Body Fat Distribution in Lean Individuals with Metabolic Abnormalities

Area of Science:

• Endocrinology
• Metabolic Health
• Body Composition Analysis

Background:

• Obesity (BMI >30 kg/m²) is linked to metabolic issues, but lean individuals (BMI 18.5-24.9 kg/m²) can also have metabolic abnormalities.
• Understanding fat distribution in metabolically unhealthy lean (MUL) individuals is crucial for identifying metabolic risks.

Purpose of the Study:

• To evaluate body fat distribution in metabolically unhealthy lean (MUL) individuals.
• To compare body composition and fat distribution between MUL and metabolically healthy lean (MHL) individuals.

Main Methods:

• Dual-energy X-ray absorptiometry (DXA) was used to assess body composition in adults with BMI 18.5-24.9 kg/m².
• Metabolic data were analyzed, defining MUL as having ≥2 metabolic syndrome (MetS) components and MHL as having ≤1.
• Multivariable logistic regression analyzed associations between metabolic abnormalities and anthropometric indexes.

Main Results:

• 119 subjects were analyzed (69 MHL, 50 MUL), with comparable total body fat and lean mass between groups.
• Increased visceral fat indices, including visceral adipose tissue, trunk-to-legs fat ratio, and android-to-gynoid fat ratio, were significantly associated with being MUL.
• MUL individuals showed increased truncal fat distribution without increased total body fat, mirroring obese individuals with MetS.

Conclusions:

• Metabolically unhealthy lean individuals exhibit altered body fat distribution, characterized by increased central/truncal fat.
• Body morphometry and visceral fat accumulation in MUL individuals resemble those seen in obese individuals with metabolic syndrome.
• Fat distribution patterns, particularly visceral fat, are critical indicators of metabolic health, even in lean individuals.