Autoimmune thyroid disease in primary Sjögren's syndrome.
OBJECTIVE
To evaluate the prevalence of autoimmune thyroid disease and thyroid dysfunction in patients with primary Sjögren's syndrome.


METHODS
Thyroid function of 33 patients with primary Sjögren's syndrome was clinically and biochemically evaluated. Thyroid hormones and autoantibodies against thyroid peroxidase, thyroglobulin, and thyroid hormones were measured.


RESULTS
Autoimmune thyroid disease and thyroid dysfunction were found in 15 cases (45%): autoimmune thyroiditis in 8 (24%); autoimmune hyperthyroidism in 2 (6%); and reversible iodine-induced hypothyroidism in the remaining 5 (15%). One or more of the evaluated autoantibodies were detected in 8 euthyroid patients (24%). Overall, the prevalence of autoantibodies against thyroid peroxidase, thyroglobulin, thyroxine, and triiodothyronine was 45%, 18%, 42%, and 36%, respectively.


CONCLUSIONS
The high prevalence of autoimmune thyroid disease and thyroid dysfunction found in primary Sjögren's syndrome, using sensitive immunologic and thyroid function tests, suggest that both diseases are more frequently associated than it was previously thought, and should be sought clinically and by laboratory tests in all patients with primary Sjögren's syndrome.
D000328:Adult; D001323:Autoantibodies / Q000097:blood; D001327:Autoimmune Diseases / Q000097:blood / Q000150:complications* / Q000276:immunology; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000150:complications; D007037:Hypothyroidism / Q000150:complications; D007453:Iodide Peroxidase / Q000276:immunology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012859:Sjogren's Syndrome / Q000097:blood / Q000150:complications* / Q000276:immunology; D013954:Thyroglobulin / Q000276:immunology; D013959:Thyroid Diseases / Q000097:blood / Q000150:complications* / Q000276:immunology; D013963:Thyroid Hormones / Q000097:blood / Q000276:immunology; D013967:Thyroiditis, Autoimmune / Q000150:complications
D001323:Autoantibodies; D013963:Thyroid Hormones; D013954:Thyroglobulin; D007453:Iodide Peroxidase