Effects of 18 months of L-T4 replacement in women with subclinical hypothyroidism.

Hdl Handle:
http://hdl.handle.net/10147/207927
Title:
Effects of 18 months of L-T4 replacement in women with subclinical hypothyroidism.
Authors:
Adrees, M; Gibney, J; El-Saeity, N; Boran, G
Affiliation:
Department of Clinical Chemistry, Adelaide and Meath Hospital incorporating the, National Children's Hospital, Dublin 24, Ireland.
Citation:
Clin Endocrinol (Oxf). 2009 Aug;71(2):298-303. Epub 2008 Dec 15.
Journal:
Clinical endocrinology
Issue Date:
1-Feb-2012
URI:
http://hdl.handle.net/10147/207927
DOI:
10.1111/j.1365-2265.2008.03509.x
PubMed ID:
19094068
Abstract:
CONTEXT: Some of the cardiovascular and renal abnormalities seen in overt hypothyroidism have also been reported in subclinical hypothyroidism (SCH). Short-term L-T4 replacement in SCH improves cardiovascular risk markers and reduces carotid intima-media thickness (CIMT), a surrogate marker of atherosclerosis. The haemodynamic and renal effects of L-T4 replacement in SCH are poorly understood. OBJECTIVES: To compare cardiovascular risk factors and renal variables in women with SCH and normal women. To study the effects of L-T4 replacement in SCH subjects on these variables and on structural and functional changes in common carotid and brachial arteries. DESIGN: Fifty-six women with SCH before and after L-T4 replacement for 18 months and 56 normal women of similar age distribution were studied. Blood Pressure (BP), plasma lipids and homocysteine were measured and renal function evaluated [estimation of glomerular filtration rate (eGFR) using standard equations and measurement of serum Cystatin-C] in women with SCH before and after 18 months of l-T4, and in healthy women. CIMT and endothelial function (using brachial artery ultrasound) were studied before and after L-T4 in a subgroup of women with SCH. RESULTS: Systolic and diastolic BP, total cholesterol, triglyceride, LDL-cholesterol, lipoprotein(a) and homocysteine were greater in SCH (P < 0.05), and following L-T4 replacement decreased (P < 0.05) to levels that no longer differed from normal subjects. Estimated GFR was reduced and serum Cystatin-C increased (P < 0.05) in SCH. These variables also normalized following L-T4. Following L-T4 replacement the carotid artery baseline diameter increased by 7.1% and CIMT decreased by a mean value of 13%, while brachial artery diameter increased basally by 12.5% and following endothelium-dependent vasodilatation by 17.5% (P < 0.05). However, the increment following reactive hyperaemia did not differ before or following L-T4 replacement. CONCLUSION: Normalization of cardiovascular risk factors following L-T4 replacement in SCH potentially explains reduced CIMT. Increased carotid and brachial artery diameters and normalized eGFR indicates a haemodynamic effect of L-T4 replacement, the importance of which requires further investigation.
Language:
eng
MeSH:
Adult; Blood Pressure; Cholesterol/blood; Female; Follow-Up Studies; Heart/physiopathology; *Hormone Replacement Therapy; Humans; Hypothyroidism/*drug therapy/metabolism/physiopathology; Kidney/physiopathology; Middle Aged; Thyroxine/*therapeutic use; Triglycerides/blood
ISSN:
1365-2265 (Electronic); 0300-0664 (Linking)

Full metadata record

DC FieldValue Language
dc.contributor.authorAdrees, Men_GB
dc.contributor.authorGibney, Jen_GB
dc.contributor.authorEl-Saeity, Nen_GB
dc.contributor.authorBoran, Gen_GB
dc.date.accessioned2012-02-01T10:50:20Z-
dc.date.available2012-02-01T10:50:20Z-
dc.date.issued2012-02-01T10:50:20Z-
dc.identifier.citationClin Endocrinol (Oxf). 2009 Aug;71(2):298-303. Epub 2008 Dec 15.en_GB
dc.identifier.issn1365-2265 (Electronic)en_GB
dc.identifier.issn0300-0664 (Linking)en_GB
dc.identifier.pmid19094068en_GB
dc.identifier.doi10.1111/j.1365-2265.2008.03509.xen_GB
dc.identifier.urihttp://hdl.handle.net/10147/207927-
dc.description.abstractCONTEXT: Some of the cardiovascular and renal abnormalities seen in overt hypothyroidism have also been reported in subclinical hypothyroidism (SCH). Short-term L-T4 replacement in SCH improves cardiovascular risk markers and reduces carotid intima-media thickness (CIMT), a surrogate marker of atherosclerosis. The haemodynamic and renal effects of L-T4 replacement in SCH are poorly understood. OBJECTIVES: To compare cardiovascular risk factors and renal variables in women with SCH and normal women. To study the effects of L-T4 replacement in SCH subjects on these variables and on structural and functional changes in common carotid and brachial arteries. DESIGN: Fifty-six women with SCH before and after L-T4 replacement for 18 months and 56 normal women of similar age distribution were studied. Blood Pressure (BP), plasma lipids and homocysteine were measured and renal function evaluated [estimation of glomerular filtration rate (eGFR) using standard equations and measurement of serum Cystatin-C] in women with SCH before and after 18 months of l-T4, and in healthy women. CIMT and endothelial function (using brachial artery ultrasound) were studied before and after L-T4 in a subgroup of women with SCH. RESULTS: Systolic and diastolic BP, total cholesterol, triglyceride, LDL-cholesterol, lipoprotein(a) and homocysteine were greater in SCH (P < 0.05), and following L-T4 replacement decreased (P < 0.05) to levels that no longer differed from normal subjects. Estimated GFR was reduced and serum Cystatin-C increased (P < 0.05) in SCH. These variables also normalized following L-T4. Following L-T4 replacement the carotid artery baseline diameter increased by 7.1% and CIMT decreased by a mean value of 13%, while brachial artery diameter increased basally by 12.5% and following endothelium-dependent vasodilatation by 17.5% (P < 0.05). However, the increment following reactive hyperaemia did not differ before or following L-T4 replacement. CONCLUSION: Normalization of cardiovascular risk factors following L-T4 replacement in SCH potentially explains reduced CIMT. Increased carotid and brachial artery diameters and normalized eGFR indicates a haemodynamic effect of L-T4 replacement, the importance of which requires further investigation.en_GB
dc.language.isoengen_GB
dc.subject.meshAdulten_GB
dc.subject.meshBlood Pressureen_GB
dc.subject.meshCholesterol/blooden_GB
dc.subject.meshFemaleen_GB
dc.subject.meshFollow-Up Studiesen_GB
dc.subject.meshHeart/physiopathologyen_GB
dc.subject.mesh*Hormone Replacement Therapyen_GB
dc.subject.meshHumansen_GB
dc.subject.meshHypothyroidism/*drug therapy/metabolism/physiopathologyen_GB
dc.subject.meshKidney/physiopathologyen_GB
dc.subject.meshMiddle Ageden_GB
dc.subject.meshThyroxine/*therapeutic useen_GB
dc.subject.meshTriglycerides/blooden_GB
dc.titleEffects of 18 months of L-T4 replacement in women with subclinical hypothyroidism.en_GB
dc.contributor.departmentDepartment of Clinical Chemistry, Adelaide and Meath Hospital incorporating the, National Children's Hospital, Dublin 24, Ireland.en_GB
dc.identifier.journalClinical endocrinologyen_GB
dc.description.provinceLeinster-

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