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

Abstract

Objective: The significance of dyslipidemia in subclinical hypothyroidism (SH) and the effect of thyroid substitution on lipids remain controversial. The present study aimed to assess the association of SH with lipid abnormalities and to quantify the effect of L-thyroxine therapy on serum lipid profiles. Design: Serum lipid parameters of 66 patients with SH and 75 age-and sex-matched euthyroid controls were evaluated in a cross-sectional study. Results: Patients with SH had higher total cholesterol (TC) ð222^45 (S.D.) vs 190^32 mg=dlÞ; lowdensity lipoprotein cholesterol (LDL-C) ð139^28 vs 118^39 mg=dlÞ; apolipoprotein B ð149^21 vs 139^18 mg=dlÞ and lipoprotein (a) (Lp(a)) (median 12.5 (0.8-101) mg/dl vs 7 (0.8 -44) mg/dl) levels compared with euthyroid controls (P , 0:05 for all comparisons). In a follow-up study including 37 patients with SH, all measurements were repeated after restoration of a euthyroid state with incremental doses of L-thyroxine. No significant changes in serum lipid profiles were observed except for a decrease in high-density lipoprotein cholesterol ð59^15 to 55^14 mg=dl; P , 0:05Þ: However, patients with high pre-treatment TC ($240 mg/dl) showed a significant reduction in both TC ð278^28 vs 257^36 mg=dl; P , 0:05Þ and LDL-C ð192^23 vs 173^28 mg=dl; P , 0:01Þ levels. Similar but more pronounced changes were observed in a subgroup of patients with pre-treatment levels of TSH $10 mU/ml. Thyroid autoimmunity had no effect on either the baseline or the posttreatment lipid profile. Conclusion: Although patients with subclinical hypothyroidism exhibit increased levels of the atherogenic parameters (mainly LDL-C and Lp(a)), thyroid substitution therapy does not seem to significantly improve dyslipidemia in the whole group of patients.

Study of serum lipid profile in subclinical hypothyroidism

“…Efstathiadou [21] found out increased levels of the atherogenic lipid parameters in SH which strengthen our findings but suggested that thyroid substitution therapy does not seem to significantly improve dyslipidemia in the whole group of patients which contradicts many other studies. Similarly, Fatourechi et al [9] and Biondi et al [10] suggest no thyroid replacement treatment for SH.…”

Hiperlipidemias e fatores dietéticos: estudo transversal entre nipo-brasileiros

“…A relação entre as presenças de hipotireoidismo e hiperlipidemias já foi relatada por diversos pesquisadores (38)(39)(40)(41)(42)(43)(44)(45)(46). No presente estudo, observou-se que, do total de indivíduos com hipotireoidismo (n= 121), 89,3% apresentavam, simultaneamente, hiperlipidemia.…”

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).…”