Comparison of air-displacement plethysmography with hydrostatic weighing and bioelectrical impedance analysis for the assessment of body composition in healthy adults

Background: Over the past decade, considerable attention has been paid to a ccurately measuring body composition in diverse populations. Recently, the use of air-displacement plethysmography (AP) was proposed as an accurate, c omfortable, and accessible method of body-composition analysis. Objective: The purpose of this study was to compare measurements of percent age body fat (%BF) by AP and 2 other established techniques, hydrostatic we ighing (HW) and bioelectrical impedance analysis (BIA), in adults. Design: The sample consisted of healthy men (n = 23) and women (n = 24). %B F was measured by AP, HW, and BIA. Results: In the total group, %BFAP (25.0 +/- 8.9%) was not significantly di fferent from %BFHW (25.1 +/- 7.7%) or %BFBIA (23.9 +/- 7.7%), and %BFAP was significantly correlated with %BFHW (r = 0.944, P < 0.001) and with %BFBIA (r = 0.859, P < 0.01). Compared with HW, AP underestimated %BF in men (by -1.24 +/- 3.12%) but overestimated %BF in women (by 1.02 +/- 2.48%), indica ting a significant sex effect (P < 0.05). The differences in estimation bet ween AP and BIA and between BIA and HW were not significantly different bet ween the sexes. Conclusion: AP is an accurate method for assessing body composition in heal thy adults. Future studies should assess further the cause of the individua l variations with this new method.