May elevated lipoprotein(a) levels in euthyroid autoimmune disease increase the risk of arteriosclerosis?

Elevated serum levels of lipoprotein(a) [Lp(a)] represent an independent risk factor in the development of arteriosclerosis and coronary heart disease. In overt but also in subclinical hypothyroidism a reversible increase of Lp(a) occurs. We compared Lp(a) serum levels, cholesterol, triglyceride, HDL- and LDL-cholesterol in 19 hypothyroid patients prior to and following the state of euthyroidism (group 1). On the other hand in group 2 we investigated 20 euthyroid patients having elevated thyroid antibodies as against 50 euthyroid normolipemic control subjects without detectable thyroid antibodies. Group 1: The elevated Lp(a) serum levels of the hypothyroid patients decreased significantly in the euthyroid state (37.9 +/- 8.24 vs. 28.1 +/- 6.13 mg/dl, mean +/- SEM). Group 2: The mean Lp(a) serum levels of the patients with increased thyroid antibodies were significantly higher than those of the control group (24.8 +/- 5.78 vs. 9.6 +/- 1.56 mg/dl, mean +/- SEM). In other parameters of lipid metabolism and thyroidal function no significant differences between both groups could be seen. The question arises whether such isolated Lp(a) elevation will lead to an increased arteriosclerotic risk. To minimize this possible risk regular controls of thyroid function should be carried out in euthyroid patients with elevated thyroid antibodies. In this way hypothyroidism may be detected and treated at an early stage.