Anthropometrics Do Not Influence Dual X‐ray Absorptiometry (DXA) Measurement of Fat in Normal to Obese Adults: A Comparison with In Vivo Neutron Activation Analysis (IVNA)

Marcus, Matthew A.; Wang, Jack; Thornton, John C.; Ma, Ruimei; Burastero, Santiago; Pierson, Richard N.

doi:10.1002/j.1550-8528.1997.tb00652.x

Cited by 6 publications

(6 citation statements)

References 38 publications

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“…Ca DXA overestimates TBCa by about 300 g when compared to Ca IVNA . This overestimation was also found by others in nonobese populations (44 g for Pierson, 3 600 g for Marcus 9 ). As previously described, the measurements of TBCa by the two in vivo methods were highly correlated (R = 0.937).…”

Section: Discussionsupporting

confidence: 85%

Total Body Calcium in Obese Women: Validation of Dual‐Energy X‐ray Absorptiometry against in Vivo Neutron Activation Analysis

Laferrère

Funkhouser

Thornton

et al. 2000

Annals of the New York Academy of Sciences

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In vivo neutron activation analysis (IVNA) allows in vivo measurement of total body calcium and is considered the gold standard technique. Dual‐energy X‐ray absorbtiometry (DXA) estimates total body calcium. Although there are a few comparisons of the two techniques, there are none with obese women. The present study compared the estimation of total body calcium by DXA with the measurement of Ca by IVNA in 69 obese women. Sixty‐nine obese women (age 44 ± 10 years, body weight [BW] 93 ± 10.4 kg, body mass index [BMI] 35 ± 4, fat mass 42 ± 7 kg, 48 pre‐ and 21 postmenopausal, 30 Caucasian and 39 African‐American) were recruited for a six‐month body composition study without weight loss intervention. Total body (TB) Ca was measured by IVNA (CaIVNA) and by DXA (CaDXA) at baseline (n= 69) and again at six months (n= 40). At baseline, CaDXA was significantly higher than CaIVNA (1018 ± 130 g vs. 706 ± 92 g, p= 0.0001). The difference remained after six months (1028 ± 153 g vs. 715 ± 96 g). There was a small but significant increase in TBCa at six months by both DXA (16.5 ± 40, p < 0.02) and IVNA (8 ± 22 g, p < 0.03). However, this change was not significantly different between the two methods (p= 0.2365). The correlation between the two methods was very high (r= 0.937) and was independent of either race or menopausal status (p= 0.5163). We generated a regression equation: CaIVNA= 0.659 × CaDXA+ 34.77; SEE = 32.2, R= 0.937. We present a model integrating the effect of weight and height on the relationship between CaIVNA and CaDXA. The higher the BMI, the bigger the difference between CaIVNA and CaDXA. In our population with a mean BMI of 35.3, CaIVNA= 69% CaDXA.

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Section: Discussionsupporting

confidence: 85%

Total Body Calcium in Obese Women: Validation of Dual‐Energy X‐ray Absorptiometry against in Vivo Neutron Activation Analysis

Laferrère

Funkhouser

Thornton

et al. 2000

Annals of the New York Academy of Sciences

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“…Normal BP values were defined according to those adopted for the definition of the MS. 37 Total and regional body composition was determined by DXA, using a fan beam Hologic QDR 4500 A absorptiometer (Hologic Europe, Zaventem, Belgium). 43,44 Total and regional (trunk, arms, and legs) body composition was evaluated to assess absolute (grams) and percent fat mass (FM). For the estimation of precision, duplicate scans were obtained on the same day for 10 patients.…”

Section: Methodsmentioning

confidence: 99%

Body fat and C-reactive protein levels in healthy non-obese men

Bo¹,

Raspo²,

Morra³

et al. 2004

Nutrition, Metabolism and Cardiovascular Diseases

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Previous studies have demonstrated that circulating levels of C-reactive protein (CRP), a marker of cardiovascular risk, are strictly related to body fatness. Elevated fibrinogen levels are also predictive of future cardiovascular events. The metabolic background of this relationship and the predictors of fibrinogen levels have not been well established. We aimed to evaluate whether fibrinogen levels are associated with body fat content and distribution and to determine the independent predictors of fibrinogen levels in a sample of healthy, non-obese, nonsmoking young adult men. Age, anthropometric measures ( -6), and acute-phase reactants levels (fibrinogen, highly sensitive [hs]-CRP) were determined in 87 healthy nonsmoking, non-obese subjects. Linear regression analysis was used to evaluate the association between body fat, fibrinogen, and metabolic variables, and multiple regression model analysis was used to examine the independent predictors of fibrinogen levels. Eighty-seven (30.5 ؎ 3.5 years) non-obese (mean BMI 24.1 ؎ 3.5) men were studied. Fibrinogen levels were strongly associated with measures of body fat and with metabolic variables. Total body fat (P < .0001) and LDLcholesterol (P < .01) were the independent predictors of fibrinogen levels, accounting for 29.5% and 10.9% of its variance, respectively. Total body fat was the best independent predictor of hs-CRP levels, accounting for 32.5 % of its variance. We conclude that in healthy, non-obese subjects, body fat content is the main predictor of fibrinogen levels, as well of hs-CRP levels. These findings support the speculation that there is a direct mechanism by which adipose tissue might regulate the levels of circulating acute-phase reactants.

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“…Therefore, it is possible that any initial error in accuracy and subsequent DXA calibration was reproduced in newer generations of DXA instruments. Three recent studies using two different DGNA systems have reported calcium results lower than previous findings, which if divided by the BMC measured by DXA, yields 29-31% [5,35,36]. This finding prompted the current study, in which chemical analysis, DXA and DGNA were all utilized to measure the same cadaver bone.…”

Section: Discussionmentioning

confidence: 60%

“…Therefore, any initial error in DGNA accuracy presumably was reproduced in newer generations of DXA instruments. In fact, three recent studies using the upgraded DGNA systems have reported calcium content as 29-31% of the BMC measured by DXA [5,35,36].…”

Section: Introductionmentioning

confidence: 97%

“…Investigations into the influence of soft tissue on DXA indicate that the magnitude of the error in accuracy varies considerably [17,[36][37][38][39][40][41][42][43]. Increasing the thickness or depth of fat has been shown to affect the BMC sufficiently, to potentially result in a misinterpretation of the findings and to suggest some fundamental limitations in the technique [41,43].…”

Section: Introductionmentioning

confidence: 99%

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Bone Mineral Measurements: A Comparison of Delayed Gamma Neutron Activation, Dual-Energy X-ray Absorptiometry and Direct Chemical Analysis

Economos

Nelson

Singh

et al. 1999

Osteoporosis International

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A system in vitro consisting of a femur from a cadaver and soft-tissue equivalent material was used to test the agreement between several techniques for measuring bone mineral. Calcium values measured by delayed gamma neutron activation (DGNA) and bone mineral content (BMC) by Lunar, Hologic and Norland dual-energy X-ray absorptiometers (DXA) were compared with calcium and ash content determined by direct chemical analysis. To assess the effect of soft-tissue thickness on measurements of bone mineral, we had three phantom configurations ranging from 15.0 to 26.0 cm in thickness, achieved by using soft-tissue equivalent overlays. Chemical analysis of the femur gave calcium and ash content values of 61.83 g +/- 0.51 g and 154.120 +/- 0.004 g, respectively. Calcium measured by DGNA did not differ from the ashed amount of calcium at any of the phantom configurations. The BMC measured by DXA was significantly higher, by 3-5%, than the amount determined by chemical analysis for the Lunar densitometer and significantly lower, by 3-6%, for the Norland densitometer (p<0.001-0.024), but only 1% lower (not significant) for the Hologic densitometer. DXA instruments showed a decreasing trend in BMC as the thickness increased from 20.5 to 26.0 cm (p<0.05). However, within the entire thickness range (15.0-26.0 cm), the overall influence of thickness on BMC by DXA was very small. These findings offer insight into the differences in these currently available methods for bone mineral measurement and challenge the comparability of different methods.

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Anthropometrics Do Not Influence Dual X‐ray Absorptiometry (DXA) Measurement of Fat in Normal to Obese Adults: A Comparison with In Vivo Neutron Activation Analysis (IVNA)

Cited by 6 publications

References 38 publications

Total Body Calcium in Obese Women: Validation of Dual‐Energy X‐ray Absorptiometry against in Vivo Neutron Activation Analysis

Total Body Calcium in Obese Women: Validation of Dual‐Energy X‐ray Absorptiometry against in Vivo Neutron Activation Analysis

Body fat and C-reactive protein levels in healthy non-obese men

Bone Mineral Measurements: A Comparison of Delayed Gamma Neutron Activation, Dual-Energy X-ray Absorptiometry and Direct Chemical Analysis

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