Effects of thyroxine replacement on endothelial function and carotid artery intima-media thickness in female patients with mild subclinical hypothyroidism
Clinics
;
66(8): 1321-1328, 2011. tab
Article
in English
| LILACS
| ID: lil-598370
ABSTRACT
BACKGROUND:
Previous studies have suggested an association between subclinical hypothyroidism and coronary artery disease that could be related to changes in serum lipids or endothelial dysfunction.METHODS:
Thirty-two female subclinical hypothyroidism patients were randomly assigned to 12 months of L-thyroxine replacement or no treatment. Endothelial function was measured by the flow-mediated vasodilatation of the brachial artery, as well as mean carotid artery intima-media thickness, and lipid profiles were studied at baseline and after 12 months of follow-up.RESULTS:
The mean ( ± SD) serum thyroid-stimulating hormone levels in the L-thyroxine replacement and control groups were 6.09±1.32 and 6.27 ± 1.39 μUI/ml, respectively. No relationship between carotid artery intima-media thickness or brachial flow-mediated vasodilatation and free T4 and serum thyroid-stimulating hormone was found. The median L-T4 dose was 44.23 ± 18.13 μg/day. After 12 months, there was a significant decrease in the flow-mediated vasodilatation in the subclinical hypothyroidism control group (before 17.33 ± 7.88 to after 13.1 ±4.75 percent, p =0.03), but there were no significant differences in flow-mediated vasodilatation in the L-thyroxine treated group (before 16.81 ± 7.0 to after 18.52 ± 7.44 percent, p = 0.39). We did not find any significant change in mean carotid intimamedia thickness after 12 months of L-thyroxine treatment.CONCLUSION:
Replacement therapy prevents a decline in flow-mediated vasodilatation with continuation of the subclinical hypothyroidism state. Large prospective multicenter placebo-controlled trials are necessaryto investigate endothelial physiology further in subclinical hypothyroidism patients and to define the role of L-thyroxine therapy in improving endothelial function in these patients.
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Thyroxine
/
Thyrotropin
/
Hormone Replacement Therapy
/
Carotid Intima-Media Thickness
/
Hypothyroidism
Type of study:
Controlled clinical trial
/
Observational study
/
Prognostic study
/
Risk factors
Limits:
Adult
/
Female
/
Humans
/
Male
Language:
English
Journal:
Clinics
Journal subject:
Medicine
Year:
2011
Type:
Article
Affiliation country:
Brazil
Institution/Affiliation country:
Centro de Estudos e Pesquisas da Mulher/BR
/
Universidade Federal do Rio de Janeiro/BR
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