Accuracy of dual-energy x-ray absorptiometry for body-composition measurements in children

Abstract

The accuracy of body-composition measurements by dual-energy x-ray absorptiometry (DXA) was assessed by comparison with total carcass chemical analysis in 16 pigs with a weight range of 5-35 kg. Two software versions for body-composition analyses with the DXA instrument were evaluated. Although both software versions accurately predicted body weight, there were significant differences in the partitioning between bone mineral content (BMC), nonbone lean tissue, and body-fat compartments. All estimates of body composition were highly correlated (r2 > or = 0.98) with the results of the direct chemical reference method. SEEs were 226-271 g for body weight, 387-429 g for fat, 3.5-4.3 kg for fat-free mass, and 35.4-36.5 g for BMC. For bone, both software versions produced BMC values that were approximately 25% below the total carcass ash content. For the absolute mass of body fat, one DXA analysis provided underestimates that averaged 19.5% below the reference chemical method, whereas the alternate software version resulted in over-estimates, averaging 15.5%. Conversely, the average fat-free compartment was initially overestimated by 968 g, then underestimated by 892 g. The impact of these differences in the body-composition analyses by DXA were examined in a group of 18 young boys 4-12 y of age.

A multi-center comparison of dual energy X-ray absorptiometers: In vivo and in vitro soft tissue measurement

“…In fact, much of the data supporting DXAs ability to accurately measure soft tissue is based on evidence that total tissue mass by DXA correlates signi®cantly to scaled weight (Gotfredsen et al, 1986;Ellis et al, 1994;Johansson et al, 1993;DawsonHughes et al, 1992;Svendsen et al, 1991;Going et al, 1993). However, simple correlation analyses can be misleading because they do not address the reproducibility, only the linear association.…”

“…Our data supports the argument that DXAs ability to predict total tissue weight is constant, but its ability to compartmentalize FM and LM is variable. Over the last few years, a number of studies have begun to investigate soft tissue accuracy by DXA, (Pierson et al, 1991;Withers et al, 1992;Jensen et al, 1993;Ellis et al, 1994;Svendsen et al, 1993;Jebb et al, 1995). Nonetheless, until a number of comparisons using well-developed measurement techniques are repeated, accuracy cannot be con®rmed.…”

Why are early maturing girls less active? Links between pubertal development, psychological well-being, and physical activity among girls at ages 11 and 13

“…Whole body scans were done using the Hologic QDR 4500W (S/N 47261) in the array scan mode and analyzed using whole body software, QDR4500 Whole Body Analysis. DXA has received widespread use and is the preferred method among children, because it provides an accurate, reliable, and non-invasive means of quantifying bone mineral content and body mass content, including fat and lean mass, while minimizing radiation exposure during measurement (Ellis, Shypailo, Pratt, & Pond, 1994;Goran, Driscoll, Johnson, Nagy, & Hunter, 1996;Lukaski, 1993;Mazess, Barden, Bisek, & Hanson, 1990).…”

Densidade mineral óssea de crianças e adolescentes com hipotireoidismo congênito

“…Entretanto, esses autores avaliaram apenas a DMO da coluna lombar e do fêmur num número menor de crianças pré-púberes. Assim como esses, outros estudos em crianças e adolescentes com HC não utilizaram densitometria óssea de corpo total pela DXA, que já foi validada e considerada, até o momento, como a melhor forma de avaliar o estado mineral ósseo durante o crescimento e a maturação sexual (35,36). Por isso, a comparação dos resultados obtidos nos pacientes desta amostra com os da literatura fica prejudicada.…”