Validation of air displacement plethysmography for assessing body composition

Wagner, Dale R.; Heyward, Vivian H.; Gibson, Ann L.

doi:10.1097/00005768-200007000-00023

Cited by 68 publications

(64 citation statements)

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“…1 According to the Centers for Disease Control and Prevention (CDC), in [2003][2004]9.5% of children between 0 and 23 months of age were overweight (X95 percentile for weight-for-length) in the United States. Between 2003 and 2006, 31.9% of children and adolescents aged 2-19 years were overweight (X85 percentile of the 2000 body mass index (BMI)-for-age growth charts) and 27.6% were obese (X 95 percentile of the 2000 BMI-for-age growth charts).…”

Section: Introductionmentioning

confidence: 99%

“…3 Although there are two main technologies commercially available: air-displacement plethysmography (ADP) and dual-energy X-ray absorptiometry (DXA); both have major drawbacks. ADP has been validated in infants up to 8 kg with the PeaPod [4][5][6] and in children 45 years of age with the BodPod, [7][8][9][10] but not in infants and children between 6 months and 5 years, which constitute a major gap in measuring early childhood body composition. DXA has been validated and used in all age ranges to estimate body fat and fat-free mass (FFM).…”

Section: Introductionmentioning

confidence: 99%

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QMR: validation of an infant and children body composition instrument using piglets against chemical analysis

2010

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Objective: This study was undertaken to validate the first quantitative nuclear magnetic resonance (QMR) instrument designed and built to assess body composition in children from birth to adulthood (up to 50 kg). Design: A total of 50 pigs weighing between 3.0 and 49.1 kg were studied. Each piglet's body composition was assessed by quantitative nuclear magnetic resonance (QMR, EchoMRI-AH small), whole-body chemical carcass analysis for lipid and water content, and dual-energy X-ray absorptiometry (DXA, Hologic QDR 4500, using infant or adult whole-body scan acquisition programs where appropriate). Twenty-five piglets (3.1-47.2 kg) were randomly selected to calibrate the QMR instrument. The remaining 25 piglets (3.0-49.1 kg) were used to validate the instrument. Results: The precision of QMR to estimate fat mass (FM), fat-free mass (FFM) and total body water (TBW) for five consecutive scans was excellent (1.3, 0.9 and 0.9%, respectively). QMR measures of FM were highly and significantly correlated with chemical carcass analyses and DXA measures (r 2 ¼ 0.99 and r 2 ¼ 0.98, respectively). QMR and DXA FFM results were highly correlated (R 2 ¼ 0.99, Po0.01). TBW measures were strongly correlated between QMR and carcass analyses (R 2 ¼ 0.99, Po0.01). QMR overestimated FM by 2% and DXA measures (using the infant and adult scan programs) overestimated FM by 15% on average. Conclusion: QMR provides precise and accurate measures of FM, FFM and TBW in piglets weighing up to 50 kg. As the piglet is considered to be an excellent model of human development, these data suggest that QMR should provide the opportunity to acquire valuable body composition data in longitudinal studies in children, which is not possible or practical with other commercially available instrumentation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

QMR: validation of an infant and children body composition instrument using piglets against chemical analysis

2010

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“…BOD POD; Life Measurement Incorporated, Concord, CA, USA), in part because of its wide applicability to many diverse populations and its relative ease both on the subject and tester as compared with more traditional techniques. This equipment has been widely validated against reference methods in healthy children, adolescents, adults and elderly (Sardinha et al, 1998;Collins et al, 1999;Levenhagen et al, 1999;Miyatake et al, 1999;Nunez et al, 1999;Wagner et al, 2000;Fields et al, 2001;Millard-Stafford et al, 2001;Bosy-Westphal et al, 2003;Silva et al, 2006). Furthermore, test-retest reliability, between-day variability, within-subject variability and between-instrument variability appear to be good to excellent (Fields et al, 2002;Ball, 2005;Going, 2005).…”

Section: Introductionmentioning

confidence: 99%

Changes in thoracic gas volume with air-displacement plethysmography after a weight loss program in overweight and obese women

et al. 2007

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Objective: This study was designed to compare measured and predicted thoracic gas volume (V TG ) after weight loss and to analyze the effect of body composition confounders such as waist circumference (WC) on measured V TG changes. Design: Prospective intervention study. Setting: Outpatient University Laboratory, Lisbon, Portugal. Subjects: Eighty-five overweight and obese women (body mass index ¼ 30.073.5 kg/m 2 ; age ¼ 39.075.7 years) participating in a 16-month university-based weight control program designed to increase physical activity and improve diet. Methods: Body weight (Wb), body volume (Vb), body density (Db), fat mass (FM), percent fat mass (%FM) and fat-free mass (FFM) were assessed by air-displacement plethysmography (ADP) at baseline and at post-intervention (16 months). The ADP assessment included a protocol to measure V TG and a software-based predicted V TG . Dual-energy X-ray absorptiometry (DXA) (Hologic QDR 1500) was also used to estimate FM, %FM and FFM. Maximal oxygen uptake (VO 2 max) was assessed with a modified Balke cardiopulmonary exercise testing protocol with a breath-by-breath gas analysis. Results: Significant differences between the baseline and post-weight loss intervention were observed for body weight and composition (Vb, Db, %FM, FM and FFM), and measures of V TG (measured: D ¼ 0.2 l, Po0.001; predicted: D ¼ 0.01 l, Po0.010) variables. Measured V TG change was negatively associated with the change in the WC (P ¼ 0.008), controlling for VO 2 max and age (P ¼ 0.007, P ¼ 0.511 and P ¼ 0.331). Linear regression analysis results indicated that %FM and FM using the measured and predicted V TG explained 72 and 76%, and 86 and 90% respectively, of the variance in %FM and FM changes using dual-energy x-ray absorptiometry. Conclusions: After weight loss, measured V TG increased significantly, which was partially attributed to changes is an indicator of body fat distribution such as WC. Consequently, measured and predicted V TG should not be used interchangeably when tracking changes in body composition. The mechanisms relating the reduction of an upper body fat distribution with an increase measured V TG are worthy of future investigation.

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“…Various studies have assessed the accuracy of body composition estimates obtained with ADP against established techniques, such as HW, in both adults [3][4][5][6][7][8][9][10][11][12] and children. 5,6,10,13,14 However, although reported estimates of mean differences (biases) between HW and ADP are generally relatively small, there are inconsistencies in the observed direction of these biases and wide variation for individuals, as shown by a large range for the limits of agreement between methods (for review, see Fields 15 ).…”

Section: Introductionmentioning

confidence: 99%

Within- and between-laboratory precision in the measurement of body volume using air displacement plethysmography and its effect on body composition assessment

et al. 2003

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OBJECTIVE:To determine and compare the extent of within-and between-laboratory precision in body volume (BV) measurements using air displacement plethysmography (ADP), the BOD POD body composition system, and to interpret any such variability in terms of body composition estimates. DESIGN: Repeated test procedures of BV assessment using the BOD POD ADP were reproduced at two laboratories for the estimation of precision, both within and between laboratories. SUBJECTS: In total, 30 healthy adult volunteers, 14 men (age, 19-48 y; body mass index (BMI), 19.7-30.3 kg/m 2 ) and 16 women (age, BMI,.7 kg/m 2 ), were each subjected to two test procedures at both laboratories. Two additional volunteers were independently subjected to 10 repeated test procedures at both laboratories. MEASUREMENTS: Repeated measurements of BV, uncorrected for the effects of isothermal air in the lungs and the surface area artifact, were obtained using the BOD POD ADP, with the identical protocol being faithfully applied at both laboratories. Uncorrected BV measurements were adjusted to give estimates of actual BV that were used to calculate body density (body weight (BWt)/actual BV) from which estimates of body composition were derived. The differences between repeated BV measurements or body composition estimates were used to assess within-laboratory precision (repeatability), as standard deviation (SD) and coefficient of variation; the differences between measurements reproduced at each laboratory were used to determine between-laboratory precision (reproducibility), as bias and 95% limits of agreement (from SD of the differences between laboratories). RESULTS: The extent of within-laboratory methodological precision for BV (uncorrected and actual) was variable according to subject, sample group and laboratory conditions (range of SD, 0.04-0.13 l), and was mostly due to within-individual biological variability (typically 78-99%) rather than to technical imprecision. There was a significant (Po0.05) bias between laboratories for the 10 repeats on the two independent subjects (up to 0.29 l). Although no significant bias (P ¼ 0.077) was evident for the sample group of 30 volunteers (À0.05 l), the 95% limits of agreement were considerable (À0.68 to 0.58 l). The effects of this variability in BV on body composition were relatively greater: for example, within-laboratory precision (SD) for body fat as % BWt was between 0.56 and 1.34% depending on the subject and laboratory; the bias (À0.59%) was not significant between laboratories, but there were large 95% limits of agreement (À3.67 to 2.50%). CONCLUSION: Within-laboratory precision for each BOD POD instrument was reasonably good, but was variable according to the prevailing conditions. Although the bias between the two instruments was not significant for the BV measurements, implying that they can be used interchangeably for groups of similar subjects, the relatively large 95% limits of agreement indicate that greater consideration may be needed for assessing individuals with different ADP in...

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Validation of air displacement plethysmography for assessing body composition

Abstract: The Bod Pod significantly and systematically underestimated Db, resulting in an overestimation of %BF. More cross-validation research is needed before recommending the Bod Pod as a reference method.

Cited by 68 publications

References 12 publications

QMR: validation of an infant and children body composition instrument using piglets against chemical analysis

QMR: validation of an infant and children body composition instrument using piglets against chemical analysis

Changes in thoracic gas volume with air-displacement plethysmography after a weight loss program in overweight and obese women

Within- and between-laboratory precision in the measurement of body volume using air displacement plethysmography and its effect on body composition assessment

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