Graves' disease in subjects with type 1 diabetes mellitus: a prevalence study in western Sicily (Italy).

OBJECTIVE

To assess the prevalence of Graves' disease in patients with type 1 diabetes mellitus all coming from a defined geographical area (western Sicily-Italy) and to investigate the clinical features of these subjects.

METHODS

The records of 470 consecutive patients with type 1 diabetes mellitus referred in a 5-year period were analyzed.

RESULTS

During the period of the survey, out of 470 patients with type 1 diabetes, 14 (3%) had a previous diagnosis of Graves' disease. There were 9 female and 5 male; these patients showed a high age at diabetes onset (mean 38 years). Diagnosis of Graves' disease was often pre-existing or simultaneous to that of diabetes. Vitiligo was coexisting in 4 subjects; none of them presented other autoimmune diseases. Graves' orbitopathy was present in two cases.

CONCLUSIONS

Our data confirm the frequent association between Graves' disease and type 1 diabetes. Graves' disease often preceded diagnosis of type 1 diabetes, particularly in female subjects with a high age at diabetes onset; therefore, in these subjects, an active search for the presence of pancreatic autoimmunity is warranted for many years after thyroid dysfunction appearance.