Assessment of EchoMRI-AH versus dual-energy X-ray absorptiometry by iDXA to measure human body composition (original) (raw)
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2007
Objective. Dual-energy X-ray absorptiometry (DXA) is a tool to measure body composition. However, its application is limited in individuals who do not fit in the scanning area. Therefore, the aim of this study was to (i) validate a new method to measure body composition in obese individuals using DXA; and (ii) compare to an existing method. Methods. Body composition was measured using DXA in 50 individuals between 17-68 years with varying body fatness (BMI: 19.9-39.3 kg/m 2 ) and body weight (56.2-120.9 kg). Body composition (fat mass, fatfree soft tissue and bone mineral content) was compared using the arm-replaced (AR) vs existing half-body (HB) method, compared to the reference whole-body scan (RS). Linear regression and Bland-Altman analyses assessed the accuracy and intra-tester reliability.
2000
Background: Dual-energy X-ray absorptiometry (DXA) has be- comeoneofthemostfrequentlyusedmethodsforestimatinghuman body composition. Although the DXA technique has been validated for the measurement of fat-free mass and fat mass, differences in calibration between instruments produced by different manufactur- ers, as well as between different models produced by the same manufacturer, have been reported. Objective: The objective was to compare the calibration of the
PloS one, 2017
Dual energy x-ray absorptiometry (DXA) is an established technique for the measurement of body composition. Reference values for these variables, particularly those related to fat mass, are necessary for interpretation and accurate classification of those at risk for obesity-related health complications and in need of lifestyle modifications (diet, physical activity, etc.). Currently, there are no reference values available for GE-Healthcare DXA systems and it is known that whole-body and regional fat mass measures differ by DXA manufacturer. To develop reference values by age and sex for DXA-derived fat mass measurements with GE-Healthcare systems. A de-identified sample of 3,327 participants (2,076 women, 1,251 men) was obtained from Ball State University's Clinical Exercise Physiology Laboratory and University of Wisconsin-Milwaukee's Physical Activity & Health Research Laboratory. All scans were completed using a GE Lunar Prodigy or iDXA and data reported included percen...
American Journal of Clinical Nutrition
Dual-energy X-ray absorptiometry (DXA) is widely used to assess body composition in research and clinical practice. Several studies have evaluated its accuracy in healthy persons; however, little attention has been directed to the same issue in patients. The objective was to compare the accuracy of the Lunar Prodigy DXA for body-composition analysis with that of the reference 4-component (4C) model in healthy subjects and in patients with 1 of 3 disease states. A total of 215 subjects aged 5.0-21.3 y (n = 122 healthy nonobese subjects, n = 55 obese patients, n = 26 cystic fibrosis patients, and n = 12 patients with glycogen storage disease). Fat mass (FM), fat-free mass (FFM), and weight were measured by DXA and the 4C model. The accuracy of DXA-measured body-composition outcomes differed significantly between groups. Factors independently predicting bias in weight, FM, FFM, and percentage body fat in multivariate models included age, sex, size, and disease state. Biases in FFM were...
2017
Background Dual energy x-ray absorptiometry (DXA) is an established technique for the measurement of body composition. Reference values for these variables, particularly those related to fat mass, are necessary for interpretation and accurate classification of those at risk for obesityrelated health complications and in need of lifestyle modifications (diet, physical activity, etc.). Currently, there are no reference values available for GE-Healthcare DXA systems and it is known that whole-body and regional fat mass measures differ by DXA manufacturer. Objective To develop reference values by age and sex for DXA-derived fat mass measurements with GE-Healthcare systems. Methods A de-identified sample of 3,327 participants (2,076 women, 1,251 men) was obtained from Ball State University\u27s Clinical Exercise Physiology Laboratory and University of Wisconsin- Milwaukee\u27s Physical Activity & Health Research Laboratory. All scans were completed using a GE Lunar Prodigy or iDXA and da...
2005
Background: Dual-energy X-ray absorptiometry (DXA) has become one of the most frequently used methods for estimating human body composition. Although the DXA technique has been validated for the measurement of fat-free mass and fat mass, differences in calibration between instruments produced by different manufacturers, as well as between different models produced by the same manufacturer, have been reported. Objective: The objective was to compare the calibration of the QDR 4500A against criterion methods in a large heterogeneous population. Design: DXA-derived body-composition data were obtained from 7 studies: 6 data sets were provided by the investigators, one of which was published. The data included fat mass and fat-free mass measured with a QDR 4500A and criteria measurements of body composition from total body water by dilution at 4 centers, densitometry from 1 center, and four-compartment analysis at 2 centers. Results: In the cohort of 1195 subjects, 602 men and 593 women aged 19-82 y with a body mass index (in kg/m 2) of 16-44, the fan-beam DXA overestimated fat-free mass (P 0.05). A significant difference was observed in all 7 data sets, and the mean (ȀSE) was 5 Ȁ 1%. Conclusions: It is recommended that the lean soft tissue mass estimate with the fan-beam QDR 4500A be reduced by 5% and that for fat mass be increased by that same mass. This finding is particularly important because the National Health and Nutrition Examination Survey is using the QDR 4500A to assess body composition in a nationally representative sample of persons in the United States.
International Journal of Obesity, 2017
BACKGROUND/OBJECTIVES: Fat distribution is a strong and independent predictor of type 2 diabetes (T2D) and cardiovascular disease (CVD) and is usually determined using conventional anthropometry in epidemiological studies. Dual-energy X-ray absorptiometry (DXA) can measure total and regional adiposity more accurately. Nonetheless, whether DXA provides more precise estimates of cardiovascular risk in relation to total and regional adiposity is not known. We determined the strength of the associations between DXA-and conventional anthropometry determined fat distribution and T2D and CVD risk markers. SUBJECTS/METHODS: Waist (WC) and hip circumference (HC) and DXA was used to measure total and regional adiposity in 4950 (2119 men) participants aged 29-55 years from the Oxford Biobank without pre-existing T2D or CVD. Cross-sectional associations were compared between WC and HC vs. DXA-determined regional adiposity (all z-score normalised) with impaired fasting glucose, hypertriglyceridemia, hypertension and insulin resistance (IR). RESULTS: Following adjustment for total adiposity, upper body adiposity measurements showed consistently increased risk of T2D and CVD risk markers except for abdominal subcutaneous fat in both sexes, and arm fat in men, which showed protective associations. Among upper adiposity depots, visceral fat mass showed stronger odds ratios (OR) ranging from 1.69 to 3.64 compared with WC 1.07-1.83. Among lower adiposity depots, HC showed modest protection for IR in both sexes (men: OR 0.80 (95% confidence interval 0.67, 0.96); women: 0.69 (0.56, 0.86)), whereas gynoid fat and in particular leg fat showed consistent and strong protective effects for all outcomes in both men and women. The differential effect of body fat distribution on CVD and T2D were more pronounced at higher levels of total adiposity. CONCLUSIONS: Compared with DXA, conventional anthropometry underestimates the associations of regional adiposity with T2D and CVD risk markers. After correcting for overall adiposity, greater subcutaneous fat mass in particular in the lower body is protective relative to greater android or visceral adipose tissue mass.
Estimates of body composition with dual-energy X-ray absorptiometry in adults
The American Journal of Clinical Nutrition, 2009
Background: Little is known about the distributions of percentage body fat (PBF), total body fat (TBF), and fat-free mass (FFM) in the adult population in the United States. Objectives: We sought to estimate the means and percentile cutoffs of PBF, TBF, and FFM and to assess the differences by sex, age, race-ethnicity, and body mass index in US adults. Design: Data from the National Health and Nutrition Examination Survey (NHANES), which were collected during the 6-y period from 1999 to 2004 and comprise a large nationally representative sample of the US population, were analyzed (n = 6559 men and 6507 nonpregnant women). TBF and FFM were measured by using dual-energy X-ray absorptiometry. PBF was calculated as TBF divided by total mass multiplied by 100. Results: There were large differences between men and women in unadjusted mean PBF (28.1% compared with 40.0%, P , 0.001), TBF (25.4 compared with 30.8 kg, P , 0.001), and FFM (62.3 compared with 44.0 kg, P , 0.001); the sex differences persisted across all body mass index categories after adjustment for age and race-ethnicity (all P , 0.001). The common percentile cutoffs of PBF, TBF, and FFM were estimated by sex, race-ethnicity, and age groups. Equations for the estimation of PBF (R 2 = 0.85), TBF (R 2 = 0.94), and FFM (R 2 = 0.94) according to demographic characteristics and simple anthropometric measures were generated. Conclusion: The estimates of means and percentile cutoffs for PBF, TBF, and FFM, on the basis of NHANES 199922004 dual-energy X-ray absorptiometry data, provide a reference in the US adult population.
Nutrition, 2014
Objective: The aim of this study was to test the relationship between anthropometry, ultrasonography, and dual-energy x-ray absorptiometry (DXA) for the assessment of body composition in clinical practice. Methods: The study was carried out in Italian blood donor volunteers belonging to five different age groups (18-70 y old; 25 men and 25 women per group; N ¼ 250 participants; n ¼ 125 men, n ¼ 125 women). A complete history was collected and routine blood analyses were performed to confirm healthy status. All participants were submitted to whole-body DXA (tricompartmental analysis, regional, and total body), ultrasonography (abdominal adiposity evaluation), and anthropometric measurements. DXA was used as gold standard and its biomarkers were taken as reference for fatlean mass balance, central-peripheral fat distribution, central or visceral fat, and subcutaneous fat. Results: Anthropometric and ultrasound parameters were closely associated with most of DXA parameters. Composite markers representative of central and abdominal visceral fat compartments were significantly correlated with waist circumference, waist-to-hip ratio, and intra-abdominal fat thickness by ultrasound, in both men and women (P < 0.025). As expected, subcutaneous depots were significantly correlated with maximum subcutaneous fat thickness measured by ultrasonography (P < 0.025). Conclusions: Both anthropometry and ultrasonography provide a reliable estimate of visceral adipose tissue in a non-obese population compared with DXA, whereas anthropometry prediction of subcutaneous adiposity is weak. Physicians should be aware of the limits of these techniques for the assessment of body composition.