Status of Serum Levels of Oxidative Stress Biochemical Markers and Total Antioxidant Capacity in Primary Hypothyroidism.

Background: Primary hypothyroidism (HT) has been demonstrated to be associated with oxidative stress. This study was designed to assess the role of oxidative stress in the pathogenesis of primary hypothyroidism. Methods: The study included 97 subjects, age range (of 29-62 years); 57 of them had been diagnosed with primary hypothyroidism, and 40 healthy subjects as controls in Baghdad, during Oct 2023 to 2024. The primary HT subjects were sub-classified into the newly diagnosed primary HT group (n=24) and the established primary HT (n=33) group. Investigations encompassed serum evaluation of total antioxidant capacity (TAC), total oxidant status (TOS), 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), NADPH oxidase-4 (NOX4), and Anti-TPO utilizing enzymatic colorimetric methods and enzyme-linked immunosorbent assay (ELISA). Results: The median and 1st -3rd quartile range values of serum 8-oxo-7,8-dihydro-2'-deoxyguanosine, NADPH oxidase-4, and total antioxidant capacity levels of newly diagnosed and established primary HT were significantly elevated when correlated with those of controls (for all, p < 0.0001), with non-significant differences between both groups of primary HT. The reservoir operating characteristic (ROC) and area under curve revealed that both total oxidant status and DNA damage 8-oxo-dG had high sensitivity and specificity in differentiation between hypothyroidism patients and controls at defined cutoff values. Conclusions: TheElevated levels of serum 8-oxodG, NOX4, and TOS reflect the underlying oxidative damage associated with reduced thyroid function and may participate to the pathogenesis of primary hypothyroidism.