Lipoprotein (a) levels in thyroid dysfunction before and after treatment.

AIM To investigate the possible effects of thyroid hormones on the lipoprotein (a) (Lp(a)) serum concentration. METHODS Eleven patients with hyperthyroidism (Grave's disease), 18 patients with hypothyroidism and low Lp(a) (Hashimoto's disease), and 13 patients with hypothyroidism (Hashimoto's disease) and elevated Lp(a) were examined before and after thyroid hormone normalization. The measurements included total cholesterol, HDL cholesterol (including HDL2 and HDL3 subfractions), LDL cholesterol, VLDL cholesterol, triglycerides, apoproteins A1 and B, and Lp(a), thyrotropin (TSH) and thyroid hormones/total thyroxine (T4), triiodothyronine (T3), free thyroxine (FT4), and free triiodothyronine (FT3). RESULTS In patients with hyperthyroidism, serum concentrations of total cholesterol, LDL cholesterol, and apo B significantly increased (p<0.05) after the treatment, whereas a moderate increase in HDL (HDL2 subfraction), triglyceride, and Lp(a) concentrations did not reach statistical significance. In both groups of patients with hypothyroidism, concentrations of total cholesterol, LDL cholesterol, apo B, and triglycerides significantly decreased after the treatment, whereas the changes in HDL (HDL2 and HDL3 subfractions), VLDL cholesterol, apo A1, and Lp(a) were not significant. CONCLUSION Thyroid hormones had only a moderate effect on the metabolism of Lp(a).