The effect of thyroid hormone status on selected antioxidant parameters in patients with Graves' disease and active thyroid-associated orbitopathy.

Hyperthyroidism is a significant contributor to oxidative stress in patients with active TAO, which manifests as upregulated lipid peroxidation and antioxidant system activation. Euthyroid state restoration leads to a relative reduction in activity and levels of most studied antioxidant parameters, which still remain above the normal values. The autoimmune inflammation of the orbital tissue seems to be a thyroid hormone status-independent modifier of oxidative stress.