Obesity and obstructive sleep apnea syndrome

Area of Science:

• Endocrinology
• Sleep Medicine
• Metabolic Syndrome

Background:

• Obesity is a significant risk factor for both obstructive sleep apnea syndrome (OSAS) and insulin resistance.
• The interplay between OSAS severity, metabolic markers, and insulin resistance requires further elucidation, especially considering the confounding effects of obesity.

Purpose of the Study:

• To investigate the association between sleep apnea severity and markers of metabolic dysfunction, including insulin resistance, leptin, adipose-fatty acid binding protein (A-FABP), and visfatin.
• To evaluate the role of obesity as a confounding factor in these associations.

Main Methods:

• A prospective study involving obese patients referred to a sleep laboratory.
• Patients were categorized based on their Apnea-Hypopnea Index (AHI) into OSAS and non-OSAS groups.
• Measurements included anthropometrics (BMI, WC, NC), blood pressure, and blood samples for HOMA index, leptin, A-FABP, and visfatin levels post-polysomnography.

Main Results:

• OSAS patients exhibited significantly higher visfatin levels compared to the non-OSAS group.
• Leptin and A-FABP showed significant correlations with BMI in both groups.
• Despite similar BMI, OSAS patients had larger neck (NC) and waist circumferences (WC), which strongly correlated with insulin resistance (HOMA).

Conclusions:

• Insulin resistance in OSAS is primarily aggravated by nocturnal hypoxemia related to apnea severity, rather than directly by BMI or AHI.
• Neck circumference (NC) is a valuable predictor of insulin resistance in OSAS patients and should be considered in treatment strategies.
• Visfatin may hold potential as a screening biomarker for identifying patients with OSAS.