EVALUATION OF A PEDIATRIC AIR-DISPLACEMENT PLETHYSMOGRAPH FOR BODY COMPOSITION ASSESSMENT IN PRETERM INFANTS

Background The accurate measurement of body composition is useful in assessments of preterm infant growth and nutritional status. Objective To evaluate the accuracy of a pediatric air-displacement plethysmograph (ADP) system (PEA POD Infant Body Composition System, Life Measurement, Inc., Concord, CA, USA) for determining percentage body fat (%BF) in a preterm infant population. Design/Methods Preterm infants (n = 10), gestational age = 30–36 (min–max) weeks (32.50 + 1.96, Mean + SD), age tested = 0.85–4.0 weeks, (2.20 + 1.34), weight = 1.48–2.10 Kg (1.83 + 0.21) were examined by ADP. Reference %BF values were determined using total body water (TBW) measurements. Results Mean %BF by ADP was 5.67 + 1.84 and mean % BF by TBW was 5.99 + 2.56. Mean difference in %BF between the two methods was −0.32 + −1.57. Regression analysis showed that %BF by ADP was significantly associated with %BF by TBW (R2 = 0.63, SEE = 1.65, P = 0.006). There was a significant correlation between %BF results obtained by the two methods (r = 0.79). Bland-Altman analysis was performed to assess potential bias. No bias was found (r = −0.48, P = 0.16) and 95% limits of agreement were −3.40 to 2.76%BF. Conclusion When compared to the TBW model, this initial study has shown that this ADP System provides an accurate assessment of %BF in preterm infants. Overall agreement between the two methods is good with individual variations in %BF consistent with previous findings. A larger study comparing TBW to ADP in preterm infants is currently underway.