parasites may protect against inflammatory bowel disease (IBD). Our aim was to examine the risk of IBD with childhood exposure to mebendazole, a broad-spectrum antihelminthic agent.

METHODS

We conducted a population-based cohort study using prospectively collected historical data of all individuals born in Denmark between 1995 and 2018. We identified mebendazole exposure at age younger than 18 years and during early life (younger than 5 years). We performed adjusted Cox proportional hazards regression analysis to determine the risk of IBD, ulcerative colitis (UC), and Crohn's disease with mebendazole exposure after adjusting for potential confounders.

RESULTS

Of 1,520,290 individuals in the cohort, 615,794 had childhood or adolescence mebendazole exposure. One thousand five hundred fifty-five and 1,499 individuals were subsequently diagnosed with pediatric-onset and adult-onset IBD, respectively. On multivariable analysis, mebendazole exposure at age younger than 18 years did not affect pediatric-onset or adult-onset IBD risk (adjusted hazard ratio [aHR] 0.97, 95% confidence interval [CI] 0.87, 1.07, and 1.08, 95% CI 0.97, 1.19, respectively). On limiting mebendazole exposure to age younger than 5 years while there was no association with pediatric-onset IBD (aHR 0.98, 95% CI 0.87, 1.11), adult-onset IBD risk was increased (aHR 1.17, 95% CI 1.04, 1.31). This increase in risk was driven by UC (aHR 1.32, 95% CI 1.12, 1.55), but not Crohn's disease (1.03, 95% CI 0.87, 1.22).

DISCUSSION

Early-life mebendazole exposure is associated with an increase in the risk of adult-onset UC. These findings suggest the importance of early-life exposures in shaping the risk of IBD later in life.

Bermúdez M, Campoy C. Impact of Total Parenteral Nutrition on Gut Microbiota in Pediatric Population Suffering Intestinal Disorders

Parenteral nutrition (PN) is a life-saving therapy providing nutritional support in patients with digestive tract complications, particularly in preterm neonates due to their gut immaturity during the first postnatal weeks. Despite this, PN can also result in several gastrointestinal complications that are the cause or consequence of gut mucosal atrophy and gut microbiota dysbiosis, which may further aggravate gastrointestinal disorders. Consequently, the use of PN presents many unique challenges, notably in terms of the potential role of the gut microbiota on the functional and clinical outcomes associated with the long-term use of PN. In this review, we synthesize the current evidence on the effects of PN on gut microbiome in infants and children suffering from diverse gastrointestinal diseases, including necrotizing enterocolitis (NEC), short bowel syndrome (SBS) and subsequent intestinal failure, liver disease and inflammatory bowel disease (IBD). Moreover, we discuss the potential use of pre-, pro- and/or synbiotics as promising therapeutic strategies to reduce the risk of severe gastrointestinal disorders and mortality. The findings discussed here highlight the need for more well-designed studies, and harmonize the methods and its interpretation, which are critical to better understand the role of the gut microbiota in PN-related diseases and the development of efficient and personalized approaches based on pro- and/or prebiotics.

Environmental risk factors for inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic, progressive immune-mediated inflammatory condition of the gastrointestinal tract. Environmental risk factors play a role in developing either type of IBD, Crohn's disease and ulcerative colitis; although the exact mechanism is still unknown. Herein, we review environmental risks from early life exposures, lifestyle and hygiene, vaccinations, surgeries, exposure to drugs and gastrointestinal pathogens that may increase the risk of developing IBD.

Implications of the changing epidemiology of inflammatory bowel disease in a changing world

The epidemiology of inflammatory bowel disease (IBD) has undergone considerable shifts since its emergence in the Western world over a century ago, especially in the last few decades, with increasing global burden of disease. IBD incidence continues to rise in developed countries in all age groups which is contributing to compounding prevalence. Further, IBD incidence is rising sharply in Asia and other recently developed and developing countries. In this review, we discuss the implications of changing trends of IBD epidemiology. First, changing patterns provide insights into IBD causes, as they occur concurrent with shifts in the environment, cultures, and attitudes. Understanding the impact of the environment on IBD risk can help towards prediction and prevention strategies. Second, we must prepare healthcare systems for the rising burden of IBD and address it at various levels towards improving outcomes and health, overall.

Early Diagnosis, Early Stratification, and Early Intervention to Deliver Precision Medicine in IBD

Despite huge advances in understanding the molecular basis of IBD, clinical management has continued to rely on a "trial and error" approach. In addition, a therapeutic ceiling has emerged whereby even the most effective interventions are only beneficial for approximately 30% of patients. Consequently, several tools have been developed to aid stratification and guide treatment-decisions. We review the potential application for many of these precision medicine approaches, which are now almost within reach. We highlight the importance of early action (and avoiding inaction) to ensure the best outcomes for patients and how combining early action with precision tools will likely ensure the right treatment is delivered at the right time and place for each individual person living with IBD. The lack of clinical impact to date from precision medicine, despite much hype and investment, should be tempered with the knowledge that clinical translation can take a long time, and many promising breakthroughs might be ready for clinical implementation in the near future. We discuss some of the remaining challenges and barriers to overcome for clinical adoption. We also highlight that early recognition, early diagnosis, early stratification, and early intervention go hand in hand with precision medicine tools. It is the combination of these approaches that offer the greatest opportunity to finally deliver on the promise of precision medicine in IBD.

Multiomics to elucidate inflammatory bowel disease risk factors and pathways

Inflammatory bowel disease (IBD) is an immune-mediated disease of the intestinal tract, with complex pathophysiology involving genetic, environmental, microbiome, immunological and potentially other factors. Epidemiological data have provided important insights into risk factors associated with IBD, but are limited by confounding, biases and data quality, especially when pertaining to risk factors in early life. Multiomics platforms provide granular high-throughput data on numerous variables simultaneously and can be leveraged to characterize molecular pathways and risk factors for chronic diseases, such as IBD. Herein, we describe omics platforms that can advance our understanding of IBD risk factors and pathways, and available omics data on IBD and other relevant diseases. We highlight knowledge gaps and emphasize the importance of birth, at-risk and pre-diagnostic cohorts, and neonatal blood spots in omics analyses in IBD. Finally, we discuss network analysis, a powerful bioinformatics tool to assemble high-throughput data and derive clinical relevance.

Tailoring Multi-omics to Inflammatory Bowel Diseases: All for One and One for All

Inflammatory bowel disease [IBD] has a multifactorial origin and originates from a complex interplay of environmental factors with the innate immune system at the intestinal epithelial interface in a genetically susceptible individual. All these factors make its aetiology intricate and largely unknown. Multi-omic datasets obtained from IBD patients are required to gain further insights into IBD biology. We here review the landscape of multi-omic data availability in IBD and identify barriers and gaps for future research. We also outline the various technical and non-technical factors that influence the utility and interpretability of multi-omic datasets and thereby the study design of any research project generating such datasets. Coordinated generation of multi-omic datasets and their systemic integration with clinical phenotypes and environmental exposures will not only enhance understanding of the fundamental mechanisms of IBD but also improve therapeutic strategies. Finally, we provide recommendations to enable and facilitate generation of multi-omic datasets.

Precision Medicine in Pediatric Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) describes a heterogenous group of diseases characterized by chronic inflammation of the intestinal tract. The IBD subtypes, Crohn's disease, ulcerative colitis, and IBD-Unspecified, each have characteristic features, but heterogeneity remains even among the subtypes. There has been an explosion of new knowledge on the possible pathogenesis of IBD over the last 2 decades mirroring innovation and refinement in technology, particularly the generation of large scale - "-omic" data. This knowledge has fostered a veritable renaissance of novel diagnostics, prognostics, and therapeutics, with patients with IBD seeing hope bloom in the increasingly large armamentarium of IBD therapies. However, while there are increased numbers of therapies and more pathways being targeted, the number of medications for IBD is still finite and the efficacy has reached a plateau. Precision medicine (PM) is much needed to rationally select and optimize IBD therapies in the new reality of wider but still limited choice with a concurrent, increasingly fine resolution on the significance and utility of clinical, genetic, microbial, and proteomic characteristics that define individual patients. PM is a rapidly changing art, but this review will strive to detail the current state and future directions of PM in pediatric IBD.

The neonatal microbiome in utero and beyond: perinatal influences and long-term impacts

The neonatal microbiome offers a valuable model for studying the origins of human health and disease. As the field of metagenomics expands, we also increase our understanding of early life influences on its development. In this review we will describe common techniques used to define and measure the microbiome. We will review in utero influences, normal perinatal development, and known risk factors for abnormal neonatal microbiome development. Finally, we will summarize current evidence that links early life microbial impacts on the development of chronic inflammatory diseases, obesity, and atopy.

Microbiota-Immune Interactions in Ulcerative Colitis and Colitis Associated Cancer and Emerging Microbiota-Based Therapies

Ulcerative colitis (UC) is a chronic autoimmune disorder affecting the colonic mucosa. UC is a subtype of inflammatory bowel disease along with Crohn's disease and presents with varying extraintestinal manifestations. No single etiology for UC has been found, but a combination of genetic and environmental factors is suspected. Research has focused on the role of intestinal dysbiosis in the pathogenesis of UC, including the effects of dysbiosis on the integrity of the colonic mucosal barrier, priming and regulation of the host immune system, chronic inflammation, and progression to tumorigenesis. Characterization of key microbial taxa and their implications in the pathogenesis of UC and colitis-associated cancer (CAC) may present opportunities for modulating intestinal inflammation through microbial-targeted therapies. In this review, we discuss the microbiota-immune crosstalk in UC and CAC, as well as the evolution of microbiota-based therapies.