Among those in primary care populations who report gastrointestinal symptoms, the rate of coeliac disease is about 3%. In Australia, approximately 1 in 70 people have the disease. The rate amongst adult blood donors in Iran, Israel, Syria and Turkey is 0.60%, 0.64%, 1.61% and 1.15%, respectively.People of African, Japanese and Chinese descent are rarely diagnosed; this reflects a much lower prevalence of the genetic risk factors, such as HLA-B8. People of Indian ancestry seem to have a similar risk to those of Western Caucasian ancestry. Population studies also indicate that a large proportion of coeliacs remain undiagnosed; this is due, in part, to many clinicians being unfamiliar with the condition and also due to the fact it can be asymptomatic. Coeliac disease is slightly more common in women than in men. A large multicentre study in the U.S. found a prevalence of 0.75% in not-at-risk groups, rising to 1.8% in symptomatic people, 2.6% in second-degree relatives (like grandparents, aunt or uncle, grandchildren, etc.) of a person with coeliac disease and 4.5% in first-degree relatives (siblings, parents or children). This profile is similar to the prevalence in Europe. Other populations at increased risk for coeliac disease, with prevalence rates ranging from 5% to 10%, include individuals with Down and Turner syndromes, type 1 diabetes, and autoimmune thyroid disease, including both hyperthyroidism (overactive thyroid) and hypothyroidism (underactive thyroid).Historically, coeliac disease was thought to be rare, with a prevalence of about 0.02%. The reason for the recent increases in the number of reported cases is unclear.
After x-ray verification of its position, suction was applied to collect part of the intestinal wall inside the capsule. Often-utilised capsule systems were the Watson capsule and the Crosby–Kugler capsule. This method has now been largely replaced by fibre-optic endoscopy, which carries a higher sensitivity and a lower frequency of errors.Capsule endoscopy (CE) allows identification of typical mucosal changes observed in coeliac disease but has a lower sensitivity compared to regular endoscopy and histology. CE is therefore not the primary diagnostic tool for coeliac disease. However, CE can be used for diagnosing T-cell lymphoma, ulcerative jejunoileitis, and adenocarcinoma in refractory or complicated coeliac disease. Pathology
The classic pathology changes of coeliac disease in the small bowel are categorised by the "Marsh classification":
Marsh stage 0: normal mucosa
Marsh stage 1: increased number of intra-epithelial lymphocytes (IELs), usually exceeding 20 per 100 enterocytes
Marsh stage 2: a proliferation of the crypts of Lieberkühn
Marsh stage 3: partial or complete villous atrophy and crypt hypertrophy
Marsh stage 4: hypoplasia of the small intestine architectureMarshs classification, introduced in 1992, was subsequently modified in 1999 to six stages, where the previous stage 3 was split in three substages. Further studies demonstrated that this system was not always reliable and that the changes observed in coeliac disease could be described in one of three stages:
A representing lymphocytic infiltration with normal villous appearance;
B1 describing partial villous atrophy; and
B2 describing complete villous atrophy.The changes classically improve or reverse after gluten is removed from the diet.