Clinical and Immunological Features of Celiac Disease in Patients With Type 1 Diabetes Mellitus

Umberto Volta; Francesco Tovoli; Giacomo Caio

Disclosures

Expert Rev Gastroenterol Hepatol. 2011;5(4):479-487. 

In This Article

Expert Commentary

Celiac disease is the autoimmune disorder most frequently found in T1DM after autoimmune thyroiditis. Gluten might be a shared causative factor for CD and T1DM, as confirmed by the possible concomitant onset of both disorders. Withdrawal of gluten in patients with an early CD diagnosis without T1DM is rarely associated with the appearance of immune markers of T1DM and the development of T1DM.

The clinical picture of CD in T1DM is often silent with the absence of both gastrointestinal and extraintestinal signs suggestive of gluten-sensitive enteropathy. Nevertheless, since untreated CD may be responsible of malabsorption with relevant clinical manifestations (anemia, osteopenia, miscarriages and liver dysfunction) and increased risk of complications (refractory CD, ulcerative jejunoileitis and lymphoma), serological screening for CD should be performed in all T1DM patients.

Owing to the frequent absence of symptoms suggestive for gluten-sensitive enteropathy, serological screening for CD acquires much more importance in T1DM than in other patient settings. The diagnostic accuracy of serological tests for identifying CD in T1DM is very high, but some pitfalls should be considered in the evaluation of antibody tests. tTGA is the first choice test owing to their higher sensitivity for CD (˜98%), but these markers give a number of false positives at T1DM onset. EmA should be used as a confirmatory test, especially in the case of low titer tTGA positives, before performing intestinal biopsy. HLA determination is of limited value in identifying patients at risk of CD among T1DM subjects, since both disorders share the same genetic pattern (HLA-DQ2 and DQ8).

It has been clearly demonstrated that CD can occur many years after T1DM diagnosis. Indeed, the estimated prevalence of CD at the onset of T1DM is approximately 1% but rises significantly in the following 10 years. Therefore, CD serology, if negative at T1DM onset, should be repeated once a year for the first 4 years and every 2 years for the following 6 years.

Duodenal histology remains the gold standard for CD diagnosis in T1DM, but it must be underlined that the finding of mild intestinal lesions, characterized by an isolated increase of IEL, is very common in T1DM. These minimal lesions are an expression of potential CD in only 10% of cases.

Since T1DM patients can show positivity for tTGA at low titer or minimal lesions of intestinal mucosa as an expression of their autoimmune condition without the coexistence of CD, it is mandatory to be very cautious before prescribing GFD, which causes a significant change in the nutritional and social habits of T1DM patients. Only T1DM patients with a certain CD diagnosis (both symptomatic and silent) on the basis of serological and histological pattern must be treated with a GFD regimen. As for potential CD cases, only those with evident symptoms related to gluten-sensitive enteropathy should be prescribed a GFD, leaving those who are symptomless on a gluten-containing diet with careful follow-up.

The advantages of GFD in T1DM patients with CD are evident with improvement of intestinal and extraintestinal CD-related symptoms, whereas the course of T1DM is not influenced so much by gluten withdrawal. Indeed, it has been demonstrated that hypoglycemic episodes decrease, but at the same time insulin needs increase and HBA1c levels do not improve. Moreover, the protection induced by GFD on the development of lymphoma and other complications in CD patients overcomes some negative effects of the diet, such as the possible development of a metabolic syndrome, which is favored by the improved intestinal absorption and by a high consumption of commercial gluten-free foods, particularly rich in carbohydrates and lipids.

On the whole, screening for CD is recommended in all T1DM patients at T1DM onset and, in case of its negativity, with well-defined intervals for at least 10 years in order to allow an early identification of CD.

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