Epidemiology of Graves' orbitopathy.

Thyroid orbitopathy is a relatively rare disease. Prevalence data are lacking and can only be estimated. The incidence of thyroid orbitopathy has been documented in one American study (16 cases per 100,000 population per year for females and 2.9 cases per 100,000 population for males). Thyroid orbitopathy can affect every race and age group. The majority of patients present in middle age with concurrent thyrotoxicosis due to Graves' disease. The onset of orbitopathy usually coincides with the hyperthyroidism, though the two may be asynchronous by months or sometimes years. A small proportion of patients with thyroid orbitopathy have primary hypothyroidism or are euthyroid. Female patients outnumber males by 2-5 to 1. Smoking increases the risk of thyroid orbitopathy up to 8-fold.