The validity of bioelectrical impedance phase angle for nutritional assessment in children

Background/Purpose: Bioelectrical impedance analysis (BIA) is a quick and noninvasive method for estimating body composition. Many prediction equations have been reported recently using bioelectrical impedance to calculate fat free mass (FFM) and fat mass (FM). These equations are based on the assumption that the composition and density of FFM are stable. In children, the composition and density of FFM vary according to age and clinical state, so the use of these equations is limited. However, phase angle is directly determined from resistance (Rz) and reactance (Xc) without equations and reflects body cell mass. The authors, therefore, investigated the validity of phase angle for nutritional assessment in children. Methods: Bioelectrical impedance analysis and anthropometric measurements were performed in 81 patients, including 71 well-nourished and 10 malnourished children. Results: Phase angle correlated with body weight (R = 0.818) and arm muscle circumference (r = 0.901) in well-nourished children. Malnourished patients showed lower phase angle than that of well-nourished children. Conclusion: Bioelectrical impedance phase angle is a useful parameter for nutritional assessment in children. Copyright (C) 2000 by W.B. Saunders Company.