The new epidemiology of celiac disease

Patients With Celiac Disease Reported Higher Consumption of Added Sugar and Total Fat Than Healthy Individuals

OBJECTIVES

The aim of the study was to compare the dietary pattern between subjects with celiac disease (CD) (cases) and subjects without (healthy controls) CD.

METHODS

A case-control design study was conducted. A total of 98 subjects with CD (age 10-23 years) were matched by age, sex, and body mass index with 98 nonceliac participants. A nonconsecutive 3-day food record was completed to assess energy, nutrient, and food intake and evaluate the participant's adherence to recommendations. Differences in energy, nutrients, food consumption, and compliance with general recommendations between cases and control groups were assessed by Student t test. Pearson chi-squared test was used to compare categorical variables. Sociodemographic, personal, and family history data were collected.

RESULTS

Compared with the control group, the cases with CD reported a significantly higher consumption of added sugar (P < 0.001) and total fat (P < 0.017). Mean fiber consumption was below the nutritional recommendations in both groups. Participants with CD consumed significantly lower amounts of foods rich in starch (P < 0.001) and higher amounts of foods rich in protein such as meat, fish, and eggs (P = 0.007). Subjects with CD showed a significantly lower percentage of adherence to recommendations for folic acid (53.2 vs 70.5; P < 0.001), calcium (49.0 vs 56.3; P = 0.025), iron (57.4 vs 78.0; P < 0.001), and magnesium (50.0 vs 63.9; P < 0.001).

CONCLUSIONS

The subjects with CD showed a more unbalanced diet than controls in terms of added sugars, total fat, and micronutrient consumption.

The progression of coeliac disease: its neurological and psychiatric implications

The aim of the paper is to show the various neurological and psychiatric symptoms in coeliac disease (CD). CD is a T cell-mediated, tissue-specific autoimmune disease which affects genetically susceptible individuals after dietary exposure to proline- and glutamine-rich proteins contained in certain cereal grains. Genetics, environmental factors and different immune systems, together with the presence of auto-antigens, are taken into account when identifying the pathogenesis of CD. CD pathogenesis is related to immune dysregulation, which involves the gastrointestinal system, and the extra-intestinal systems such as the nervous system, whose neurological symptoms are evidenced in CD patients. A gluten-free diet (GFD) could avoid cerebellar ataxia, epilepsy, neuropathies, migraine and mild cognitive impairment. Furthermore, untreated CD patients have more symptoms and psychiatric co-morbidities than those treated with a GFD. Common psychiatric symptoms in untreated CD adult patients include depression, apathy, anxiety, and irritability and schizophrenia is also common in untreated CD. Several studies show improvement in psychiatric symptoms after the start of a GFD. The present review discusses the state of the art regarding neurological and psychiatric complications in CD and highlights the evidence supporting a role for GFD in reducing neurological and psychiatric complications.

Serological screening for Celiac Disease in 382 pre-schoolers with Autism Spectrum Disorder

Background

Recent investigations suggest a possible common genetic background between Autism Spectrum Disorders (ASD) and Celiac Disease (CD). However, studies regarding this association are scarce and often limited by the small sample sizes and/or large heterogeneity among ASD groups in terms of demographic and clinical features. The present study aims to investigate the overall CD prevalence (biopsy proven-CD patients plus screening detected tTG and EMA positive cases) in a large population of pre-schoolers with ASD referred to a tertiary care University Hospital.

Methods

We retrospectively collected data about 382 children (mean age: 46.97 ± 13.55 months; age-range: 18-72 months) consecutively diagnosed as ASD (according to the Diagnostic and Statistical Manual of Mental Disorders 4th edition criteria) over the period 2010–2013, and who performed a serological CD screening.

Results

The overall CD prevalence was 2.62%, which is statistically significant higher to that reported in the Italian paediatric population (p = 0.0246). Half of these children had no symptoms or risk factors related to CD when they performed the serological screening.

Conclusions

If replicated, these data suggest the importance of regular screening for CD in young patients with ASD, and are of relevance for clinical and public health.

Fecal Gluten Peptides Reveal Limitations of Serological Tests and Food Questionnaires for Monitoring Gluten-Free Diet in Celiac Disease Patients

OBJECTIVES

Treatment for celiac disease (CD) is a lifelong strict gluten-free diet (GFD). Patients should be followed-up with dietary interviews and serology as CD markers to ensure adherence to the diet. However, none of these methods offer an accurate measure of dietary compliance. Our aim was to evaluate the measurement of gluten immunogenic peptides (GIP) in stools as a marker of GFD adherence in CD patients and compare it with traditional methods of GFD monitoring.

METHODS

We performed a prospective, nonrandomized, multicenter study including 188 CD patients on GFD and 84 healthy controls. Subjects were given a dietary questionnaire and fecal GIP quantified by enzyme-linked immunosorbent assay (ELISA). Serological anti-tissue transglutaminase (anti-tTG) IgA and anti-deamidated gliadin peptide (anti-DGP) IgA antibodies were measured simultaneously.

RESULTS

Of the 188 celiac patients, 56 (29.8%) had detectable GIP levels in stools. There was significant association between age and GIP in stools that revealed increasing dietary transgressions with advancing age (39.2% in subjects ≥13 years old) and with gender in certain age groups (60% in men ≥13 years old). No association was found between fecal GIP and dietary questionnaire or anti-tTG antibodies. However, association was detected between GIP and anti-DGP antibodies, although 46 of the 53 GIP stool-positive patients were negative for anti-DGP.

CONCLUSIONS

Detection of gluten peptides in stools reveals limitations of traditional methods for monitoring GFD in celiac patients. The GIP ELISA enables direct and quantitative assessment of gluten exposure early after ingestion and could aid in the diagnosis and clinical management of nonresponsive CD and refractory CD. Trial registration number NCT02711397.

Cost effectiveness of routine duodenal biopsies in iron deficiency anemia

AIM

To investigate the cost effectiveness of routine small bowel biopsies (SBBs) in patients with iron deficiency anemia (IDA) independent of their celiac disease (CD) serology test results.

METHODS

We used a state transition Markov model. Two strategies were compared: routine SBBs during esophagogastroduodenoscopy (EGD) in all patients with IDA regardless their celiac serology status (strategy A) vs SBBs only in IDA patients with positive serology (strategy B). The main outcomes were quality adjusted life years (QALY), average cost and the incremental cost effectiveness ratio (ICER). One way sensitivity analysis was performed on all variables and two way sensitivity analysis on selected variables were done. In order to validate the results, a Monte Carlo simulation of 100 sample trials with 10, and an acceptability curve were performed.

RESULTS

Strategy A of routine SBBs yielded 19.888 QALYs with a cost of $218.10 compared to 19.887 QALYs and $234.17 in strategy B. In terms of cost-effectiveness, strategy A was the dominant strategy, as long as the cost of SBBs stayed less than $67. In addition, the ICER of strategy A was preferable, providing the cost of biopsy stays under $77. Monte Carlo simulation demonstrated that strategy A yielded the same QALY but with lower costs than strategy B.

CONCLUSION

Our model suggests that EGD with routine SBBs is a cost-effective approach with improved QALYs in patients with IDA when the prevalence of CD is 5% or greater. SBBs should be a routine screening tool for CD among patients with IDA, regardless of their celiac antibody status.

Feasibility of screening for T1D and celiac disease in a pediatric clinic setting

OBJECTIVE

Type 1 diabetes (T1D) or celiac disease (CD) develops in at least 2% of the general population. Early detection of disease-specific autoimmunity and subsequent monitoring would be possible if screening tests were more widely available. Currently, screening for islet autoimmunity is available only in a research setting, and CD-specific autoimmunity screening is limited to those in high-risk groups. This study assessed the feasibility of incorporating T1D and CD autoantibody screening into a pediatric practice.

METHODS

Patient engagement strategies, blood collection preference, blood sample volume, rate of autoantibody detection in the general population, and parental satisfaction were assessed. Over 5 weeks, research staff recruited 200 patients, aged 2-6 yr from two pediatric practices in the Denver area to be screened for islet autoantibodies (IAs) and the transglutaminase antibody.

RESULTS

Of the 765 parents approached, 200 (26%) completed the same-day screening. Of the 565 subjects who did not complete the screening, 345 expressed interest, but were unable to make a participation decision. A finger stick, compared with a venous draw, was the preferred method of sample collection. Both methods yielded sufficient blood volume for autoantibody determination. IAs or the transglutaminase antibody were detected in 11 subjects. Parents expressed satisfaction with all aspects of participation.

CONCLUSIONS

The results of this study suggest that it is feasible to conduct this type of screening in a pediatric clinic. Such screening could lead to increased disease awareness and the possible benefits that can result from early detection.

Immunopathogenesis and therapeutic approaches in pediatric celiac disease

Celiac Disease is an autoimmune enteropathy with increasing incidence worldwide in both adults and children. It occurs as an inflammatory condition with destruction of the normal architecture of villi on consumption of gluten and related protein products found in wheat, barley and rye. However, the exact pathogenesis is not yet fully understood. A gluten-free diet remains the main modality of therapy to date. While some patients continue to have symptoms even on a gluten-free diet, adherence to this diet is also difficult, especially for the children. Hence, there is continued interest in novel methods of therapy and the current research focus is on the promising novel non-dietary modalities of treatment. Here, we critically reviewed the existing literature regarding the pathogenesis of celiac disease in children including the role of in-utero exposure leading to neonatal and infant sensitization and its application for the development of new therapeutic approaches for these patients.

Gluten Introduction and the Risk of Coeliac Disease: A Position Paper by the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition

BACKGROUND

The European Society for Paediatric Gastroenterology, Hepatology and Nutrition recommended in 2008, based on observational data, to avoid both early (<4 months) and late (≥7 months) introduction of gluten and to introduce gluten while the infant is still being breast-fed. New evidence prompted ESPGHAN to revise these recommendations.

OBJECTIVE

To provide updated recommendations regarding gluten introduction in infants and the risk of developing coeliac disease (CD) during childhood.

SUMMARY

The risk of inducing CD through a gluten-containing diet exclusively applies to persons carrying at least one of the CD risk alleles. Because genetic risk alleles are generally not known in an infant at the time of solid food introduction, the following recommendations apply to all infants, although they are derived from studying families with first-degree relatives with CD. Although breast-feeding should be promoted for its other well-established health benefits, neither any breast-feeding nor breast-feeding during gluten introduction has been shown to reduce the risk of CD. Gluten may be introduced into the infant's diet anytime between 4 and 12 completed months of age. In children at high risk for CD, earlier introduction of gluten (4 vs 6 months or 6 vs 12 months) is associated with earlier development of CD autoimmunity (defined as positive serology) and CD, but the cumulative incidence of each in later childhood is similar. Based on observational data pointing to the association between the amount of gluten intake and risk of CD, consumption of large quantities of gluten should be avoided during the first weeks after gluten introduction and during infancy. The optimal amounts of gluten to be introduced at weaning, however, have not been established.

Effects of Gluten Intake on Risk of Celiac Disease: A Case-Control Study on a Swedish Birth Cohort

BACKGROUND & AIMS

Early nutrition may affect the risk of celiac disease. We investigated whether amount of gluten in diet until 2 years of age increases risk for celiac disease.

METHODS

We performed a 1-to-3 nested case-control study of 146 cases, resulting in 436 case-control pairs matched for sex, birth year, and HLA genotype generated from Swedish children at genetic risk for celiac disease. Newborns were annually screened for tissue transglutaminase autoantibodies (tTGA). If tested tTGA positive, time point of seroconversion was determined from frozen serum samples taken every 3 months. Celiac disease was confirmed by intestinal biopsies. Gluten intake was calculated from 3-day food records collected at ages 9, 12, 18 and 24 months. Odds ratios (OR) were calculated through conditional logistic regression.

RESULTS

Breastfeeding duration (median, 32 wk) and age at first introduction to gluten (median, 22 wk) did not differ between cases and tTGA-negative controls. At the visit before tTGA seroconversion, cases reported a larger intake of gluten than controls (OR, 1.28; 95% confidence interval [CI], 1.13-1.46; P = .0002). More cases than controls were found in the upper third tertile (ie, >5.0 g/d) before they tested positive for tTGA seroconversion than controls (OR, 2.65; 95% CI, 1.70-4.13; P < .0001). This finding was similar in children homozygous for DR3-DQ2 (OR, 3.19; 95% CI, 1.61-6.30; P = .001), heterozygous for DR3-DQ2 (OR, 2.24; 95% CI, 1.08-4.62; P = .030), and for children not carrying DR3-DQ2 (OR, 2.43; 95% CI, 0.90-6.54; P = .079).

CONCLUSIONS

The amount of gluten consumed until 2 years of age increases the risk of celiac disease at least 2-fold in genetically susceptible children. These findings may be taken into account for future infant feeding recommendations.

Assessment of coeliac disease prevalence in patients with Down syndrome in Poland - a multi-centre study

Introduction

The results of studies assessing whether patients with Down syndrome have increased risk of coeliac disease are contradictory. The prevalence of coeliac disease in patients with Down syndrome is estimated at a wide range between 1% to as much as 18.6%.

Aim

To assess coeliac disease prevalence in patients with Down syndrome in Poland.

Material and methods

The study enrolled 301 patients with Down syndrome from six centres in Poland (Wroclaw, Sandomierz, Rzeszow, Grudziadz, Katowice, and Bydgoszcz). We measured the concentration of anti-tissue transglutaminase IgA antibodies and anti-deamidated gliadin peptide IgG antibodies in all patients. Patients with abnormal positive (> 10 U/ml) or inconclusive (7–10 U/ml) result of the serological test were offered endoscopic biopsy of the small intestine in the main centre.

Results

In 31 (10.3%) patients increased concentrations of the investigated antibodies were found, including 19 (6.3%) patients with increased tTg-IgA concentration, 27 (8.97%) patients with increased concentration of DGP-IgG, and 15 (4.98%) patients with increased concentration of both types of antibodies. Endoscopic biopsy of the small intestine was planned for all 31 patients with abnormal results of at least one antibody test and for 2 patients with inconclusive results. One of them suffered from previously diagnosed and histologically confirmed coeliac disease. Biopsy was not conducted in 9 patients due to contraindications, lack of their consent, or introduction of a gluten-free diet by the parents before the examination. In a group of 23 patients who underwent endoscopic biopsy of the small intestine, in 15 patients the histopathological picture of the small intestinal mucosa was typical for coeliac disease, 2 patients were diagnosed with lesions of grade 1 according to the classification by Marsh-Oberhuber, 1 patient was diagnosed with focal shortening of villi and hypertrophy of the crypts with no intraepithelial lymphocytosis (remains under gastrological observation), 2 patients were diagnosed with mucosal inflammation of the duodenum, and 3 patients were found to have a normal histopathological picture of the small intestine. Analysis of the data included in the questionnaires of all patients showed no statistically significant differences in the body height, body mass index, prevalence of abdominal pain, diarrhoea, constipations, recurrent stomatitis, enamel hypoplasia, thyroid diseases, or hypertransaminasaemia between the groups of patients with normal and abnormal serological test results. Significantly higher prevalence of abdominal flatulence (p < 0.05) and epilepsy (p < 0.05) was found in the group of patients whose serological test results were negative.

Conclusions

Patients with Down syndrome are a high-risk group for coeliac disease in the Polish population, with an estimated prevalence of at least 5.4%. Serological tools based on tTG-IgA and DGP-IgG tests are useful for the diagnosis of coeliac disease in Down syndrome patients. tTG-IgA test may be superior to DGP-IgG test in patients with normal total IgA level. Tests for coeliac disease should be carried out in all Polish patients with Down syndrome, regardless of the clinical picture.

The celiac iceberg: from the clinical spectrum to serology and histopathology in children and adolescents with type 1 diabetes mellitus and Down syndrome

OBJECTIVE

The objective of this study is to investigate the occurrence of gastrointestinal (GI) and extraintestinal symptoms in children and adolescents with type 1 diabetes mellitus (DM1) and Down syndrome (DS) and their association with specific antibodies and histopathology of celiac disease (CelD), representing its clinical forms in the iceberg.

MATERIAL AND METHODS

Cross-sectional study (November 2009-December 2012) conducted at an outpatient care facility in Northeast Brazil including patients [DM1 (n = 111); DS (n = 77)] aged 10 months-18 years old. Measurement of anti-endomysial (EmA) and anti-tissue transglutaminase (anti-tTG) IgA antibodies was performed, as was that of anti-tTG-IgG in the cases with low serum IgA. The patients with antibody positivity were subjected to small intestine biopsy.

RESULTS

GI symptoms occurred in 53.7% of the sample, extraintestinal symptoms in 4.3%, and antibody positivity in 28.2% (n = 53). Of those who underwent biopsy (n = 40), histopathological findings of CelD were found in 37.5% [DM1 = 5/111 (4.5%), DS = 10/77 (13.0%)]. GI symptoms were associated with antibody positivity, but not with the histopathology. The GI (32.5%), silent (5.0%), and potential (62.5%) forms of disease were detected.

CONCLUSIONS

The prevalence of GI symptoms was high in groups DM1 and DS, and the occurrence of such symptoms was associated with antibody positivity. The lack of association between the symptoms and histopatholological findings points to the inconsistency of the former as indicators of CelD. Although the GI form predominated among the cases with active CelD, its contribution to the celiac iceberg was smaller compared with the potential form, which determined the large and submerged base of the iceberg representing the high-risk groups investigated.

Prevalence of Adult Celiac Disease in India: Regional Variations and Associations

OBJECTIVES

Although celiac disease (CeD) affects 1% of people in the northern part of India, it is believed to be uncommon in the southern and northeastern parts because of significant differences in dietary pattern and ethnicity. We estimated the prevalence of CeD in these three populations. In a subset, we also investigated differences in the prevalence of HLA-DQ 2/8 allelotype and dietary grain consumption.

METHODS

A total of 23,331 healthy adults were sampled from three regions of India-northern (n=6207), northeastern (n=8149), and southern (n=8973)-and screened for CeD using IgA anti-tissue transglutaminase antibody. Positive tests were reconfirmed using a second ELISA. CeD was diagnosed if the second test was positive and these participants were further investigated. A subsample of participants was tested for HLA-DQ2/-DQ8 and underwent detailed dietary evaluation.

RESULTS

Age-adjusted prevalence of celiac autoantibodies was 1.23% in northern, 0.87% in northeastern, and 0.10% in southern India (P<0.0001). Prevalence of CeD and latent CeD, respectively, was 8.53/1,000 and 3.70/1,000 in northern, 4.66/1,000 and 3.92/1,000 in northeastern, and 0.11/1,000 and 1.22/1,000 in the southern part. The population prevalence of genes determining HLA-DQ2 and/or -DQ8 expression was 38.1% in northern, 31.4% in northeastern, and 36.4% in southern India. Mean daily wheat intake was highest in northern (455 g) compared with northeastern (37 g) or southern part (25 g), whereas daily rice intake showed an inverse pattern.

CONCLUSIONS

CeD and latent CeD were most prevalent in northern India and were the least in southern India. The prevalence correlated with wheat intake and did not reflect differences in the genetic background.

Presentation of Celiac Disease in Finnish Children Is No Longer Changing: A 50-Year Perspective

OBJECTIVES

To chart trends in the presentation of celiac disease in a large cohort of Finnish children diagnosed over a period of 48 years.

STUDY DESIGN

Clinical and serologic data, severity of small-bowel mucosal damage, and presence of associated conditions were gathered from 596 children diagnosed with celiac disease in 1966-2013. The children were divided into 4 groups based on the year of diagnosis (before 1980, 1980-1999, 2000-2009, and 2010-2013), and the variables were compared between the periods. The incidence of celiac disease autoimmunity in 2001-2013 was calculated based on the number of new antibody-positive cases in each year.

RESULTS

Age at diagnosis rose from median 4.3 years before 1980 to between 7.6 and 9.0 years in the later periods. The severity of clinical presentation, in general, became milder and poor growth less common during the entire study period of 50 years. Percentages of children with classical gastrointestinal presentation decreased, and those with atypical or subclinical presentation increased after the 1990s, these changes leveling off in 2000-2013. Similarly, the severity of small-bowel mucosal damage was milder after the 1990s. The incidence of celiac disease autoimmunity increased in the early 2000s but then fluctuated without a clear trend. There were no significant secular changes in sex distribution, presence of anemia, levels of celiac antibodies, or celiac disease-associated conditions.

CONCLUSIONS

The clinical and histologic presentation of celiac disease in children became milder, especially in the 1980s and 1990s. However, most of these changes have reached a plateau in recent years.

Coeliac disease and gluten-related disorders in childhood

Gluten-related disorders such as coeliac disease, wheat allergy and noncoeliac gluten sensitivity are increasingly being diagnosed in children. Coeliac disease occurs frequently, affecting 1-3% of the Western population. The condition manifests at a very young age, more so in girls, and is related to the HLA genotype. Coeliac disease might be considered a public health problem and, as primary prevention is not possible, the debate on mass screening should be reopened. Wheat proteins, including gluten, are responsible for one of the most common food allergies in children: wheat allergy. Unlike coeliac disease and wheat allergy, noncoeliac gluten sensitivity is an unclear and controversial entity. These three gluten-related disorders are treated with a gluten-free diet. In coeliac disease, the diet should be strictly followed, whereas wheat allergy only requires wheat elimination and in noncoeliac gluten sensitivity occasional trials of gluten reintroduction can be done. A good diagnostic work-up is important for gluten-related disorders in childhood to avoid unnecessary restrictive diets in children. In this Review, we provide an overview of the pathogenesis, diagnosis and management of the most common gluten-related disorders in children.

Analysis of Body Composition and Food Habits of Spanish Celiac Women

The purpose of the present work was both to analyze composition of Spanish celiac women and to study the food habits and gluten-free diet of these celiac patients, in order to determine whether they achieve a balanced and healthy diet as well as to highlight nutritional qualitative and/or quantitative differences. 54 adult celiac women (34 ± 13 years) took part in the six-month study. Height, weight and body composition were measured. An analysis of energy consumption and of the macronutrient distribution of their diet was carried out. Their fulfillment of micronutrient intake recommendations was verified. Participants showed a Body Mass Index of 21.6 ± 2.4 kg/m2. Energy Intake was slightly lower than the Dietary Reference Intakes. Excessive protein apart from over-consumption of fat was observed. More than three quarters of participants consumed meat in excess. Carbohydrate consumption along with that of fiber was below recommended levels. Vitamin D, iron, and iodine had a low percentage of recommendation compliance. In general, participants followed the recommendations of dairy products and fruit intake whereas vegetable consumption was not enough for the vast majority. We conclude that although the diet of celiac women does not differ much from the diet of general population, some considerations, such as reducing fat and protein consumption and increasing fiber intake, must be taken into account.

Diagnosis of Non-Celiac Gluten Sensitivity (NCGS): The Salerno Experts' Criteria

Non-Celiac Gluten Sensitivity (NCGS) is a syndrome characterized by intestinal and extra-intestinal symptoms related to the ingestion of gluten-containing food, in subjects that are not affected by either celiac disease or wheat allergy. Given the lack of a NCGS biomarker, there is the need for standardizing the procedure leading to the diagnosis confirmation. In this paper we report experts’ recommendations on how the diagnostic protocol should be performed for the confirmation of NCGS. A full diagnostic procedure should assess the clinical response to the gluten-free diet (GFD) and measure the effect of a gluten challenge after a period of treatment with the GFD. The clinical evaluation is performed using a self-administered instrument incorporating a modified version of the Gastrointestinal Symptom Rating Scale. The patient identifies one to three main symptoms that are quantitatively assessed using a Numerical Rating Scale with a score ranging from 1 to 10. The double-blind placebo-controlled gluten challenge (8 g/day) includes a one-week challenge followed by a one-week washout of strict GFD and by the crossover to the second one-week challenge. The vehicle should contain cooked, homogeneously distributed gluten. At least a variation of 30% of one to three main symptoms between the gluten and the placebo challenge should be detected to discriminate a positive from a negative result. The guidelines provided in this paper will help the clinician to reach a firm and positive diagnosis of NCGS and facilitate the comparisons of different studies, if adopted internationally.

Microscopic colitis (lymphocytic and collagenous), eosinophilic colitis, and celiac disease

Multiple tests are needed to diagnose a patient with noninfectious diarrhea. Some patients will be mistakenly labeled as diarrhea-predominant irritable bowel syndrome (IBS-D) because of nonspecific computed tomographic scans and grossly normal endoscopic findings. It is crucial to understand other less common pathologies to avoid these instances of misdiagnosis. This article focuses on microscopic colitis (MC), eosinophilic colitis (EC), and celiac disease. MC is an inflammatory condition of the colon that presents with two subtypes, only to be differentiated by histology. EC is a rare chronic inflammatory process. Depending on the extent of the disease, it can present with mild diarrhea, malabsorption, or at its worst, cause obstruction and perforation. Celiac disease affects the small bowel, but interestingly can present similarly to colitis. Both MC and EC respond to oral budesonide. Patients with celiac disease improve on gluten-free diets. These treatments are distinctly different from typical IBS-D care plans.

The prevention of coeliac disease

Primary prevention of coeliac disease is currently not possible. Previously, a 'window of opportunity' was suggested for primary prevention, by introducing gluten between four and six months of age. However, results from recent prospective studies establish that the timing of gluten introduction and the duration or maintenance of breastfeeding do not influence the development of the disease. Secondary prevention is possible through early diagnosis and treatment. Since coeliac disease is severely underdiagnosed, the only way to achieve large-scale secondary prevention is by mass screening. Prospective studies indicate that important health problems, such as reduced foetal growth and birth weight, delayed growth in height and weight in children, and reduced bone mineral density in both children and adults can be prevented by mass screening. Adherence to a strict gluten-free diet may be considered as tertiary prevention.

Celiac disease from a global perspective

Celiac disease (CD) is one of the commonest lifelong disorders in countries populated by individuals of European origin, affecting approximately 1% of the general population. This is a common disease also in North Africa, Middle East and India. The widespread diffusion of CD is not surprising given that its causal factors (HLA predisposing genotypes and consumption of gluten-containing cereals) show a worldwide distribution. Further studies are needed to quantify the incidence of CD in apparently "celiac-free" areas such as Sub-Saharan Africa and Far East. Several reports have shown that CD is increasing in frequency in different geographic areas. Genetic factors do not explain the rising incidence during the last decades; environmental or lifestyle factors may be responsible for these changes over time. The majority of patients with CD are still undiagnosed all over the world, leading to debate about the need of screening program.

World perspective and celiac disease epidemiology

In Europe and the USA, the mean frequency of celiac disease (CD) in the general population is approximately 1%, with some regional differences, the reasons for which remain elusive. A similar disease prevalence has been found in other countries mostly populated by individuals of European origin, e.g. Australia and Argentina. In Western countries, a true rise in overall CD prevalence of CD has been documented. CD is a common disorder in North Africa, the Middle East and India; however, the diagnostic rate is low in these countries due to low availability of diagnostic facilities and poor disease awareness. The highest CD prevalence in the world (5.6%) has been described in an African population originally living in Western Sahara, the Saharawi, of Arab-Berber origin. The reasons for this high CD frequency are unclear but could be primarily related to recent dietary changes and genetic factors, given the high level of consanguinity of this population. Further studies are needed to quantify the incidence of the celiac condition in apparently 'celiac-free' areas such as Sub-Saharan Africa and the Far East. In many developing countries, the frequency of CD is likely to increase in the near future given the diffuse tendency to adopt Western, gluten-rich dietary patterns. As most cases currently escape diagnosis all over the world, an effort should be made to increase the awareness of CD polymorphism. A cost-effective case-finding policy and new strategies of mass CD screening could significantly reduce the morbidity and mortality associated with untreated disease. The current high prevalence of CD is just the last link in a chain of events started about 10,000 years ago after wheat domestication and diffusion from the Middle East. We hypothesize different mechanisms to explain the so-called evolutionary celiac paradox of co-localization of gluten consumption and HLA CD-predisposing genotypes.

Celiac disease and the gluten-free diet: consequences and recommendations for improvement

BACKGROUND

Celiac disease (CD) is a chronic small intestinal immune-mediated enteropathy precipitated by exposure to dietary gluten in genetically susceptible individuals. CD-related enteropathy leads to multiple nutritional deficiencies involving macro- and micronutrients. Currently, medical nutrition therapy consisting of the gluten-free diet (GFD) is the only accepted treatment for CD.

KEY MESSAGES

The GFD is the cornerstone of treatment for CD. Prior published studies have concluded that maintenance of the GFD results in improvement of the majority of nutritional deficiencies. In the past, counseling for CD focused mainly on the elimination of gluten in the diet. However, the GFD is not without its inadequacies; compliance to the GFD may result in certain deficiencies such as fiber, B vitamins, iron, and trace minerals. Paucity of fortified gluten-free foods may be responsible for certain deficiencies which develop on the GFD. Weight gain and obesity have been added to the list of nutritional consequences while on the GFD and have been partially attributed to hypercaloric content of commercially available gluten-free foods. Follow-up of patients diagnosed with CD after starting the GFD has been reported to be irregular and, hence, less than ideal.

CONCLUSIONS

Monitoring of the nutritional status using blood tests and use of appropriate gluten-free supplementation are integral components in the management of CD. The ideal GFD should be nutrient-dense with naturally gluten-free foods, balanced with macro- and micronutrients, reasonably priced, and easily accessible. Rotation of the pseudo-cereals provides a good source of complex carbohydrates, protein, fiber, fatty acids, vitamins and minerals. Fortification/enrichment of commonly consumed gluten-free commercial grain products should be encouraged. Dietitians specializing in CD play a critical role in the education and maintenance of the GFD for patients with CD.

Gut microbes and adverse food reactions: Focus on gluten related disorders

Immediately following birth, the gastrointestinal tract is colonized with a complex community of bacteria, which helps shape the immune system. Under conditions of health, the immune system is able to differentiate between innocuous antigens, including food protein and commensals, and harmful antigens such as pathogens. However, patients with celiac disease (CD) develop an intolerance to gluten proteins which results in a pro-inflammatory T-cell mediated immune response with production of anti-gluten and anti-tissue transglutaminase antibodies. This adaptive immune response, in conjunction with activation of innate inflammatory cells, lead to destruction of the small intestinal mucosa. Overall 30% of the global population has genetic risk to develop CD. However, only a small proportion develop CD, suggesting that additional environmental factors must play a role in disease pathogenesis. Alterations in small intestinal microbial composition have recently been associated with active CD, indicating a possible role for the microbiota in CD. However, studies demonstrating causality are lacking. This review will highlight the recent data on the potential role of the microbiota in CD pathogenesis, the potential mechanisms, and discuss future research directions.