Introduction: Atherosclerosis and its complications constitute the most common causes of death in developed countries. This disease is associated with multiple risk factors. Hypo- and hyper-thyroidism are well known causes of atherosclerosis. Smoking is another important risk factor of atherosclerosis, causing increase of oxidative stress. However, the exact relationship of thyroid hormones and oxidative stress is not yet known.
Methods: We examined 110 randomly selected females divided into smoking (18) and non-smoking (92) subgroups. Determination of free T4 and TSH hormones and antiTPO antibodies was done by standard methods.
Results: Smoking and nonsmoking females haven't any significant difference in level of free T4 (13.4±5.1 vs 14.0±3.6; NS) and TSH (2.59±2.33 vs. 6.79±18.65; NS) hormones and antiTPO (20.4±14.4 vs. 19.1±6.2; NS). However, we found significant correlations between freeT4 and uric acid (r=0.23; p<0.01), HDL cholesterol (r=-0.20; p<0.05) and oxidized LDL cholesterol (r=0.49; p<0.05) and between TSH and uric acid (r=-0.22;p<0.05), total cholesterol (r=0.19;p<0.05), LDL cholesterol (r=0.22;p<0.05) and oxidized LDL cholesterol (r=-0.19;p<0.05).
Conclusions: Females with higher TSH levels had tendency to have higher levels of total and LDL cholesterol. However, high free T4 values in combination with low TSH values would lead to increased oxidative stress, marked by higher level of uric acid and oxidized LDL cholesterol.
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