Decrease of brachial-ankle pulse wave velocity in female subclinical hypothyroid patients during normalization of thyroid function: a double-blind, placebo-controlled study.
OBJECTIVE
Subclinical hypothyroidism affects 5-15% of the general population, is especially prevalent in females, and may be associated with increased morbidity from cardiovascular disease, although it remains controversial. We recently reported a significant increase in the brachial-ankle pulse wave velocity (baPWV), a parameter of arterial stiffening and an independent predictor of cardiovascular events, in subclinical hypothyroidism without thyroiditis. The current study was performed to assess changes in baPWV in female subclinical hypothyroidism with autoimmune chronic thyroiditis (Hashimoto's disease) after restoration of normal thyroid function.


METHODS
In a randomized placebo-controlled study, 95 female subclinical hypothyroid patients were monitored for changes in baPWV before and after levothyroxine (l-T(4)) replacement therapy. Changes in baPWV were also measured in 42 age-matched normal female subjects.


RESULTS
The baseline baPWV values in patients with subclinical hypothyroidism were significantly higher than in normal subjects. With attainment of euthyroidism, baPWV showed a significant decrease from 1776.7+/-86.0 to 1674.3+/-79.2 cm/s (P=0.006) in patients treated with l-T(4), but the changes in baPWV and TSH were not correlated. The change in baPWV was significantly and negatively correlated with age and baseline pulse pressure, but multiple regression analysis revealed that these parameters failed to be associated with the change in baPWV.


CONCLUSIONS
Sustained normalization of thyroid function during l-T(4) replacement therapy significantly decreases baPWV in female subclinical hypothyroid patients with autoimmune chronic thyroiditis, suggesting the improvement of arterial stiffening and, consequently, possible prevention of cardiovascular disease.
Nagasaki
Toshiki
T
Department of Metabolism, Endocrinology and Molecular Medicine, Internal Medicine, Osaka City University Graduate School of Medicine, Osaka-City, Japan.
Inaba
Masaaki
M
Yamada
Shinsuke
S
Shirakawa
Kumi
K
Nagata
Yuki
Y
Kumeda
Yasuro
Y
Hiura
Yoshikazu
Y
Tahara
Hideki
H
Ishimura
Eiji
E
Nishizawa
Yoshiki
Y
D000368:Aged; D000843:Ankle Joint / Q000098:blood supply; D001783:Blood Flow Velocity / Q000187:drug effects*; D001916:Brachial Artery / Q000502:physiology; D002318:Cardiovascular Diseases / Q000517:prevention & control; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy* / Q000503:physiopathology*; D008875:Middle Aged; D010919:Placebos; D011673:Pulsatile Flow / Q000187:drug effects*; D013967:Thyroiditis, Autoimmune / Q000188:drug therapy / Q000503:physiopathology; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood / Q000627:therapeutic use*
D010919:Placebos; D013972:Thyrotropin; D013974:Thyroxine