Insulin sensitivity, plasma adiponectin and sICAM-1 concentrations in patients with subclinical hypothyroidism: response to levothyroxine therapy.

Subclinical hypothyroidism is associated with an increased risk of atherosclerosis. The aim of this study was to investigate the concentration of plasma soluble intercellular adhesion molecule-1 and adiponectin in relation to insulin sensitivity in patients with subclinical hypothyroidism and to estimate if L-thyroxine treatment had an influence on these parameters. 13 women with subclinical hypothyroidism and 14 euthyroid controls were included in the study. A physical examination was conducted, hyperinsulinemic euglycemic clamp and plasma soluble intercellular adhesion molecule-1, adiponectin and lipids profiles were measured at baseline in both groups and in the group with subclinical hypothyroidism the above procedures were performed after L-thyroxine therapy (mean time of treatment 5.0 months) in stable euthyroid state. Insulin sensitivity and adiponectin were not different at baseline in the two studied groups. Plasma soluble intercellular adhesion molecule-1 concentration was significantly higher in the patients with subclinical hypothyroidism (P = 0.011). The comparison of lipids profiles revealed that only LDL-cholesterol concentration was higher (P = 0.011) in the group with subclinical hypothyroidism. After therapy, we observed an improvement of insulin sensitivity (P = 0.012) and a decrease of plasma glucose (P = 0.019) and soluble intercellular adhesion molecule-1 (P = 0.01), whereas adiponectin concentration remained unchanged. We concluded that L-thyroxine treatment in patients with subclinical hypothyroidism might exert a beneficial effect by reducing cardiovascular risk factors.