Thyroid disorders in Brazilian patients with celiac disease

Patients with celiac disease (CD) can develop a gluten related autoimmune disorder that affects not only the small intestine but other tissues as well. An increased prevalence of autoimmune diseases has been reported, particularly autoimmune thyroiditis. The aim of this study was to characterize thyroid disorders in patients with CD.

Fifty-two patients with CD (43 female, 9 male; mean age, 41.1 years) were studied. Nine were on a gluten-free diet (GFD). They were divided into four groups: Group 1, without thyroid involvement (n=30); Groups 2A-C, with thyroid involvement (n=22); Group 2A, subclinical hypothyroidism (n=11); Group 2B, clinical hypothyroidism (n=10); and Group 2C, other thyroid disorders (n=1). CD was confirmed by serologic and histologic criteria. Thyroid involvement was detected by measurement of thyroid stimulating hormone (TSH) and anti-thyroperoxidase antibodies (anti-TPO).

Increased levels of TSH and/or anti-TPO levels were detected in Groups 2A (21.1%) and 2B (19.2%). The patients of Group 2B presented clinical symptoms of hypothyroidism before the diagnosis of CD, and 5 of these patients were receiving levothyroxine. One woman (Group 2C; 1.92%) had a medullary carcinoma. There was statistical significance between the age when thyroid disease was diagnosed (current age) and the age of CD diagnosis between Groups 1 and 2B. Patients with thyroid involvement presented associated diseases such as diabetes mellitus (2), Down's syndrome (2), ulcerative colitis (1), and dermatitis herpetiformis (2).

Our findings demonstrated an increased prevalence of thyroid disorders (hypothyroidism, 19.2%; and subclinical hypothyroidism, 21.2%), and other associated diseases in celiac patients, even on a GFD, increasing with the age of the patients. Screening for associated diseases is recommended for patients with CD, independent of age at diagnosis or treatment duration.