A comparative analysis of the lipid tissue hormones concentration, lipid metabolism and insulin resistance in subclinical hypothyroidism depending on the presence/absence of the levothyroxin replacement therapy

Abstract

The aim of the present research was to study the influence of lipid tissue hormones on the mechanisms of insulin resistance development and rates of lipid metabolism in patients with subclinical hypothyroidism (SH) aged over 50 years, depending on the body mass index (BMI), as well as the presence or absence of the levothyroxin (L-T4) replacement therapy. In patients with SH there were revealed disturbances of lipid metabolism which were manifested by low concentration of HDL-C, as well as the reduction in insulin sensitivity (an increase in the insulin level in normoglycemia and elevation of HOMA-IR rates). The analyses of lipid tissue hormones levels in studied groups showed an increase in adiponectin level within the reference values range, but they significantly differed from those of the controls. The values of leptin and resistin in the studied groups did not show significant difference from those of the healthy persons of the corresponding age, sex, and BMI. A correlation analysis of the values of lipid tissue hormones, TSH, lipid spectrum, insulin, glucose, and HOMA-IR was carried out. The results obtained were analyzed by two main points: the replacement therapy and BMI. The analyses of the results in accordance with BMI revealed that in patients with the normal body mass (BMI<24.9 kg/m2) the adiponectin rate was higher against the background of the lipid metabolism disturbance. In patients with the excessive body mass (BMI>25–29.9 kg/m2) the values of insulin and HOMA-IR increased, the disturbance of lipid metabolism aggravated, and adiponectin concentration decreased. The L-T4 replacement therapy was effective and resulted in the normalization of the rates of lipid and carbohydrate metabolism, adiponectin, and leptin. However the comparison of the results obtained in the groups with compensated and noncompensated SH shows that after 6 months significant differences were revealed only in the levels of adiponectin, resistin, and insulin.