Anomalies in dual energy X-ray absorptiometry measurements of total-body bone mineral during weight change using Lunar, Hologic and Norland instruments.

Tothill, P.; Laskey, M A; Orphanidou, C I; Wijk, Michiel P. van

doi:10.1259/bjr.72.859.10624323

Cited by 93 publications

(62 citation statements)

References 14 publications

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“…Therefore, this potential artifact would not explain our results. Fat mass has also been shown to overestimate BMC [78]. Again, this possible artifact should not affect the interpretation of our results because the paretic leg, with its higher fat mass, still had a lower proximal femur BMC than the nonparetic leg.…”

Section: Limitationsmentioning

confidence: 61%

Reduced hip bone mineral density is related to physical fitness and leg lean mass in ambulatory individuals with chronic stroke

et al. 2005

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Following a stroke, reduced level of physical activity and functional use of the paretic leg may lead to bone loss and muscle atrophy. These factors and the high incidence of falls may contribute to hip fractures in the stroke population. This study was the first to examine total proximal femur bone mineral content (BMC) and bone mineral density (BMD) and their relationship to strokespecific impairments in ambulatory individuals with chronic stroke (onset >1 year). We utilized dual-energy X-ray absorptiometry (DXA) to acquire proximal femur and total body scans on 58 (23 women) community-dwelling individuals with chronic stroke. We report total proximal femur BMC (g) and BMD (g/cm 2 ) derived from the proximal femur scans, and lean mass (g) and fat mass (g) for each leg derived from the total body scans. Each subject was evaluated for ambulatory capacity (Six Minute Walk Test), knee extension strength (hand-held dynamometry), physical fitness [Maximal oxygen uptake (VO 2 max)], and spasticity (Modified Ashworth Scale). Results showed that the paretic leg had significantly lower proximal femur BMD, lean mass, and percent lean mass but higher fat mass than the non-paretic leg for both men and women. Proximal femur BMD of the paretic leg was significantly related to ambulatory capacity (r=0.33, p=0.011), muscle strength (r=0.39, p=0.002), physical fitness (r=0.57, p<0.001) but not related to spasticity (r= −0.23, p=0.080). Multiple regression analysis showed that lean mass in the paretic leg was a major predictor (R 2 =0.371, p<0.001) of the paretic proximal femur BMD. VO 2 max was a significant predictor of both paretic proximal femur BMD (R 2 =0.325, p<0.001) and lean mass in the paretic leg (R 2 =0.700, p<0.001). Further study is required to determine whether increasing physical fitness and lean mass is important to improve hip bone health in chronic stroke.

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Section: Limitationsmentioning

confidence: 61%

Reduced hip bone mineral density is related to physical fitness and leg lean mass in ambulatory individuals with chronic stroke

et al. 2005

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“…Thus, discordant BMD and BMC results are biologically implausible, and are probably artifacts of DXA, which result from errors in determination of bone area. Tothill et al (1999) and Tothill (2005) evaluated the effect of changes in fat mass or distribution on measurement of BMC, BMD and bone area by placement of known quantities of lard on human volunteers or a phantom with BMC, BMD and bone area approximately equivalent to that of an adult male (Tothill et al, 1999). Addition of B6 kg of lard resulted in erroneous increases in BMC and bone area as measured using DXA scanners of various manufacturers, including the Lunar DPX used in this study.…”

Section: Discussionmentioning

confidence: 99%

Total body bone mineral content and density during weight loss and maintenance on a low- or recommended-dairy weight-maintenance diet in obese men and women

et al. 2010

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Background: Diets high in either dairy or calcium during moderate weight reduction both prevent loss of bone mineral density (BMD) and suppress bone turnover. The purpose of this study was to determine whether recommended dairy and calcium intakes during weight maintenance favorably affect total body BMD (TBBMD) and bone mineral content (TBBMC) in obese adults. Methods: Obese men (n ¼ 49) and women (n ¼ 64), aged 40.8 ± 0.6 years, underwent 12 weeks of moderate energy restriction (B1200 kcal/day) followed by 24 weeks on either a low or recommended dairy weight maintenance diet. The TBBMC and TBBMD values were measured using dual energy X-ray absorptiometry at baseline, 12, 24 and 36 weeks. Concentrations of calcium, intact parathyroid hormone (iPTH), 25OH and 1,25 (OH) 2 vitamin D in plasma were also measured. Data were analyzed using a two-factor repeated measures analysis of variance. Results: After weight loss, women exhibited a small, but statistically significant, increase in TBBMC (1.17±0.57%), whereas TBBMD increased in the men (1.34 ± 0.28%). The iPTH concentration decreased significantly in all subjects. Despite significantly greater intakes of calcium, vitamin D and protein compared with the recommended dairy diet, there were no treatment-related differences in outcome variables after 24 weeks of weight maintenance. The TBBMC remained unchanged in women during weight stabilization; both TBBMC and TBBMD decreased in men (À1.59±0.51% and À0.70±0.25%, respectively). Conclusions: In summary, results of this study do not provide convincing evidence that moderate weight loss through energy restriction and mild exercise reduces TBBMC in obese men and women. Similarly, a weight-maintenance diet providing the recommended daily servings of dairy does not seem to affect changes in BMC after weight loss.

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“…Differences in whole-body scan results have also been reported between manufacturers. (2)(3)(4)(5)(6)(7)(8)(9) To overcome comparability problems, the International Committee for Standards in Bone Measurements (ICSBM) conducted a study in 1994 in which 100 women were scanned on all three DXA systems. The study was performed at UCSF using first-generation pencil-beam DXA systems produced by all three dominant manufacturers at that time: Hologic QDR 2000 pencil beam, GE Healthcare Lunar DPX_L and Norland XR26 Mark II.…”

Section: J Jbmrmentioning

confidence: 99%

A multinational study to develop universal standardization of whole-body bone density and composition using GE Healthcare Lunar and Hologic DXA systems

Shepherd

Fan

Lü

et al. 2012

Journal of Bone and Mineral Research

172

132

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Dual-energy x-ray absorptiometry (DXA) is used to assess bone mineral density (BMD) and body composition, but measurements vary among instruments from different manufacturers. We sought to develop cross-calibration equations for whole-body bone density and composition derived using GE Healthcare Lunar and Hologic DXA systems.This multinational study recruited 199 adult and pediatric participants from a site in the US (n ¼ 40, ages 6 through 16 years) and one in China (n ¼ 159, ages 5 through 81 years). The mean age of the participants was 44.2 years. Each participant was scanned on both GE Healthcare Lunar and Hologic Discovery or Delphi DXA systems on the same day (US) or within 1 week (China) and all scans were centrally analyzed by a single technologist using GE Healthcare Lunar Encore version 14.0 and Hologic Apex version 3.0. Paired t-tests were used to test the results differences between the systems. Multiple regression and Deming regressions were used to derive the crossconversion equations between the GE Healthcare Lunar and Hologic whole-body scans.Bone and soft tissue measures were highly correlated between the GE Healthcare Lunar and Hologic and systems, with r ranging from 0.96 percent fat [PFAT] to 0.98 (BMC). Significant differences were found between the two systems, with average absolute differences for PFAT, BMC, and BMD of 1.4%, 176.8 g and 0.013 g/cm 2 , respectively. After cross-calibration, no significant differences remained between GE Healthcare Lunar measured results and the results converted from Hologic.The equations we derived reduce differences between BMD and body composition as determined by GE Healthcare Lunar and Hologic systems and will facilitate combining study results in clinical or epidemiological studies. ß

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Anomalies in dual energy X-ray absorptiometry measurements of total-body bone mineral during weight change using Lunar, Hologic and Norland instruments.

Cited by 93 publications

References 14 publications

Reduced hip bone mineral density is related to physical fitness and leg lean mass in ambulatory individuals with chronic stroke

Reduced hip bone mineral density is related to physical fitness and leg lean mass in ambulatory individuals with chronic stroke

Total body bone mineral content and density during weight loss and maintenance on a low- or recommended-dairy weight-maintenance diet in obese men and women

A multinational study to develop universal standardization of whole-body bone density and composition using GE Healthcare Lunar and Hologic DXA systems

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