<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Thyroid hormones have multiple complex effects on lipid synthesis and metabolism. These physiological actions are well documented in overt hypothyroidism where the elevated levels of total cholesterol, low density lipoporotein cholesterol and possibly triglycerides are reverted by levo-thyroxine therapy. Subclinical hypothyroidism, defined as elevated serum thyroid stimulating hormone in the presence of reference range of free thyroxine and free triiodothyronine concentrations, is a relatively frequent clinical conditions. Many clinical and epidemiological studies have evaluated lipid metabolism, markers of subclinical atherosclerosis and other cardiovascular risk factors in subclinical hypothyroidism as well as the need of replacement therapy in these patients. The available results are rather conflicting, with variable and inconclusive results. Moreover, no consensus still exists on the clinical significance and treatment of this mild form of thyroid failure. On the contrary, available evidences suggest that patients with plasma thyroid stimulating hormone levels above 10 mU/L should be treated with levo-thyroxine, since may have an increased risk of cardiovascular disease. However, the epidemiological evidences suggest being rather conservative in older people, since higher thyroid stimulating hormone is associated with lower risk of multiple adverse events in this population. In this review, we summarized the current evidences on the association between subclinical hypothyroidism and lipid metabolism and the effect of levo-thyroxine therapy on lipid parameters.</p></abstract>

Thyroid hormones have multiple complex effects on lipid synthesis and metabolism. These physiological actions are well documented in overt hypothyroidism where the elevated levels of total cholesterol, low density lipoporotein cholesterol and possibly triglycerides are reverted by levo-thyroxine therapy. Subclinical hypothyroidism, defined as elevated serum thyroid stimulating hormone in the presence of reference range of free thyroxine and free triiodothyronine concentrations, is a relatively frequent clinical conditions. Many clinical and epidemiological studies have evaluated lipid metabolism, markers of subclinical atherosclerosis and other cardiovascular risk factors in subclinical hypothyroidism as well as the need of replacement therapy in these patients. The available results are rather conflicting, with variable and inconclusive results. Moreover, no consensus still exists on the clinical significance and treatment of this mild form of thyroid failure. On the contrary, available evidences suggest that patients with plasma thyroid stimulating hormone levels above 10 mU/L should be treated with levo-thyroxine, since may have an increased risk of cardiovascular disease. However, the epidemiological evidences suggest being rather conservative in older people, since higher thyroid stimulating hormone is associated with lower risk of multiple adverse events in this population. In this review, we summarized the current evidences on the association between subclinical hypothyroidism and lipid metabolism and the effect of levo-thyroxine therapy on lipid parameters.

Subclinical Hypothyroidism and Lipid Metabolism: To Treat or Not to Treat?

Experimental and Applied Biomedical Research (EABR)

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

{"article-title":"Subclinical Hypothyroidism and Lipid Metabolism: To Treat or Not to Treat?"}

Thyroid hormones have multiple complex effects on lipid synthesis and metabolism. These physiological actions are well documented in overt hypothyroidism where...

Subclinical Hypothyroidism and Lipid Metabolism: To Treat or Not to Treat?

Published Online: Dec 11, 2019

Page range: -

Received: Jan 22, 2019

Accepted: Jul 28, 2019

DOI: https://doi.org/10.2478/sjecr-2019-0069

Keywords
atherosclerosis, cardiovascular disease, levothyroxine, lipid metabolism, subclinical hypothyroidism, treatment

© 2019 Federica Decandia et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Subclinical Hypothyroidism and Lipid Metabolism: To Treat or Not to Treat?

Published Online: Dec 11, 2019

Page range: -

Received: Jan 22, 2019

Accepted: Jul 28, 2019

DOI: https://doi.org/10.2478/sjecr-2019-0069

Keywordsatherosclerosis, cardiovascular disease, levothyroxine, lipid metabolism, subclinical hypothyroidism, treatment

© 2019 Federica Decandia et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
atherosclerosis, cardiovascular disease, levothyroxine, lipid metabolism, subclinical hypothyroidism, treatment