Objective: To study the prevalence of autoimmune thyroiditis (AT) in Sardinian children with celiac disease (CD) and the effects of a gluten-free diet (GFD) on thyroid function.
Study design: Children with biopsy-proven CD (n = 324; female:male 2:1; mean age, 6.6 years) followed from 1 to 15 years, were retrospectively evaluated for AT at onset of CD and during GFD. Serum thyroid peroxidase and thyroglobulin antibodies (AbTPO, AbTG), thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), and thyroid ultrasonography were considered. Age-matched Sardinian schoolchildren (n = 8040), previously evaluated for antithyroid antibodies and thyroid function, were used as controls.
Results: Thirty-four patients with CD (10.5%) developed AT (female:male 4,5:1; mean age, 10.5 years), 11 at onset of CD and 23 during GFD, with a higher prevalence than controls (P = 2.9(-13)). Twenty-eight patients were euthyroid and 6 hypothyroid. AbTPO and/or AbTG persisted elevated for 2 to 9 years despite the GFD in 9 of 11 patients with AT at onset of CD.
Conclusions: AT is strongly associated with CD in Sardinian children, has an age of onset of 10.5 years, and appears to be gluten-independent. In children with CD with AT, the female:male bias reported in adult AT is present before puberty.