Association between oxidative stress and coronary lipid risk factors in hypothyroid women is independent of body mass index

Hypothyroidism enhances the progression of atherogenesis. Furthermore, dyslipidemia, hypertension, and obesity are known risk factors for atherosclerosis. Oxidative stress is implicated in the pathogenesis of cardiovascular diseases. However, there are contradicting reports on the existence of oxidative stress in hypothyroidism. Thus, the aim of the study is to evaluate the presence of oxidative stress in hypothyroidism and, if so, its possible association with various coronary lipid risk factors. The present study was carried out in a group of 27 freshly diagnosed normotensive primary hypothyroid female patients in comparison with healthy subjects. Their body mass index (BMI), serum thyroid profile, lipid profile, glucose, protein carbonylation, thiobarbituric acid reactive substances (TBARS), and blood antioxidant enzyme levels were estimated. The TBARS and protein carbonylation were significantly higher in cases compared with those in controls. Reduced glutathione was lower and glutathione peroxidase was higher in the test group compared with those in controls. Various lipid risk factors for coronary artery disease were significantly higher among the hypothyroid women in comparison with those in controls. The level of TBARS correlated significantly with various lipid risk factors among the hypothyroid women even after correcting the effect of BMI. However, no significant associations were observed between BMI and these risk factors when the effect of TBARS was nullified. In hypothyroidism, the coronary lipid risk factors seem to be more associated with lipid peroxidation than BMI. In conclusion, the present study indicates the presence of oxidative stress in hypothyroid patients and its association with atherogenic dyslipidemia, which is independent of BMI.