Original Communication
European Journal of Clinical Nutrition (2005) 59, 996–1001. doi:10.1038/sj.ejcn.1602202; published online 22 June 2005
Interdevice variability in percent fat estimates using the BOD POD
S D Ball1
1Department of Nutritional Sciences, University of Missouri-Columbia, Columbia, MO, USA
Correspondence: SD Ball, Department of Nutritional Sciences, University of Missouri, 315 Gwynn Hall, Columbia, MO, USA. E-mail: ballsd@missouri.edu
Received 20 July 2004; Revised 8 March 2005; Accepted 14 April 2005; Published online 22 June 2005.
Abstract
Objective:
To evaluate interdevice reliability in body density (Db) and percent body fat (%BF) using air-displacement plethysmography, the BOD POD (BP) body composition system.
Design and Setting:
Duplicate body composition tests were performed in immediate succession on 50 adults (26 M, 24F; 21–53 y) using two BP units located in the same body composition laboratory.
Results:
Mean Db and %BF between BP1 and BP2 did not differ significantly for men (
Db=0.0003
0.0008 g/ml, P=0.632; %BF=0.11.3, P=0.665), while for women, there were small but significant differences in Db and %BF between BP1 and BP2 (Db=0.00180.0003 g/ml, P=0.001; %BF=0.81.1, P=0.001). The regression between %BF by BP1 and BP2 did not deviate significantly from the line of identity for both men and women (R
2=0.95, standard error of estimate (s.e.e.)=1.23 %BF for men; R
2=0.97, s.e.e=1.13 %BF for women). Individual variations in %BF estimates between the two BP units were within acceptable ranges (95% limits of agreement=-2.5–2.7 %BF for men; -1.4–3.0 %BF for women), and there was no trend in individual differences as %BF varied (r=-0.19, P=0.359 for men; r=0.09, P=0.677 for women). Other subject characteristics, including age, body mass, height, and body mass index, did not significantly contribute to the differences in %BF estimates by the two BP units.
Conclusions:
No clinically significant differences in Db and %BF estimates exist between the BP units, and the interdevice variability of the BP has minimal impact on %BF estimates. Further, test-to-test reliability between BP units appears to be as good as within one unit.
Keywords:
air-displacement plethysmography, body fat, interdevice reliability, hydrostatic weighing
