Antithyroid antibodies in Hispanic patients with type I diabetes mellitus. Prevalence and significance.

Antithyroglobulin antibodies (ATA) and antithyroid microsomal antibodies (AMA) were sought and thyroid function was determined in 90 Hispanic patients with type I diabetes mellitus followed up for up to seven years. We detected ATA in 7.5% of our patients and AMA in 34.8%. All serum samples positive for ATA also contained AMA. There was no sex difference in the prevalence of thyroid autoimmunity. A small, firm goiter was present in eight patients, one of whom developed Graves' disease. Our results suggest that a relatively high prevalence of AMA and no sex difference in thyroid autoimmunity may be unique features of Hispanic children and adolescents with type I diabetes mellitus. Such patients should be clinically evaluated for thyroid dysfunction and should be screened annually for the presence of AMA. When antibodies are present, laboratory evaluation of thyroid function should be performed frequently.