Endocrine Abstracts

Introduction: The interrelationship between autoimmune thyroiditis, Graves’ disease and plasma adipokines levels remains elusive.

Aims: We aimed to compare the levels of adiponectin, resistin and PAI-1 levels in patients with autoimmune thyroiditis and Graves’ disease.

Subjects and methods: We recorded thyroid function tests, BMI, the levels of total cholesterol (TC), HDL, LDL-cholesterol, triglycerides (TG), apolipoprotein B (ApoB), ApoA1, lipoprotein(a) (Lp[a]), homocysteine, CRP (C-reactive protein), folic acid, vitamin B12, adiponectin, resistin and plasminogen activator inhibitor-1 (PAI-1) in 98 patients with autoimmune thyroid disease (75.9% woman, with a mean age of 46.7±15.3 years). We considered three groups of patients based on their thyroid function: euthyroidism (n=30), hypothyroidism (n=35) or hyperthyroidism (n=33). Statistical analysis was performed with Mann-Whitney test and spearman correlations. The results are expressed as mean±S.D. A two-tailed P≤0.05 was considered significant.

Results: BMI values were significant higher in hypothyroidism compared to hyperthyroid subjects (30.3±9.3vs 25.3±4.7 kg/m², P=0.03). Serum levels of CRP were significantly elevated in hyperthyroid compared to euthyroid subjects (0.56±0.55 vs 0.30±0.24 mg/dl, P<0.001). The levels of Lp(a) were significantly elevated in hypothyroid compared to hyperthyroid subjects (24.6±30.1 vs 18.6±17.8 mg/dl, P<0.001). When compared to hyperthyroid subjects, those with hypothyroidism showed higher levels of resistin (20.7±22.6 vs 12.7±10.9 ng/ml, P<0.01) and PAI-1 (27.3±25.1 vs 19.9±17.4 ng/ml, P<0.01), and lower levels of adiponectin (21.0±13.vs28.3±14.7 μg/ml, P<0.01). In both hypothyroid and hyperthyroid states the levels adiponectin, resistin and PAI-1 were not correlated with BMI. Adiponectin levels were negatively correlated with free T3 in hyperthyroid subjects (r=−0.35, P<0.05) and with TSH in euthyroid group (r=−0.61, P<0.001). Resistin levels were not correlated with TSH, free T3 or free T4. PAI-1 levels were negatively correlated with free T3 in both hypothyroid (r=−0.42, P<0.05) and hyperthyroid subjects (r=−0.36, P<0.05).

Conclusions: Patients with hypothyroidism due to autoimmune thyroiditis present higher levels of resistin and PAI-1 and lower levels of adiponectin comparing with patients with hyperthyroidism due to Graves’ disease. The interrelations between thyroid function and adiponectin, resistin and PAI-1 may be associated with the pathogenesis of autoimmune thyroid disease and may contribute to the increased cardiovascular risk observed in these patients.