Serum Thyroid Stimulating Hormone and Antioxidant Status in Patients with Suspected Thyroid Dysfunction

Abstract

The incidence of thyroid disorders is reported in significant numbers globally. Patients referred for thyroid function tests to the Nuclear Medicine unit, University of Peradeniya, Sri Lanka were assessed for antioxidant status in addition to routine investigations. Among the patients investigated 41.9% had enlarged thyroid glands while others (58.1%) did not show any thyroid enlargement. Majority (79.5%) of the patients with enlarged thyroid, had multi nodular goiter, while only 12.8% had diffused enlargement and 7.7% had solitary thyroid nodules. Ninety three subjects formed the study group and their mean Thyroid stimulating hormone (TSH) concentration was 5.4 ± 12.3 mU/L with a range from 0.1 to 58.0 mU/L. Their mean serum Total antioxidant capacity (TAC) was 719.1 ± 164.5 µmol/L and mean serum Protein thiol concentration was 517.7 ± 89.8 µmol/L. Age had a significant positive correlation with TAC (r= 0.268, P= 0.009), and a significant negative correlation with protein thiol (r= -0.481, P < 0.001). BMI of the patients increased significantly with age. Among the patients, 9 (9.7%) were hyperthyroid, 68 (73.1%) were euthyroid while 16 (17.2%) were hypothyroid. There was a significant positive correlation between TSH and TAC (r=0.526, P=0.036) in hypothyroid patients which had not been reported previously. The mean serum TAC in males (928.7 ± 60.4 µmol/L) was significantly higher than that of females (699.4 ± 150.5 µmol/L) (P =0.006). Similarly, mean serum protein thiol concentration of males (570.7 ± 23.6 µmol/L) was significantly higher than that of females (512.7 ± 90.0 µmol/L) (P=0.049). No significant differences in TAC and protein thiol concentration were evident among euthyroid, hyperthyroid and hypothyroid patients which suggest that the antioxidant status does not differ among the different categories of patients investigated.