Changes in Lipoprotein(a) Levels in Overt and Subclinical Hypothyroidism Before and During Treatment

Abstract

The aim of this prospective, follow-up study was to examine the influence of overt hypothyroidism (OHP) and subclinical (SHP), before and during thyroxine (T4) treatment, on lipoprotein(a) [Lp(a)], other lipoproteins, and apolipoproteins. 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, respectively. All patients received T4 therapy in a stepwise fashion until euthyroidism was reached. Thyrotropin (TSH), free thyroxine (FT4), and total triiodothyronine (TT3) levels were measured before T4 therapy and repeatedly every 4 weeks after the initiation of treatment until the euthyroid state was reached. Levels of Lp(a), total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDLc), high-density lipoprotein cholesterol (HDLc), apolipoprotein A1 (apoA1) and apolipoprotein B (apoB) were measured before and 4 months after the achievement of euthyroidism. Additionally, body mass index (BMI) was also evaluated. We found that in OHP patients, levels of TC, LDLc, and apoB were elevated before treatment and decreased significantly after the return to the euthyroid state. BMI and levels of triglycerides also decreased significantly; Lp(a) was higher in OHP patients in comparison with controls and decreased significantly by 14.56% (25.29% in men and 10.34% in women) during T4 treatment. In SHP patients, levels of all common lipoproteins, apolipoproteins, and Lp(a) did not differ significantly from controls before treatment and did not change after the euthyroid stage was reached. It is concluded that in overt hypothyroidism, Lp(a) levels and most of the lipoproteins were elevated before treatment and decreased significantly. In subclinical hypothyroidism, lipoproteins and Lp(a) levels were normal at baseline and did not change during treatment.

Lipid profile in subclinical hypothyroidism: is L-thyroxine substitution beneficial?

“…There is limited information with regard to the effect of SH on Lp(a) levels (Table 4). Lp(a) levels and their response to treatment in SH have been evaluated in five previous studies (11,12,20,24,38) (Table 5). All but one failed to demonstrate any significant changes in Lp(a) levels following L-thyroxine substitution therapy.…”

Association between Subclinical Hypothyroidism and Proliferative Diabetic Retinopathy in Type 2 Diabetic Patients: A Case-Control Study

“…SCH is associated with atherogenic lipid profile (Bindels et al 1999;Tsimihodimos et al 1999;Pirich et al 2000;Tzotzas et al 2000;Vierhapper et al 2000;Efstathiadou et al 2001;Meier et al 2001;Kanaya et al 2002;Caraccio et al 2002;Monzani et al 2004), impaired vascular function (Taddei et al 2003), impaired cardiac function, and increased risk for the development of atherosclerosis and myocardial dysfunction (Hak et al 2000;Biondi et al 2002). With respect to the metabolic syndrome, as might be expected, the prevalence of SCH is higher in patients with metabolic conditions than that in non-metabolic syndrome subjects (Uzunlulu et al 2007).…”

Relationship between Lipoprotein(a) and Thyroid Hormones in Hypothyroid Patients

“…In cases of hypothyroidism, how the serum Lp(a) levels are influenced by thyroid hormone remains unknown and contradictory results on the effect of thyroid hormone replacement on serum Lp(a) levels have been reported [6][7][8][9][10][11][12][13]. Although an altered lipid profile is frequently observed in patients with thyroid dysfunction, published data on the relationship between Lp(a) and thyroid status are controversial [14].…”