Objective:

In this study, we aimed to evaluate the free radical-mediated oxidative stress and its relationship to vitamin E in women with hyperthyroidism.

Material and Methods:

Twenty-four female patients with hyperthyroidism (mean age, 40.78±9.62 yrs) and twenty-two euthyroid female patients (mean age, 42.5±10.66 yrs) were recruited into this study. Fasting blood samples were analyzed for vitamin E, thiobarbituric acid reactive substances (TBARS), protein carbony group (PCG), free T3, free T4, TSH, total cholesterol, trigylceride, LDL-cholesterol and HDLcholesterol levels.

Results:

The levels of vitamin E in patients with hyperthyroid were significantly lower compared to euthyroid control group (p<0,001). TBARS and PCG levels in hyperthyroid patients were significantly higher than the euthyroid control group (p<0.001, p<0.01, respectively). Vitamin E levels in hyperthyroid patients over age 40 were significantly lower (p<0.005) but TBARS and PCG levels were higher (p<0.01, p<0.05, respectively) than the patients below age 40. Vitamin E levels were negatively correlated with TBARS and age (r=-0.612**, r =- 0.755***) respectively and positively with triglyceride level (r=0.428*) in hyperthyroid patients. In addition, TBARS was correlated positively with PCG levels (r=0.497*).

Conclusion:

Our study shows that increased oxidative stress in hyperthyroid women triggers protein oxidation and lipid peroxidation which a cause a decrease in vitamin E levels. Interestingly, lower levels of vitamin E were detected in patients over age 40.

Keywords: Hyperthyroidism, Vitamin E, lipid peroxidation, protein oxidation