Prevalence, incidence, and autoimmune comorbidities of celiac disease: a nation-wide, population-based study in Denmark from 1977 to 2016

Associations of Clinical Presentation of Coeliac Disease with Comorbidities and Complications: A Retrospective Single-Centre Analysis

Background: The clinical presentation of coeliac disease (CD) is various and may influence disease course. We aimed to investigate the associations of clinical presentation with comorbidities and disease complications in a cohort of Hungarian coeliac patients. Methods: In this retrospective study, data of consecutive CD patients were analysed. Clinical presentation (classical vs. non-classical), extraintestinal manifestations and comorbidities (anaemia, metabolic bone disease, dermatitis herpetiformis, IgA deficiency, chromosomal abnormalities, autoimmune diseases and malignancy) were assessed. Student's t-test (for age at diagnosis) and the Chi-squared test or Fisher's exact test (for categorical variables) were applied as analyses. Results: A total of 738 patients were included. In classical vs. non-classical comparisons, classical presentation was significantly associated with metabolic bone disease (59 vs. 36%, respectively, p < 0.001), anaemia (47 vs. 38%, respectively, p = 0.027) and malignancy (6 vs. 2%, respectively, p = 0.006); however, autoimmune diseases and dermatitis herpetiformis were more common with non-classical presentation (23 vs. 31%, p = 0.02, and 5 vs. 16%, p = 0.014, respectively). Conclusions: Our findings confirm that clinical presentation is associated with certain comorbidities and complications in CD. More personalised follow-up may be recommended based on clinical presentation.

Causal relationships between autoimmune diseases and celiac disease: A Mendelian randomization analysis

The aim of this study was to investigate the causal relationship between autoimmune disorders and celiac disease (CeD) through Mendelian randomization (MR). Single nucleotide polymorphisms (SNPs) significantly associated with 13 autoimmune diseases were extracted from the summary statistics of European genome-wide association studies (GWAS), and their effects were examined by Inverse variance-weighted (IVW) in a large European GWAS on CeD. Finally, reverse MR was performed to investigate the causal effects of CeD on autoimmune traits. Following the application of Bonferroni correction for multiple testing, genetically determined seven autoimmune diseases are causally associated with CeD: Crohn's disease (CD) (OR [95%CI] = 1.156 [1.106 ± 1.208], P = 1.27E-10), primary biliary cholangitis (PBC) (1.229 [1.143 ± 1.321], P = 2.53E-08), primary sclerosing cholangitis (PSC) (1.688 [1.466 ± 1.944], P = 3.56E-13), rheumatoid arthritis (RA) (1.231 [1.154 ± 1.313], P = 2.74E-10), systemic lupus erythematosus (SLE) (1.127 [1.081 ± 1.176], P = 2.59E-08), type 1 diabetes (T1D) (1.41 [1.238 ± 1.606], P = 2.24E-07), and asthma (1.414 [1.137 ± 1.758], P = 1.86E-03). The IVW analysis indicated that CeD increased the risk for seven diseases: CD (1.078 [1.044 ± 1.113], P = 3.71E-06), Graves' disease (GD) (1.251 [1.127 ± 1.387], P = 2.34E-05), PSC (1.304 [1.227 ± 1.386], P = 8.56E-18), psoriasis (PsO) (1.12 [1.062 ± 1.182], P = 3.38E-05), SLE (1.301[1.22 ± 1.388], P = 1.25E-15), T1D (1.3[1.228 ± 1.376], P = 1.57E-19), and asthma (1.045 [1.024 ± 1.067], P = 1.82E-05). The sensitivity analyses deemed the results reliable without pleiotropy. There are positive genetic correlations between various autoimmune diseases and CeD, and the latter also affects the predisposition to multiple autoimmune disorders in the European population.

The epithelial barrier theory and its associated diseases

The prevalence of many chronic noncommunicable diseases has been steadily rising over the past six decades. During this time, over 350,000 new chemical substances have been introduced to the lives of humans. In recent years, the epithelial barrier theory came to light explaining the growing prevalence and exacerbations of these diseases worldwide. It attributes their onset to a functionally impaired epithelial barrier triggered by the toxicity of the exposed substances, associated with microbial dysbiosis, immune system activation, and inflammation. Diseases encompassed by the epithelial barrier theory share common features such as an increased prevalence after the 1960s or 2000s that cannot (solely) be accounted for by the emergence of improved diagnostic methods. Other common traits include epithelial barrier defects, microbial dysbiosis with loss of commensals and colonization of opportunistic pathogens, and circulating inflammatory cells and cytokines. In addition, practically unrelated diseases that fulfill these criteria have started to emerge as multimorbidities during the last decades. Here, we provide a comprehensive overview of diseases encompassed by the epithelial barrier theory and discuss evidence and similarities for their epidemiology, genetic susceptibility, epithelial barrier dysfunction, microbial dysbiosis, and tissue inflammation.

Exploring the role of gut microbiome in autoimmune diseases: A comprehensive review

As the industrialized society advances, there has been a gradual increase in the prevalence of autoimmune disorders. A probe into the fundamental causes has disclosed several factors in modern society that have an influence on the gut microbiome. These dramatic shifts in the gut microbiome are likely to be one of the reasons for the disarray in the immune system, and the relationship between the immune system and the gut microbiome emerging as a perennial hot topic of research. This review enumerates the findings from sequencing studies of gut microbiota on seven autoimmune diseases (ADs): Rheumatoid Arthritis (RA), Systemic Lupus Erythematosus (SLE), Ankylosing Spondylitis (AS), Systemic Sclerosis (SSc), Sjögren's Syndrome (SjS), Juvenile Idiopathic Arthritis (JIA), and Behçet's Disease (BD). It aims to identify commonalities in changes in the gut microbiome within the autoimmune disease cohort and characteristics specific to each disease. The dysregulation of the gut microbiome involves a disruption of the internal balance and the balance between the external environment and the host. This dysregulation impacts the host's immune system, potentially playing a role in the development of ADs. Damage to the gut epithelial barrier allows potential pathogens to translocate to the mucosal layer, contacting epithelial cells, disrupting tight junctions, and being recognized by antigen-presenting cells, which triggers an immune response. Primed T-cells assist B-cells in producing antibodies against pathogens; if antigen mimicry occurs, an immune response is generated in extraintestinal organs during immune cell circulation, clinically manifesting as ADs. However, current research is limited; advancements in sequencing technology, large-scale cohort studies, and fecal microbiota transplantation (FMT) research are expected to propel this field to new peaks.

Celiac disease and nonceliac enteropathies

PURPOSE OF REVIEW

This review highlights recent research in the field of celiac disease.

RECENT FINDINGS

Epidemiological studies continue to identify celiac disease-associated diseases such as inflammatory arthritis, irritable bowel syndrome, and cardiovascular disease. Recently published consensus guidelines provide recommendations for the long-term management and monitoring of patients with celiac disease. There are multiple pharmaceutical therapies for celiac disease under investigation, and recent phase I and phase II trials are reviewed here. Finally, a recent trial of patients with nonceliac gluten sensitivity demonstrates a significant nocebo effect in this condition.

SUMMARY

Recent advances in celiac disease include the development of new clinical guidelines as well as promising new therapeutics. Continued high-quality research is needed to improve the outcomes of patients with celiac disease and nonceliac enteropathies.

Causal association between celiac disease and inflammatory bowel disease: A two-sample bidirectional Mendelian randomization study

Background

An epidemiological link between celiac disease (CeD) and inflammatory bowel disease (IBD) has been well established recently. In this study, Mendelian randomization (MR) analysis was performed employing pooled data of publicly available genome-wide association studies (GWAS) to determine the causal relationship between CeD and IBD, encompassing ulcerative colitis (UC) and Crohn's disease (CD).

Methods

Dataset of CeD was acquired from GWAS for 12,041 cases and 12,228 controls. A GWAS of more than 86,000 patients and controls was used to identify genetic variations underlying IBD. MR analyses were performed with an inverse-variance-weighted approach, an MR-Egger regression, a weighted-mode approach, a weighted-median method, and sensitivity analyses of MR pleiotropy residual sum and outlie (MR-PRESSO).

Results

MR demonstrated that genetic predisposition to CeD was linked to a augmented risk of IBD (OR: 1.1408; 95% CI: 1.0614-1.2261; P = 0.0003). In the analysis of the two IBD subtypes, genetic predisposition to CeD was also linked to increased risks of UC (OR: 1.1646; 95% CI: 1.0614-1.2779; P = 0.0012) and CD (OR: 1.1865; 95% CI: 1.0948-1.2859; P = 3.07E-05). Reverse MR analysis results revealed that genetic susceptibility to IBD and CD was correlated with an augmented risk of CeD. However, there was no genetic correlation between UC and CeD. All of the above results were validated with other GWAS databases.

Conclusion

There is a bidirectional causal relationship of CeD with IBD and CD. However, UC only augments the risk of developing CeD.

Risk of Juvenile Idiopathic Arthritis and Rheumatoid Arthritis in Patients With Celiac Disease: A Population-Based Cohort Study

INTRODUCTION

Celiac disease (CD) is associated with many immune-mediated conditions, but a definitive epidemiological association between CD and juvenile idiopathic arthritis (JIA) or rheumatoid arthritis (RA) has not been established. We quantified the risk of JIA and RA among patients with CD using a population-based cohort.

METHODS

We identified patients diagnosed with biopsy-proven CD between 2004 and 2017 using data from a national histopathology cohort in Sweden. Each patient was matched by age, sex, calendar year, and geographic region to reference individuals in the general population. We calculated the incidence and estimated the relative risk, through Cox proportional hazards models, of JIA in individuals with CD aged <18 and of RA in individuals with CD aged ≥18.

RESULTS

We identified 24,014 individuals with CD who were matched to 117,397 reference individuals from the general population. Among individuals aged <18, the incidence rate of JIA was 5.9 per 10,000 person-years in patients with CD and 2.2 per 10,000 person-years in the general population (n events = 40 and 73, respectively; hazard ratio [HR] 2.68, 95% confidence interval 1.82-3.95) over a follow-up of 7.0 years. Among individuals aged ≥ 18, the incidence of RA was 8.4 per 10,000 person-years in CD and 5.1 per 10,000 person-years in matched comparators (n events = 110 and 322, respectively; HR 1.70, 95% confidence interval 1.36-2.12) over a follow-up of 8.8 years.

DISCUSSION

Among children with CD, JIA develops nearly 3 times as often as it does in the general population, and among adults with CD, RA occurs nearly 2 times as often. Clinicians caring for patients with CD with joint symptoms should have a low threshold to evaluate for JIA or RA.

The association of Inflammatory Bowel Disease with Celiac Disease and Celiac Autoimmunity in children and adults: A nationwide study from the epi-IIRN

BACKGROUND AND AIMS

Given the paucity of population-based data on the association between inflammatory bowel diseases (IBD), celiac disease (CeD) and celiac autoimmunity (CeA) we aimed to study the associations in a nationwide study.

METHODS

Utilizing health administrative data for all four health maintenance organizations in Israel, covering 98% of the population, we explored the prevalence of CeD in children and adults with IBD versus non-IBD matched controls. CeD was defined by three ICD-9 codes and CeA by positivity for tissue transglutaminase antibodies.

RESULTS

In total, 34,375 IBD patients (56% Crohn's disease [CD] and 44% ulcerative colitis [UC]) were compared with 93,603 non-IBD controls. Among IBD patients, 319 (0.93%) had CeD versus 294 (0.31%) non-IBD controls (odds ratio [OR]=2.97 [95%CI 2.54-3.48]; p<0.001). CeA was identified in 575 (1.67%) IBD patients vs. 158 (0.17%) controls (OR=10.06 [95%CI 8.43-12], p<0.001). The prevalence of CeD was higher in pediatric-onset IBD (87/5,243 [1.66%]) than adult-onset IBD (232/29,132 [0.79%]; p<0.001). CD patients had a higher prevalence of CeD (229/19,264 [1.19%]) than UC patients (90/15,111 [0.56%]; OR=2.01 [95%CI 1.57-2.56]; p<0.001). The diagnosis of CeD preceded the diagnosis of IBD in 241/319 cases (76%). The time to treatment escalation was shorter in patients with both IBD and CeD than in patients with IBD without CeD (p=0.017).

CONCLUSION

CeD and CeA are more prevalent in IBD patients, especially in pediatric-onset IBD and in CD. The diagnosis of CeD usually precedes that of IBD. Having CeD is associated with more intensified treatment for IBD.

Causal association between rheumatoid arthritis and celiac disease: A bidirectional two-sample mendelian randomization study

Objectives: Rheumatoid Arthritis (RA) has been associated with Celiac Disease (CD) in previous observational epidemiological studies. However, evidence for this association is limited and inconsistent, and it remains uncertain whether the association is causal or due to confounding or reverse causality. This study aimed to assess the bidirectional causal relationship between RA and CD. Methods: In this two-sample Mendelian randomization (MR) study, instrumental variables (IVs) for RA were derived from a genome-wide association studies (GWAS) meta-analysis including 58,284 subjects. Summary statistics for CD originated from a GWAS meta-analysis with 15,283 subjects. The inverse-variance weighted (IVW) method was used as the primary analysis. Four complementary methods were applied, including the weighted-median, weighted mode, MR pleiotropy residual sum and outlier (MR-PRESSO) test and MR-Egger regression, to strengthen the effect estimates. Results: Positive causal effects of genetically increased RA risk on CD were derived [IVW odds ratio (OR): 1.46, 95% confidence interval (CI): 1.19-1.79, p = 3.21E-04]. The results of reverse MR analysis demonstrated no significant causal effect of CD on RA (IVW OR: 1.05, 95% CI: 0.91-1.21, p = 0.499). According to the sensitivity analysis, horizontal pleiotropy was unlikely to distort the causal estimates. Conclusion: This study reveals a causality of RA on CD but not CD on RA among patients of European descent. This outcome suggests that the features and indicators of CD should regularly be assessed for RA patients.

Phenome of coeliac disease vs. inflammatory bowel disease

Coeliac disease (CeD) is characterized by gliadin-induced intestinal inflammation appearing in genetically susceptible individuals, such as HLA-DQ2.5 carriers. CeD, as well as other chronic intestinal disorders, such as Crohn's disease (CD) and ulcerative colitis, has been associated with increased morbidity and mortality, but the causes are unknown. We systematically analysed CeD-associated diagnoses and compared them to conditions enriched in subjects with CD/UC as well as in HLA-DQ2.5 carriers without CeD. We compared the overall and cause-specific mortality and morbidity of 3,001 patients with CeD, 2,020 with CD, 4,399 with UC and 492,200 controls in the community-based UK Biobank. Disease-specific phenotypes were assessed with the multivariable Phenome Wide Association Study (PheWAS) method. Associations were adjusted for age, sex and body mass index. All disease groups displayed higher overall mortality than controls (CD: aHR = 1.91[1.70-2.17]; UC: aHR = 1.32 [1.20-1.46]; CeD: aHR = 1.38 [1.22-1.55]). Cardiovascular and cancer-related deaths were responsible for the majority of fatalities. PheWAS analysis revealed 166 Phecodes overrepresented in all three disorders, whereas only ~ 20% of enriched Phecodes were disease specific. Seven of the 58 identified CeD-specific Phecodes were enriched in individuals homozygous for HLA-DQ2.5 without diagnosed CeD. Four out of these seven Phecodes and eight out of 19 HLA-DQ2.5 specific Phecodes were more common in homozygous HLA-DQ2.5 subjects with vs. without CeD, highlighting the interplay between genetics and diagnosis-related factors. Our study illustrates that the morbidity and mortality in CeD share similarities with CD/UC, while the CeD-restricted conditions might be driven by both inherited and acquired factors.

Review article: Systemic consequences of coeliac disease

BACKGROUND

The best-known symptoms of coeliac disease are related to the gastrointestinal tract, but the disease may also present with various systemic manifestations outside the intestine. Some of these consequences may remain permanent in undiagnosed individuals or if the diagnostic delay is prolonged. However, for many of the systemic manifestations, the scientific evidence remains scant and contradictory.

AIMS AND METHODS

We conducted a narrative review of the most thoroughly studied and clinically relevant systemic consequences of coeliac disease, especially those that could be prevented or alleviated by early diagnosis. The review is intended particularly for physicians encountering these patients in daily clinical practice.

RESULTS

The possible systemic consequences of coeliac disease extend to multiple organ systems, the best studied of which are related to skeletal, reproductive, cardiovascular and neurological systems. Furthermore, the disease is associated with an elevated risk of psychiatric comorbidities, non-Hodgkin lymphomas and intestinal adenocarcinoma.

CONCLUSIONS

The various systemic consequences of coeliac disease play a significant role in the overall health of patients. Early diagnosis and treatment with a gluten-free diet appear to be beneficial for most, but not all of these conditions. The possible negative metabolic and psychosocial effects of the diet should be acknowledged during follow-up.

Two waves of coeliac disease incidence in Sweden: a nationwide population-based cohort study from 1990 to 2015

OBJECTIVES

To assess the incidence of biopsy-verified coeliac disease (CD) in Sweden and examine the incidence of duodenal/jejunal biopsies with normal mucosa over time as a proxy for CD awareness and investigation.

DESIGN

Nationwide population-based cohort study 1990-2015 based on biopsy reports indicating villous atrophy (VA) or normal mucosa in the duodenum/jejunum.

RESULTS

We identified 44 771 individuals (63% females) with a biopsy report specifying VA and 412 279 (62% females) with a biopsy report indicating normal mucosa (without a prior biopsy indicating VA). The median age at diagnosis of CD was 28 years. The mean age-standardised incidence rate during the study period was 19.0 per 100 000 person-years (95% CI 17.3 to 20.8). The incidence reached a peak in 1994 for both sexes and a second higher peak in 2002-2003 for females and in 2006 for males. The lifetime risk of developing CD was 1.8% (2.3% in females and 1.4% in males).Prior to 2015, there was a parallel rise in rates for biopsies showing normal duodenal/jejunal mucosa.

CONCLUSIONS

In Sweden, the incidence of CD increased until 2002-2003 in females and until 2006 in males. Since then, the incidence of CD has declined despite increasing duodenal/jejunal biopsies, suggesting that increased awareness and investigation are unlikely to elevate the incidence of the disease in Sweden. Across a lifetime, 1 in 44 females and 1 in 72 males are expected to be diagnosed with CD in Sweden, indicating a relatively high societal burden of disease.

Biochemical abnormalities among patients referred for celiac disease antibody blood testing in a primary health care setting

To investigate possible biochemical abnormalities associated with celiac disease (CD) antibody positivity in a primary health care setting and thereby identify predictors that could potentially reduce diagnostic delay and underdiagnosis of CD. This observational cohort study included measurements of CD antibodies in the Copenhagen Primary Care Laboratory (CopLab) database from 2000 to 2015; CD antibody positivity was defined as tissue transglutaminase antibody IgA or IgG ≥ 7 kU/L and/or deamidated gliadin peptide antibody IgG ≥ 10 kU/L. Individuals with a prior diagnosis of CD were excluded. We examined differences between individuals with positive and negative CD antibody tests regarding the results of biochemical tests performed six months before and one month after the date of the CD antibody test. We identified 76,265 measurements of CD antibodies during 2000–2015, and 57,061 individuals met the inclusion criteria (706 antibody-positive and 56,355 antibody-negative). We found lower ferritin, hemoglobin, cobalamin and folic acid levels and higher levels of transferrin, ALAT (alanine transaminase), and alkaline phosphate among individuals with a positive CD antibody test. Furthermore, we illustrated more measurements below the sex-specific reference intervals for hemoglobin, mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), ferritin, cobalamin and folic acid among individuals with a positive CD antibody test. This study identified several biochemical abnormalities associated with CD antibody positivity among individuals referred to CD antibody testing. The pattern of abnormalities suggested that micronutrient deficiencies were prevalent among CD antibody-positive individuals, confirming malabsorption as a sign of CD. These findings illustrate the possibility of reducing diagnostic delay and underdiagnosis of CD.

Epidemiological, clinical, and histological presentation of celiac disease in Northwest China

BACKGROUND

Research on celiac disease (CD) in northwest China is still in its infancy. At present, large-sample data on the epidemiological, clinical, and pathological characteristics of CD are limited.

AIM

To investigate the epidemiological, clinical, and pathological characteristics of CD in northwest China.

METHODS

The clinical data of 2884 patients with gastrointestinal (GI) symptoms were retrospectively analyzed. Total immunoglobulin A (IgA) and anti-tissue transglutaminase (tTG) IgA levels were examined in all patients. Gastroscopy and colonoscopy were performed in patients with positive anti-tTG IgA and deficient total IgA levels. Atrophy of the duodenal and ileal villi was examined and histopathological examinations were performed. The modified Marsh–Oberhuber classification system was used to grade villous atrophy in the duodenum or distal ileum. The patients’ Helicobacter pylori (H. pylori) infection status was compared in terms of clinical presentation and Marsh grade. Statistical analyses were performed using the t-test or chi-square test.

RESULTS

Among the 2884 patients, 73 were positive for serum anti-tTG IgA, and 50 were diagnosed with CD. The CD detection rate was significantly higher in Kazakhs (4.39%) than in Uyghurs (2.19%), Huis (0.71%), and Hans (0.55%). The main symptoms of CD were chronic diarrhea, anorexia, anemia, fatigue, weight loss, sleep disorders, osteopenia, and osteoporosis. The body mass index of patients with CD was significantly lower than that of patients without CD. A total of 69 patients with positive serum anti-tTG IgA and two patients with deficient total IgA levels underwent GI endoscopy. Endoscopy revealed crypt hyperplasia and/or duodenal villous atrophy, mainly manifested as nodular mucosal atrophy, grooves, and fissures. The difference in H. pylori infection rates was not statistically significant between CD and non-CD patients but was significantly different among CD patients with different Marsh grades.

CONCLUSION

Among the patients with GI symptoms in northwestern China, the prevalence of CD was more in the Uyghur and Kazakh populations. H. pylori infection may be associated with CD severity.

Gut-derived short-chain fatty acids modulate skin barrier integrity by promoting keratinocyte metabolism and differentiation

Barrier integrity is central to the maintenance of healthy immunological homeostasis. Impaired skin barrier function is linked with enhanced allergen sensitization and the development of diseases such as atopic dermatitis (AD), which can precede the development of other allergic disorders, for example, food allergies and asthma. Epidemiological evidence indicates that children suffering from allergies have lower levels of dietary fibre-derived short-chain fatty acids (SCFA). Using an experimental model of AD-like skin inflammation, we report that a fermentable fibre-rich diet alleviates systemic allergen sensitization and disease severity. The gut-skin axis underpins this phenomenon through SCFA production, particularly butyrate, which strengthens skin barrier function by altering mitochondrial metabolism of epidermal keratinocytes and the production of key structural components. Our results demonstrate that dietary fibre and SCFA improve epidermal barrier integrity, ultimately limiting early allergen sensitization and disease development.The Graphical Abstract was designed using Servier Medical Art images ( https://smart.servier.com ).

Autoimmune diseases in microscopic colitis: A Danish nationwide case-control study

BACKGROUND

The association between autoimmune diseases and microscopic colitis remains uncertain.

AIMS

To describe the association between autoimmune diseases and microscopic colitis by using a matched case-control design based on nationwide registry data.

METHODS

All adult Danish patients with a diagnosis of microscopic colitis from 2001 to 2018 were identified from nationwide registries. Odds of autoimmune diseases were compared between cases with microscopic colitis and sex- and age-matched controls from the background population in a 1:10 ratio and evaluated by logistic regression calculating odds ratios (OR) with 95% confidence intervals (CI) adjusted for comorbidity. Analyses were stratified according to sex, age and the subtypes of lymphocytic and collagenous colitis.

RESULTS

We identified 15 597 cases with microscopic colitis and matched to 155 910 controls. In total, 3491 (22%) of patients with microscopic colitis had concomitant autoimmune disease compared to 16 521 (11%) of controls (OR, 2.46; 95% CI, 2.36-2.56). Adjusting for comorbidities reduced the OR to 2.09 (95% CI, 2.01-2.19). Analyses showed increased ORs with 16 different autoimmune diseases, particularly of gastrointestinal and endocrine origin, and connective tissue disorders. The highest ORs were for coeliac disease (OR = 10.15; 95% CI, 8.20-12.6), Crohn's disease (OR = 2.47; 95% CI, 2.10-2.91) and ulcerative colitis (OR = 6.73; 95% CI, 6.20-7.30). In stratified analyses younger age at diagnosis and collagenous colitis were associated with higher odds.

CONCLUSION

Using nationwide registry data, microscopic colitis was associated with a wide range of autoimmune diseases, especially of gastrointestinal origin. The results suggest an autoimmune predisposition to microscopic colitis.

Does the epithelial barrier hypothesis explain the increase in allergy, autoimmunity and other chronic conditions?

There has been a steep increase in allergic and autoimmune diseases, reaching epidemic proportions and now affecting more than one billion people worldwide. These diseases are more common in industrialized countries, and their prevalence continues to rise in developing countries in parallel to urbanization and industrialization. Intact skin and mucosal barriers are crucial for the maintenance of tissue homeostasis as they protect host tissues from infections, environmental toxins, pollutants and allergens. A defective epithelial barrier has been demonstrated in allergic and autoimmune conditions such as asthma, atopic dermatitis, allergic rhinitis, chronic rhinosinusitis, eosinophilic esophagitis, coeliac disease and inflammatory bowel disease. In addition, leakiness of the gut epithelium is also implicated in systemic autoimmune and metabolic conditions such as diabetes, obesity, multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, ankylosing spondylitis and autoimmune hepatitis. Finally, distant inflammatory responses due to a 'leaky gut' and microbiome changes are suspected in Alzheimer disease, Parkinson disease, chronic depression and autism spectrum disorders. This article introduces an extended 'epithelial barrier hypothesis', which proposes that the increase in epithelial barrier-damaging agents linked to industrialization, urbanization and modern life underlies the rise in allergic, autoimmune and other chronic conditions. Furthermore, it discusses how the immune responses to dysbiotic microbiota that cross the damaged barrier may be involved in the development of these diseases.

Systematic review and meta-analysis: the incidence and prevalence of paediatric coeliac disease across Europe

BACKGROUND

Coeliac disease is one of the most prevalent immune-mediated gastrointestinal disorders in children.

AIM

To review the incidence and prevalence of paediatric coeliac disease, and their trends, regionally across Europe, overall and according to age at diagnosis.

METHODS

Systematic review and meta-analysis from January 1, 1950 to December 31, 2019, based on PubMed, CINAHL and the Cochrane Library, searches of grey literature and websites and hand searching of reference lists. A total of 127 eligible studies were included.

RESULTS

The prevalence of previously undiagnosed coeliac disease from screening surveys (histology based) ranged from 0.10% to 3.03% (median = 0.70%), with a significantly increasing annual trend (P = 0.029). Prevalence since 2000 was significantly higher in northern Europe (1.60%) than in eastern (0.98%), southern (0.69%) and western (0.60%) Europe. Large increases in the incidence of diagnosed coeliac disease across Europe have reached 50 per 100 000 person-years in Scandinavia, Finland and Spain. The median age at diagnosis increased from 1.9 years before 1990 to 7.6 since 2000. Larger increases in incidence were found in older age groups than in infants and ages <5 years.

CONCLUSIONS

Paediatric coeliac disease incidence and prevalence have risen across Europe and appear highest in Scandinavia, Finland and Spain. The most recent evidence shows large increases in incidence in most regions, but stabilisation in some (notably Sweden and Finland). Sharp increases in the age at diagnosis may reflect increases in milder and asymptomatic cases diagnosed since reliable serology testing became widely used, through endomysial antibodies after 1990 and tissue transglutaminase antibodies around 2000.

Wheat consumption and prevalence of celiac disease: Correlation from a multilevel analysis

Celiac disease (CD) is triggered by both genetic and environmental factors. More than 1% of the world's population is affected by CD. In recent years, studies have confirmed a worldwide rising trend in CD prevalence. "Westernized diet" is one of the main factors of this increasing prevalence. However, the relationship between wheat consumption, its dynamics, and CD has not been adequately investigated on a global scale. This study aimed to perform a multilevel analysis of the association between wheat consumption and CD. Wheat consumption data from countries and continents were obtained from the database. The relative increase/decrease in wheat consumption over a long period (since 1961) and a short period (since 2004) were calculated using various statistical tools. The relationship between wheat consumption and celiac frequency was determined using the R-commander R package version 2.6-2. Pearson's correlation coefficient (r = 0.88) confirmed a high positive correlation between wheat consumption and the prevalence of biopsy-proven CD by estimating continent-wide wheat consumption data, but an insignificant correlation was found when the data were compared country-wide.

Symptoms and biomarkers associated with undiagnosed celiac seropositivity

BACKGROUND

Studies have indicated that underdiagnosis and diagnostic delay are common in celiac disease. Therefore, it is important to increase our knowledge of what symptoms and biomarkers could identify undiagnosed cases of celiac disease.

METHODS

We screened for celiac disease antibodies in stored blood samples from 16,776 participants in eight population-based studies examined during 1976-2012. Undiagnosed celiac seropositivity was defined as celiac disease antibody positivity (IgG-deamidated gliadin peptide above 10.0 U/mL and/or IgA-tissue transglutaminase (TTG) or IgG-TTG above 7.0 U/mL) without a known diagnosis of celiac disease in the National Patient Register. In all studies general health symptoms were recorded by participant-completed questionnaire, including self-perceived health, tiredness, headache and gastrointestinal symptoms. Furthermore, blood samples were drawn for analyses of biomarkers e.g. hemoglobin, blood glucose, cholesterol, liver parameters and vitamins. The participants with undiagnosed celiac seropositivity were matched by sex, age and study with four controls among the celiac disease antibody negative participants.

RESULTS

We excluded, five participants with known celiac disease, resulting in a population of 16,771 participants. In this population 1% (169/16,771) had undiagnosed celiac seropositivity. There were no statistically significant differences in symptoms between cases and controls. Undiagnosed celiac seropositivity was associated with low blood cholesterol (< 5 mmol/L) and low hemoglobin (< 7.3 mmol/L for women and < 8.3 mmol/L for men).

CONCLUSION

In this general population study, undiagnosed cases of celiac seropositivity did not have more symptoms than controls, confirming the diagnostic difficulties of celiac disease and the low prognostic value of symptoms for a diagnosis of celiac disease. Furthermore, decreased levels of cholesterol and/or hemoglobin in the blood were associated with undiagnosed celiac seropositivity.

Oral manifestations of celiac disease in French children

Celiac disease (CD) is an immune-mediated systemic disorder caused by ingestion of the gluten found in wheat, rye, and barley. The currently estimated prevalence in children is about 1%. CD is a chronic enteropathy with gastrointestinal manifestations including diarrhea, abdominal distension and weight loss, but extra-intestinal features are increasingly being reported. Dental and oral manifestations such as dental enamel defects (ED), delay in dental eruption, and recurrent aphthous stomatitis (RAS) are well-recognized manifestations of CD. The aim of this study was to compare the frequency of oral manifestations (ED, RAS and delay in dental eruption) on deciduous and permanent teeth between children with CD and a control population. An oral examination was performed on 28 CD children and 59 control children. All children were younger than 12 years old and had deciduous or mixed dentition. CD children had significantly more ED and RAS than the control group (67.9% vs. 33.9% P=0.004 and 50.0% vs. 21.8% P=0.011, respectively). No delay in dental eruption was observed in CD children. ED were mainly grade I and II of Aine's classification (color defects and slight structural defects). ED were more often seen on CD children's deciduous teeth than on permanent teeth (57.1% and 13.6%, respectively; P<0.001). The main teeth affected by ED are the second molar and canines of the deciduous teeth, and the first molar, central incisor, and lateral incisors of the permanent teeth. RAS and ED that were symmetrical in all quadrants and occurred firstly in teeth that mineralize during the first year of life both seem to be signs of CD. Thus, more information for dentists and pediatricians on these oral manifestations should help improve detection of CD.

Could Global Intensification of Nitrogen Fertilisation Increase Immunogenic Proteins and Favour the Spread of Coeliac Pathology?

Fertilisation of cereal crops with nitrogen (N) has increased in the last five decades. In particular, the fertilisation of wheat crops increased by nearly one order of magnitude from 1961 to 2010, from 9.84 to 93.8 kg N ha-1 y-1. We hypothesized that this intensification of N fertilisation would increase the content of allergenic proteins in wheat which could likely be associated with the increased pathology of coeliac disease in human populations. An increase in the per capita intake of gliadin proteins, the group of gluten proteins principally responsible for the development of coeliac disease, would be the responsible factor. We conducted a global meta-analysis of available reports that supported our hypothesis: wheat plants growing in soils receiving higher doses of N fertilizer have higher total gluten, total gliadin, α/β-gliadin, γ-gliadin and ω-gliadin contents and higher gliadin transcription in their grain. We thereafter calculated the per capita annual average intake of gliadins from wheat and derived foods and found that it increased from 1961 to 2010 from approximately 2.4 to 3.8 kg y-1 per capita (+1.4 ± 0.18 kg y-1 per capita, mean ± SE), i.e., increased by 58 ± 7.5%. Finally, we found that this increase was positively correlated with the increase in the rates of coeliac disease in all the available studies with temporal series of coeliac disease. The impacts and damage of over-fertilisation have been observed at an environmental scale (e.g., eutrophication and acid rain), but a potential direct effect of over-fertilisation is thus also possible on human health (coeliac disease).

The Two Faces of Wheat

Wheat-based foods have been staple foods since about 10,000 years and constitute a major source of energy, dietary fiber, and micronutrients for the world population. The role of wheat in our diet, however, has recently been scrutinized by pseudoscientific books and media reports promoting the overall impression that wheat consumption makes people sick, stupid, fat, and addicted. Consequently, numerous consumers in Western countries have started to question their dietary habits related to wheat consumption and voluntarily decided to adopt a wheat-free diet without a medical diagnosis of any wheat-related disorder (WRD), such as celiac disease, wheat allergy, or non-celiac gluten sensitivity. The aim of this review is to achieve an objective judgment of the positive aspects of wheat consumption as well as adverse effects for individuals suffering from WRDs. The first part presents wheat constituents and their positive nutritional value, in particular, the consumption of products from whole-grain flours. The second part is focused on WRDs that affect predisposed individuals and can be treated with a gluten-free or -reduced diet. Based on all available scientific knowledge, wheat consumption is safe and healthy for the vast majority of people. There is no scientific evidence to support that the general population would benefit from a wheat-free diet.

Duodenal Histological Findings and Risk of Coeliac Disease in Subjects with Autoimmune Atrophic Gastritis: A Retrospective Evaluation

BACKGROUND AND AIM

Autoimmune atrophic gastritis (AAG) is characterized by a variable spectrum of gastric and extra-gastric symptoms and has been associated with other autoimmune diseases. It is still unknown whether AAG patients have a higher risk of coeliac disease (CeD) or of any other particular duodenal histological damage. Our study aimed at evaluating the duodenal histological findings and the risk of CeD in patients with AAG, with and without other concurrent autoimmune diseases.

METHODS

We retrospectively collected all the histological findings of the adult patients undergoing upper gastrointestinal endoscopy with concurrent duodenal and gastric biopsies at our gastroenterology unit between 2015 and 2018 and who were regularly followed up at our centre. Date of endoscopy evaluation, endoscopy indication, data on previous CeD diagnosis and on other autoimmune-associated diseases, and a description of histological diagnosis were recorded.

RESULTS

Of the 2,423 evaluated endoscopies, 209 patients had an AAG diagnosis (8.6%). One hundred thirty-nine patients, aged 57.4 (standard deviation 13.2) years, were regularly followed up at our centre and were included. Of them, 4 subjects had a previous diagnosis of CeD and one had CeD diagnosis at index endoscopy. Additionally, 8 patients had an isolated increase of intraepithelial lymphocytes (IELs, 6%) and 2 villous atrophy with a normal IEL count. The risk of CeD in AAG was not modulated by the presence of other concurrent autoimmune diseases.

CONCLUSIONS

We support the screening of all AAG patients with CeD autoantibodies. Findings of isolated IEL or villous atrophy are not exclusively related to CeD.

Long-term Consequences of Undiagnosed Celiac Seropositivity

INTRODUCTION

Diagnosed celiac disease (CD) is associated with lymphoproliferative malignancy and gastrointestinal cancer, but little is known about the long-term consequences of undiagnosed CD. We aimed to investigate long-term consequences of undiagnosed CD for mortality and incidence of cancer and other chronic diseases.

METHODS

We screened biobank serum samples for immunoglobulin (Ig) A and IgG tissue transglutaminase (TTG) and IgG deamidated gliadin peptide in a study of 8 population-based cohort studies comprising 16,776 participants examined during 1976-2012 and followed with >99% complete follow-up in Danish nationwide registries until December 31, 2017, regarding vital status and incidence of diseases. Undiagnosed CD was defined as antibody positivity (IgA-TTG or IgG-TTG ≥ 7 U/mL and/or IgG deamidated gliadin peptide ≥ 10 U/mL) in individuals without a diagnosis of CD recorded in the National Patient Register. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated by Cox regression analyses with age as the underlying time scale.

RESULTS

The prevalence of undiagnosed CD was 1.0% with no statistically significant increase over time. Undiagnosed CD was associated with increased risk of cancer overall (HR, 1.57; 95% CI, 1.16-2.11), gastrointestinal cancer (HR, 2.33; 95% CI, 1.35-4.04), cancer of the uterus (HR, 3.95; 95% CI, 1.46-10.69), breast cancer (HR, 1.98; 95% CI, 1.02-3.82), head and neck cancer (HR, 3.12; 95% CI, 1.15-8.43), and cardiovascular disease (HR, 1.37; 95% CI, 1.01-1.85). We found no statistically significant association between undiagnosed CD and mortality (HR, 1.19; 95% CI, 0.87-1.61).

DISCUSSION

Undiagnosed CD was associated with increased risk of cardiovascular disease and cancer suggesting that untreated CD has serious long-term health consequences not only affecting the gastrointestinal tract (see Visual Abstract, Supplementary Digital Content, http://links.lww.com/AJG/B566).

Association Between Inflammatory Bowel Diseases and Celiac Disease: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

There is controversy over the association between celiac disease (CeD) and inflammatory bowel diseases (IBD). We performed a systematic review and meta-analysis to assess evidence for an association between CeD and IBD.

METHODS

We searched databases including MEDLINE, EMBASE, CENTRAL, Web of Science, CINAHL, DARE, and SIGLE through June 25, 2019 for studies assessing the risk of CeD in patients with IBD, and IBD in patients with CeD, compared with controls of any type. We used the Newcastle-Ottawa Scale to evaluate the risk of bias and GRADE to assess the certainty of the evidence.

RESULTS

We identified 9791 studies and included 65 studies in our analysis. Moderate certainty evidence found an increased risk of CeD in patients with IBD vs controls (risk ratio [RR] 3.96; 95% confidence interval [CI] 2.23-7.02) and increased risk of IBD in patients with CeD vs controls (RR 9.88; 95% CI 4.03-24.21). There was low-certainty evidence for the risk of anti-Saccharomyces antibodies, a serologic marker of IBD, in patients with CeD vs controls (RR 6.22; 95% CI 2.44-15.84). There was low-certainty evidence for no difference in risk of HLA-DQ2 or DQ8 in patients with IBD vs controls (RR 1.04; 95% CI 0.42-2.56), and very low-certainty evidence for an increased risk of anti-tissue transglutaminase in patients with IBD vs controls (RR 1.52; 95% CI 0.52-4.40). Patients with IBD had a slight decrease in risk of anti-endomysial antibodies vs controls (RR 0.70; 95% CI 0.18-2.74), but these results are uncertain.

CONCLUSIONS

In a systematic review and meta-analysis, we found an increased risk of IBD in patients with CeD and increased risk of CeD in patients with IBD, compared with other patient populations. High-quality prospective cohort studies are needed to assess the risk of CeD-specific and IBD-specific biomarkers in patients with IBD and CeD.

The Value of Screening for Celiac Disease in Systemic Lupus Erythematosus: A Single Experience of a Tertiary Medical Center

INTRODUCTION

Systemic lupus erythematosus (SLE) is a multi-organ inflammatory disease associated with autoimmune diseases. The aim of the study is to assessed the frequency of celiac disease (CD) in adults and children with SLE (aSLE and cSLE, respectively) and compare them with rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA) patients; the study also explored the clinical impact of CD serologic markers on SLE disease activity and severity.

METHODS

This was a cross-sectional study. Patients with SLE who had regular follow-up in rheumatology clinics were evaluated for laboratory and clinical variables using serology and the SLE Disease Activity Index (SLEDAI). To assess the occurrence of CD serology in cSLE and aSLE and the clinical impact of CD serologic markers on SLE, patients were tested for antigliadin (AGA), anti-endomysium (EmA) and anti-tissue transglutaminase (tTG) antibodies. RA and JIA patients were included for comparison. Duodenal biopsy was conducted in patients who exhibited CD markers.

RESULTS

The CD marker was found in 29 (11.6%) of the 250 patients. AGA was present in seven aSLE patients and tTG in two (11.1%). Among cSLE patients, the autoantibody was present in 17.6% (AGA in four, tTG in two, and EmA in three). For RA patients, five had AGA and tTG and one had EmA, with an overall positivity of 9.7%. Five JIA patients had AGA (four with EmA and five with tTG) with overall positivity of 10.9%; the serum IgA level was normal in all patients except one. Duodenal endoscopic biopsy was performed in patients with positive CD markers (two declined). Histologic confirmation of CD was reported in one RA and one JIA patient but in none of the SLE patients. There was no correlation between the presence of CD markers and autoantibodies in SLE.

CONCLUSION

CD antibodies did not influence SLE activity. Thus, SLE patients may not need to be screened for CD antibodies.

Current Evidence on the Efficacy of Gluten-Free Diets in Multiple Sclerosis, Psoriasis, Type 1 Diabetes and Autoimmune Thyroid Diseases

In this review, we summarize the clinical data addressing a potential role for gluten in multiple sclerosis (MS), psoriasis, type 1 diabetes (T1D) and autoimmune thyroid diseases (ATDs). Furthermore, data on the prevalence of celiac disease (CD) and gluten-related antibodies in the above patient groups are presented. Adequately powered and properly controlled intervention trials investigating the effects of a gluten-free diet (GFD) in non-celiac patients with MS, psoriasis, T1D or ATDs are lacking. Only one clinical trial has studied the effects of a GFD among patients with MS. The trial found significant results, but it is subject to major methodological limitations. A few publications have found beneficial effects of a GFD in a subgroup of patients with psoriasis that were seropositive for anti-gliadin or deamidated gliadin antibodies, but no effects were seen among seronegative patients. Studies on the role of gluten in T1D are contradictive, however, it seems likely that a GFD may contribute to normalizing metabolic control without affecting levels of islet autoantibodies. Lastly, the effects of a GFD in non-celiac patients with ATDs have not been studied yet, but some publications report that thyroid-related antibodies respond to a GFD in patients with concomitant CD and ATDs. Overall, there is currently not enough evidence to recommend a GFD to non-celiac patients with MS, psoriasis, ATDs or T1D.

Co-aggregation and heritability of organ-specific autoimmunity: a population-based twin study

OBJECTIVE

Co-aggregation of autoimmune diseases is common, suggesting partly shared etiologies. Genetic factors are believed to be important, but objective measures of environmental vs heritable influences on co-aggregation are absent. With a novel approach to twin studies, we aimed at estimating heritability and genetic overlap in seven organ-specific autoimmune diseases.

DESIGN

Prospective twin cohort study.

METHODS

We used a cohort of 110 814 twins to examine co-aggregation and heritability of Hashimoto's thyroiditis, atrophic gastritis, celiac disease, Graves' disease, type 1 diabetes, vitiligo and Addison's disease. Hazard ratios (HR) were calculated for twins developing the same or different disease as compared to their co-twin. The differences between monozygotic and dizygotic twin pairs were used to estimate the genetic influence on co-aggregation. Heritability for individual disorders was calculated using structural equational modeling adjusting for censoring and truncation of data.

RESULTS

Co-aggregation was more pronounced in monozygotic twins (median HR: 3.2, range: 2.2-9.2) than in dizygotic twins (median HR: 2.4, range: 1.1-10.0). Heritability was moderate for atrophic gastritis (0.38, 95% CI: 0.23-0.53) but high for all other diseases, ranging from 0.60 (95% CI: 0.49-0.71) for Graves' disease to 0.97 (95% CI: 0.91-1.00) for Addison's disease.

CONCLUSIONS

Overall, co-aggregation was more pronounced in monozygotic than in dizygotic twins, suggesting that disease overlap is largely attributable to genetic factors. Co-aggregation was common, and twins faced up to a ten-fold risk of developing diseases not present in their co-twin. Our results validate and refine previous heritability estimates based on smaller twin cohorts.

Exposure to the Danish Mandatory Vitamin D Fortification Policy in Prenatal Life and the Risk of Developing Coeliac Disease-The Importance of Season: A Semi Ecological Study

Few studies have examined the role of maternal diet in relation to development of coeliac disease (CD). In Denmark, cancellation of mandatory vitamin D fortification of margarine in June 1985 provided this opportunity. This study examined if season of birth or prenatal exposure to extra vitamin D from food fortification were associated with developing CD later in life. A strength of this study is the distinctly longer follow-up of patients (30 years). This register-based study has a semi-ecological design. Logistic regression analysis was used to estimate odds ratios and to calculate 95% confidence intervals. The odds ratio for developing CD was 0.81 (95% CI 0.66; 1.00 p = 0.054), comparing those with fetal exposure to mandatory vitamin D fortification policy of margarine to those without after adjusting for gender and season of birth. There was a statistically significant season effect particularly for children born in autumn (OR 1.6 95% CI 1.16; 2.21) and born in summer (OR 1.5 95% CI 1.1; 2.1) when compared to children born in winter. Although this study did not find evidence to support the premise that prenatal exposure to small extra amounts of vitamin D from a mandatory food fortification policy lowered risk of developing CD, the small number of CD cases and observed association between season of birth and CD suggest that environmental exposure ought to be further explored.

Reproductive life in women with celiac disease; a nationwide, population-based matched cohort study

STUDY QUESTION

How does celiac disease (CD) influence women's reproductive life, both prior to and after the diagnosis?

SUMMARY ANSWER

Prior to the diagnosis of CD, an increased risk of adverse pregnancy outcomes was seen, whereas after the diagnosis, no influence on reproductive outcomes was found.

WHAT IS KNOWN ALREADY

CD has been associated with several conditions influencing female reproduction and pregnancy outcomes including spontaneous abortion and stillbirth.

STUDY DESIGN, SIZE, DURATION

A nationwide matched cohort study following 6319 women diagnosed with CD and 63166 comparison women and identifying reproductive events between the ages of 15 and 50 years.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Through linkage of several Danish national health registers, we identified all women diagnosed with CD between 1977 and 2016. We identified an age- and sex-matched comparison cohort and obtained data on reproductive outcomes for both cohorts. Adjusted stratified Cox and logistic regression models were used to estimate differences in reproductive outcomes between women with and without CD.

MAIN RESULTS AND THE ROLE OF CHANCE

Comparing women with diagnosed CD with the non-CD women, the chance of pregnancy, live birth and risk of stillbirth, molar and ectopic pregnancy, spontaneous abortion and abortion due to foetal disease was the same. However, prior to being diagnosed, CD women had an excess risk of spontaneous abortion equal to 11 extra spontaneous abortions per 1000 pregnancies (adjusted odds ratio (OR) = 1.12, 95% CI: 1.03, 1.22) and 1.62 extra stillbirths per 1000 pregnancies (adjusted OR = 1.57, 95% CI: 1.05, 2.33) compared with the non-CD women. In the period 0-2 years prior to diagnosis fewer pregnancies occurred in the undiagnosed CD group, equal to 25 (95% CI: 20-31) fewer pregnancies per 1000 pregnancies compared to the non-CD group and in addition, fewer undiagnosed CD women initiated ART-treatment in this period, corresponding to 4.8 (95% CI: 0.9, 8.7) fewer per 1000 women compared to non-CD women.

LIMITATIONS, REASONS FOR CAUTION

Validity of the diagnoses in the registers was not confirmed, but reporting to the registers is mandatory for all hospitals in Denmark. Not all spontaneous abortions will come to attention and be registered, whereas live- and stillbirths, ectopic and molar pregnancies and abortion due to foetal disease are unlikely not to be registered. We adjusted for several confounding factors but residual confounding cannot be ruled out.

WIDER IMPLICATIONS OF THE FINDINGS

These findings suggest that undiagnosed CD can affect female reproduction and the focus should be on early detection of CD in risk groups.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by the Health Research Fund of Central Denmark Region and The Hede Nielsens Foundation, Denmark. The authors report no conflicts of interest in this work.

Incidence of Celiac Disease Is Increasing Over Time: A Systematic Review and Meta-analysis

OBJECTIVES

To conduct a systematic review and meta-analysis that defines the worldwide incidence of celiac disease (CD) and examines temporal trends.

METHODS

MEDLINE and EMBASE were searched for population-based studies reporting the incidence of CD in the overall population, children, or adults. No limits were placed on year or language of publication. Studies solely examining at-risk populations (e.g., patients with type 1 diabetes) were excluded. Random-effects models were performed to meta-analyze sex- and age-specific incidence in the 21st century. Temporal trend analyses assessed the average annual percent change in CD incidence over time.

RESULTS

Of 11,189 citations, 86 eligible studies were identified for inclusion, of which 50 were deemed suitable for analyses. In the 21st century, the pooled female incidence of CD was 17.4 (95% confidence interval [CI]: 13.7, 21.1) (I = 99.5%) per 100,000 person-years, compared with 7.8 (95% CI: 6.3, 9.2) (I = 98.6%) in males. Child-specific incidence was 21.3 per 100,000 person-years (95% CI: 15.9, 26.7) (I = 99.7%) compared with 12.9 (95% CI: 7.6, 18.2) (I = 99.9%) in adults. Pooling average annual percent changes showed the incidence of CD to be increasing by 7.5% (95% CI: 5.8, 9.3) (I = 79.6%) per year over the past several decades.

DISCUSSION

Incidence of CD is highest in females and children. Overall, the incidence has been significantly rising in the latter half of the 20th century and into the 21st century throughout the Western world. Population-based studies in Africa, Asia, and Latin America are needed to provide a comprehensive picture of the global incidence of CD.

Recent Progress and Recommendations on Celiac Disease From the Working Group on Prolamin Analysis and Toxicity

Celiac disease (CD) affects a growing number of individuals worldwide. To elucidate the causes for this increase, future multidisciplinary collaboration is key to understanding the interactions between immunoreactive components in gluten-containing cereals and the human gastrointestinal tract and immune system and to devise strategies for CD prevention and treatment beyond the gluten-free diet. During the last meetings, the Working Group on Prolamin Analysis and Toxicity (Prolamin Working Group, PWG) discussed recent progress in the field together with key stakeholders from celiac disease societies, academia, industry and regulatory bodies. Based on the current state of knowledge, this perspective from the PWG members provides recommendations regarding clinical, analytical and legal aspects of CD. The selected key topics that require future multidisciplinary collaborative efforts in the clinical field are to collect robust data on the increasing prevalence of CD, to evaluate what is special about gluten-specific T cells, to study their kinetics and transcriptomics and to put some attention to the identification of the environmental agents that facilitate the breaking of tolerance to gluten. In the field of gluten analysis, the key topics are the precise assessment of gluten immunoreactive components in wheat, rye and barley to understand how these are affected by genetic and environmental factors, the comparison of different methods for compliance monitoring of gluten-free products and the development of improved reference materials for gluten analysis.

Evaluation of adult celiac disease from a tertiary reference center: a retrospective analysis

OBJECTIVE

It has been observed that celiac disease (CD) is not restricted to a single type characterized by diarrhea but also has atypical, asymptomatic (silent), and latent forms. The prevalence of this autoimmune disease, which affects approximately 1% of the world, is estimated to be around 3%, including atypical and asymptomatic cases. In our study, we aimed to evaluate adult celiac patients.

METHODS

Between December 2008-2015, patients diagnosed with CD over the age of 18 years old were included in the study. Patients' symptoms at admission, frequency and type of anemia, transaminase levels, and celiac antibody positivity, and autoimmune diseases diagnosed at follow up were evaluated retrospectively.

RESULTS

Of 195 patients, 151 (77.4%) were female. The mean age of the patients was 35.73 ± 12.19 years (range, 18-71 years). A hundred patients (51.3%) had gastrointestinal symptoms. At the time of admission, 118 patients (60.5%) had anemia, and 52 (26.7%) had hypertransaminasemia. During the mean follow-up period of 58 months (36-120 months), 84 (43.1%) of the patients presented at least one autoimmune disease, and this rate was 96.6% in individuals diagnosed above the age of 50 years.

CONCLUSION

In adult CD, resistant anemia, dyspepsia, and hypertransaminasemia are very common findings at the time of diagnosis, and the association with other autoimmune diseases, especially Hashimoto's thyroiditis, is high.

Thyro-entero-gastric autoimmunity: Pathophysiology and implications for patient management

The association between autoimmune atrophic gastritis and thyroid disorders has been observed since the early 1960s and the expression "thyrogastric syndrome" was coined to indicate the presence of thyroid autoantibodies or autoimmune thyroid disease in patients with pernicious anemia, a late clinical stage of autoimmune atrophic gastritis. More recently, it was confirmed that autoimmune thyroid disorders, in particular Hashimoto's thyroiditis, may be frequently associated with other organ-specific, immune-mediated disorders, such as autoimmune atrophic gastritis or celiac disease. The association of Hashimoto's thyroiditis with autoimmune atrophic gastritis or celiac disease in adult patients is currently considered part of the polyglandular autoimmune syndromes which include several autoimmune disorders associated with an autoaggressive impairment of endocrine glands. From a clinical point of view, the thyro-entero-gastric autoimmunity may lead to potentially serious consequences like anemia, micronutrients deficiencies, and drugs malabsorption, as well as to an increased risk for malignancies. These alterations may frequently present in an underhand manner, with consequent diagnostic and treatment delays. Many aspects of the association between thyroid, gastric and intestinal autoimmune diseases still await clarification. The present review focuses on the embryological, genetic and pathophysiological aspects of thyro-entero-gastric autoimmunity. In particular, the current diagnostic criteria of autoimmune thyroid disease, autoimmune atrophic gastritis, and celiac disease are reviewed, along with the evidences for their association in poly-autoimmunity syndromes. The benefits of proactive screening of autoimmune thyroid disorders in patients with autoimmune gastritis or enteropathy and viceversa are also discussed.

Association between psoriasis and celiac disease: A systematic review and meta-analysis

BACKGROUND

Multiple studies have examined the association between psoriasis and celiac disease (CD). However, these studies have shown conflicting results.

OBJECTIVE

To analyze the association between psoriasis and CD.

METHODS

We conducted a systematic review of the case-control, cross-sectional, and cohort studies examining the association between psoriasis and CD in the PubMed, Scopus, and Cochrane databases. The adjusted effect sizes or crude data were extracted for quantitative analysis.

RESULTS

Of 754 citations initially identified, 18 studies were included. Random effects meta-analysis found significant odds ratios of 2.16 (95% confidence interval, 1.74-2.69; 9 studies) for CD in patients with psoriasis and 1.8 (95% confidence interval, 1.36-2.38; 8 studies) for psoriasis in patients with CD. We also found a significantly increased risk of new-onset psoriasis in CD (hazard ratio, 1.75; 95% confidence interval, 1.58-1.93). Subgroup analyses according to disease severity and geographic region could not be performed due to limited data.

CONCLUSION

This 2-way meta-analysis found a significant association between psoriasis and CD. Clinicians should be aware of this association. Patients with psoriasis with bowel complaints might benefit from screening for CD through questionnaires or interviews with subsequent gastroenterology consultation.

Incidence of Immune-Mediated Inflammatory Diseases Among Patients With Inflammatory Bowel Diseases in Denmark

BACKGROUND & AIMS

It is not clear whether the co-occurrence of immune-mediated inflammatory diseases (IMIDs) affects the course of inflammatory bowel diseases (IBD). We investigated the occurrence of IMIDs in relation to onset of IBD and the effects of concurrent IMIDs on IBD outcomes in a nationwide study of the Danish population.

METHODS

We used a nationwide cohort of all individuals diagnosed with IBD, including Crohn's disease (CD) or ulcerative colitis (UC), in Denmark from 2007 through 2016 (n = 14,377). Patients were match with individuals without IBD from the general population (controls, n = 71,885). All cohort members were followed from birth until 2016, their migration, or their death. The occurrence of IMIDs was assessed using the Danish national patient register and Registry of Medicinal Products Statistics.

RESULTS

A total of 3,235 patients with a diagnosis of IBD (22.5%) has also received a diagnosis of an IMID; most IMIDs occurred before the onset of IBD (n = 2,600, 80.3%). The most common IMIDs observed were psoriasis, asthma, type 1 diabetes, and iridocyclitis. Patients with IBD treated with infliximab were at reduced risk of developing IMIDs (CD adjusted odds ratio [aOR], 0.52; 95% CI, 0.34-0.81 and UC aOR, 0.47; 95% CI, 0.29-0.76). Co-occurrence of IMIDs increased the risk of surgery in patients with CD that developed IMIDs after CD onset (aOR, 2.30; 95% CI, 1.46-4.20) but not in UC.

CONCLUSIONS

In a nationwide study of the Danish population, 22.5% of patients with IBD also had at least 1 concurrent IMID. Co-occurrence of IMIDs increased the risk of surgery in patients with CD.

Sex Difference in Celiac Disease in Undiagnosed Populations: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

A higher proportion of female vs male patients receive a diagnosis of celiac disease. Little is known about sex-based differences in the prevalence of celiac disease in undiagnosed populations. We aimed to address this knowledge gap with a systematic review and meta-analysis.

METHODS

We searched MEDLINE, Embase, Cochrane, and Scopus databases through 2017 for studies of screen-detected or undiagnosed celiac disease. Our final analysis included studies that included screening and confirmatory tests (either second serologic analysis or a small intestine biopsy) and provided information on the sex of participants. Studies were excluded if they were performed with specific, high-risk, or referral populations. The primary outcome was the percentage of undetected celiac disease among female and male patients.

RESULTS

We identified 4070 articles and analyzed data from 87. Our meta-analysis comprised data from 291,969 study participants. The pooled prevalence of undetected celiac disease in female participants was 0.589% (95% CI, 0.549%-0.629%) and in male participants was 0.415% (95% CI, 0.343%-0.487%). The risk of undetected celiac disease was higher among female than male participants (relative risk [RR], 1.42; 95% CI, 1.27-1.57; P < .00001). The I² was 5% (low heterogeneity among studies). In subgroup analyses, the RR of celiac disease for girls vs boys was 1.79 (95% CI, 1.44-2.22; P < .00001; I² = 18%), the RR for female vs male blood donors was 1.13 (95% CI, 0.76-1.69; P = .54; I² = 0), and the RR for women vs men with villous atrophy was 1.38 (95% CI, 1.07-1.79; P = .01; I² = 0).

CONCLUSIONS

In a systematic review and meta-analysis, we found a higher risk for celiac disease in women than men in an undiagnosed populations (identified through general population screening). The increased risk for celiac disease among girls and women should be considered for screening, diagnosis, and management strategies.

Changing Pattern of Childhood Celiac Disease Epidemiology: Contributing Factors

Up until the 1960s and 1970s, diarrhea, malabsorption syndrome, and failure to thrive were the presenting symptoms and signs of celiac disease (CD) in young infants; however this disease was also at the same time reported to be disappearing. Indeed, clinical childhood CD was seen to transform into a milder form, resulting in an upward shift in age at diagnosis during the 1970s (and years later for many countries). This changing pattern of CD presentation then altered the epidemiology of the disease, with major differences between and within countries observed. An awareness of the changing clinical nature of CD and use of case-finding tools to detect even clinically silent CD became an important factor in this changing epidemiology. Countries report both low and high prevalence but it seems to be on the increase resulting in a population-based level of 1-2%. This paper discusses the potential causes and environmental factors behind these observed clinical changes, identifying new clues from different studies published at the time this transformation took place. For instance, it was found that breastfeeding postponed the diagnosis of the disease but did not altogether prevent it. Moreover, gluten introduction at a young age, specifically at the mean age of 2 months, seemed to also have a clear impact in inducing malabsorption syndrome and failure to thrive in young infants in addition to other factors such as gluten intake volume and type of cereal present in the weaning food. Further, the impact of cow's milk and its high osmolarity might have played an important role; humanized milk formulas were not yet invented. Future epidemiological studies on the contributing environmental factors to the shift in CD presentation are thus recommended for countries in which these changing clinical features are still being observed.

Diagnostic Accuracy of a Point-of-Care Test for Celiac Disease Antibody Screening among Infertile Patients

BACKGROUND

Screening for celiac disease among infertile patients has been suggested. Several rapid point-of-care (POC) tests aimed at detecting celiac disease antibodies have been developed. It has been suggested that these POC tests can be implemented as a replacement for standard laboratory tests.

OBJECTIVE

To evaluate the diagnostic accuracy of a POC test (Simtomax®) that detects celiac disease antibodies compared with standard laboratory tests when screening for celiac disease among patients referred for fertility treatment in 2 Danish fertility clinics.

METHODS

Serum samples were analyzed for IgA anti-tissue transglutaminase (TGA) as the reference standard test with a cutoff of ≥7 kU/L and by the index POC test based on IgA and IgG antibodies against deamidated gliadin peptides (DGP). In IgA deficiency, the reference standard test was IgG DGP with a cutoff of ≥7 kU/L. Participants answered a questionnaire on gluten intake, symptoms, and risk factors. Diagnostic confirmation was made by duodenal biopsies. IgA TGA/IgG DGP were used as the reference standard to calculate positive and negative predictive values.

RESULTS

A total of 622 men and women (51.6%) were enrolled during 2015. The reference standard IgA TGA/IgG DGP was positive in 7 participants (1.1% [95% CI 0.5-2.3]) and the POC test was positive in 84 participants (13.5% [95% CI 10.9-16.4]), 3 of whom also had positive reference standard tests. This yields a sensitivity of the index POC test of 42.9% (95% CI 9.9-81.6) and a specificity of 86.8% (95% CI 83.9-89.4). Positive and negative predictive values were 3.57% (95% CI 0.7-10.1) and 99.3% (95% CI 98.1-99.8).

CONCLUSION

The sensitivity of the POC test was low; however, the specificity was moderately good. The POC test had a high negative predictive value in this low prevalent population but missed 1 patient with biopsy-confirmed celiac disease. However, because of many false-positive tests, it cannot be recommended as replacement for standard laboratory tests but rather as a triage test to decide if the standard serology tests should be performed.

Evolving patterns in the presentation of coeliac disease over the last 25 years

OBJECTIVE

To document changes in the clinical features of coeliac disease (CD) at presentation over the last 25 years.

DESIGN

Observational study.

PATIENTS

802 subjects diagnosed between 1993 and 2017 at a single general hospital.

OUTCOME MEASURES

Date of diagnosis, age, sex, postcode, symptoms, haematinic deficiency, smoking status, serology, family history and autoimmune phenomena.

RESULTS

The incidence of diagnosed CD rose threefold during the course of the study, with a rising prevalence of positive coeliac serology and positive family history of CD, and a falling prevalence of symptoms and haematinic deficiencies. There was little change in the female predominance, age at diagnosis or high prevalence of other autoimmune conditions over the 25 years, and a paucity throughout of cigarette smokers, particularly heavy smokers. A cohort of patients with seronegative CD was identified who shared many of the characteristics of seropositive CD, but with a significantly older age at diagnosis and a higher prevalence of cigarette smokers.

CONCLUSION

There have been major changes in the epidemiology of CD over the last 25 years, of relevance to both our understanding of the aetiopathogenesis of CD and the requirement for service provision. The implications are discussed.

Rising prevalence of celiac disease is not universal and repeated testing is needed for population screening

Background

Recent studies suggest that the prevalence of celiac disease is rising. We previously established the prevalence of celiac disease in healthy blood donors in 2002.

Objective

The purpose of this study was to examine whether the prevalence of celiac disease and celiac disease autoimmunity has changed over time by performing a similar prospective study.

Methods

Healthy blood donors (n = 1908) were tested for tissue transglutaminase antibodies and for anti-endomysial antibodies when positive. Further evaluation followed accepted criteria for diagnosis.

Results

Overall, 32 donors had abnormal tissue transglutaminase antibodies (1.68%). Eight donors had tissue transglutaminase antibodies >3 × upper limit of normal (0.42%), two of them with tissue transglutaminase antibodies >10 × upper limit of normal, while 24 donors had tissue transglutaminase antibodies <3 × upper limit of normal (1.26%). Most of the donors with positive tissue transglutaminase antibodies <3 × upper limit of normal had negative tissue transglutaminase antibodies levels on repeated testing (18/19). Celiac disease was diagnosed in four donors with positive tissue transglutaminase antibodies, establishing a prevalence of 1.68% (95% confidence interval 1.15-2.3) for celiac disease autoimmunity and 0.21% for celiac disease (95% confidence interval 0.07-0.5%).

Conclusion

The prevalence of celiac disease in blood donors in Israel did not rise in the last 15 years, suggesting that the increased prevalence of diagnosed celiac disease is mainly due to increased awareness. As most of the donors with elevated tissue transglutaminase antibodies <3 × upper limit of normal were endomysial antibody negative and had a negative tissue transglutaminase antibodies result upon re-testing, repeated tissue transglutaminase antibodies testing is required when screening asymptomatic populations for celiac disease.

Unrecognised coeliac disease among men and women undergoing fertility treatment: A screening study

BACKGROUND

Coeliac disease is an autoimmune disease triggered by dietary gluten and has been associated with several conditions influencing female and male reproduction. Due to unspecific symptoms, coeliac disease can be unrecognised for years.

OBJECTIVE

To estimate the prevalence of unrecognised coeliac disease among couples referred to fertility treatment.

METHODS

Cross-sectional screening for coeliac disease in men and women referred to fertility treatment using IgA tissue transglutaminase antibodies as a marker of coeliac disease and small-bowel biopsies to confirm the diagnosis. Participants answered a questionnaire on gluten intake, gastrointestinal symptoms and reproductive history.

RESULTS

A total of 893 participants (51% women) were screened and eight were coeliac disease antibody positive. Small-bowel biopsies were obtained from seven antibody positive participants and unrecognised coeliac disease was confirmed in one woman and three men, corresponding to a prevalence of 0.45% (95% confidence interval 0.12-1.14). The total prevalence, combining already diagnosed and unrecognised CD cases, was 0.63% (95% confidence interval 0.29-1.12).

CONCLUSION

The prevalence of unrecognised coeliac disease in a group of infertile patients was equivalent to that of the Danish general population and low compared with that observed in the majority of other screening studies of infertile patients. Surprisingly, it should be noted that more men than women had coeliac disease. This result does not support a need for routine screening among infertile patients.

The association of celiac disease and allergic disease in a general adult population

Background

The relationship between allergy and celiac disease (CD) is not clear.

Objective

The objective of this article is to investigate the association of CD and CD antibody positivity with hay fever, asthma and immunoglobulin (Ig)E sensitization in a general adult population.

Methods

A total of 2297 individuals were screened for CD antibodies and underwent allergy testing. CD antibody-positive participants were invited to undergo clinical evaluation including biopsies. Additionally, biobank blood samples from four population-based studies (6423, 973, 1718 and 1101 participants) with data on IgE sensitization to inhalant allergens were screened for CD antibodies. CD antibody-positive participants were screened for serum IgE against food allergens in three biobank studies. CD-antibody positivity was defined as IgA or IgG tissue transglutaminase ≥7 U/ml and/or IgG deamidated gliadin peptide ≥10 U/ml.

Results

The nine participants (0.4%) diagnosed with CD had significantly higher prevalence of IgE sensitization to wheat and dust mites. The prevalence of CD antibody positivity was 0.8% (18/2297), and these participants had a significantly higher prevalence of IgE sensitization to food allergens (Fx5), egg, dust mites and mugwort. In the biobank studies, the prevalence of CD antibody positivity was 0.8% to 1.2%. One study showed a positive association between CD antibody positivity and IgE sensitization for dog, horse and food allergens.

Conclusion

We found a possible association of CD and IgE sensitization to some food and inhalant allergens in the Health2006 study. In further studies, however, we could not consistently replicate these associations.

The distribution of HLA DQ2 and DQ8 haplotypes and their association with health indicators in a general Danish population

Background

Human leukocyte antigen (HLA) DQ2 and DQ8 are important risk factors for some autoimmune diseases such as celiac disease (CD), but their possible role in other diseases and health conditions is not fully explored.

Objectives

The objective of this article is to examine the distribution of HLA DQ2 and HLA DQ8 in an adult general population, and their association with health indicators (diseases, symptoms and biomarkers).

Methods

In this cross-sectional, population-based study, 2293 individuals were screened for HLA DQ2 and DQ8; CD-associated alleles (DQA*0201*03*05/DQB*02*0301/0304*0302/0305) and DQB1*02 homozygosity were determined for screen-positive participants. The National Patient Registry provided diagnosis information.

Results

A total of 47.7% (1093/2293) individuals were positive for DQ2 and/or DQ8: 31.2% (716/2293) only DQ2, 11.9% (273/2293) only DQ8, 4.1% (93/2293) both DQ2 and DQ8. Among nine individuals diagnosed with CD, 89.9% (8/9) had DQ2.5cis, 22.2% (2/9) DQ8 and 22.2% (2/9) DQ2.2 (two both DQ2 and DQ8). HLA DQ2.5 was associated with higher thyroid-stimulating hormone levels, while DQ2/DQ8-positive participants had significantly lower prevalence of irritable bowel syndrome (IBS). DQ2/DQ8 were strongly associated with CD, but no other registry-based diagnoses.

Conclusion

In this general Danish population, 47.7% were HLA DQ2/DQ8 positive and thus potentially at risk for CD. All individuals with CD were DQ2/DQ8 positive; the majority DQ2.5. Surprisingly, DQ2/DQ8-positivity was associated with lower IBS prevalence.