Alimentary TractPrevalence of celiac disease in inflammatory bowel diseases: An IG-IBD multicentre study
Introduction
Celiac disease, Crohn's disease, and ulcerative colitis are inflammatory disorders of the gastrointestinal tract with genetic, immunological and environmental factors involved in their pathogenesis.
One in two ulcerative colitis patients reveal p-ANCA antibodies, which are fairly specific for the disease, but can be found in association with other autoimmune conditions too, such as primary sclerosing cholangitis and vasculitis. Snook et al. [1] also reported a high frequency of anti-nuclear antibody (ANA) positivity in patients with inflammatory bowel disease (IBD), having found ANA in 25–51% of ulcerative colitis patients and 8–17% of Crohn's disease patients. MYO IXB, a gene previously found associated with celiac disease [2], has recently been found mutated in more than 40% of IBD patients too [3], [4].
A 67% prevalence of anti-Saccharomyces cerevisiae antibody (ASCA) positivity has been reported in celiac patients [5]. A close correlation has also emerged between anti-transglutaminase antibodies and disease activity in Crohn's disease [6].
Such evidence suggests similarities between the three different conditions, and possibly even similar pathological mechanisms.
The prevalence of celiac disease in the general population is estimated at around 1% [7], [8], but the ratio of known-to-undiagnosed cases may be as high as 1:7. This is probably because of its non-specific symptoms, e.g. dyspepsia and gastroesophageal reflux, and symptoms unrelated to the gastrointestinal tract, such as anaemia [9], osteoporosis [10], diabetes mellitus type 1 [11], increased liver enzyme levels [12] and neurological symptoms [13].
Celiac disease may be difficult to diagnose, particularly in a patient already suffering from IBD; in fact, the two conditions often have symptoms such as diarrhoea, weight loss, and abdominal pain in common. Biochemical test results (e.g. blood count and proteins) can also be altered in both diseases. Even the finding most characteristic of celiac disease, i.e. scalloped duodenal mucosa folds, can be seen in Crohn's disease patients [14] and villous atrophy has been reported in up to 20% of patients [15].
Previous studies to screen IBD patients for celiac disease have produced conflicting results. An association between celiac disease and IBD (and ulcerative colitis in particular) has been described in several case reports, but few studies have evaluated the prevalence of celiac disease in IBD patients; the first prospectively analysed its prevalence in newly-diagnosed Crohn's disease patients screened for the presence of anti-tissue transglutaminase antibodies (TgA), anti-endomysial antibodies (EMA) and anti-gliadin antibodies, finding that 5/27 (18%) also had celiac disease [16]. A second study found only 4 of 354 (0.8%) IBD patients with concomitant celiac disease [17].
Whether patients with IBD should be screened for celiac disease thus remains controversial. Hence the present study aims to assess the prevalence of celiac disease in a large series of Italian IBD patients.
Section snippets
Patients
This multicentre study was conducted by the Italian Group for Inflammatory Bowel Disease between January 2002 and December 2004. Twenty-two gastroenterologists at 5 university hospitals and 17 general hospitals all over Italy enrolled 1711 consecutive outpatients with IBD: 860 had Crohn's disease (415 females, mean age 40, range 18–75), 791 had ulcerative colitis (371 females, mean age 40, range 18–80) and 60 had indeterminate colitis (27 females, mean age 40, range 18–78). One male patient
Results
Nine of the 1711 patients (0.5%) had serological and histological findings compatible with a diagnosis of celiac disease; six of them had ulcerative colitis and three had Crohn's disease. Both EMA and anti-TgA were positive in eight patients, while one patient was positive for EMA and negative for anti-TgA (no conclusive diagnosis of celiac disease was reached for this 35-year-old female patient). IgA deficiency was identified in five patients but none of them had celiac disease at endoscopy.
Discussion
Celiac disease is an immune-mediated enteropathy triggered by gluten ingestion in genetically susceptible individuals [22]. A greater frequency of other autoimmune disorders has been reported in celiac patients, especially in long-standing untreated cases [23].
The prevalence of IBD is reportedly 5–10 times higher in celiac disease than in the general population [24]. Shah et al. [25] described a fivefold relative risk of ulcerative colitis in first-degree relatives of probands with celiac
Conflicts of interest
The authors declare that they have no conflict of interest.
Acknowledgements
The following gastroenterology centres participated in the study: Department of Surgical and Gastroenterological Sciences, University of Padua (Prof. G.C. Sturniolo); Gastroenterology Unit and Clinical Medicine, IRCCS “Casa Sollievo della Sofferenza” San Giovanni Rotondo (Foggia) (A. Latiano, F. Bossa, O. Palmieri); Gastroenterology Unit, “Mauriziano” Hospital, Turin (Prof A Pera) II Gastroenterology Chair, Milan University, Milan (Dr. S. Saibeni, Prof. M. Vecchi); Medical Dept, Cento Hospital,
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