Lp(A) levels in thyroid disfunctions
Cristina-Corina Pop-Radu1 & Ana Iazigian2
The aim of the study was to assess lipid status in subjects with hypothyroidism (overt and subclinical) and hyperthyroidism. Therefore, we analyzed the relationship between the levels of blood lipids (Lp(a), Apo AI, Apo B, Apo AI/B, total cholesterol (TC), triglyceride (TG), LDL, HDL, LDL) and TSH, FT4, T3, TPOAb concentration. The study groups included 38 subjects with overt hypothyroidism (mean±S.E.M., age 48.6±13.25 years), 30 with subclinical hypothyroidism (47.6±13.23 years), 30 with hyperthyroidism (age 41.53±12.29 years) and 55 with euthyroidism. Lp(a) was found to register increased average serial levels in hypothyroidic subjects, (483.28±281.55 mg/l, with limits between 214 and 1550 mg/l), apparently normal ones in hyperthyroidic persons (253.13±94.29 mg/l, with limits between 140 and 530 mg/l), but significantly lower than hypothyroidic patients and slightly increased ones in the control group (305±100.44 mg/l). In hypothyroidism Lp(a) levels were positively correlated, significantly strong with TSH, Apo B, TC/HDL, CT, TG, VLDL and significantly mild with LDL/HDL (P<0.01) and with LDL (P<0.05). Lp(a) levels were negatively correlated significantly strong with Apo AI/B, FT4 and T3 (P<0.01). In subclinical hypothyroidism subgroup Lp(a) was not correlated with FT4, but it was significantly correlated with TSH. TC, HDL, LDL were neither correlated with FT4, nor with the TSH concentration. Between TPOAb and Lp(a) levels no correlation was found. In hyperthyroidism no correlation between Lp(a) levels and the parameters under study was found. The association of hypothyroidism with increased serial levels of Lp(a) which represents independently a relevant factor of cardiovasculary risk, contributing to atherosclerosis even in case of relatively normal cholesterol levels, seems to increase the higher cardiovasculary risk in hypothyroidic subjects. In conclusion, increased levels of Lp(a), in association with an increase in TSH level can be another argument in favour of the active treatment of the subclinical hypothyroidism.