Epidemiology of celiac disease: What are the prevalence, incidence, and progression of celiac disease?

Abstract

Celiac disease (CD) is a chronic systemic autoimmune disorder induced by gluten proteins present in wheat, barley, and rye. Contrary to common belief, gluten enteropathy is a systemic disease rather than merely an ailment of the alimentary tract. Genetically susceptible persons develop autoimmune injury to the gut, skin, liver, joints, uterus, brain, heart, and other organs (Figure 1). The classical definition of CD included gastrointestinal manifestations (chronic diarrhea, failure to grow, weight loss, vomiting, abdominal pain, bloating, distention, and constipation), confirmed by a small bowel biopsy (SBB) with findings of villous atrophy, crypt hyperplasia, and normalization of the villous architecture in response to a gluten-free diet. 1,2 Previously, CD was thought to be a disease primarily of infancy; however, with the widespread delay in introduction of wheat into the infant diet, the clinical manifestations have become more subtle, and diagnosis is now typically made in older children and adults. 3‐5 SBB is poorly accepted by a majority of patients with mild or no symptoms, and the pathologic examination of biopsy material is suboptimal in most settings. The use of SBB as a “gold standard” for diagnosis has significant limitations. It is occasionally false-negative because of patchy mucosal changes. Villous atrophy is often most severe in the proximal jejunum, typically not reached by endoscopic biopsy. This has led some to propose a new definition of CD, based on the presence of serum IgA autoantibodies to tissue transglutaminase (IgA TG) and HLA-DQB1*0201 or *0302 alelles. 6 These markers are increasingly used in screening for CD, but their true sensitivity and specificity are debatable. Although efforts to standardize IgA TG assays have been undertaken, 7,8 previous reports have likely overestimated the sensitivity and underestimated the specificity because of verification bias 9 caused by the lack of SBB studies in patients negative on TG screening.