Estimation of Body Fatness by Air Displacement Plethysmography in African American and White Children

Abstract

The purpose of this study was to determine the ability of air displacement plethysmography (ADP) to estimate body fatness in prepubertal and early pubertal African American and white children. One hundred nineteen nonoverweight and overweight boys (N ϭ 56) and girls (N ϭ 63), age (mean Ϯ SD) 9.8 Ϯ 1.7 y, body mass index 25.9 Ϯ 7.6 kg/m 2 (range, 14.2-47.0 kg/m 2 ), and mean percent body fat (%BF) by dual-energy x-ray absorptiometry (DXA) 39.2 Ϯ 11.7% (range, 12.2-57.5%), were studied. %BF by ADP was compared with DXA %BF estimates and with body fat by several field methods: skinfold thicknesses using the Slaughter et al. equations (Hum Biol 60: 709 -723, 1988), bioelectrical impedance analysis (BIA) using the Houtkooper et al. equation (J Appl Physiol 72: 366 -373, 1992), and a predictive equation using skinfold thicknesses, BIA, and weight (Goran et al.: Am J Clin Nutr 63: 299 -305, 1996). All methods used to estimate %BF were significantly correlated with DXA (all p Ͻ 0.0001), with r 2 ranging from 0.85 (skinfold measurements) to 0.95 (ADP). ADP using the Siri equation underestimated %BF by Ϫ1.9% (p Ͻ 0.001); the Bland-Altman limits of agreement (defined as Ϯ2 SD) were Ϯ7.4%. %BF by ADP-Siri underestimated %BF by DXA by 3.0% for girls (p Ͻ 0.001) and by 0.6% for boys (NS). Agreement between body fat estimation by ADP and DXA did not vary with age, race, or pubertal stage. Application of the age-adjusted Lohman model to ADP significantly increased the magnitude of the underestimation to Ϫ6.9% (p Ͻ 0.0001). Prediction of %BF by the Slaughter skinfold thickness equation showed no significant mean bias for the overall data, but significantly underestimated %BF in girls (Ϫ3.7%) while overestimating %BF in boys (ϩ2.4%) with wide limits of agreement (Ϯ17.7%, p Ͻ 0.01 versus ADP). %BF by the Houtkooper BIA equation or Goran model underestimated %BF to a significantly greater degree than ADP (Houtkooper, Ϫ8.1%; Goran, Ϫ10.1%; both p Ͻ 0.0001 versus DXA or ADP). Determination of %BF from ADP using the Siri model slightly underestimates %BF as determined by DXA in girls, but appears to be superior to existing field methods both in accuracy and limits of agreement. Because of the ease with which it can be performed, ADP may prove useful for investigations of adiposity in children. Excessive body weight has become increasingly common among children in the United States (1). The prevalence of overweight in children and adolescents has almost doubled during the past two decades, and is now approximately 14% of young children and 12% of adolescents (2, 3).Accurate assessment of body composition, particularly body fatness, is a key component for both research about and clinical treatment of childhood obesity. Assessing body fatness and changes in body adiposity while children are growing can be difficult, because of the confounding effects of growth on lean and fat mass. Several different methods for estimation of body fat mass have been developed that depend on measurements of total body water, total body potassium, x-ray ab...

Percent body fat measured by BIA and DEXA in obese, African-American adolescent girls

“…Even equations that were unbiased displayed this underestimation and most childhood studies show similar results. 6,8,10,11 The findings of the current study closely match the BIA findings of Bray et al 1 Although their criterion was the fourcompartment model and ours was DEXA, common equations between both studies 1,5,17,19 show similar results when viewing participants of comparable body fat. For example, the Bray equation resulted in a mean difference close to zero in both studies, and the slopes of the Bray, Deurenberg and Suprasongsin equations were significantly different from zero in both studies.…”

“…Although many BIA equations were developed from children across all weight ranges, it has been recognized that BIA tends to overestimate percent body fat in leaner children and underestimate percent body fat in overweight children. [6][7][8][9][10][11] Due to this phenomenon, Lewy et al developed a separate equation from a sample of overweight children. The accuracy of this obesity-specific equation has not been tested outside of the validation sample.…”

The use of air displacement plethysmography in children and adolescents with cystic fibrosis

“…This is the first study to our knowledge that has attempted to validate ADP in children and adolescents with CF. In recent studies that have compared fatness measurements between ADP and DEXA in healthy children and adolescents, Lockner et al (2000) and Nicholson et al (2001) have demonstrated a significant negative mean difference between the methods, while a study by Nunez et al (1999) was consistent with the current study findings, showing no significant difference between the methods. Differences between findings may be attributed to interlaboratory method variation, differences in test conditions and the combined limitations of the methods (Fields et al, 2002).…”

“…ADP uses the pressure and volume relationship of Poisson's law to determine body volume, which in turn can be used to determine density and consequently fat and fat-free mass (FFM) (Dempster & Aitkens, 1995). ADP has been validated in adults (McCrory et al, 1995), and recently investigated in healthy children and adolescents, where it was found to be an acceptable, reliable and accurate technique (Nunez et al, 1999;Dewit et al, 2000;Fields & Goran, 2000;Nicholson et al, 2001;Demerath et al, 2002). However, to our knowledge no studies have examined the use of ADP in children and adolescents with CF.…”

Air-displacement plethysmography for the measurement of body composition in children aged 6–48 months

“…The adult ADP system, commercially produced under the trade name BOD POD (Life Measurement, Concord, CA), has been validated in adult populations (17,18) and shows promise for the measurement of body composition of children aged 5 y and older (12,(19)(20)(21)(22)(23)(24)(25)(26)(27). To date, no published studies report the accuracy of the adult ADP system in children younger than 4 y.…”