Context: Selenium is effective in improving quality of life and reducing the progression of active Graves’ orbitopathy, possibly by reducing oxidative stress. The effect of correcting relative selenium deficiency on improving Graves’ orbitopathy is unknown, as baseline selenium levels have not previously been measured.
Objective: To determine if serum selenium levels are reduced in patients with Graves’ orbitopathy compared with patients without orbitopathy.
Design and Setting: A prospective, case-control study performed between 2009 and 2012 at endocrine and ophthalmology clinics in Australia.
Patients: A total of 200 patients with Graves’ disease participated in the study: 101 with Graves’ orbitopathy and 99 without Graves’ orbitopathy.
Intervention: No intervention
Main outcome measure: Serum selenium levels in both groups.
Results: Mean serum selenium levels were significantly lower in patients with Graves’ orbitopathy (1.10+/-0.19mmol/L) compared with patients without orbitopathy (1.19+/-0.20mmol/L) (P=0.002). Serum selenium levels remained significantly lower in Grave’s orbitopathy cases after adjusting for age, smoking status, thyroidectomy and radio-active iodine treatment.
Conclusion: Serum selenium levels are lower in patients with Graves’ orbitopathy compared with controls. Relative selenium deficiency may be an independent risk factor for orbitopathy in patients with Graves’ disease.