Celiac.com 03/01/2010 - Common autoimmune disorders often coexist in the same subjects, and to cluster in families. A research team recently set out to quantify the risk of diagnosis of coexisting autoimmune diseases in more than 3000 index cases with clinically proven Graves' disease or Hashimoto's thyroiditis.
To establish the prevalence of coexisting autoimmune disorders, the team conducted a cross-sectional multi-center study of 3286 Caucasian subjects from UK hospital thyroid clinics. 2791 of those had Graves' disease, 495 had Hashimoto's thyroiditis.
The team used a comprehensive questionnaire to obtain complete personal and parental history for each subject, including information on common autoimmune disorders, and parental history of hyperthyroidism or hypothyroidism.
The frequency of other autoimmune disorders was 9.67% for patients with Graves' disease and 14.3% for those with Hashimoto's thyroiditis index cases (P=.005).
Rheumatoid arthritis was the most common coexisting autoimmune disorder, striking 3.15% of patients with Graves' disease, and 4.24% of Hashimoto's thyroiditis cases.
However, both conditions carried substantially higher relative risks for nearly all other autoimmune diseases (>10 for pernicious anemia, systemic lupus erythematosus, Addison's disease, celiac disease, and vitiligo).
Cases of Graves' disease showed relative “clustering” among index subjects with parental hyperthyroidism, while cases of Hashimoto's thyroiditis showed relative “clustering” among index subjects with parental hypothyroidism.
Relative risks for most other coexisting autoimmune disorders were markedly increased among parents of index cases.
This study is one of the largest so far to quantify the risk of diagnosis of coexisting autoimmune diseases among more than 3000 index cases with clinically proven Graves' disease or Hashimoto's thyroiditis.
These results emphasize the the importance of screening for other autoimmune diagnoses when patients with autoimmune thyroid disease show new or nonspecific symptoms.