COMPARISON OF AIR DISPLACEMENT PLETHYSMOGRAPHY WITH DUAL-ENERGY X-RAYABSORPTIOMETRY AND 3 FIELD METHODS FOR ESTIMATING BODY-COMPOSITION INMIDDLE-AGED MEN

This study was designed to compare air displacement plethysmography wi th dual-energy X-ray absorptiometry (DXA) and 3 other field methods fo r estimation of body composition. Subjects were 62 healthy, white men aged 37.6 +/- 2.9 y (weight: 81.8 +/- 11.3 kg; height: 171.5 +/- 4.9 c m). Body composition was also assessed by using body mass index, singl e-frequency bioelectrical impedance analysis, multifrequency bioelectr ical impedance spectroscopy, and the skinfold-thickness equations of J ackson and Pollock and Durnin and Womersley. Percentage body fat (%BF) with the plethysmograph was 23.4 +/- 7.0 and with DXA was 26.0 +/- 7. 4. The 2.6% mean difference was significant (P < 0.05). Total error wa s 3.7%BF As assessed by multiple regression analysis, %BF with the ple thysmograph, age, weight, and height yielded a DXA-adjusted R-2 value of 89.5% fat and an SEE of 2.4% fat. All other models had higher SEEs and lower adjusted R-2 values: 4.3% and 66.5% for body mass index, 3.3 % and 79.8% for bioelectrical impedance analysis, 3.6% and 76.2% for b ioelectrical impedance spectroscopy, 3.7% and 74.55% for the equations of Jackson and Pollock, and 3.9% and 71.6% for the equations of Durni n and Womersley, respectively. The plethysmograph also predicted fat m ass and fat-free mass more accurately than all other models, with a lo wer SEE and higher adjusted R-2 value. In conclusion, although %BF was systematically underestimated, body composition was closely estimated with air displacement plethysmography in middle-aged men.