Motility disorders in patients with celiac disease

Gallbladder motility in children with celiac disease before and after gluten-free diet

Background

Gallbladder (GB) hypomotility has been reported in adults with celiac disease (CD), but there is no literature on GB dysfunction in children with CD. We aimed to study GB motility in children with CD, before and after a gluten-free diet (GFD), using ultrasonography (USG) and technetium-99 labeled mebrofenin hepatobiliary scintigraphy (HBS).

Methods

Children with newly diagnosed CD were enrolled and evaluated for GB ejection fraction (GBEF) using HBS and USG. Those with reduced GBEF on initial HBS were again evaluated after 6 months of strict GFD and the results were compared.

Results

Of the 50 children with CD (mean age 9±2.1 years, 54% boys), 16% (n=8) had a low GBEF at baseline (19±13%). These children had a significantly greater delay in diagnosis compared to those with normal GBEF (6.5±2.0 vs. 2.3±1.2 years, P<0.001). A significant improvement in GBEF was noted on HBS post GFD (74±12%1 vs. 9±13%, P<0.001). GBEF also improved significantly as assessed by USG parameters after GFD (P<0.001). The fasting GB volume decreased (5.7±1.4 vs. 10.2±2.6, P=0.002), with a significant improvement in percentage postprandial GB volume change (52±10.5% vs. 24±16.5%, P=0.007) compared to baseline pre-GFD values. Orocecal transit time was also increased in children with reduced GBEF.

Conclusions

GB function is impaired in at least 16% of children with CD at diagnosis and is reversible with GFD. GB dysfunction is significantly associated with a delayed diagnosis and may be a part of general gastrointestinal dysmotility.

Motility Disorders in Celiac Disease and Non-Celiac Gluten Sensitivity: The Impact of a Gluten-Free Diet

Background: There is evidence that digestive motor disorders are frequently present in untreated celiac disease (CD) patients. Similarly, non-celiac gluten sensitivity (NCGS) can be associated with gut motor disorders. In both cases, gut dysmotility can improve or be completely reversed with a gluten-free diet (GFD). Methods: A literature search for motility disorders in CD and NCGS patients was carried out using the online databases PubMed, Medline and Cochrane. Results: Esophageal, gastric, small bowel and gallbladder motor disorders are common in both children and adults with CD. Although the clinical consequences of these disorders are not clearly defined, gastric dysfunction could affect drug absorption and metabolism in the thyroid and neurological conditions associated with CD. The impact of a GFD on motility disorders is, however, controversial. No systematic studies are available on NCGS. NCGS frequently overlaps with irritable bowel syndrome (IBS) and similar pathophysiological mechanisms may be hypothesized. Conclusions: Mucosal damage may affect gut motility in untreated CD through perturbation of hormonal and neuro-immunomodulatory regulation. A persistent low-grade mucosal inflammation could explain the cases of persistent motor disorders despite a GFD. Further studies are needed to definitely assess the role of gut motor disorders in NCGS.

Nomenclature and diagnosis of gluten-related disorders: A position statement by the Italian Association of Hospital Gastroenterologists and Endoscopists (AIGO)

BACKGROUND

"Gluten-related disorders" is a term that encompasses different diseases induced by the ingestion of gluten-containing food. Because of their incidence the scientific community has been intensively studying them.

AIM

To support gastroenterologists with a correct nomenclature and diagnostic approach to gluten-related disorders in adulthood.

METHODS

The Italian Association of Hospital Gastroenterologists and Endoscopists (AIGO) commissioned a panel of experts to prepare a position statement clarifying the nomenclature and diagnosis of gluten-related disorders, focusing on those of gastroenterological interest. Each member was assigned a task and levels of evidence/recommendation have been proposed.

RESULTS

The panel identified celiac disease, wheat allergy and non-celiac gluten sensitivity as the gluten-related disorders of gastroenterological interest. Celiac disease has an autoimmune nature, wheat allergy is IgE-mediated while the pathogenesis of non-celiac gluten sensitivity is still unknown as is the case of non-IgE mediated allergy. Diagnosis should start with the serological screening for celiac disease and wheat allergy. In case of normal values, the response to a gluten-free diet should be evaluated and a confirmatory blind food challenge carried out.

CONCLUSIONS

Gluten-related disorders are clinically heterogeneous. Patients should be carefully managed and specific protocols applied for a correct differential diagnosis in gastroenterological setting.

Delayed gastric emptying does not normalize after gluten withdrawal in adult celiac disease

Objective Delayed gastric emptying has been frequently detected in patients with untreated celiac disease. According to several studies, gluten withdrawal showed to be effective in normalizing the gastric emptying rate. The aim of this study was to evaluate the gastric emptying rate of solids in patients with celiac disease before and after a gluten-free diet. Methods Twelve adult patients with celiac disease (age range 20-57 years) and 30 healthy controls (age range 30-54 years) underwent a (13)C-octanoic acid breath test to measure gastric emptying. Half emptying time (t1/2) and lag phase (tlag) were calculated. After at least 12 months of a gluten-free diet, celiac patients underwent a new (13)C-octanoic acid breath test. A symptom score was utilized to detect dyspeptic and malabsorption symptoms in all the patients. Results The gastric motility parameters, t1/2 and tlag, were significantly longer in patients than in controls. On a gluten-free diet, surprisingly, the gastric emptying did not normalize despite an improvement of symptom score. No significant correlation between abnormal gastric emptying and specific symptom patterns, anthropometric parameters or severity of histological damage was found. Conclusions This finding supports the hypothesis that gluten-driven mucosal inflammation might determine motor abnormalities by affecting smooth muscle contractility or impairing gut hormone function. The persistence of these abnormalities on a gluten free diet suggests the presence of a persistent low-grade mucosal inflammation with a permanent perturbation of the neuro-immunomodulatory regulation.

Trends in celiac disease research

BACKGROUND

To improve diagnosis and treatment of celiac disease (CD), research efforts are being made in many different areas. However, the focus, trend, and direction of such efforts require clarity, so that future efforts and directions can be appropriately planned.

METHOD

In this study, MEDLINE was used to search for trends in CD research. The keyword 'celiac disease' and its variants were searched in tandem with keywords commonly associated with CD. This search was done for each year from 1960 to 2013. Year of first instance of the associated keyword, linear regression coefficient, and trend in terms of the slope of the regression line were tabulated. For perspective, the same keywords were searched in tandem with 'inflammatory bowel disease' (IBD).

RESULTS

CD appeared in the medical literature prior to 1960, and IBD first appeared in 1964. However, IBD overtook CD in terms of the number of research papers published per year, beginning in 1988. Keywords with strong positive trends (r(2)>0.7) in association with CD were: 'diagnosis', 'gluten', 'serology', 'autoimmune', 'treatment', 'gluten-free diet', 'endoscopy', 'villous atrophy', 'wasting', 'inflammation', and 'microbiome'. The keyword 'malabsorption' had the sole strong negative trend in association with CD. Keywords with strong positive trends (r(2)>0.7) in association with IBD also had strong positive association with CD: 'autoimmune', 'treatment, 'inflammation', and 'microbiome'.

CONCLUSIONS

The MEDLINE search approach is helpful to show first instance, association, and trend of keywords that are affiliated with CD in published biomedical research, and to compare CD research trends with those of other diseases.

Increased Mercury Levels in Patients with Celiac Disease following a Gluten-Free Regimen

Background and Aim. Although mercury is involved in several immunological diseases, nothing is known about its implication in celiac disease. Our aim was to evaluate blood and urinary levels of mercury in celiac patients. Methods. We prospectively enrolled 30 celiac patients (20 treated with normal duodenal mucosa and 10 untreated with duodenal atrophy) and 20 healthy controls from the same geographic area. Blood and urinary mercury concentrations were measured by means of flow injection inductively coupled plasma mass spectrometry. Enrolled patients underwent dental chart for amalgam fillings and completed a food-frequency questionnaire to evaluate diet and fish intake. Results. Mercury blood/urinary levels were 2.4 ± 2.3/1.0 ± 1.4, 10.2 ± 6.7/2.2 ± 3.0 and 3.7 ± 2.7/1.3 ± 1.2 in untreated CD, treated CD, and healthy controls, respectively. Resulting mercury levels were significantly higher in celiac patients following a gluten-free diet. No differences were found regarding fish intake and number of amalgam fillings. No demographic or clinical data were significantly associated with mercury levels in biologic samples. Conclusion. Data demonstrate a fourfold increase of mercury blood levels in celiac patients following a gluten-free diet. Further studies are needed to clarify its role in celiac mechanism.

Use of shape-from-shading to estimate three-dimensional architecture in the small intestinal lumen of celiac and control patients

BACKGROUND

As measured from videocapsule endoscopy images, the small intestinal mucosa of untreated celiac patients has significantly greater and more varied texture compared to normal patients. Three-dimensional modeling using shape-from-shading principles may further increase classification accuracy.

METHODS

A sequence of 200 consecutive videocapsule images acquired at a 2s(-1) frame rate and 576×576 pixel dimension, were obtained at four locations in the small intestinal lumen of ten patients with biopsy-proven celiac disease and ten control patients. Each two-dimensional image was converted to a three-dimensional architectural approximation by considering the 256 grayscale level to be linearly representative of image depth. From the resulting three-dimensional architecture, distinct luminal protrusions, representative of the macro-architecture, were automatically identified by computer algorithm. The range and number of protrusions per image, and their width and height, were determined for celiacs versus controls and tabulated as mean±SD.

RESULTS

The mean number of villous protrusions per image was 402.2±15.0 in celiacs versus 420.8±24.0 in controls (p<0.001). The average protrusion width was 14.7 pixels in celiacs versus 13.9 pixels in controls (p=0.01). The mean protrusion height was 3.10±2.34 grayscale levels for celiacs versus 2.70±0.43 grayscale levels for controls (p<0.001). Thus celiac patients had significantly fewer protrusions on the luminal surface of the small intestine as compared with controls, and these protrusions had greater dimensions, suggesting they are indicative of a mosaic (cobblestone) macro-architectural pattern which is common in celiacs.

CONCLUSIONS

Shape-from-shading modeling is useful to explore luminal macro-architecture and to detect significant differences in luminal morphology in celiac versus normal patients, which can increase the usefulness of videocapsule studies.

Extracellular matrix proteins and displacement of cultured fibroblasts from duodenal biopsies in celiac patients and controls

BACKGROUND

Celiac disease (CD) is mainly characterised by villous atrophy and mucosal architectural rearrangement. The fibroblasts (FBs) are the most abundant mesenchymal cell type in the intestinal mucosa and are responsible for both the architectural arrangement of the villi and the formation of the extracellular matrix (ECM). This study aimed at the evaluation of both the intracellular distribution of different proteins involved in ECM and FBs characterisation, and the cellular displacement of primary FBs obtained from duodenal endoscopic biopsies of healthy subjects and celiac patients.

METHODS

Primary healthy and celiac duodenal FBs were evaluated by means of immuno-fluorescence assay for collagen type I and IV, fibronectin, actin, alpha-Smooth Muscle Actin (alpha-SMA), Fibroblast Surface Protein (FSP) and transglutaminase type 2 (TG2). The geometric indexes of the fluorescence signals were investigated by image analysis software (Image J, NIH). Both morphology and kinetic were evaluated during a 72 hours time course movie. TG2 medium activity was evaluated by means of ELISA.

RESULTS

All the cells examined were immunopositive for FSP, alpha-SMA, actin, collagen I, collagen IV and TG2. CD cells showed a signet collagen-I and collagen-IV pattern, as compared to the controls being characterised by a spindle geometry. Moreover, the collagen signals in CD FBs showed a significantly higher circularity index (major orthogonal diameter ratio) than the controls (p<0.0001), whereas the perimeter and area ratio were significantly lower (p<0.0001). The TG2 signal had a decreased area (p<0.05), but a two-fold increased medium activity. The time course highlighted a reduction of the displacement of CD FBs.

CONCLUSIONS

The isolated primary CD FBs showed a different collagen and TG2 pattern of distribution associated with a different cellular displacement. The reasons for such CD cell peculiar characteristics are yet unknown but they might represent a factor in the progression of the intestinal damage.

Risk of intestinal lymphoma in undiagnosed coeliac disease: results from a registered population with different coeliac disease prevalence

BACKGROUND

Coeliac disease is often undiagnosed, early diagnosis and treatment could be relevant to avoid fearful complications as intestinal lymphoma. Our aim is to estimate the risk of intestinal lymphoma in undiagnosed coeliac patients, evaluating the real incidences and applying different theoretical settings of coeliac prevalence.

METHODS

We collected cases of intestinal lymphomas from the Lombardy Cancer Registry and coeliac patients through computerized search of all Pathology Departments; duodenal pathological reports compatible with a Marsh 3 grade were included. The lymphoproliferative risk was calculated for theoretical different settings of coeliac prevalence (from 1:50 to 1:200), relative risks for intestinal lymphomas and compared to the real incidence of the lymphomas in this population.

RESULTS

Population consisted in 815,362 inhabitants; during the investigated period of time, 237 intestinal lymphomas and 326 coeliac patients were diagnosed. None of the coeliac patients had lymphoma. In the different scenarios calculated and compared with the real lymphoma incidence the relative risks of undiagnosed celiac disease for gastrointestinal B- and T-cell lymphomas ranges from 1.0 to 2.0 for 1:100 coeliac disease prevalence.

CONCLUSIONS

Undiagnosed coeliac patients have no increased risk of developing intestinal lymphoma; population screening programmes, aimed at early diagnosis of lymphoma may not be useful in this setting.

Immunological comorbity in coeliac disease: associations, risk factors and clinical implications

PURPOSE

Coeliac disease is frequently associated with other immunomediated diseases. Our aim was to identify immunological comorbidities and possible risk factors for their development in coeliac patients.

METHODS

We recruited a cohort of 1,015 coeliac patients followed from 0 to 46 years in a single tertiary referral centre. Data were collected from the yearly scheduled clinical and serological evaluations. Possible risk factors such as demographic parameters, type of symptomatic presentation, gluten exposure, gluten-free diet compliance and family history were all evaluated. Subjects (848,606) from the regional health registry were investigated as controls.

RESULTS

The prevalence of immunomediated diseases was higher in patients with coeliac disease compared to the registry population (23 % vs 0.4 %, p < 0.001). Diagnosis during paediatric age represented a risk factor for the presence of at least an immunomediated disease (hazard ratio = 1.62, 95 % confidence interval 1.15-2.29, p = 0.0061). Type of presentation and dietetic compliance did not represent risk factors. Long-standing gluten exposure reduced the risk of developing immunomediated diseases in coeliac subjects (hazard ratio for 1 year longer exposure 0.23, 95 % confidence interval 0.16-0.33, p < 0.0001). A familiar background characterized by the presence of immunological disorders was not a risk factor, although 419 (13 %) first degree relatives of coeliac patients out of 3,195 had an immunomediated disease.

CONCLUSIONS

Our study suggests the need to investigate coeliac patients for other associated immunomediated diseases, independently of sex, gluten exposure and compliance to therapy; also subjects diagnosed in paediatric age should be carefully screened during follow up.

Slow gallbladder emptying reverts to normal but small intestinal transit of a physiological meal remains slow in celiac patients during gluten-free diet

BACKGROUND

Alterations of small intestinal transit and gallbladder (GB) motility have been reported in celiac disease (CD) in studies involving, in most cases, non-physiological experimental conditions and artificial stimuli to motility. Our aims were to quantitate non-invasively small intestinal transit time and GB emptying during administration of a physiological and palatable solid meal, and to assess the effect of gluten-free diet (GFD).

METHODS

We simultaneously measured mouth-to-cecum transit time (MCTT) using a validated H(2) breath test, and GB motility using ultrasonography. We studied CD patients before (n = 19) and during (n = 14) GFD, and healthy volunteers (n = 24) following administration of a physiological solid meal (Kcal 539).

KEY RESULTS

Mouth-to-cecum transit time was more prolonged in CD (mean ± SEM: 235 ± 96 min) than in controls (169 ± 65 min, P = 0.0039). The GB fasting volume and postprandial residual volume were significantly higher in CD than in controls, and GB emptying constant was slower in CD than in controls. During GFD, GB emptying reverted to normal, but MCTT remained unchanged (229 ± 69 min) and more prolonged in CD than in controls (P = 0.0139). During GFD, duodenal infiltration with lymphocytes and mast cells persisted higher than that in controls, and the number of mast cells lying in proximity of nervous endings did not change.

CONCLUSIONS & INFERENCES

Slow postprandial MCTT in response to a physiological meal does not revert to normal during GFD, an effect mirroring incomplete histopathologic recovery.

The Prevalence of Occult Celiac Disease among Patients with Functional Dyspepsia: A Study from the Western Region of Iran

Objective. The prevalence of Celiac Disease (CD) is high in Iran, and evaluation of CD is not part of the routine screening procedure for dyspeptic patients; therefore, cases of occult CD may be missed. This study aimed to investigate the prevalence of occult CD among dyspeptic patients who presented at a gastroenterology clinic in the Western region of Iran. Methods. In this descriptive, cross-sectional prospective study, patients who had a history of at least 12 weeks of upper abdominal discomfort were eligible to participate in the study during a 14-month recruitment period. Patients with a clinical or paraclinical data in favor of organic causes were excluded from the study. Enrolled patients were screened for IgA antiendomysium antibody (EMA) and IgA antitissue transglutaminase antibody (tTG). Those who screened positive for EMA/tTG received a confirmatory diagnostic biopsy for Marsh classification of CD. Results. From 225 potential participants with dyspepsia, 55 patients were excluded due to having explainable organic causes. The study sample included 170 patients with "functional dyspepsia." Mean age of participants was 31 years and 55.8% were female. Twelve patients (7%) had positive tests (EMA/tTG), of which 10 were female (83.4%). According to Rome II criteria, all twelve patients with positive tests had "dysmotility type dyspepsia." Based on Marsh classification, six patients were consistent with "Marsh I," four with "Marsh II," and two with the "Marsh III" classification. Conclusions. In this study, the prevalence of CD in dyspeptic patients was high. As a result, this study suggests that screening by serology tests (EMA/tTG) is justifiable for the detection of CD among functional dyspeptic patients in the tertiary centers in our country.

Imaging analysis of the gliadin direct effect on tight junctions in an in vitro three-dimensional Lovo cell line culture system

Tight junctions play a pivotal role in maintaining the integrity of the intestinal barrier. Their alteration is involved in the pathogenesis of celiac disease. Our aim was to investigate the gliadin effect on the tight junction proteins in an in vitro three-dimensional cell culture model through imaging analyses. Lovo multicellular spheroids were treated with enzymatically digested (PT) gliadin 500 μg/mL and its effect on actin, occludin and zonula occludens-1, was evaluated by means of confocal laser microscopy, transmission electron microscopy and image capture analysis. Compared to untreated spheroids, PT-gliadin-treated ones showed enlargement of the paracellular spaces (9.0±6.9 vs. 6.2±1.7 nm, p<0.05) at transmission electron microscopy and tight junction protein alterations at confocal microscopy and image analyses. In untreated cell cultures thickness of the fluorescence contour of actin, zonula occludens-1 and occludin appeared significantly larger and more intense than in the treated ones. In occludin planimetric analysis the lengths of the integral uninterrupted cellular contour appeared longer in untreated than in PT-gliadin treated spheroids (71.8±42.8 vs. 23.4±25.9 μm, p<0.01). Our data demonstrated that tight junction proteins are directly damaged by gliadin as shown by means of quantitative imaging analysis.

Isolation and culture of fibroblasts from endoscopic duodenal biopsies of celiac patients

BACKGROUND

Fibroblasts are actually considered pivotal in inflammation and tissue remodelling process and for these reasons they are involved in the pathogenesis of autoimmune disorders such as celiac disease. Investigations to define the role of fibroblasts in celiac diseases are obstructed by the absence of specific models. Our objective is to isolate and culture primary fibroblasts from endoscopic duodenal biopsies of celiac and non-celiac subjects, to analyze their growth patterns and the morphometric characteristics.

METHODS

60 duodenal bioptic specimens from 20 celiac patients and 114 from 38 non-celiac subjects were mechanically chopped and enzymatically digested in order to obtain primary cell cultures. Growth patterns, karyotype (Q-banding analysis), expression of typing proteins (fibroblast surface protein and cytokeratin 20) and morphometric parameters (diameters and their ratio, perimeter, area and perimeter/area ratio at computerised image analysis) were investigated on cultured cells.

RESULTS

Primary cells were successfully cultured in 78% of the collected duodenal biopsies. Cultured cells, expressing the fibroblast surface protein, were negative for cytokeratine 20 and maintained a normal kariotype. Cells grew slowly without differences between the celiac and the non celiac group. Morphometric analysis of celiac fibroblasts revealed significantly increased dimensions, with a preserved diameters ratio, and a reduced perimeter/area ratio.

CONCLUSION

For the first time this study demonstrates the feasibility of culturing primary fibroblast cell from endoscopic duodenal biopsies in celiac and non-celiac subjects, opening a new window of opportunity in studies intended to establish the role of fibroblasts as a possible partaker in the pathogenesis of the celiac mucosal damage.

Prevalence of celiac disease in adult patients with refractory functional dyspepsia: value of routine duodenal biopsy

AIM

To investigate the prevalence of celiac disease (CD) in adult patients referred to an open access gastroenterology clinic in the south of Italy and submitted to esophago-gastro-duodenoscopy (EGD) for evaluation of refractory functional dyspepsia.

METHODS

Seven hundred and twenty six consecutive dyspeptic patients (282 male, 444 female; mean age 39.6 years, range 18-75 years) with unexplained prolonged dyspepsia were prospectively enrolled. Duodenal biopsies were taken and processed by standard staining. Histological evaluation was carried out according to the Marsh-Oberhuber criteria.

RESULTS

The endoscopic findings were: normal in 61.2%, peptic lesions in 20.5%, malignancies in 0.5%, miscellaneous in 16.7%. CD was endoscopically diagnosed in 8 patients (1.1%), histologically in 15 patients (2%). The endoscopic features alone showed a sensitivity of 34.8% and specificity of 100%, with a positive predictive value (PPV) of 100% and a negative predictive value (NPP) of 97.9%.

CONCLUSION

This prospective study showed that CD has a high prevalence (1:48) in adult dyspeptic patients and suggests the routine use of duodenal biopsy in this type of patient undergoing EGD.

Antroduodenojejunal motor activity in untreated and treated celiac disease patients

BACKGROUND AND AIM

Patients with celiac disease may present with abnormal upper gut motor activity. However, it is not known if these abnormalities persist after the introduction of a gluten-free diet. The present study aimed to compare antroduodenojejunal motor variables recorded in untreated celiac patients with those of celiac patients given a gluten-free diet and healthy volunteers.

METHODS

Eleven untreated celiac disease patients, 12 age- and sex-matched celiac patients on a gluten-free diet (at least 12 months), and 33 controls entered the study. Antroduodenojejunal motility was recorded for 6 h during fasting and for 3 h after a standard meal by means of a perfused, multiple lumen catheter.

RESULTS

More than 80% of untreated celiac patients had discrete motor abnormalities of the upper gut, in both fasting and fed recordings, compared to the other subjects. Patients on a gluten-free diet also showed motor abnormalities, albeit to a lesser extent. In these patients histological evaluation showed the persistence of mild mucosal abnormalities.

CONCLUSIONS

Upper gut motor abnormalities are frequent in patients with celiac disease, even in those on a gluten-free diet. In the latter group, these abnormalities may suggest an incomplete adherence to the dietary regimen.

Cervical esophageal web and celiac disease

BACKGROUND AND AIM

There is paucity of prospective data on association between cervical esophageal webs and celiac disease. It is not clear whether all patients with cervical esophageal web need screening for celiac disease. Hence, the present study was carried out to determine the association of cervical esophageal web with celiac disease.

METHODS

This prospective study included consecutive patients with symptomatic cervical esophageal web diagnosed over a period of 4.5 years. Tissue transglutaminase antibody was measured in serum of each patient. Patients with elevated tissue transglutaminase antibody titer were subjected to esophagogastroduodenoscopy and biopsies were obtained from the descending duodenum to look for histological changes of celiac disease. Esophageal web was treated with bougie dilatation. Celiac disease was diagnosed on the basis of elevated tissue transglutaminase antibody and suggestive duodenal histology.

RESULTS

Twenty one patients were diagnosed to have cervical esophageal web. Eighteen (85.7%) had evidence of iron deficiency. Five (23.8%) patients with cervical esophageal web fulfilled criteria for diagnosis of celiac disease. All five had evidence of iron deficiency. None of these patients gave a history of chronic diarrhea. All patients were treated with bougie dilatation. Patients with celiac disease were advised of a gluten-free diet. All five celiac disease patients are free of dysphagia without recurrence after a mean follow up of 10 months (range: 3 to 16 months).

CONCLUSIONS

There is association between cervical esophageal web and celiac disease. All adult patients with cervical esophageal web and iron deficiency need screening for celiac disease even in the absence of chronic diarrhea.