Changes in lipoprotein(a) levels in overt and subclinical hypothyroidism before and during treatment

The aim of this prospective, follow-up study was to examine the influence o f overt hypothyroidism (OHP) and subclinical (SHP), before and during thyro xine (T-4) treatment, on lipoprotein(a) [Lp(a)], other lipoproteins, and ap olipoproteins. Twenty-four patients (17 females, 7 males) with OHP, aged 54 +/- 11.1 years (group A) and 23 patients (females) with SHP aged 50.1 +/- 13.2 years (group B) were evaluated and compared to 34 and 38 controls, res pectively. All patients received T-4 therapy in a stepwise fashion until eu thyroidism was reached. Thyrotropin (TSH), free thyroxine (FT4), and total triiodothyronine (TT3) levels were measured before T-4 therapy and repeated ly every 4 weeks after the initiation of treatment until the euthyroid stat e was reached. Levels of Lp(a), total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDLc), high-density lipoprotein chole sterol (HDLc), apolipoprotein A1 (apoA1) and apolipoprotein B (apoB) were m easured before and 4 months after the achievement of euthyroidism. Addition ally, body mass index (BMI) was also evaluated. We found that in OHP patien ts, levels of TC, LDLc, and apoB were elevated before treatment and decreas ed significantly after the return to the euthyroid state. BMI and levels of triglycerides also decreased significantly; Lp(a) was higher in OHP patien ts in comparison with controls and decreased significantly by 14.56% (25.29 % in men and 10.34% in women) during T-4 treatment. In SHP patients, levels of all common lipoproteins, apolipoproteins, and Lp(a) did not differ sign ificantly from controls before treatment and did not change after the euthy roid stage was reached. It is concluded that in overt hypothyroidism, Lp(a) levels and most of the lipoproteins were elevated before treatment and dec reased significantly. In subclinical hypothyroidism, lipoproteins and Lp(a) levels were normal at baseline and did not change during treatment.