Log on / register
BioMed Central home | Journals A-Z | Feedback | Support | My details
Open AccessResearch

Validity of air-displacement plethysmography in the assessment of body composition changes in a 16-month weight loss program

Cláudia S Minderico1 email, Analiza M Silva1 email, Pedro J Teixeira1 email, Luis B Sardinha1 email, Holly R Hull2 email and David A Fields3,4 email

Exercise and Health Laboratory, Faculty of Human Movement, Health and Exercise Science, Technical University of Lisbon, Portugal

University of Oklahoma, Norman, OK, USA

Department of Pediatrics, Children's Medical Research Institute's Metabolic Research Center, University of Oklahoma Health Science Center, OK, USA

Assistant Professor, University of Oklahoma Health Science Center, School of Medicine Department of Pediatrics, OUCP Diabetes & Endocrinology, 940 NE 13th Street, CH 2B2426, OKC, OK 73104, USA

author email corresponding author email

Nutrition & Metabolism 2006, 3:32doi:10.1186/1743-7075-3-32

Published: 22 August 2006

Abstract

Objective

To compare the accuracy of air displacement plethysmography (ADP) and dual energy x-ray absorptionmetry (DXA) in tracking changes in body composition after a 16 month weight loss intervention in overweight and obese females.

Methods

93 healthy female subjects (38.9 ± 5.7 yr, 159.8 ± 5.6 cm, 76.7 ± 9.9 kg, 30.0 ± 3.4 kg/m2) completed a 16 month weight loss intervention. Eligible subjects attended 15 treatment sessions occurring over the course of 4 months with educational content including topics relating to physical activity and exercise, diet and eating behavior, and behavior modification. In the remaining 12 months, subjects underwent a lifestyle program designed to increase physical activity and improve eating habits. Before and after the intervention, subjects had their percent body fat (%fat), fat mass (FM), and fat-free mass (FFM)) assessed by DXA and ADP.

Results

Significant differences (p ≤ 0.001) were found between DXA and ADP at baseline %fat (46.0 % fat vs. 42.0 % fat), FM (35.3 kg vs. 32.5 kg) and FFM (40.8 kg vs. 44.2 kg) as well as at post intervention for %fat (42.1% fat vs. 38.3 % fat), FM (30.9 kg vs. 28.4 kg) and FFM (41.7 kg vs. 44.7 kg). At each time point, ADP %fat and total FM was significantly lower (p ≤ 0.001) than DXA while FFM was significantly higher (p ≤ 0.001). However, both techniques tracked %fat changes similarly considering that there were no differences between the two means. Furthermore, a Bland-Altman analysis was performed and no significant bias was observed, thus demonstrating the ability of ADP to measure body fat across a wide range of fatness.

Conclusion

At baseline and post weight loss, a significant difference was found between ADP and DXA. However, the results indicate both methods are highly related and track changes in %fat similarly after a weight loss program in overweight and obese females. Additionally, the mean changes in %fat were similar between the two techniques, suggesting that ADP can be translated to its use in clinical practice and research studies as DXA currently is used.


© 1999-2010 BioMed Central Ltd unless otherwise stated. Part of Springer Science+Business Media.