Relationship of TSH with atherosclerosis-related factors in subclinical hypothyroidism

Abstract

Two hundred and fifty patients with subclinical hypothyroidism(SCH)and 120 euthyroid volunteers were recruited for the study, SCH patients were stratified into 2 groups according to TSH levels(group A: TSH 10 mIU/L). All subjects were examined for clinical characteristics, thyroid profile, lipid profile, and biomarkers of early atherosclerosis. Patients in group B received L-thyroxine replacement treatment to achieve euthyroidism. After 6 months of stable euthyroidism all measurements were repeated. SCH patients had higher levels of total cholesterol(TC), low-density lipoprotein-cholesterol(LDL-C), asymmetric dimethyl arginine(ADMA), carotid artery intima media thickness(CIMT), thromboxane B2(TXB2), and C-reactive protein(CRP)but with lower nitric oxide(NO)level compared with euthyroid subjects. Levels of TC, LDL-C, CIMT, TXB2, and ADMA decreased, and NO level increased significantly after 6 months of euthyroidism. TSH was positively correlated with TC, LDL-C, CIMT, ADMA, and TXB2; and negatively correlated with NO. Based on multivariate regression analysis, TSH was an independent influential factor of CIMT and NO. We conclude that raised TSH is an important risk factor of atherosclerosis in SCH. (Chin J Endocrinol Metab, 2015, 31: 133-135) Key words: Hypothyroidism; Thyroid-stimulating hormone; Atherosclerosis; L-thyroxine