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18 Comparison between air-displacement plethysmography and dual energy X-ray absorptiometry in 176 Chinese adolescents
Y. Li, Q. Zhang, W. Du, A. Liu, H. Pan and G. Ma
19 Comparison of foot-to-foot impedance with air-displacement plethysmography to evaluate body
composition in African women
A. Gartner, A. Dioum, B. Maire, F. Delpeuch and Y. Schu
20 Body composition in Singapore Chinese elderly aged 60 to 79 years
Paul Deurenberg, Mabel Deurenberg-Yap, Ching Ching Teo, Swee Ai Ng, Vina Doshi and Carol Tan
21 Measurement of body and liver fat in small animals using peripheral quantitative computed tomography
Tim R. Nagy and Maria S. Johnson
22 Total-body protein mass in adults: development of a dual-energy X-ray absorptiometry prediction model
ZiMian Wang, Stanley Heshka, Lucian Wielopolski, F. Xavier Pi-Sunyer, Richard N. Pierson Jr and Steven
B. Heymsfield
International Journal of Body Composition Research 2004, Vol. 1 No. 4: 131-136
Y. Li, Q. Zhang, W. Du, A. Liu, H. Pan and G. Ma
National Institute for Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, Beijing,
China.
In order to assess the reliability of Air Displacement Plethysmography (BOD POD) in measuring body fat of Chinese adolescents, and to compare the reliability and validity of BOD POD with dual-energy X-ray absorptiometry (DXA) in assessing body fat, 176 healthy Chinese adolescents (85 boys, 91 girls; 12–15 yr; BMI 13.6- 31.4 kg/m2) living in Beijing were selected to participate in a body composition study. Same-day test-retest reliability was assessed in a subsample of 55 subjects (27 boys, 28 girls) and eight of them finished the BOD POD and DXA repeated test the same day. Comparison between the BOD POD and DXA was finished in all subjects. %BF was highly correlated between the first and second trials (r=0.98, P<0.01) and the test-retest coefficients of variation for %BF measured by BOD POD and DXA were not significantly different (4.2%±2.8% and 3.0%±3.1% for BOD POD and DXA, respectively), indicating a good reliability. The mean difference in %BF (BOD POD – DXA) was –2.1 ± 3.9 (BOD POD: 22.7%BF; DXA: 24.9 %BF), with a 95% confidence interval of –9.9 to 5.7 %BF. There was a significant difference between the two methods for assessing body fat of girls (–3.8±3.1), but not for boys (–0.4±4.0). The regression equation (%BFDXA = 2.60 + 0.98 %BFBOD POD, r2 = 0.80, SEE = 3.9) was significantly different from the line of identity (%BFDXA = %BFBOD POD). Intercept and slope significant difference was from 0 and 1 respectively. Further analysis including gender and age as covariates in the regression model showed that gender was significantly independently associated with %BFDXA (P < 0.001), and explained an additional 5% of the variance in %BFDXA. It is concluded that BOD POD is a reliable and valid method for determining %BF in Chinese adolescents.
International Journal of Body Composition Research 2004 Vol. 1 No. 4: 137-145
1A. Gartner, 2A. Dioum, 1B. Maire, 1F. Delpeuch and 3Y. Schutz
1Nutrition Unit, UR 106 (WHO Collaborating Centre for Nutrition), IRD (Institut de Recherche pour le
Développement), Montpellier, France. 2Equipe de Nutrition, Laboratoire de Physiologie, Département de
Biologie Animale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop de Dakar, Sénégal, West
Africa. 3Institute of Physiology, Faculty of Medicine, University of Lausanne, Switzerland.
The new foot-to-foot impedance (FFI) device, the BodymasterTM (SEB, France), provides a precise method for estimating lean or fat mass within a large range of body composition, but the influence of ethnicity has yet to be accounted for. The first objective of this study was to test the validity of body composition estimated from the FFI method compared with whole body densitometry performed by air displacement plethysmography (ADP) in African women. The second objective was to derive new prediction equations to estimate lean body mass (LBM) and percentage body fat (%BF) in African women from FFI results. A total sample of 170 African women from Dakar (Senegal, West Africa), volunteered for the study. Mean (SD) age was 30.6 y (8.7), weight 63.4 kg (15.2) and BMI 23.4 kg/m2 (5.2). Body composition values estimated by FFI were compared to those measured by ADP. The higher specific density of lean body tissue in black subjects as compared to Caucasian subjects was taken into account for the calculation of %BF from body density. Estimations from FFI showed a bias (mean difference) of 2.4 kg LBM, ie 6%, (P<10-4) and –3.5 %BF, ie 10%, (P<10-4) and errors (SD of the bias) of 2.7 kg LBM and 4.2 %BF. In order to correct for the bias, specific predictive equations were developed. With the FFIresult as a single predictor, error values were of 2.6 kg LBM and 4.3 %BF in the prediction group (n=112), and of 2.6 kg LBM and 4.1 %BF in the cross-validation group (n=58). The addition of anthropometrical predictors was not necessary. The study found that the FFI analyser slightly but significantly overestimated LBM, and underestimated %BF in African women, suggesting that the ethnic factor may jeopardize its accuracy. However, after correction for the bias, using an independent sub-sample, it was easy to estimate the body compartments with reasonable accuracy in African women by using the FFI result in a single predictor equation.
International Journal of Body Composition Research 2004, Vol. 1 No. 4: 147-153
1Paul Deurenberg, 2Mabel Deurenberg-Yap, 2Ching Ching Teo, 2Swee Ai Ng, 3Vina Doshi and 4Carol Tan 1Nutrition Consultant, Singapore; 2Health Promotion Board, Research and Information Management Division, Singapore; 3Changi General Hospital, Singapore; 4Ministry of Health, Singapore.
Body composition was measured in 23 Singapore Chinese elderly females and 17 Singapore Chinese elderly males, aged 60–79 years. Weight, height, waist and hip circumference, four skinfolds (biceps, triceps, subscapular, supra-iliac) and hand-to-hand impedance were measured and formulas from the literature were used to predict percentage body fat (%BF). Total-body water was measured using deuterium oxide dilution and %BF was calculated assuming a fat-free mass hydration of 0.73. Body fat was also measured using dual energy X-ray absorptiometry (DXA). Males were taller and heavier than females, but their body mass index (BMI) was not different. Body fat from all methods was higher in females than in males and all measures of %BF were highly intercorrelated. In males and females %BF from deuterium oxide and from DXA were not different from each other, but were lower compared to body fat estimated from hand-to-hand impedance, BMI and skinfolds thickness, using the Durnin & Womersley equation. A prediction equation based on skinfolds developed in Singaporean adults gave comparable results compared to %BF from deuterium oxide or from DXA. It is concluded that the deuterium oxide methodology and DXA give identical values and that, at a population level, the Singapore skinfold prediction equation can also be used to obtain valid estimates of %BF. Impedance predictions and predictions based on BMI needs adaptation. Generally, all predictive methods had high individual biases (compared to deuterium oxide) and individual values obtained with these methods should be interpreted with care.
International Journal of Body Composition Research 2004, Vol. 1 No. 4: 155-160
Tim R. Nagy and Maria S. Johnson
Division of Physiology and Metabolism, Department of Nutrition Sciences, and the Clinical Nutrition Research Center, The University of Alabama at Birmingham, Birmingham, AL 35294-3360, USA.
Peripheral quantitative computed tomography (pQCT) was used to determine percent body fat (%BF) in mice, and relative liver fat in lemmings fasted for 0, 6, 12 or 18 h to induce a wide range of liver fat content. Accuracy of the pQCT was determined by comparing pQCT-derived fat to that from chemical extraction using 30 male mice (whole body) and 26 female lemmings (liver only). To determine whether pQCT could measure changes in liver fat (%) in live animals, two groups of lemmings were scanned on 4 consecutive days under anesthesia. Controls (n = 3) had ad-libitum access to food, whereas the fasted group (n = 5) was deprived of food for 18 h before being measured on day 2 and then refed. The coefficient of variation (CV) for determining %BF in mice using the pQCT was 3.9% (±1.8 SD). Percentage body fat determined by pQCT significantly overestimated percentage fat as measured by chemical extraction (14.5 ± 3.2 vs 12.3 ± 2.9% respectively, P<0.01, mean ± SD). However, %BF by pQCT was highly related to chemical extraction %BF (r = 0.95, P<0.001). The liver attenuation values from pQCT were highly related to % liver fat (r = 0.98, P<0.001) in lemmings. The technique showed excellent precision with a CV of 0.3 ± 0.1%. The two groups (control vs fasted) did not differ in their percent liver fat on day 1 (5.4% vs 5.8%). On day 2 the fasted group had a significantly higher percent liver fat than controls (5.9% vs 17.3%; P<0.05). Following refeeding, there were no significant group differences in percent liver fat on days 3 and 4. Our data indicate that pQCT has good accuracy and precision for determining %BF and liver fat in small animals and can be used to track changes in liver fat over time.
International Journal of Body Composition Research 2004, Vol. 1 No. 4: 161-167
1ZiMian Wang, 1Stanley Heshka, 2Lucian Wielopolski, 1F. Xavier Pi-Sunyer, 1Richard N. Pierson Jr and 1Steven
B. Heymsfield
1St. Luke’s-Roosevelt Hospital Center, Columbia University College of Physicians and Surgeons, New York;
2Medical Department, Brookhaven National Laboratory, Upton, New York, USA
Protein is a large body component of biological importance, which remains difficult to quantify using affordable and practical methods that can be applied in clinical settings. The aim of the present study was to develop and cross-validate a total-body protein (TBPro) prediction model from fat-free mass (FFM) measured by dual-energy X-ray absorptiometry (DXA). For this, a total of 148 adult subjects (116 men and 32 women) were randomly separated into two groups, model-development and cross-validation. Total-body protein mass, measured using in-vivo prompt g-neutron activation analysis, was set as the dependent variable and FFM, age, and sex as potential independent variables in the prediction model. A TBPro prediction model was developed and crossvalidated, with the final equation: TBPro (kg) = 0.156 x FFM (kg) – 0.028 x Age (yr) + 0.55 x Sex + 2.77; r = 0.91, P<0.001; SEE = 0.86 kg; Sex = 0 for women and 1 for men. It is concluded that this TBPro prediction model, using widely available DXA and biological measures, should provide a useful method of estimating total-body protein for body composition research.