LAUSR

Abstract Objective: We aimed to investigate the effects of oxidative stress in the pathogenesis and progression of Hashimoto’s thyroiditis (HT). Methods: Forty euthyroid and 40 subclinical hypothyroid patients older than 18 years and not yet had received treatment were enrolled in the study. Results: In the 9 months follow-up, 14 of the HT patients developed overt hypothyroidism. The mean total oxidant status (TOS) and oxidative stress index (OSI) were higher in patients who developed overt hypothyroidism than those who did not (p < .001). And no significant difference was found between the two groups in terms of paraoxanase-1 and arylesterase (p > .05). Multivariable Cox regression model showed thyroid stimulating hormone level (HR = 1.348, p < .001), free-thyroxine level (HR = 0.481, p = .017) and OSI ratio (HR = 2.349, p < .001) to be independent predictors of development of overt hypothyroidism. OSI level, being over 2.96 with 92.9% sensitivity and 62.5% specificity, predicts the risk of hypothyroidism. Conclusion: Oxidative stress may be an effective risk factor in the development of overt hypothyroidism in HT.