Abstract
Objective and Aim: Selenium supplementation can decrease anti-TPO levels in patients with autoimmune thyroiditis (AIT. This study was performed to evaluate the relationship between serum selenium concentrations and the course of anti-TPO over time.
Methods: Seventy consecutive AIT patients were randomly grouped according to the degree of the disease based on ultrasound examination and anti-TPO determination: severe: anti-TPO >1000 U/L, (Gr1, n=31) and moderate: anti-TPO < 1.000 U/L (Gr2, n=39). All patients were treated with selenomethionine 200μg/day and LT4 individually tailored to maintain TSH at around 1 mU/L. Selenium, TSH and anti-TPO were determined at the baseline, at 4 and 24 weeks thereafter.
Results: Gr1 had significantly higher anti-TPO values (2335±1133,mean±sd) at baseline compared to Gr2 (485±247; p<0.001). A notable reduction of anti-TPO levels in both groups over time (Gr1: -39.86%; Gr2: -14.80%, p><0.001, from baseline to W24) was detected. Anti-TPO levels were differently reduced by 2.45% from baseline to W4 and by 38.35% from W4 to W24 in Gr1 and by 2.29% and 12.80% in Gr2, respectively. The interaction between time and basal selenium values and groups was statistically significant (p><0.01). Ignoring the time character of the data, it may be hypothesized that basal Se does not directly affect anti-TPO when using longitudinal models. Anti-TPO had a highly significant (p><0.001) negative relation with Se.
Conclusions: The results indicate that the reduction of anti-TPO by Se depends on baseline Se values and that the main effect of time (reduction of anti-TPO) depends on the severity of disease, since different reductions were achieved in group 1 and 2.The effect of Se in anti-TPO over time was negative (higher Se leads to lower anti-TPO), being statistical significant (p><0.001)for both groups.