Validation of a new pediatric air-displacement plethysmograph for assessing body composition in infants.
BACKGROUND
The accurate measurement of body composition is useful in assessments of infant growth and nutritional status.


OBJECTIVE
This study evaluated the reliability and accuracy of a new air-displacement plethysmography (ADP) system for body-composition assessment in infants.


METHODS
Between- and within-day reliability was assessed by comparing the percentage body fat (%BF) obtained on consecutive days and on the same day, respectively, in 36 full-term infants. Accuracy was assessed by comparing %BF measured with the use of ADP and %BF measured with the use of deuterium (2H2O) dilution in 53 infants.


RESULTS
There were no significant differences in %BF between days (-0.50 +/- 1.21%BF) or within days (0.16 +/- 1.44%BF). Mean between- and within-day test-retest SDs of 0.69 and 0.72%BF, respectively, indicated excellent reliability. The %BF measurements obtained by using ADP were not significantly influenced by infant behavioral state. Mean %BF obtained by using ADP (20.32%BF) did not differ significantly from that obtained by using 2H2O dilution (20.39%BF), and the regression line [%BF(2H2O) = 0.851%BF (ADP) + 3.094] gave a high R2 (0.76) and a low SEE (3.26). The 95% limits of agreement between ADP and 2H2O (-6.84%BF, 6.71%BF) were narrower than those reported for other body-composition techniques used in infants. Individual differences between the 2 methods were not a function of body mass or fatness.


CONCLUSIONS
ADP is a reliable and accurate instrument for determining %BF in infants, and it has the potential for use in both research and clinical settings.
Ma
Guansheng
G
National Institute for Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, Beijing.
Yao
Manjiang
M
Liu
Yan
Y
Lin
Aiwei
A
Zou
Hui
H
Urlando
Alessandro
A
Wong
William W
WW
Nommsen-Rivers
Laurie
L
Dewey
Kathryn G
KG
D001823:Body Composition; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D010991:Plethysmography / Q000379:methods*; D015203:Reproducibility of Results