Low-normal thyroid function and the pathogenesis of common cardio-metabolic disorders

Area of Science:

• Endocrinology
• Cardiology
• Metabolic Disorders

Background:

• Subclinical hypothyroidism is linked to cardiovascular disease (CVD).
• The impact of low-normal thyroid function on cardio-metabolic disorders is less understood.
• This review examines low-normal thyroid function's role in CVD, lipids, metabolic syndrome (MetS), chronic kidney disease (CKD), and nonalcoholic fatty liver disease (NAFLD).

Purpose of the Study:

• To review the relationship between low-normal thyroid function and cardio-metabolic disorders.
• To assess the impact on cardiovascular disease, plasma lipids, lipoprotein function, metabolic syndrome, CKD, and NAFLD.

Main Methods:

• Narrative review of clinical and basic research papers.
• Included systematic reviews and meta-analyses.
• Literature search up to November 2014 via MEDLINE and PubMed.

Main Results:

• Low-normal thyroid function may contribute to atherosclerosis.
• Associated with increased total cholesterol, LDL cholesterol, and triglycerides.
• Linked to metabolic syndrome, insulin resistance, and CKD, but not consistently with high blood pressure or NAFLD.

Conclusions:

• Low-normal thyroid function may be involved in the pathogenesis of CVD, MetS, insulin resistance, and CKD.
• Its association with NAFLD requires further investigation.
• Prospective predictive value for cardio-metabolic disorders remains insufficiently established.