Phase Angle in Bioelectrical Impedance: New Perspectives in Health and Body Composition Assessment.

Area of Science:

• Nutrition Science
• Physiology
• Biomedical Engineering

Background:

• Bioelectrical impedance analysis (BIA) is a non-invasive method to assess body composition.
• Phase angle (PhA) is a BIA-derived parameter reflecting cell membrane integrity and fluid distribution.
• Understanding PhA's relationship with body composition across sexes is crucial for clinical applications.

Purpose of the Study:

• To analyze the relationship between phase angle (PhA) and body composition parameters.
• To investigate sex-specific determinants of PhA in healthy adults.
• To evaluate PhA as a potential marker for nutritional status.

Main Methods:

• Observational, descriptive, cross-sectional study design.
• Inclusion of 265 healthy adults (122 women, 143 men).
• Segmental multi-frequency BIA using Tanita MC-780 MA analyzer.

Main Results:

• Mean PhA was higher in men (6.29°) than women (5.57°).
• Strong negative correlation between ECW/TBW ratio and PhA in men (r = -0.78), moderate in women (r = -0.33).
• Strong positive correlation between PhA and ICW volume in women (r = 0.71), weaker in men (r = 0.17).

Conclusions:

• PhA is significantly correlated with body fluid distribution and composition.
• Fat mass is a key determinant in men, while muscle mass is dominant in women.
• PhA is a valid, non-invasive marker for assessing nutritional status and physiological condition.