Higher predicted vitamin D status is associated with reduced risk of Crohn's disease

Urban-associated diseases: Candidate diseases, environmental risk factors, and a path forward

BACKGROUND

Cities are home to over half the global population; that proportion is expected to rise to 70% by mid-century. The urban environment differs greatly from that in which humans evolved, with potentially important consequences for health. Rates for allergic, inflammatory and auto-immune diseases appear to rise with urbanization and be higher in the more urbanized nations of the world which has led some to suggest that cities promote the occurrence of these diseases. However, there are no syntheses outlining what urban-associated diseases are and what characteristics of cities promote their occurrence.

OBJECTIVES

To synthesize the current understanding of "urban-associated diseases", and discover the common, potentially modifiable features of cities that may be driving these associations.

METHODS

We focus on any diseases that have been associated with cities or are particularly prominent in today's urban societies. We draw on expertise across diverse health fields to examine the evidence for urban connections and drivers.

DISCUSSION

We found evidence for urban associations across allergic, auto-immune, inflammatory, lifestyle and infectious disease categories. Some conditions (e.g. obesity and diabetes) have complex relationships with cities that have been insufficiently explored. Other conditions (e.g. allergies and asthma) have more evidence demonstrating their relationship with cities and the mechanisms driving that association. Unsurprisingly, air pollution was the characteristic of cities most frequently associated with disease. Other identified urban risk factors are not as widely known: altered microbial exposure and a disconnect from environmental microbiomes, vitamin D deficiency, noise and light pollution, and a transient, over-crowded, impoverished population. However, many complexities and caveats to these relationships beg clarification; we highlight the current knowledge gaps and outline ways to fill those gaps. Identifying urban-associated diseases and their drivers will allow us to prepare for the urban-disease burden of the future and create healthy cities that mitigate that disease burden.

Inflammatory bowel diseases: interrelationships between dietary vitamin D, exposure to UV radiation and the fecal microbiome

Introduction: Environmental factors and an altered fecal microbiome are believed to be central to the pathogenesis of inflammatory bowel diseases (IBD). Vitamin D and ultraviolet radiation (UVR) are environmental factors that are associated by several pathways, including changes to the gastrointestinal microbiome, with the development and course of IBD.Area covered: This review explores the interaction of vitamin D, and UVR, with the intestinal innate and adaptive immune systems, and how they may influence the gut microbiome and the subsequent development, and progression, of IBD.Expert opinion: Vitamin D and UVR both regulate innate and adaptive immunity through a combination of common and independent mechanisms, with the overall effect being the promotion of immune tolerance. Vitamin D, and to a lesser extent UVR, can modify the gastrointestinal microbiome either directly, or through immune-mediated mechanisms and this may explain the effect on intestinal inflammation in animal models of IBD and some clinical studies. Thus, both vitamin D and UVR exposure can be considered potential 'master regulators' of gastrointestinal immunity, fine-tuning the complex interaction between genetics, host immunity and the gut microbiome. Further research and increased understanding of environment-host interactions is essential to achieving the ultimate goal of preventing and curing IBD.

Nutritional approach as therapeutic manipulation in inflammatory bowel disease

Malnutrition is observed more frequently in patients with inflammatory bowel disease (IBD) than in the general population and associated with adverse clinical outcomes. This study aimed to review the current knowledge regarding the efficacy of dietary and nutritional intervention in IBD patients. Exclusive enteral nutrition might be inferior to corticosteroid treatment in adults with active Crohn’s disease (CD) but might even be superior considering the adverse effects of corticosteroid treatment in children. Total parenteral nutrition has no advantage over enteral nutrition, which is considered a more physiologic modality in organ function. Current guidelines do not yet recommend ω3-polyunsaturated fatty acid supplementation for the prevention and maintenance of remission in IBD patients. Dietary fiber supplementation could be effective in the relief of symptoms and maintenance of remission in ulcerative colitis (UC). Although vitamin D may be favorable to clinical course of IBD and bone density. Probiotic supplementation has proven to be effective in preventing and treating pouchitis for UC but is less effective in treating CD. Nutritional interventions not only correct nutritional deficiencies but also improve symptoms and clinical courses of the disease. Hence, nutritional approaches need to be developed to significantly evaluate the effectiveness of dietary interventions used to treat IBD.

Managing vitamin D deficiency in inflammatory bowel disease

Management of inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, is generally cumbersome for patients and is a massive health-economic burden. In recent years, the immunomodulating effects of vitamin D have gained a huge interest in its possible pathogenic influence on the pathophysiology of IBD. Vitamin D deficiency is frequent among patients with IBD. Several clinical studies have pointed to a critical role for vitamin D in ameliorating disease outcomes. Although causation versus correlation unfortunately remains an overwhelming issue in the illusive chicken versus egg debate regarding vitamin D and IBD, here we summarise the latest knowledge of the immunological effects of vitamin D in IBD and recommend from available evidence that physicians regularly monitor serum 25(OH)D levels in patients with IBD. Moreover, we propose an algorithm for optimising vitamin D status in patients with IBD in clinical practice. Awaiting well-powered controlled clinical trials, we consider vitamin D supplementation to be an affordable and widely accessible therapeutic strategy to ameliorate IBD clinical outcomes.

Vitamin D deficiency associated with Crohn's disease and ulcerative colitis: a meta-analysis of 55 observational studies

PURPOSE

To investigate the association of serum levels of 25(OH)D and 1,25(OH)₂D₃ in healthy and non-healthy controls with Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

Three electronic databases: PubMed, EMbase and EBSCOhost CINAHL, were searched for observational studies to measure the relationship between serum levels of vitamin D (VitD) and CD (or UC).

RESULTS

Fifty-five studies were included in the meta-analysis. We found that mean serum 25(OH)D levels in patients with CD were significantly lower than those in healthy controls (MD: - 3.17 ng/mL; 95% CI - 4.42 to - 1.93). Results from the meta-analysis examining 1,25(OH)₂D₃ levels in Crohn's patients revealed higher levels in the CD group than in healthy (MD: 3.47 pg/mL; 95% CI - 7.72 to 14.66) and UC group (MD: 5.05 pg/mL; 95% CI - 2.42 to 12.52). Serum 25(OH)D levels were lower in the UC group than in the healthy control group (MD: - 2.52 ng/mL; 95% CI - 4.02 to - 1.02). In studies investigating the level of 1,25(OH)₂D₃ in UC and healthy control groups, the level of 1,25(OH)₂D₃ in the UC groups were found to be higher than that in the control groups (MD: 3.76 pg/mL; 95% CI - 8.36 to 15.57). However, the 1,25(OH)₂D₃ level in patients with UC was lower than that in CD groups (MD: - 6.71 pg/mL; 95% CI - 15.30 to 1.88). No significant difference was noted between CD patients and UC patients in terms of average serum 25(OH)D levels.

CONCLUSIONS

This study found that VitD levels were inversely related to CD and UC. Serum levels of 25(OH)D were lower in patients with CD and UC than in healthy people, and more than half of the patients had insufficient vitamin D levels. The serum level of 1,25(OH)₂D₃ in both the CD and UC groups was higher than that in healthy people.

Vitamin D Deficiency is Associated with Increased Disease Activity in Patients with Inflammatory Bowel Disease

Background and Aims: Vitamin D has an inhibitory role in the inflammatory signaling pathways and supports the integrity of the intestinal barrier. Due to its immunomodulatory effect, vitamin D plays a role in chronic inflammatory bowel disease (IBD) and a deficiency is associated with an increased risk for a flare. We aimed to investigate to what extent the 25-hydroxyvitamin D (25(OH)D₃) level correlates with disease activity and whether a cut-off value can be defined that discriminates between active disease and remission. Methods: Patients with IBD, treated at the University Hospital Frankfurt were analyzed retrospectively. The 25(OH)D3 levels were correlated with clinical activity indices and laboratory chemical activity parameters. A deficiency was defined as 25(OH)D3 levels <30 ng/mL. Results: A total of 470 (257 female) patients with IBD were included, 272 (57.9%) with Crohn’s disease (CD), 198 (42.1%) with ulcerative colitis (UC). The median age of the patients was 41 (18–84). In 283 patients (60.2%), a vitamin D deficiency was detected. 245 (53.6%) patients received oral vitamin D supplementation, and supplemented patients had significantly higher vitamin D levels (p < 0.0001). Remission, vitamin D substitution, and male gender were independently associated with the 25(OH)D3 serum concentration in our cohort in regression analysis. A 25(OH)D3 serum concentration of 27.5 ng/mL was the optimal cut-off value. Conclusion: Vitamin D deficiency is common in IBD patients and appears to be associated with increased disease activity. In our study, vitamin D levels were inversely associated with disease activity. Thus, close monitoring should be established, and optimized supplementation should take place.

Relationship(s) between obesity and inflammatory bowel diseases: possible intertwined pathogenic mechanisms

The inflammatory bowel diseases, Crohn's and ulcerative colitis have increased in incidence and prevalence from the mid-eighteen to the late nineteen centuries. From then to the current twenty-first century there has been a more rapid expansion of these disease to areas previously experiencing low rates. This latter expansion coincides with the current obesity pandemic which also began toward the end of the last century. Although the two diseases have radically different frequencies, there are interesting links between them. Four areas link the diseases. On an epidemiological level, IBD tends to follow a north-south gradient raising the importance of vitamin D in protection. Obesity has very weak relationship with latitude, but both diseases follow adult lactase distributions colliding in this plane. Is it possible that obesity (a low vitamin D condition with questionable response to supplements) reduces effects in IBD? On a pathogenic level, pro-inflammatory processes mark both IBD and obesity. The similarity raises the question of whether obesity could facilitate the development of IBD. Features of the metabolic syndrome occur in both, with or without obesity in IBD. The fourth interaction between the two diseases is the apparent effect of obesity on the course of IBD. There are suggestions that obesity may reduce the efficacy of biologic agents. Yet there is some suggestion also that obesity may reduce the need for hospitalization and surgery. The apparent co-expansion of both obesity and IBD suggests similar environmental changes may be involved in the promotion of both.

Current evidence for vitamin D in intestinal function and disease

Vitamin D activity is associated with the modulation of a wide variety of biological systems, in addition to its roles in calcium homeostatic mechanisms. While vitamin D is well known to promote gastrointestinal calcium absorption, vitamin D also plays a role in attenuating and/or preventing the progression of several gastrointestinal diseases including Crohn’s disease, ulcerative colitis, and colorectal cancer, and may also play a role in chemotherapy-induced intestinal mucositis. The pro-differentiation, immunomodulatory, and anti-inflammatory effects of vitamin D, which has been reported in numerous circumstances, are key potential mechanisms of action in the prevention of gastrointestinal disorders. While the debate of the effectiveness of vitamin D to treat bone pathologies continues, the clinical importance of vitamin D therapy to prevent gastrointestinal disorders should be investigated given current evidence, using both nutritional and pharmaceutical intervention approaches.

Impact statement

The non-skeletal functions of vitamin D play an important role in health and disease. The anti-inflammatory properties and maintenance of intestinal function fulfilled by vitamin D impact other systems in the body though downstream processing. This review provides insight into the mechanisms underpinning the potential benefits of vitamin D in both maintaining intestinal homeostasis and associated diseased states.

Impact of Genes and the Environment on the Pathogenesis and Disease Course of Inflammatory Bowel Disease

Crohn's disease and ulcerative colitis constitute two major subgroups of inflammatory bowel diseases (IBD), a group of complex polygenic diseases characterized by chronic and progressive inflammation in the gastrointestinal tract. In recent years, methodological advances in genetic analysis have greatly expanded our understanding of the genetic background of IBD. So far, more than 240 genetic risk loci have been identified for IBD. However, these risk alleles explain less than 30% of the susceptibility to disease development, suggesting that environmental factors contribute considerably. The increasing occurrence of IBD in Eastern countries following their 'westernization', as well as the increased risk of disease among those who migrate to high-incidence regions, also suggest that the environment is key in the pathogenesis of IBD. In this review, we summarize the current evidence on the role of genetic and environmental factors in the susceptibility to, and disease course of, IBD, and we suggest how these findings might be applied to clinical practice.

Diet as Adjunctive Treatment for Inflammatory Bowel Disease: Review and Update of the Latest Literature

PURPOSE OF REVIEW

Diet plays an integral role in development of inflammatory bowel disease (IBD) and continues to act as a mediator of intestinal inflammation once disease sets in. Most clinicians provide little dietary guidance to IBD patients, in part due to lack of knowledge in nutrition and lack of available nutritional resources. The purpose of this review is to provide clinicians with a brief summary of the latest evidence behind diets popular among IBD patients, to highlight diets with known efficacy, and to provide guidance that may help busy practitioners.

RECENT FINDINGS

The latest studies show that exclusive enteral nutrition (EEN) remains the most effective diet for induction of remission in Crohn's disease (CD), either in the form of elemental, semi-elemental, or polymeric formulas. Recent studies also show that EEN can be useful in complicated CD including in enterocutaneous fistulas closure and to optimize nutrition in the pre-operative setting. Although new studies suggest that partial enteral nutrition supplemented with elimination diets may be beneficial in ulcerative colitis (UC) and CD, larger controlled studies are needed to support their use. The autoimmune diet also shows promise but lacks larger studies. Recent uncontrolled clinical studies evaluating the specific carbohydrate diet (SCD) suggest that this diet may improve biochemical markers of inflammation and induce mucosal healing, although larger studies are needed to support its use, especially because the SCD is very restrictive. Short-term use of the low FODMAP diet is appropriate when in the setting of an acute flare up and/or in stricturing disease, but long-term restriction of FODMAPs is not recommended given long-term changes observed in the microbiome. Recent studies suggest that avoidance of processed foods, packaged with preservatives and emulsifiers, may be important in decreasing intestinal inflammation; many of the recent popular diets share a common concept, avoidance of processed foods. In this review of the latest literature, we highlight that dietary studies are still in a rudimentary stage. Large prospective randomized control studies are underway evaluating head to head comparisons on the efficacy of some of these diets. We offer general guiding principles that may help gastroenterologists in the meantime.

Seasonal variability of vitamin D status in patients with inflammatory bowel disease - A retrospective cohort study

Objectives

Vitamin D deficiency predicts unfavorable disease outcomes in inflammatory bowel disease. Endogenous vitamin D synthesis is affected by seasonal factors including sunlight exposure, raising the question whether seasonality determines the risk of vitamin D deficiency and may mask other clinical risk factors.

Methods

Univariable and multiple regression analyses were performed in a retrospective cohort of 384 patients to determine risk factors for vitamin D deficiency. Since the observed 25-hydroxyvitamin D [25(OH)D] concentrations followed a sinusoidal pattern over the year, all 25(OH)D concentrations were normalized for the predicted variability of the respective day of analysis based on a sinusoidal regression analysis of 25(OH)D test results obtained in more than 86,000 control serum samples.

Results

Vitamin D deficiency was highly prevalent in patients with Crohn’s disease or ulcerative colitis (63% and 55%, respectively) and associated with winter/spring seasons. After normalization of 25(OH)D concentrations for the day of analysis, vitamin D deficiency was associated with histories of complications related to inflammatory bowel disease, surgery, smoking and ongoing diarrhea while initial disease manifestation during adulthood, ongoing vitamin D supplementation and diagnosis of ulcerative colitis vs. Crohn’s disease appeared to be protective. Multiple regression analyses revealed that vitamin D deficiency was associated with disease activity in Crohn’s disease and anemia in ulcerative colitis patients. Only few deficient patients achieved sufficient 25(OH)D concentrations over time. However, increasing 25(OH)D concentrations correlated with improved Crohn’s disease activity.

Conclusions

Vitamin D deficiency was highly prevalent in patients with Crohn’s disease and ulcerative colitis and dependent on the season of the year. Following normalization for seasonality by sinusoidal regression analysis, vitamin D deficiency was found to be associated with parameters of complicated disease course while increasing 25(OH)D concentrations over time correlated with reduced activity of Crohn’s disease.

The vitamin D positive feedback hypothesis of inflammatory bowel diseases

While it appears that there are a variety of factors that exacerbate IBD, it is frustrating that symptoms can persist and worsen even when environmental insults are removed. We suggest that there may be a positive feedback loop which perpetuates the inflammatory response in IBD patients. The loop is triggered by vitamin D deficiency which reduces calcium uptake. Lowered vitamin D and calcium interfere with anti-inflammatory pathways. Inflammation of the mucosa inhibits absorption of calcium and thus perpetuates the reduced anti-inflammatory response. A number of predictions follow from this hypothesis and are supported by geographic and lifestyle patterns in IBD incidence and prevalence.

The Role of Vitamin D in Inflammatory Bowel Disease: Mechanism to Management

Vitamin D has been linked to human health benefits that extend far beyond its established actions on calcium homeostasis and bone metabolism. One of the most well studied facets of extra-skeletal vitamin D is its activity as an immuno-modulator, in particular its potent anti-inflammatory effects. As a consequence, vitamin D deficiency has been associated with inflammatory diseases including inflammatory bowel disease (IBD). Low serum levels of the major circulating form of vitamin D, 25-hydroxyvitamin D (25-OH-D) are significantly more prevalent in patients with IBD, particularly in the winter and spring months when UV-induced synthesis of vitamin D is lower. Dietary malabsorption of vitamin D may also contribute to low serum 25(OH)D in IBD. The benefits of supplementation with vitamin D for IBD patients are still unclear, and improved vitamin D status may help to prevent the onset of IBD as well as ameliorating disease severity. Beneficial effects of vitamin D in IBD are supported by pre-clinical studies, notably with mouse models, where the active form of vitamin D, 1,25-dihydroxyvitamin D (1,25-(OH)2D) has been shown to regulate gastrointestinal microbiota function, and promote anti-inflammatory, tolerogenic immune responses. The current narrative review aims to summarise the different strands of data linking vitamin D and IBD, whilst also outlining the possible beneficial effects of vitamin D supplementation in managing IBD in humans.

Factors affecting vitamin D deficiency in active inflammatory bowel diseases

BACKGROUND

Hypovitaminosis D is prevalent in inflammatory bowel disease (IBD) and may be associated with disease activity.

AIM

This study evaluated vitamin D (VitD) status in an Italian cohort of IBD patients, not taking VitD supplementation. We investigated risk factors for VitD deficiency and its correlation with disease activity.

METHODS

VitD levels were measured in 300 consecutive outpatients (42% with Crohn's Disease (CD) and 58% with ulcerative colitis (UC), 56% male) from a tertiary referral center. Data from the IBD cohort were compared with those of 234 healthy controls, matched by sex, age, and the month in which VitD levels were measured.

RESULTS

The mean VitD level in IBD patients was significantly lower than in controls (18.9 ng/ml vs. 25 ng/ml, p < 0.001) when accounting for gender, age, and season. VitD deficiency was present in 62% of IBD patients. Risk factors for deficiency were: age <40 and ≥60 years, winter, previous surgery, C-reactive protein (CRP) ≥0.5 mg/dl, and erythrocyte sedimentation rate ≥20 mm/h. In multivariate analysis, VitD levels were negatively influenced by disease location and CRP in UC.

CONCLUSIONS

Although VitD deficiency was more prevalent than expected in healthy controls living in a Mediterranean country not at high risk of hypovitaminosis D, it was more common and severe in IBD patients. This study also found an association between VitD status and disease activity.

Systematic review with meta-analysis: risk of post-operative complications associated with pre-operative exposure to anti-tumour necrosis factor agents for Crohn's disease

BACKGROUND

Post-operative complications after anti-tumour necrosis agent treatment for Crohn's disease (CD) have been analysed with conflicting results.

AIM

To assess the effects of pre-operative anti-tumour necrosis factor (TNF) therapy on post-operative complications within 30 days post-operatively in patients with CD undergoing abdominal surgery.

METHODS

Systematic review with meta-analysis was performed on articles found in MEDLINE, Embase, Cochrane Library, Scopus, and the International Clinical Trials Registry Platform until September 2018.

RESULTS

Twenty studies (7115 patients) were included. Without confounder adjustment, pre-operative anti-TNF therapy in patients with CD undergoing abdominal surgery was associated with increased rates of infectious complications (unadjusted odds ratio, OR, 1.49; 95% CI, 1.08-2.06). After confounder adjustment, Pre-operative anti-TNF therapy was significantly associated with both increased rates of total and infectious complications (adjusted OR, 1.53 and 2.09; 95% CI, 1.11-2.09 and 1.19-3.65, respectively). After subgroup analyses, the association between anti-TNF agents and total complications was significant in high incidence countries (adjusted OR, 1.86; 95% CI, 1.43-2.42) but not in low incidence countries (adjusted OR, 0.77; 95% CI, 0.48-1.25).

CONCLUSIONS

Exposure to anti-TNF agents is an independent risk factor for post-operative infectious complications in patients with CD, especially in countries with a high incidence of Crohn's disease. We suggest postponing elective surgery or carefully monitoring these patients post-operatively.

Impact of red meat, processed meat and fibre intake on risk of late-onset chronic inflammatory diseases: prospective cohort study on lifestyle factors using the Danish 'Diet, Cancer and Health' cohort (PROCID-DCH): protocol

INTRODUCTION

Chronic inflammatory diseases (CIDs) (Crohn's disease, ulcerative colitis, psoriasis, psoriatic arthritis, rheumatoid arthritis and multiple sclerosis) are diseases of the immune system that have some shared genetic and environmental predisposing factors, but still few studies have investigated the effects of lifestyle on disease risk of several CIDs. The primary aim of this prospective cohort study is to investigate the impact of fibre, red meat and processed meat on risk of late-onset CID, with the perspective that results of this study can contribute in supporting future diet recommendations for effective personalised prevention.

METHODS AND ANALYSIS

The study will use data from 57 053 persons from the prospective Danish cohort study 'Diet, Cancer and Health' together with National Health Registry data. The follow-up period is from December 1993 to December 2018. Questionnaire data on diet and lifestyle were collected at entry to the Diet, Cancer and Health study. The outcome CID is defined as having a diagnosis of one of the CIDs registered in the National Patient Registry or, for multiple sclerosis, in the Danish Multiple Sclerosis Registry during follow-up and being treated with a drug used for the specific disease. The major outcome of the analyses will be to detect variability in risk of late onset of any CID and, if power allows, disease risk of late onset of each CID diagnosis between persons with different fibre and red meat, and processed meat intake. The outcome will be adjusted for age, sex, body mass index, physical activity, energy, alcohol, fermented dairy products, education, smoking status, hormone replacement therapy and comorbidity.

ETHICS AND DISSEMINATION

The study is approved by the Danish Data Protection Agency (2012-58-0018). The core study is an open register-based cohort study. The study does not need approval from the Ethics committee or Institutional Review Board by Danish law. Study findings will be disseminated through peer-reviewed journals, patient associations and presentations at international conferences.

TRIAL REGISTRATION NUMBER

NCT03456206; Post-results.

1,25(OH)2D3 deficiency-induced gut microbial dysbiosis degrades the colonic mucus barrier in Cyp27b1 knockout mouse model

Background

The relationship between disturbances of the gut microbiota and 1,25(OH)₂D₃ deficiency has been established both in humans and animal models with a vitamin D poor diet or a lack of sun exposure. Our prior study has demonstrated that Cyp27b1^−/− (Cyp27b1 knockout) mice that could not produce 1,25(OH)₂D₃ had significant colon inflammation phenotypes. However, whether and how 1,25(OH)₂D₃ deficiency due to the genetic deletion controls the gut homeostasis and modulates the composition of the gut microbiota remains to be explored.

Results

1,25(OH)₂D₃ deficiency impair the composition of the gut microbiota and metabolite in Cyp27b1^−/− mice, including Akkermansia muciniphila, Solitalea Canadensis, Bacteroides-acidifaciens, Bacteroides plebeius and SCFA production. 1,25(OH)₂D₃ deficiency cause the thinner colonic mucus layer and increase the translocation of the bacteria to the mesenteric lymph nodes. We also found 1,25(OH)₂D₃ supplement significantly decreased Akkermansia muciniphila abundance in fecal samples of Cyp27b1^−/− mice.

Conclusion

Deficiency in 1,25(OH)₂D₃ impairs the composition of gut microbiota leading to disruption of intestinal epithelial barrier homeostasis and induction of colonic inflammation. This study highlights the association between 1,25(OH)₂D₃ status, the gut microbiota and the colonic mucus barrier that is regarded as a primary defense against enteric pathogens.

Influence of Environmental Factors in the Development and Outcomes of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), which mainly comprises Crohn's disease (CD) and ulcerative colitis (UC), is a term for chronic inflammatory diseases of the gut arising due to a dysregulated immune response to a dysbiotic gut microbiome on a background of genetic predisposition. However, genetics explains a small fraction of risk, and the external environment plays a large and important role in disease pathogenesis and natural history. Cigarette smoking, one of the earliest- and most-studied risk factors, increases the risk of CD onset and is associated with severe disease. In contrast, although smoking cessation increases the risk of UC onset and relapse, current smoking appears to be protective. Appendectomy is inversely associated with the risk of UC. Various dietary factors may influence risk of IBD, including an inverse association with dietary fiber. Exclusion diets have anecdotal reports of efficacy but lack evidence from rigorous clinical trials. Psychosocial factors such as depression, stress, and sleep disturbance play a role in onset as well as in determining natural history. There is an important need for rigorous studies robustly informing the association and mechanism(s) of influence of the external environment on IBD risk and for clinical trials examining the efficacy of alteration of the environment in ameliorating the course of IBD.

Identification of Recent Trends in Research on Vitamin D: A Quantitative and Co-Word Analysis

Background

In recent years, many studies on vitamin D have been published. We combed these data for hot spot analyses and predicted future research topic trends.

Material/Methods

Articles (4625) concerning vitamin D published in the past 3 years were selected as a study sample. Bibliographic Items Co-occurrence Matrix Builder (BICOMB) software was used to screen high-frequency Medical Subject Headings (MeSH) terms and construct a MeSH terms-source article matrix and MeSH terms co-occurrence matrix. Then, Graphical Clustering Toolkit (gCLUTO) software was employed to analyze the matrix by double-clustering and visual analysis to detect the trends on the subject.

Results

Ninety high-frequency major MeSH terms were obtained from 4625 articles and divided into 5 clusters, and we generated a visualized matrix and a mountain map. Strategic coordinates were established by the co-occurrence matrix of the MeSH terms based on the above classification, and the 5 clusters described above were further divided into 7 topics. We classified the vitamin D-related diseases into 12 categories and analyzed their distribution.

Conclusions

The analysis of strategic coordinates revealed that the epidemiological study of vitamin D deficiency and vitamin D-related diseases is a hot research topic. The use of vitamin D in the prevention and treatment of some diseases, especially diabetes, was found to have a significant potential future research value.

Development and validation of a web-based questionnaire to identify environmental risk factors for inflammatory bowel disease: the Groningen IBD Environmental Questionnaire (GIEQ)

BACKGROUND

In the complex etiology of inflammatory bowel disease (IBD), the exposome is a major contributor. Though many environmental exposures have been identified, quality of evidence varies greatly and overall evidence for the exposome is inconclusive. A universal, precise, and reproducible measurement tool is needed to study the exposome in IBD.

METHODS

We built the web-based Groningen IBD Environmental Questionnaire (GIEQ), an extensive and structured questionnaire measuring potentially involved environmental exposures, consisting of 848 items, subdivided into 15 categories. For validation, 76 IBD patients completed the GIEQ twice (2-month interval). Cohen's kappa and correlation coefficients were used to compare both fills. Internal consistency was evaluated using Cronbach's alpha tests. Proportional bias was examined using Bland-Altman plots.

RESULTS

In general, we obtained a mean kappa coefficient of 0.78 (standard deviation 0.17) for categorical questions and a mean intraclass correlation coefficient of 0.88 (0.15) for numeric questions. Cronbach's alpha ranged from 0.64 to 1.0 with a mean of 0.79 (0.14). Bland-Altman plots showed proportional bias only for current physical activity score.

CONCLUSIONS

The GIEQ is a reliable measurement tool to study the exposome in IBD, enabling consistent measurement of an extended number of environmental factors and their interactions. Use of the GIEQ across IBD cohorts will lead to more standardized, generalizable, and comparable results. Also, the GIEQ can be used for calculation of an exposome risk score, applicable for secondary prevention by identifying high-risk patients as well as to analyze interactions between the exposome and other aspects of IBD etiology.

The Role of Vitamin D in Elderly Inflammatory Bowel Disease Patients

The role of vitamin D has long been discussed in many chronic diseases, and its significance in inflammatory bowel disease has recently gained attention. This article reviews vitamin D homeostasis, the involvement of vitamin D in the pathophysiology of inflammatory bowel disease, and vitamin D deficiency as a result of inflammatory bowel disease. In addition, this article explores the possibility of age, specifically in the elderly population, as a risk factor for developing vitamin D deficiency in patients with inflammatory bowel disease.

Single high-dose oral vitamin D3 treatment in New Zealand children with inflammatory bowel disease

BACKGROUND

High-dose oral vitamin D (stoss) is a novel treatment in children with inflammatory bowel disease (IBD). Vitamin D supplementation may have benefits in IBD beyond bone health including reduced disease activity and improvements in inflammatory markers. The aim of this study was to retrospectively assess the efficacy, safety and impact on disease activity of single oral high-dose vitamin D3 therapy in New Zealand (NZ) children with IBD and vitamin D deficiency.

METHODS

In this retrospective chart review, children with IBD and vitamin D deficiency [serum 25-OH vitamin D level (25-OHD) <50 nmol/L] in Christchurch, NZ, who were managed with single high-dose vitamin D3 therapy were identified. Measurements of serum 25-OHD, calcium and standard serum inflammatory markers prior to and up to 6 months following stoss therapy were extracted from patient records. Disease activity was also defined using the Pediatric Crohn's Disease (CD) Activity Index (PCDAI) at time points before and 3 months following stoss.

RESULTS

Twenty-eight doses of stoss were given to 23 children, aged 3-16 years. Mean 25-OHD levels increased after stoss therapy from 39 nmol/L (95% CI: 37-42 nmol/L) at baseline to 189 nmol/L (148-231 nmol/L) at 1-2 months (P<0.001). All children with 1 month levels measured achieved 25-OHD >75 nmol/L. One child had a serum calcium of 2.7 (normal range, 2.2 to 2.6 mmol/L) 2 weeks after treatment, which normalized on repeat testing 10 days later. PCDAI scores, mean platelet count, erythrocyte sedimentation rate (ESR) and C reactive protein (CRP) all reduced significantly from baseline to 3 months following stoss therapy.

CONCLUSIONS

Single high-dose oral vitamin D therapy was used successfully and safely to manage vitamin D deficiency in these children with IBD. An improvement in inflammatory markers and disease activity scores also occurred following stoss therapy.

A New Model Based on 25-Hydroxyvitamin D3 for Predicting Active Crohn's Disease in Chinese Patients

Background

The association between vitamin D3 and activity of Crohn's disease (CD) is unclear in Chinese patients. In this study, we aimed to evaluate the correlations between serum levels of 25-hydroxyvitamin D3 (25(OH)D3) and disease activity and predict active disease based on vitamin D status.

Methods

Between January 2014 and December 2017, 346 CD patients from the First Affiliated Hospital of Sun Yat-sen University were recruited and categorized into a group with 25(OH)D3 ≤ 20 ng/ml and a group with 25(OH)D3 > 20 ng/ml. The clinical characteristics, medication, and health-care needs were compared between the groups. The correlations among 25(OH)D3 and routine serum biomarkers and disease activity were examined. The predictive efficiency of 25(OH)D3 and other biomarkers for active diseases was also explored using receiver-operating characteristic (ROC) curve analysis. A new predictive model, −(5^∗25(OH)D3 + 2^∗Hb) + ESR, and a nomogram were established using Logistic Regression.

Results

Patients with 25(OH)D3 ≤ 20 ng/ml had higher serum levels of C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and platelets (PLT) and lower levels of hemoglobin (Hb) and albumin (ALB). Serum levels of 25(OH)D3 were inversely correlated with the score of Crohn's Disease Activity Index (CDAI) (r_s = −0.608). ROC analysis showed a better predictive value of −25(OH)D3 and the new model with areas under curve (AUC) of 0.804 and 0.879, respectively, than those of CRP (0.693) and ESR (0.713) in disease activity. A nomogram for prediction was established with a c-index of 0.882.

Conclusions

Serum levels of 25(OH)D3 negatively correlated with CD activity in Chinese patients. The new model and a nomogram based on 25(OH)D3 showed a better efficiency in predicting disease activity in CD patients but warrants further study.

Vitamin D deficiency is associated with hepatic decompensation and inflammation in patients with liver cirrhosis: A prospective cohort study

Background

Vitamin D is required to maintain the integrity of the intestinal barrier and inhibits inflammatory signaling pathways.

Objective

Vitamin D deficiency might be involved in cirrhosis-associated systemic inflammation and risk of hepatic decompensation in patients with liver cirrhosis.

Methods

Outpatients of the Hepatology Unit of the University Hospital Frankfurt with advanced liver fibrosis and cirrhosis were prospectively enrolled. 25-hydroxyvitamin D (25(OH)D₃) serum concentrations were quantified and associated with markers of systemic inflammation / intestinal bacterial translocation and hepatic decompensation.

Results

A total of 338 patients with advanced liver fibrosis or cirrhosis were included. Of those, 51 patients (15%) were hospitalized due to hepatic decompensation during follow-up. Overall, 72 patients (21%) had severe vitamin D deficiency. However, patients receiving vitamin D supplements had significantly higher 25(OH)D₃ serum levels compared to patients without supplements (37 ng/mL vs. 16 ng/ml, P<0.0001). Uni- and multivariate analyses revealed an independent association of severe vitamin D deficiency with the risk of hepatic decompensation during follow-up (multivariate P = 0.012; OR = 3.25, 95% CI = 1.30–8.2), together with MELD score, low hemoglobin concentration, low coffee consumption, and presence of diabetes. Of note, serum levels of C-reactive protein, IL-6 and soluble CD14 were significantly higher in patients with versus without severe vitamin D deficiency, and serum levels of soluble CD14 levels declined in patients with de novo supplementation of vitamin D (median 2.15 vs. 1.87 ng/mL, P = 0.002).

Conclusions

In this prospective cohort study, baseline vitamin D levels were inversely associated with liver-cirrhosis related systemic inflammation and the risk of hepatic decompensation.

The Impact of Inflammatory Bowel Disease in Canada 2018: Epidemiology

Canada has among the highest incidence and prevalence of inflammatory bowel disease (IBD) in the world. After decades of rising incidence of IBD in Canada during the 20th Century, the prevalence of IBD in 2018 is 0.7% of the Canadian population. Forecasting models predict that prevalence of IBD will continue to rise to 1.0% of the population by 2030. In 2018, the number of Canadians living with IBD is approximately 270,000 and is predicted to rise to 403,000 Canadians in 2030. Inflammatory bowel disease affects all age groups with adolescents and young adults at highest risk of diagnosis. Canadians of all ethnicities are being diagnosed with IBD including known high-risk groups such as Ashkenazi Jews and offspring of South Asian immigrants who were previously thought to be low risk. Moreover, IBD has evolved into a global disease with rising incidence in newly industrialized countries in Asia and South America. The causes of IBD remain unsolved; however, the high rates of disease in Western countries and its emergence in newly industrialized countries suggest that environmental factors associated with urbanization, modernization, or Western diets may be pertinent to understanding the pathogenesis of the disease.

Highlights

1. Canada continues to have among the highest prevalence of IBD in the world.

2. Today, approximately 270,000 Canadians live with IBD. By 2030 it is estimated that nearly 403,000 Canadians will have a diagnosis of IBD.

3. Inflammatory bowel disease has become a worldwide disease with increasing rates in Asia, Africa, and South America—continents where IBD was rarely diagnosed prior to 1990.

4. The causes of IBD are unknown, but the high rates of disease over the past 60 years in Western countries and the emergence of disease in developing countries suggest that factors associated with urbanization, modernization, or Western diets may be pertinent to understanding the pathogenesis of the disease.

5. Many of the leading hypotheses as to the causes of IBD tie in with alteration of the gut microbiome, the suite of organisms that reside in the bowel and maintain bowel health throughout life.

Key Summary Points

1. The incidence (the number of new diagnoses annually) of IBD rose throughout the 20th century in Canada and then stabilized at the turn of the 21st century.

2. The prevalence (the total number of diagnosed persons in the population) of IBD in Canada is among the highest in the world.

3. Today, 270,000 (0.7%, or 7 in 1000) Canadians are estimated to live with IBD. By 2030, that number is expected to rise to 403,000 Canadians (1% or 1 in 100).

4. Inflammatory bowel disease can be diagnosed at any age. However, the age groups that are most likely to be diagnosed are adolescents and young adults from 20 to 30 years of age.

5. Inflammatory bowel disease in Canada affects the lives of Canadians of all ethnicities, including known high-risk groups such as Ashkenazi Jews, and those thought previously to be at low risk, such as first-generation offspring of South Asian immigrants.

6. Canadian health policy makers will need to prepare the Canadian health care system for the rising burden of IBD.

7. As newly industrialized countries in Asia, Africa, and South America are transitioning to a Westernized society, IBD has emerged and its incidence in these countries is rising rapidly.

8. The gut microbiome includes microorganisms that maintain digestive health. Thus, changes in the microbiome, which may change the immune system’s response to triggers, may be important in initiating and perpetuating IBD.

9. A number of factors can alter the gut microbiome and early childhood may be a particularly important time such that breastfeeding, early life diet, use of antibiotics, infections, and other environmental exposures may impact the gut microbiome in such a way that facilitates developing IBD.

10. Smoking is associated with an increased risk and worsening disease course of Crohn’s disease. Quitting smoking is associated with an increased risk of developing ulcerative colitis. Therefore, never initiating smoking can mitigate the risk for IBD. Educational programs aimed at those at-risk for IBD should emphasize the risk of starting to smoke tobacco.

11. Modifying exposure to environmental risk factors associated with the Westernization of society (e.g., Western diet and lifestyles) may provide an avenue for reducing the risk of IBD in Canada and worldwide.

Gaps in Knowledge and Future Directions

1. While the incidence of IBD appears to be stabilizing in some regions in Canada, IBD may be occurring more frequently in certain populations such as in children, South Asians, Ashkenazi Jews, and immigrants. Future research should focus on the changing demographics of IBD in Canada.

2. The prevalence of IBD will rise steadily over the next decade. To enable better health care system planning and to respond adequately to the increasing burden of IBD, ongoing surveillance of the epidemiology and health services utilization of IBD in Canada is necessary.

3. Most studies have focused on the mortality associated with IBD. Future research is necessary to assess health-adjusted life expectancy and overall life expectancy for those living with IBD.

4. Analyses of resources, infrastructure, and personnel need to be modeled into the future in order to prepare our health care system for the rising burden of IBD.

5. Research on the interaction between genes, microbes, and our environment will inform our understanding of the pathogenesis of IBD, information necessary to prevent IBD in the future.

Vitamin D deficiency in a European inflammatory bowel disease inception cohort: an Epi-IBD study

BACKGROUND

Serum vitamin D level is commonly low in patients with inflammatory bowel disease (IBD). Although there is a growing body of evidence that links low vitamin D level to certain aspects of IBD such as disease activity and quality of life, data on its prevalence and how it varies across disease phenotype, smoking status and treatment groups are still missing.

MATERIALS AND METHODS

Patients diagnosed with IBD between 2010 and 2011 were recruited. Demographic data and serum vitamin D levels were collected. Variance of vitamin D level was then assessed across different treatment groups, disease phenotype, disease activity and quality of life scores.

RESULTS

A total of 238 (55.9% male) patients were included. Overall, 79% of the patients had either insufficient or deficient levels of vitamin D at diagnosis. Patients needing corticosteroid treatment at 1 year had significantly lower vitamin D levels at diagnosis (median 36.0 nmol/l) (P=0.035). Harvey-Bradshaw Index (P=0.0001) and Simple Clinical Colitis Activity Index scores (P=0.0001) were significantly lower in patients with higher vitamin D level. Serum vitamin D level correlated significantly with SIBQ score (P=0.0001) and with multiple components of SF12. Smokers at diagnosis had the lowest vitamin D levels (vitamin D: 34 nmol/l; P=0.053).

CONCLUSION

This study demonstrates the high prevalence of low vitamin D levels in treatment-naive European IBD populations. Furthermore, it demonstrates the presence of low vitamin D levels in patients with IBD who smoke.

From Colitis to Cancer: An Evolutionary Trajectory That Merges Maths and Biology

Patients with inflammatory bowel disease have an increased risk of developing colorectal cancer, and this risk is related to disease duration, extent, and cumulative inflammation burden. Carcinogenesis follows the principles of Darwinian evolution, whereby somatic cells acquire genomic alterations that provide them with a survival and/or growth advantage. Colitis represents a unique situation whereby routine surveillance endoscopy provides a serendipitous opportunity to observe somatic evolution over space and time in vivo in a human organ. Moreover, somatic evolution in colitis is evolution in the ‘fast lane': the repeated rounds of inflammation and mucosal healing that are characteristic of the disease accelerate the evolutionary process and likely provide a strong selective pressure for inflammation-adapted phenotypic traits. In this review, we discuss the evolutionary dynamics of pre-neoplastic clones in colitis with a focus on how measuring their evolutionary trajectories could deliver a powerful way to predict future cancer occurrence. Measurements of somatic evolution require an interdisciplinary approach that combines quantitative measurement of the genotype, phenotype and the microenvironment of somatic cells–paying particular attention to spatial heterogeneity across the colon–together with mathematical modeling to interpret these data within an evolutionary framework. Here we take a practical approach in discussing how and why the different “evolutionary ingredients” can and should be measured, together with our viewpoint on subsequent translation into clinical practice. We highlight the open questions in the evolution of colitis-associated cancer as a stimulus for future work.

Low Sun Exposure and Vitamin D Deficiency as Risk Factors for Inflammatory Bowel Disease, With a Focus on Childhood Onset

The incidence and prevalence of inflammatory bowel disease (IBD) are increasing worldwide. Some ecological studies show increasing incidence with increasing latitude. Ambient ultraviolet radiation varies inversely with latitude, and sun exposure of the skin is a major source of vitamin D. Vitamin D deficiency is common in patients with IBD. Sun exposure and vitamin D have immune effects that could plausibly reduce, or be protective for, IBD. One quarter of new IBD cases are diagnosed in childhood or adolescence, but most research is for adult-onset IBD. Here, we review the evidence for low sun exposure and/or vitamin D deficiency as risk factors for IBD, focusing where possible on pediatric IBD, where effects of environmental exposures may be clearer. The literature provides some evidence of a latitude gradient of IBD incidence, and evidence for seasonal patterns of timing of birth or disease onset is inconsistent. High prevalence of vitamin D deficiency occurs in people with IBD, but cannot be interpreted as being a causal risk factor. Evidence of vitamin D supplementation affecting disease activity is limited. Further research on predisease sun exposure and well-designed supplementation studies are required to elucidate whether these potentially modifiable exposures are indeed risk factors for IBD.

Vitamin D and Inflammatory Bowel Disease: Mendelian Randomization Analyses in the Copenhagen Studies and UK Biobank

CONTEXT

Vitamin D may be a modifiable risk factor for inflammatory bowel disease (IBD).

OBJECTIVES

We tested the hypothesis that plasma 25-hydroxyvitamin D levels are causally associated with risk of Crohn disease (CD) and ulcerative colitis (UC).

DESIGN, SETTING, PATIENTS, AND INTERVENTIONS

We used a Mendelian randomization design to study 120,013 individuals from the Copenhagen City Heart Study, the Copenhagen General Population Study, and a Copenhagen-based cohort of patients with IBD. Of these, 35,558 individuals had plasma 25-hydroxyvitamin D measurements available, and 115,110 were genotyped for rs7944926 and rs11234027 in DHCR7 and rs10741657 and rs12794714 in CYP2R1, all variants associated with plasma 25-hydroxyvitamin D levels. We identified 653 cases of CD and 1265 cases of UC, of which 58 and 113, respectively, had 25-hydroxyvitamin D measurements available. We also included genetic data from 408,455 individuals from the UK Biobank, including 1707 CD cases and 3147 UC cases.

MAIN OUTCOME MEASURE

Hazard ratios for higher plasma 25-hydroxyvitamin D levels.

RESULTS

The multivariable-adjusted hazard ratios for 10 nmol/L higher 25-hydroxyvitamin D level were 1.04 (95% CI: 0.93 to 1.16) for CD and 1.13 (95% CI: 1.06 to 1.21) for UC. A combined 25-hydroxyvitamin D allele score was associated with a 1.4-nmol/L increase in plasma 25-hydroxyvitamin D level and hazard ratios of 0.98 (95% CI: 0.94 to 1.03) for CD and 1.01 (95% CI: 0.97 to 1.05) for UC. Combining genetic data from the Copenhagen studies and the UK Biobank, genetically determined vitamin D did not appear to influence the risk of CD or UC.

CONCLUSIONS

Our results do not support a major role for vitamin D deficiency in the development of IBD.

Vitamin D receptor FokI polymorphism and the risks of colorectal cancer, inflammatory bowel disease, and colorectal adenoma

Based on an inverse association between vitamin D levels and the risks of colorectal diseases, a functional start codon polymorphism in the vitamin D receptor (VDR) gene is speculated to affect the risks for these diseases. To validate this hypothesis, we first conducted a case-control study of 695 colorectal cancer patients and 1,397 controls. The association of VDR FokI polymorphism with colorectal cancer risk was analyzed using a logistic regression model. In the present case-control study, compared to the F allele, the f allele seemed to be associated with lower risks of colon cancer and advanced colorectal cancer. Additionally, a meta-analysis of 27 studies was conducted to combine findings from previous studies investigating the association of FokI polymorphism with colorectal disease using a random effects model. In the present meta-analysis, the f allele was positively associated with the risk of inflammatory bowel disease, including Crohn’s disease and ulcerative colitis. However, this allele was inversely associated with colon cancer and was not associated with the risk of rectal cancer or colorectal adenoma. In conclusion, the findings from this study imply that the role of VDR FokI polymorphism may differ based on the type and severity of colorectal disease.

Vitamin D, the gut microbiome and inflammatory bowel disease

Vitamin D has an important role in bone metabolism but recently has been recognized as an immunoregulator, and this has led to investigations on the effect of Vitamin D supplementation in various autoimmune diseases and its anti-inflammatory effects. There is some evidence that Vitamin D can regulate gastrointestinal inflammation. In addition, previous studies have shown that Vitamin D can affect the gut microbiome. The aim of this review is to evaluate the effect of Vitamin D on inflammatory processes, especially its relation to the inflammatory bowel disease (IBD) and gut microbiome. There is some evidence that Vitamin D can regulate gastrointestinal inflammation, with epidemiological studies showing that individuals with higher serum Vitamin D have a lower incidence of IBD, particularly Crohn's disease. Vitamin D changes transcription of cathelicidin and DEFB4 (defensin, beta 4) that can affect the gut microbiome. Several cell types of the immune system express Vitamin D receptor, and hence the use of Vitamin D in immune regulation has some potential. Furthermore, Vitamin D deficiency leads to dysbiosis of gut microbiome and reported to cause severe colitis. Vitamin D supplementation is low cost and available and can be a therapeutic option.

Phenotype and Clinical Course of Inflammatory Bowel Disease With Co-existent Celiac Disease

BACKGROUND AND AIMS

Inflammatory bowel diseases, principally Crohn's disease and ulcerative colitis, and celiac disease are among the most common immune-mediated gastrointestinal diseases. We aim to elucidate the clinical course and outcomes of patients with concomitant inflammatory bowel disease and celiac disease, a unique population that remains scarcely studied to date.

METHODS

A retrospective matched case-control study of adults with co-existent inflammatory bowel disease [IBD] and celiac disease was performed at a tertiary referral institution in North America. Logistic regression and Kaplan-Meier curves compared disease characteristics and clinical outcomes of the two groups.

RESULTS

A total of 342 inflammatory bowel disease patients were included in this study, of whom 114 had co-existent celiac disease and 228 did not. Patients with co-existent inflammatory bowel disease and celiac disease had higher rates of primary sclerosing cholangitis [19.3% vs 5.7%; odds ratio, 4.4; 95% confidence interval, 2.1-9.4; p <0.001], extensive ulcerative colitis [78.1% vs 59.0%; odds ratio, 2.8; 95% confidence interval, 1.5-5.5; p =0.002], and family history of celiac disease [10.5% vs 3.5%; odds ratio 3.2; 95% confidence interval, 1.3-8.2; p =0.01], compared with patients without concomitant celiac disease.

CONCLUSIONS

Patients with inflammatory bowel disease with concomitant celiac disease have unique phenotypic features compared with non-celiac inflammatory bowel disease, with higher risks for colitis-related hospitalisations, extensive colitis, and primary sclerosing cholangitis. Increased recognition of co-existent IBD and celiac disease can prompt clinicians to investigate for concomitant disease sooner, particularly in patients with seemingly refractory disease.

The role of UVR and vitamin D on T cells and inflammatory bowel disease

Vitamin D deficiency is associated with the development of inflammatory bowel disease (IBD). In experimental IBD the targets of vitamin D that result in protection from IBD include gut epithelial cells, innate immune cells, T cells, and the microbiota. Ultraviolet radiation (UVR) induces production of vitamin D in the skin and suppresses T cell responses in the host. There is limited data demonstrating an effect of UVR on experimental IBD but the mechanisms of UVR suppression in IBD have not been defined. There are several shared effects of vitamin D and UVR on T cells including inhibition of proliferation and suppression of IFN-γ and IL-17 producing T cells. Conversely UVR decreases and vitamin D increases IL-4 production from T cells. Together the data suggest that UVR suppression of T cells and potentially IBD are both vitamin D dependent and independent.

Role of Vitamin D in the Natural History of Inflammatory Bowel Disease

Inflammatory bowel disease [IBD], including ulcerative colitis and Crohn's disease, is a chronic and unpredictable condition characterised by alternating periods of remission interspersed with relapses. In recent years, accumulating support for an immunomodulating effect of vitamin D on both the innate and the adaptive immune systems has been presented. Through the vitamin D receptor, the active form of vitamin D, 1,25[OH]2D, induces antimicrobial peptide secretion, decreases dendritic cell activity, and promotes Th2 and regulatory T cell development and activity. In addition, vitamin D promotes an increased ratio of anti-inflammatory cytokines to pro-inflammatory cytokines. Studies in IBD point to a role for vitamin D in ameliorating disease outcome. Suboptimal circulating levels of 25-hydroxyvitamin D are common in IBD and appear to be associated with an increased risk of flares, IBD-related hospitalisations and surgeries, an inadequate response to tumour necrosis factor [TNF] inhibitors, a deterioration in quality of life, and low bone mineral density. With only few available randomised double-blind, placebo-controlled studies investigating therapeutic effects of vitamin D related to IBD, further research is necessary to determine the true therapeutic potential of vitamin D, as well as to define its optimal range in serum to achieve and maintain quiescence of disease. This review aims to summarise the latest knowledge on the extraskeletal effects of vitamin D in IBD, and outlines the potential deleterious consequences of vitamin D deficiency in this patient cohort.

Impact of Paneth Cell Autophagy on Inflammatory Bowel Disease

Intestinal mucosal barrier, mainly consisting of the mucus layer and epithelium, functions in absorbing nutrition as well as prevention of the invasion of pathogenic microorganisms. Paneth cell, an important component of mucosal barrier, plays a vital role in maintaining the intestinal homeostasis by producing antimicrobial materials and controlling the host-commensal balance. Current evidence shows that the dysfunction of intestinal mucosal barrier, especially Paneth cell, participates in the onset and progression of inflammatory bowel disease (IBD). Autophagy, a cellular stress response, involves various physiological processes, such as secretion of proteins, production of antimicrobial peptides, and degradation of aberrant organelles or proteins. In the recent years, the roles of autophagy in the pathogenesis of IBD have been increasingly studied. Here in this review, we mainly focus on describing the roles of Paneth cell autophagy in IBD as well as several popular autophagy-related genetic variants in Penath cell and the related therapeutic strategies against IBD.

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.

Vitamin D administration leads to a shift of the intestinal bacterial composition in Crohn's disease patients, but not in healthy controls

OBJECTIVE

Dysbiosis is a common feature in the pathogenesis of inflammatory bowel diseases (IBD). Environmental factors, such as vitamin D deficiency, seem to play a role in the intestinal inflammation of IBD. The aim of this study was to investigate whether vitamin D administration has an impact on the bacterial composition in Crohn's disease (CD) compared to healthy controls (HC).

METHODS

A prospective, longitudinal, controlled interventional analysis was conducted in seven patients with CD in clinical remission and 10 HC to investigate the effect of orally administrated vitamin D on the intestinal bacterial composition using 16S ribosomal RNA gene amplicon sequencing. Clinical parameters were assessed.

RESULTS

In contrast to HC, microbial communities of CD patients changed significantly during early vitamin D administration. However, a further increase in vitamin D level was associated with a reversal of this effect and additionally with a decrease in the bacterial richness in the CD microbiome. Specific species with a high abundancy were found during vitamin D administration in CD, but not in HC; the abundancy of Alistipes, Barnesiella, unclassified Porphyromonadaceae (both Actinobacteria), Roseburia, Anaerotruncus, Subdoligranulum and an unclassified Ruminococaceae (all Firmicutes) increased significantly after 1-week vitamin D administration in CD.

CONCLUSIONS

Vitamin D has a specific influence on the bacterial communities in CD, but not in HC. Administration of vitamin D may have a positive effect in CD by modulating the intestinal bacterial composition and also by increasing the abundance of potential beneficial bacterial strains.

Treatment of vitamin D deficiency in Chinese inflammatory bowel disease patients: A prospective, randomized, open-label, pilot study

OBJECTIVE

To assess the necessity and efficacy of vitamin D (VitD) supplementation in Chinese ulcerative colitis (UC) and Crohn's disease (CD) patients with vitamin D insufficiency/deficiency.

METHODS

UC and CD patients were randomly assigned into one of the three arms for 12 months: arm A (VitD₃ 150 000 IU once per 3 months plus elemental calcium 200 mg thrice daily), arm B (elemental calcium 200 mg thrice daily) and arm C (vehicle control group), in addition to conventional treatment. Improvement in 25-hydroxyvitamin D [25(OH)D] level was the primary outcome of the study. Secondary outcomes were changes in bone mineral density (BMD) and disease activity.

RESULTS

Sixty-five UC and 59 CD patients completed the study. The difference in the pre-and post-treatment 25(OH)D [Δ25(OH)D] of arm A was significantly higher than in arm B or C (UC: 17.47 ± 13.01 ng/mL vs 5.30 ± 6.28 ng/mL or 2.02 ± 6.19 ng/mL, P < 0.001; CD: 12.47 ± 9.15 ng/mL vs 4.73 ± 6.97 ng/mL or 1.36 ± 4.75 ng/mL, P < 0.01). There was no significant difference between pre- and post-treatment BMD and disease activity in arm A compared to those in arms B and C (P > 0.05). Although the Mayo score and Crohn's disease activity index decreased by conventional treatment, serum 25(OH)D did not improve in arm C without vitamin D supplementation (P > 0.05).

CONCLUSION

VitD supplementation is necessary to treat hypovitaminosis D in UC and CD patients, even with background amelioration of disease activity.

Vitamin D deficiency in childhood: old lessons and current challenges

Hypovitaminosis D in childhood is a re-emerging public health problem in developed countries. New life style habits, current "epidemics" of obesity in children and adolescents worldwide, and other preventable risk factors may play a role in favoring the occurrence of vitamin D deficiency. In addition to skeletal consequences, hypovitaminosis D has been found to be involved in the development of serious health extra-skeletal problems in childhood, including atopy and autoimmunity. The increasing concerns about the global health impact of vitamin D deficiency make further research necessary to fill the gaps of knowledge in this field, and particularly to establish universally accepted "normal" serum 25(OH)D levels in the pediatric population, and to improve strategies for the screening, prevention and treatment of hypovitaminosis D. This review discusses the key points of hypovitaminosis D in childhood in the light of new knowledge, and highlights the limitations of current strategies to control this condition.

NOD2- and disease-specific gene expression profiles of peripheral blood mononuclear cells from Crohn’s disease patients

AIM

To investigate disease-specific gene expression profiles of peripheral blood mononuclear cells (PBMCs) from Crohn’s disease (CD) patients in clinical remission.

METHODS

Patients with CD in clinical remission or with very low disease activity according to the Crohn’s disease activity index were genotyped regarding nucleotide-binding oligomerization domain 2 (NOD2), and PBMCs from wild-type (WT)-NOD2 patients, patients with homozygous or heterozygous NOD2 mutations and healthy donors were isolated for further analysis. The cells were cultured with vitamin D, peptidoglycan (PGN) and lipopolysaccharide (LPS) for defined periods of time before RNA was isolated and subjected to microarray analysis using Clariom S assays and quantitative real-time PCR. NOD2- and disease-specific gene expression profiles were evaluated with repeated measure ANOVA by a general linear model.

RESULTS

Employing microarray assays, a total of 267 genes were identified that were significantly up- or downregulated in PBMCs of WT-NOD2 patients, compared to healthy donors after challenge with vitamin D and/or a combination of LPS and PGN (P < 0.05; threshold: ≥ 2-fold change). For further analysis by real-time PCR, genes with known impact on inflammation and immunity were selected that fulfilled predefined expression criteria. In a larger cohort of patients and controls, a disease-associated expression pattern, with higher transcript levels in vitamin D-treated PBMCs from patients, was observed for three of these genes, CLEC5A (P < 0.030), lysozyme (LYZ; P < 0.047) and TREM1 (P < 0.023). Six genes were found to be expressed in a NOD2-dependent manner (CD101, P < 0.002; CLEC5A, P < 0.020; CXCL5, P < 0.009; IL-24, P < 0.044; ITGB2, P < 0.041; LYZ, P < 0.042). Interestingly, the highest transcript levels were observed in patients with heterozygous NOD2 mutations.

CONCLUSION

Our data identify CLEC5A and LYZ as CD- and NOD2-associated genes of PBMCs and encourage further studies on their pathomechanistic roles.

Vitamin D Status and Its Relation to Inflammatory Markers in Patients with Mild to Moderate Ulcerative Colitis

BACKGROUND

Inflammatory bowel disease (IBD), Crohn’s disease (CD), and Ulcerative colitis (UC) are autoimmune inflammatory diseases of the alimentary tract, which seems to be caused by the interaction of environmental and genetic factors as well as diet and nutritional factors such as vitamin D. The aim of this study was to assess the vitamin D status and its associations with erythrocyte sedimentation rate (ESR), and high-sensitivity C-reactive protein (hs-CRP) as inflammatory markers in patients with UC.

METHODS

In this analytical cross-sectional study 90 patients with mild to moderate UC who were resident of Tehran were assessed. 25(OH)D, parathyroid hormone (PTH), ESR and hs-CRP were measured. Dietary intake was assessed by 3-day 24h diet recall. Statistical analyses were performed using STATA (Version 12).

RESULTS

The average serum 25-OH-vitamin D3 was 33.1 ± 8.3 ng/mL and 38.9% of the patients were vitamin D deficient or insufficient (37.3% of men and 41% of women). No significant correlation between serum 25(OH)D and hs-CRP, ESR, body mass index (BMI), and disease duration was found. There were no significant differences in serum 25(OH)D between men and women. Mean daily dietary vitamin D and calcium intakes were 189.5 Iu (95% CI: 176.0 - 203.1) and 569.5 mg (95% CI: 538.8 - 600.2) respectively.

CONCLUSION

In this cross-sectional study 38.9% of the patients with mild to moderate UC were vitamin D deficient or insufficient and vitamin D level was not correlated to ESR and/or hs-CRP. More studies are needed to investigate the effect of vitamin D in the pathogenesis of UC or as a part of its treatment.

Nutritional Interventions in the Patient with Inflammatory Bowel Disease

Nutritional strategies have been explored as primary or adjunct therapies for inflammatory bowel disease (IBD). Exclusive enteral nutrition is effective for the induction of remission in Crohn disease and is recommended as a first-line therapy for children. Dietary strategies focus on adjusting the ratio of consumed nutrients that are proinflammatory or antiinflammatory. Treatments with dietary supplements focus on the antiinflammatory effects of the individual supplements (eg, curcumin, omega-3 fatty acids, vitamin D) or their positive effects on the intestinal microbiome (eg, prebiotics, probiotics). This article discusses the role of diets and dietary supplements in the treatment of IBD.

Prediagnostic Serum Vitamin D Levels and the Risk of Crohn's Disease and Ulcerative Colitis in European Populations: A Nested Case-Control Study

Background

A low vitamin D status has been put forward as a potential risk factor for the development of inflammatory bowel disease (IBD). This study investigated the association between prediagnostic circulating vitamin D concentrations and dietary intakes of vitamin D, and the risk of Crohn's disease (CD) and ulcerative colitis (UC).

Methods

Among 359,728 participants of the European Prospective Investigation into Cancer and Nutrition cohort, individuals who developed CD or UC after enrollment were identified. Each case was matched with2 controls by center, gender, age, date of recruitment, and follow-up time. At cohort entry, blood samples were collected and dietary vitamin D intakes were obtained from validated food frequency questionnaires. Serum 25-hydroxyvitamin D levels were measured using liquid chromatography-tandem mass spectrometry. Conditional logistic regression was performed to determine the odds of CD and UC.

Results

Seventy-two participants developed CD and 169 participants developed UC after a median follow-up of 4.7 and 4.1 years, respectively. Compared with the lowest quartile, no associations with the 3 higher quartiles of vitamin D concentrations were observed for CD (p trend = 0.34) or UC (p trend = 0.66). Similarly, no associations were detected when serum vitamin D levels were analyzed as a continuous variable. Dietary vitamin D intakes were not associated with CD (p trend = 0.39) or UC (p trend = 0.83).

Conclusions

Vitamin D status was not associated with the development of CD or UC. This does not suggest a major role for vitamin D deficiency in the etiology of IBD, although larger studies are needed to confirm these findings.

Impact of red and processed meat and fibre intake on treatment outcomes among patients with chronic inflammatory diseases: protocol for a prospective cohort study of prognostic factors and personalised medicine

INTRODUCTION

Chronic inflammatory diseases (CIDs) are frequently treated with biological medications, specifically tumour necrosis factor inhibitors (TNFi)). These medications inhibit the pro-inflammatory molecule TNF alpha, which has been strongly implicated in the aetiology of these diseases. Up to one-third of patients do not, however, respond to biologics, and lifestyle factors are assumed to affect treatment outcomes. Little is known about the effects of dietary lifestyle as a prognostic factor that may enable personalised medicine. The primary outcome of this multidisciplinary collaborative study will be to identify dietary lifestyle factors that support optimal treatment outcomes.

METHODS AND ANALYSIS

This prospective cohort study will enrol 320 patients with CID who are prescribed a TNFi between June 2017 and March 2019. Included among the patients with CID will be patients with inflammatory bowel disease (Crohn's disease and ulcerative colitis), rheumatic disorders (rheumatoid arthritis, axial spondyloarthritis, psoriatic arthritis), inflammatory skin diseases (psoriasis, hidradenitis suppurativa) and non-infectious uveitis. At baseline (pretreatment), patient characteristics will be assessed using patient-reported outcome measures, clinical assessments of disease activity, quality of life and lifestyle, in addition to registry data on comorbidity and concomitant medication(s). In accordance with current Danish standards, follow-up will be conducted 14-16 weeks after treatment initiation. For each disease, evaluation of successful treatment response will be based on established primary and secondary endpoints, including disease-specific core outcome sets. The major outcome of the analyses will be to detect variability in treatment effectiveness between patients with different lifestyle characteristics.

ETHICS AND DISSEMINATION

The principle goal of this project is to improve the quality of life of patients suffering from CID by providing evidence to support dietary and other lifestyle recommendations that may improve clinical outcomes. The study is approved by the Ethics Committee (S-20160124) and the Danish Data Protecting Agency (2008-58-035). Study findings will be disseminated through peer-reviewed journals, patient associations and presentations at international conferences.

TRIAL REGISTRATION NUMBER

NCT03173144; Pre-results.