Thyroid function, autoimmune thyroiditis and coeliac disease in juvenile idiopathic arthritis.

OBJECTIVES Autoimmune diseases have been associated with some organ non-specific rheumatological disorders such as rheumatoid arthritis and systemic lupus erythematosus; however, few studies have been performed in an extensive cohort of children with juvenile idiopathic arthritis (JIA). Our objective was to evaluate the thyroid function and the prevalence of antithyroid antibodies, autoimmune thyroiditis and coeliac disease in children with JIA. METHODS One hundred and fifty-one children (120 female, 31 male, median age 8.3 yr, range 2.4-16.9 yr) with JIA were evaluated. All patients underwent thyroid function tests (u-TSH, free T(4) and free T(3)), antithyroglobulin (TgA) and antiperoxidase (TPOA) antibodies, antigliadin, anti-endomysium and antitransglutaminase antibodies. All patients with raised thyroid stimulating hormone levels, low thyroid hormone levels or positive TPOA and/or TgA values had a thyroid high-resolution sonography examination. Coeliac disease was confirmed by jejunal biopsy if the specific antibodies profile was positive. One hundred and fifty-eight age- and sex-matched Caucasian children from the same geographical area acted as controls. RESULTS Fourteen (9.3%) patients showed subclinical hypothyroidism, 17 (11.9%) patients showed autoimmune thyroiditis with nine patients also showing a non-homogeneous thyroid parenchyma at ultrasound evaluation. Coeliac disease was demonstrated in 10 (6.6%) patients. Compared with controls, JIA patients had higher prevalence of subclinical hypothyroidism (P < 0.01), autoimmune thyroiditis (P < 0.0001) and coeliac disease (P < 0.005). CONCLUSIONS JIA children have an increased prevalence of autoimmune thyroiditis, subclinical hypothyroidism and coeliac disease. These data seem to suggest careful monitoring of thyroid function, thyroid autoantibodies and coeliac disease in JIA children.