Purpose: To evaluate the relationship between oxidative stress and clinical evolution in patients with Graves' ophthalmopathy (GO).
Methods: Thirty-one euthyroid GO patients and 25 healthy subjects participated in this study. Oxidative DNA damage was assessed by determination of the 8-hydroxy-2'-deoxyguanosine (8-OHdG) level in urine by ELISA. The relationship of oxidative DNA damage to the clinical evolutions of GO, especially the smoking status, clinical activity scores (CAS), and ophthalmopathy index was examined.
Results: The mean 8-OHdG was significantly higher in GO patients than that of normal controls (12.6+/-5.7 vs 6.7+/-2.5 ng/mg creatinine, P<0.001). Smokers had significant higher 8-OHdG than did never smokers in GO patients (P=0.029), but not in healthy controls (P=0.374). Among GO patients, only CAS remained significantly correlated with 8-OHdG (P=0.001) after adjusting for age, sex, disease duration, the status of antithyroid drug and smoking, and thyroid-stimulating hormone level. Patients with active GO (CAS>3) had higher 8-OHdG than did the patients with CAS <or=3 (16.3+/-4.9 vs 8.6+/-3.0 ng/mg creatinine).
Conclusions: Our findings suggest that urinary 8-OHdG is increased in GO patients and is correlated with the disease activity. Smoking had a higher impact on the increased 8-OHdG among GO patients.