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.