Comparison of Hologic QDR‐1000/W and 4500W DXA Scanners in 13‐ to 18‐Year Olds

Litaker, Mark S.; Barbeau, Paule; Humphries, Matthew C.; Gutin, Bernard

doi:10.1038/oby.2003.206

Cited by 38 publications

(23 citation statements)

References 19 publications

(20 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The multiple R 2 value for %BF was 0.99. 24 Magnetic resonance imaging VAT measurement was conducted as described previously. 25 In brief, VAT was determined using a 1.5 T MRI system.…”

Section: Anthropometrics and Body Compositionmentioning

confidence: 99%

General and visceral adiposity in black and white adolescents and their relation with reported physical activity and diet

et al. 2007

View full text Add to dashboard Cite

Background: Excess body fat accumulation may begin in youth and is linked with increased risk of cardiovascular disease. Examination of physical activity (PA) and diet behaviours predictive of adiposity may help target efforts to reduce chronic disease risk. Objective: We hypothesized that energy intake (EI) from fat, vigorous PA (VPA), and their interaction would predict body fat percentage (%BF) and visceral adipose tissue (VAT) in youth and that sedentary behaviours and intake of dairy, fruit, vegetable and whole grain foods would be related to adiposity. Design: A cross-sectional, observational study of reported PA and diet behaviours and objective adiposity measures. Subjects: Six-hundred sixty-one healthy black and white adolescents aged 14-18 years. Measurements: Diet by 24-h recalls using Nutrition Data Systems for Research (Minneapolis, MN, USA), VPA by previous day physical activity recalls (PAR), and %BF with dual-energy X-ray absorptiometry. VAT by magnetic resonance imaging for 434 subjects. Results: Reported EI and VPA were positively correlated with each other and were negative predictors of %BF. Time spent watching television or movies and %EI from protein were positive predictors of %BF. Adjusted for EI, none of the independent variables predictive of %BF retained their significance. %BF and VAT were highly correlated (r ¼ 0.73, Po0.0001). EI was the sole and negative predictor of VAT. Conclusions: Higher energy 'throughput', not energy restriction, characterize leaner youths. Youths should be advised to engage in VPA so that they can eat sufficient calories to obtain the nutrients required for optimal health while remaining lean.

show abstract

“…The multiple R 2 value for %BF was 0.99. 24 Magnetic resonance imaging VAT measurement was conducted as described previously. 25 In brief, VAT was determined using a 1.5 T MRI system.…”

Section: Anthropometrics and Body Compositionmentioning

confidence: 99%

General and visceral adiposity in black and white adolescents and their relation with reported physical activity and diet

et al. 2007

View full text Add to dashboard Cite

show abstract

“…DXA provides reliable measurement of %BF. In the first 219 youths from the current project, we performed repeat measurements and found the intraclass correlation to be 0.99 (11). For some subjects, DXA values were not available from the Hologic QDR-4500W model, but were available only from the Hologic QDR-1000W model.…”

Section: Subjectsmentioning

confidence: 99%

Relations of Body Fatness and Cardiovascular Fitness to Lipid Profile in Black and White Adolescents

et al. 2005

Self Cite

View full text Add to dashboard Cite

High body fatness is associated with unfavorable cardiovascular disease risk profiles in juveniles. However, the degree to which the deleterious effects attributed to fatness may actually be due to the low cardiovascular fitness (CVF) that is usually confounded with fatness is not known. This study determined in 14-to 18-y-old (n ϭ 398) youths the degree to which percentage body fat (%BF) and CVF explained variability in lipids and lipoproteins. Blood samples were taken after a 12-h fast. %BF was measured with dual-energy x-ray absorptiometry. CVF was determined with a multistage treadmill test. The degree to which %BF and CVF explained variance in outcome variables was determined by regression analyses, controlling for demographic variables before entering %BF or CVF and their interactions with race and sex. Because %BF and CVF were highly correlated (r ϭ -0.69, p Ͻ 0.001), they were first entered separately in the regression models before being considered together. Both higher %BF and lower CVF were associated with unfavorable concentrations of total cholesterol to HDLC ratio and triglycerides. However, the effects of %BF and CVF were not additive; once %BF was in the regression model, CVF did not explain additional variance. For Lp(a), only %BF explained a significant portion of the variance. For triglycerides, there was a %BF by race interaction, such that the deleterious effects of high %BF were greater in whites than in blacks. These results suggest that interventions to improve lipid profile in youths should be designed primarily to minimize fatness. Pathophysiologic processes underlying CVD begin in childhood (1,2), suggesting that preventive measures should begin early in life. Observational studies have shown that childhood adiposity is associated with an unfavorable lipid profile (3,4), which continues into adulthood (4). However, less is known about the role of CVF. Because of the strong inverse correlation between CVF and fatness (5), it is possible that deleterious consequences ascribed to adiposity may be partially due to the influence of low CVF, which is frequently unmeasured. If so, it would imply that interventions to prevent unfavorable lipid profiles should focus on CVF as well as adiposity. In adults, both fatness and fitness predict future mortality (6); in fact, the effects of CVF may even be more robust than the effects of fatness (7). There is some recent evidence that both fatness and fitness are related to unfavorable CVD risk factor status in youths (8).Another issue concerns the degree to which the relations are similar for different races and sexes. We recently reported that the deleterious consequences on insulin levels of high fatness and low fitness are more clearly seen in boys than in girls (5). With respect to lipid profile, there is some evidence that the deleterious consequences of excess adiposity are clearer in white than in black youths (9), but little is known about the degree to which this is also true for CVF.

show abstract

“…%bF was assessed by dual-energy X-ray absorptiometry (DXA; Hologic QDR-4500W, Waltham, MA). 18,19 CRF was assessed by heart rate (HR) at the completion of the yMCA submaximal bench-stepping test, 20 which was chosen over the PACeR 21 due to its sensitivity to CRFrelated changes in heart rate and ease of implementation in a mobile laboratory. We also measured height, weight, waist circumference (WC), nonfasting total cholesterol (tC), and high-density lipoprotein cholesterol (HDL-C), and resting blood pressure (bP) as secondary outcomes.…”

Section: Study Measuresmentioning

confidence: 99%

The Impact of a 3-Year After-School Obesity Prevention Program in Elementary School Children

et al. 2012

Self Cite

View full text Add to dashboard Cite

Background: Children tend to be sedentary during the after-school hours, and this has deleterious effects on their health. the objective of the present study was to determine the effects of a 3-year after-school physical activity (PA) program, without restriction of dietary energy intake, on percent body fat (%bF), cardiorespiratory fitness (CRF), and cardiometabolic markers in children.Methods: A cluster randomization design was employed. A total of 574 3 rd grade children from 18 elementary schools in the southeastern United states participated. the intervention consisted of 80 minutes of age-appropriate moderate-to-vigorous PA each school day. the main outcomes of interest were %bF measured by dual-energy X-ray absorptiometry; CRF measured by heart rate in response to a submaximal step test; nonfasting total and high-density lipoprotein cholesterol (HDL-C); and resting blood pressure (bP).Results: intent-to-treat analyses showed significant treatment by time interactions for %bF (p = 0.009) and CRF (p = 0.0003). the change pattern of the means suggested that %bF and CRF in intervention children improved relative to control children during the school months, rebounding to the levels of control children over the summers following years 1 and 2. year-by-year analyses of what occurred during the months when the program was offered revealed dose-response relations for %bF and CRF, such that the clearest beneficial effects were seen for those youth who attended at least 60% of the after-school sessions. No significant intervention effects were seen for cholesterol or bP.Conclusions: An after-school PA program was effective in reducing adiposity and improving CRF, especially in the children who attended the sessions at least 3 days/week. However, the favorable effects on %bF and CRF were lost over the summer. thus, it is critical to incorporate strategies that attract and retain the children to receive an adequate dose of PA year-round.

show abstract

Comparison of Hologic QDR‐1000/W and 4500W DXA Scanners in 13‐ to 18‐Year Olds

Abstract: LITAKER, MARK S

Cited by 38 publications

References 19 publications

General and visceral adiposity in black and white adolescents and their relation with reported physical activity and diet

General and visceral adiposity in black and white adolescents and their relation with reported physical activity and diet

Relations of Body Fatness and Cardiovascular Fitness to Lipid Profile in Black and White Adolescents

The Impact of a 3-Year After-School Obesity Prevention Program in Elementary School Children

Contact Info

Product

Resources

About