T. Tzotzas et al., Changes in lipoprotein(a) levels in overt and subclinical hypothyroidism before and during treatment, THYROID, 10(9), 2000, pp. 803-808
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.