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Decrease in carotid intima‐media thickness in hypothyroid patients after normalization of thyroid function
Author(s) -
Nagasaki Toshiki,
Inaba Masaaki,
Henmi Yasuko,
Kumeda Yasuro,
Ueda Misako,
Tahara Hideki,
Sugiguchi Shigeru,
Fujiwara Shigehiko,
Emoto Masanori,
Ishimura Eiji,
Onoda Naoyoshi,
Ishikawa Tetsuro,
Nishizawa Yoshiki
Publication year - 2003
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1046/j.1365-2265.2003.01893.x
Subject(s) - medicine , intima media thickness , levothyroxine , endocrinology , cholesterol , common carotid artery , basal (medicine) , thyroid function , tunica media , thyroid , tunica intima , carotid arteries , cardiology , insulin
Summary objective This case–control study was carried out to assess whether levothyroxine (L‐T4) replacement might cause regression of the enhanced atherosclerosis seen in hypothyroid patients. patients and methods Intima‐media thickness (IMT) in the common carotid artery (CCA) was measured from digitalized still images taken during scanning by high‐resolution ultrasonography as an indicator of early atherosclerosis. Thirty‐five hypothyroid patients were examined for their CCA IMT before and 1 year after normalization of thyroid function by L‐T4 replacement. As control, 35 healthy subjects were enrolled from among the participants in a local health‐check programme conducted at the Osaka City University Hospital. results Basal CCA IMT was significantly higher in hypothyroid patients [0·635 ± 0·018 (mean ± SE) mm] than in control subjects (0·559 ± 0·021 mm, P < 0·005). After 1 year of euthyroidism, 34 out of 35 patients showed a significant decrease of CCA IMT, to 0·552 ± 0·015 mm ( P < 0·0001), a level comparable to normal controls. CCA IMT change was closely associated with basal levels of total cholesterol ( r = −0·472, P = 0·0031), low‐density lipoprotein (LDL) cholesterol ( r = −0·441, P = 0·0076) and the total/HDL cholesterol ratio ( r =−0·435, P = 0·0057), but not with any of the other variables measured except for age ( r = −0·353, P = 0·0296). conclusions This study demonstrated that L‐T4 treatment might have the potential to reverse the progression of atherosclerosis in hypothyroid patients. Furthermore, it suggests that increased levels of LDL cholesterol and the total/HDL cholesterol ratio have an important role in the increased common carotid intima‐media thickness in hypothyroid patients.