Thyroid and Systemic Autoimmune Diseases
How They're Related and What This Means for You
Jan 6, 2009
Autoimmune diseases are either organ specific or systemic (affecting multiple organs and bodily systems). Although the association of autoimmune thyroid disease and systemic diseases has been apparent for a long time, it’s only in recent years that researchers have started to study just how strong this association is. In their studies researchers have also determined which systemic disorders are most prevalent in patients with Hashimoto’s thyroiditis and which have a stronger association with Graves’ disease.
University of Debrecen, Hungary
In a study published in Clinical Rheumatology, researchers describe the prevalence of AITD in systemic sclerosis (SSc), mixed connective tissue disease (MCTD), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), Sjogren’s syndrome (SS), and polymyositis/dermatomyositis (PM/DM). The study included 1,517 patients with systemic disease and 426 patients known to have an autoimmune thyroid disorder. The presence of AITD was determined by thorough clinical evaluation, imaging studies and fine needle aspiration (FNA) biopsy.
The researchers found that 8.2 percent of the patients with systemic disease had an autoimmune thyroid disorder. Patients with systemic sclerosis and mixed connective tissue disease were most likely to have an AITD. Hashimoto’s thyroiditis was more common in patients with rheumatoid arthritis, mixed connective tissue disease, and Sjogren’s syndrome than Graves’ disease. Patients with MCTD were 556 times more likely to have Hashimoto’s thyroiditis than people in the general population. Patients with MCTD were 74 times more likely to have Graves’ disease than people in the general population.
Among all thyroid patients studied only 30 percent were found to have also have an autoimmune systemic disorder. Overall, 51 percent of patients wit Hashimoto’s thyroiditis and 16 percent of patients with Graves’ disease were found to have autoimmune systemic disorders. The researchers concluded that patients with systemic autoimmune disorders should be screened for thyroid disease.
Oklahoma Medical Research Foundation
In an earlier study researchers in the Arthritis and Immunology Program at the Oklahoma Medical Research Foundation found that patients with systemic lupus erythematosus and Sjogren’s syndrome commonly have thyroid antibodies and overt conditions of thyroid disease. However, while they found that patients with Sjogren’s syndrome had an increased risk of thyroid disease, they concluded that patients with autoimmune thyroid disease did not have an increased risk of developing Sjogren’s disease. The researchers concluded that because SS is a systemic disorder affecting multiple organs, the thyroid gland is sometimes target by SS autoantibodies.
Institute of Rheumatology, Belgrade
Serbian researchers have found that musculoskeletal manifestations often occur in patients with both Graves’ disease and Hashimoto’s thyroiditis. These researchers link this finding to the presence of systemic autoimmune disorders in these patients. They note that Sjogren’s syndrome is seen in 10 percent of patients with autoimmune thyroid disease.
Patients with evidence of both systemic lupus erythematosus and AITD were significantly older than patients with SLE who did not have thyroid antibodies. AITD was seen 3 times more often in women with RA than in women with non-inflammatory rheumatic diseases. In addition, those with thyroid disease tended to have a shorter disease course of their arthritis.
Nagasaki, Japan
Graduate school researchers in Nagasaki Japan found that autoantibodies for systemic diseases were not common in patients with AITD. However, patients with type 1 diabetes had a high incidence of thyroid antibodies. Thyroglobulin antibodies were found to be common in patients with primary biliary cirrhosis and autoimmune hepatitis. TPO antibodies were also seen in patients with primary biliary cirrhosis and myasthenia gravis. The study concluded that thyroid antibodies were common in patients with systemic thyroid diseases indicating an increased risk for thyroid disease in these patients. Overall, patients with thyroid disease did not commonly have antibodies to other systemic diseases.
Conclusions:
The risk of developing concurrent systemic and thyroid disorders increases with age. The risk is higher for patients with systemic autoimmune diseases to develop autoimmune thyroid disorders than it is for patients with thyroid disorders to develop systemic autoimmune diseases. However, patients with either type of autoimmune disorder (systemic or thyroid) are more likely than people in the normal population to develop the other autoimmune disorder.
Resources:
E. Biro, Z. Szekanecz, K. Danko, Association of systemic and thyroid autoimmune diseases, Clinical Rheumatology, Mar 2006, 240-5.
RH Scofield, Autoimmune thyroid disease in systemic lupus erythematosus and Sjogren’s syndrome, Clinical and Experimental Rheumatology, May-June 1996; 321-30.
D Keromovic-Morinam Autoimmune thyroid disease and associated rheumatic disorders, Srp Arh Celok Lek, Oct 2005 Supplement
Nakamura H, Usa T, Motomura M, Ichikawa T, Nakao K, Kawasaki E, Tanaka M, Ishikawa K, Eguchi K., Prevalence of interrelated autoantibodies in thyroid diseases and autoimmune disorders, J Endocrinol Invest. 2008 Oct; 31(10): 861-5
