The Relationship between Thyroid-Stimulating Hormone and Insulin Resistance in Incipient Elderly Type 2 Diabetics...

Area of Science:

• Endocrinology
• Metabolic Syndrome
• Geriatrics

Background:

• Insulin resistance is a key factor in the development of type 2 diabetes, particularly in elderly populations.
• Thyroid-stimulating hormone (TSH) plays a crucial role in metabolic regulation, and its levels within the normal range may have implications for metabolic health.

Purpose of the Study:

• To investigate the association between serum TSH concentrations within the normal range and insulin resistance in elderly patients with incipient type 2 diabetes.
• To explore the potential mechanisms linking TSH to insulin resistance, including its effect on adipocytes and inflammatory markers.

Main Methods:

• Analysis of serum TSH levels, body mass index (BMI), waist-to-hip ratio (WHR), fasting plasma glucose (FPG), fasting insulin (FINS), homeostasis model assessment of insulin resistance (HOMA-IR), and blood lipids in 453 elderly patients.
• Correlation and regression analyses were performed to assess relationships between TSH and metabolic parameters.
• In vitro stimulation of 3T3-L1 adipocytes with bovine TSH to measure tumor necrosis factor-alpha (TNF-α) secretion.

Main Results:

• Serum TSH levels showed a positive correlation with FPG, FINS, HOMA-IR, total cholesterol (TC), and low-density lipoprotein (LDL).
• Higher TSH quartiles were associated with increasing trends in TC, LDL, and BMI.
• TSH stimulation of adipocytes resulted in a dose-dependent increase in TNF-α secretion.

Conclusions:

• Elevated TSH levels within the normal range are positively associated with insulin resistance and dyslipidemia (increased TC and LDL) in elderly patients with incipient type 2 diabetes.
• Higher TSH may play a role in the pathogenesis of insulin resistance in this demographic, potentially through mechanisms involving adipocyte inflammation.