Endocrine Abstracts

Introduction: Given the significant impact of thyroid function on body weight, energy metabolism and adipocytes physiology, our aim was to study the impact of subclinical thyroid dysfunction in plasmatic levels of adipokines and ICAM-1 (intercellular adhesion molecule 1).

Methods: We evaluated 98 patients with autoimmune thyroid disease divided into three groups: 30 who were euthyroid (TSH=0.35–4.94 UI/ml), 35 with subclinical hypothyroidism (hypoSC, TSH >4.94 UI/ml) and 33 with subclinical hyperthyroidism (hiperSC, TSH <0.35 UI/ml). We evaluated BMI, serum concentration of FT₃, FT₄, TSH, C-reactive protein (CRP), adiponectin, resistin, PAI-1 (plasminogen activator inhibitor-1) and ICAM-1. The statistical analysis was performed using ANOVA, Student’s t-test and Spearman’s correlations.

Results: We observed no significant differences in age between euthyroid (50±16 years), hypoSC (46±17 years) and hiperSC (44±13 years) groups, or gender (90.0%, 97.1% and 90.9% of the female gender respectively). The plasmatic levels of CRP were higher in individuals with hypoSC in comparison to individuals who were euthyroid (0.56±0.55 vs 0.30±0.24, P<0.001). The resistin levels were significantly higher in the hypoSC group compared with the euthyroid group (20.7±22.6 vs 19.3±9.0, P<0.01) and the hiperSC (20.7±22.6 vs 12.7±10.9 ng/ml, P<0.01). We observed higher levels of PAI-1 in the hypoSC group when compared with the euthyroid group (27.3±25.1 vs 18.7±11.8 ng/ml, P<0.01) and the hiperSC group (27.3±25.1 vs 19.9±17.4 ng/ml, P<0.01). The patients with hypoSC had lower levels of adiponectin in comparison to patients with hiperSC (21.0±13.3 vs 28.3±14.7 ng/ml, P<0.01). The PAI-1 levels were negatively correlated with FT3 levels in the hypoSC group (r=−0.42, P<0.05) and in the hiperSC group (r=−0.36, P<0.05). The levels of adiponectin had a significant correlation with the FT3 levels in the hiperSC group (r=−0.35, P<0.05) and with TSH in the euthyroid group (r=0.61, P<0.001). ICAM-1 levels were positively correlated with resistin in hypoSC group (r=0.38, P=0.03).

Conclusions: In this study, we found significantly higher levels of resistin and PAI-1 in subclinical hypothyroidism. The interrelations between thyroid function, adipokines and ICAM-1 may contribute to the metabolic and cardiovascular complications in autoimmune thyroid disease.