dual energy X-ray absorptiometry (DXA)

双能 X射线吸收法 (DXA)
  • 文章类型: Journal Article
    素食主义的日益流行决定了需要全面研究这些饮食对健康,特别是骨骼代谢的影响。我们假设素食主义者之间的饮食差异很大,乳卵素食者,杂食动物也会导致其营养状况的显着差异,这可能会影响骨骼健康。
    该研究评估了腰椎和股骨颈的双能X射线吸收测量参数,平均营养素摄入量,血清营养素浓度,血清PTH水平,46名素食者的尿液pH值,38名乳卵素食者,和44个杂食动物。
    两组之间的骨矿物质密度(BMD)没有差异。然而,与杂食动物相比,纯素食者的甲状旁腺激素(PTH)水平仍然更高,尽管所有组甲状旁腺功能亢进的患病率相同。这些发现可能是因为每个小组都有自己的“优势和劣势”。\"因此,素食主义者和,在较小程度上,乳卵素食者消耗更多的钾,镁,铜,锰,和维生素B6,B9和C。杂食动物的饮食含有更多的蛋白质和维生素D和B12。所有受试者消耗的维生素D比推荐的少。超过一半的素食主义者和杂食动物血液中维生素D不足甚至缺乏。锰的低血清浓度及其足够的摄入量也值得注意:在57%的素食主义者中观察到锰的缺乏,79%的乳卵素食者,和63%的杂食动物。
    目前,不再可能得出乳卵素食者的BMD低于杂食动物的结论,我们的研究支持。我们研究中的素食者也没有表现出较低的BMD值,只有更高的PTH血液浓度,与杂食动物相比,然而,大量的研究,包括最近,显示相反的观点。在这方面,需要进一步的大规模研究。素食主义者和乳卵素食者现在有各种富含维生素D和B12以及钙的食物。道德来源的膳食补充剂也有很大的多样性。发现的低浓度锰需要进一步研究。
    UNASSIGNED: The growing prevalence of vegetarianism determines the need for comprehensive study of the impact of these diets on health and particularly on bone metabolism. We hypothesized that significant dietary differences between vegans, lacto-ovo-vegetarians, and omnivores also cause significant differences in their nutrient status, which may affect bone health.
    UNASSIGNED: The study assessed dual-energy X-ray absorptiometry parameters in lumbar spine and femoral neck, average nutrient intake, serum nutrient concentrations, serum PTH levels, and urinary pH among 46 vegans, 38 lacto-ovo-vegetarians, and 44 omnivores.
    UNASSIGNED: There were no differences in bone mineral density (BMD) between the groups. However, the parathyroid hormone (PTH) levels were still higher in vegans compared to omnivores, despite the same prevalence of hyperparathyroidism in all groups. These findings may probably be explained by the fact that each group had its own \"strengths and weaknesses.\" Thus, vegans and, to a lesser extent, lacto-ovo-vegetarians consumed much more potassium, magnesium, copper, manganese, and vitamins B6, B9, and C. At the same time, the diet of omnivores contained more protein and vitamins D and B12. All the subjects consumed less vitamin D than recommended. More than half of vegans and omnivores had insufficiency or even deficiency of vitamin D in the blood. Low serum concentrations of manganese with its quite adequate intake are also noteworthy: its deficiency was observed in 57% of vegans, 79% of lacto-ovo-vegetarians, and 63% of omnivores.
    UNASSIGNED: Currently, it is no longer possible to conclude that lacto-ovo-vegetarians have lower BMD than omnivores, as our research supported. Vegans in our study also did not demonstrate lower BMD values, only higher PTH blood concentrations, compared to omnivores, however, a large number of studies, including recent, show the opposite view. In this regard, further large-scale research is required. Vegans and lacto-ovo-vegetarians now have a variety of foods fortified with vitamins D and B12, as well as calcium. There is also a great diversity of ethically sourced dietary supplements. The found low concentrations of manganese require further investigation.
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  • 文章类型: Journal Article
    背景:肠衰竭儿童骨骼健康的纵向变化尚不清楚。我们旨在更好地了解肠衰竭患儿骨矿物质状态随时间的轨迹,并确定影响轨迹的临床因素。
    方法:回顾2012-2021年辛辛那提儿童医院医疗中心肠道康复中心患者的临床记录。纳入3岁前诊断为IF的儿童,腰椎双能量X射线吸收法扫描≥2次。我们提取了病史信息,肠外营养,骨密度,和增长。我们计算骨密度Z评分,有和没有调整身高Z评分。
    结果:34例肠衰竭患儿符合纳入标准。儿童短于平均水平,平均身高Z评分为-1.5±1.3。平均骨密度Z评分为-1.5±1.3,其中25%的组群具有<-2.0的Z评分。高度调整后,平均骨密度Z评分为-0.42±1.4,11%低于-2.0。大多数DXA扫描(60%)具有饲管伪影。骨密度Z评分随着年龄的增长和肠外营养依赖性的降低而略有增加,并且在没有伪影的扫描中更高。肠衰竭的病因,线感染,早产和维生素D状态与身高校正骨密度Z评分无关.
    结论:肠衰竭患儿的年龄短于预期。调整身材矮小时,骨矿物质状态的缺陷较少见。肠衰竭的病因,早产,维生素D缺乏与骨密度无关。本文受版权保护。保留所有权利。
    Longitudinal changes in bone health in children with intestinal failure (IF) are unclear. We aimed to better understand the trajectory of bone mineral status over time in children with IF and identify clinical factors that influence the trajectory.
    Clinical records of patients attending the Intestinal Rehabilitation Center of Cincinnati Children\'s Hospital Medical Center between 2012 and 2021 were reviewed. Children diagnosed with IF before age 3 years with at least two lumbar spine dual-energy x-ray absorptiometry scans were included. We abstracted information on medical history, parenteral nutrition, bone density, and growth. We calculated bone density z scores with and without adjustment for height z scores.
    Thirty-four children with IF met inclusion criteria. Children were shorter than average with a mean height z score of -1.5 ± 1.3. The mean bone density z score was -1.5 ± 1.3 with 25 of the cohort having a z score < -2.0. After height adjustment, the mean bone density z score was -0.42 ± 1.4 with 11% below -2.0. Most dual-energy x-ray absorptiometry scans (60%) had a feeding tube artifact. Bone density z scores increased slightly with age and lower parenteral nutrition dependency and were higher in scans without an artifact. Etiologies of IF, line infections, prematurity, and vitamin D status were not associated with height-adjusted bone density z scores.
    Children with IF were shorter than expected for age. Deficits in bone mineral status were less common when adjusting for short stature. Etiologies of IF, prematurity, and vitamin D deficiency were not associated with bone density.
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  • 文章类型: Journal Article
    Lumbar spine volumetric bone mineral density (BMD) measured using quantitative computed tomography (QCT) can discriminate between postmenopausal women with low areal BMD with and without vertebral fractures. QCT provides a 3D measure of BMD, excludes the vertebral posterior elements and accounts for bone size. This knowledge could contribute to effective treatment targeting of patients with low BMD.
    BACKGROUND: We evaluated the ability of lumbar spine bone mineral apparent density (BMAD), trabecular bone score (TBS) and volumetric bone mineral density (vBMD) to discriminate between postmenopausal women with low areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry (DXA) with and without vertebral fractures. The discriminatory ability of lumbar spine aBMD was compared with that of BMAD, TBS and vBMD.
    METHODS: We studied three groups of postmenopausal women, i.e. group 1, aBMD T-score < - 1.0 and ≥ 1 vertebral fracture (n = 39); group 2, aBMD T-score < - 1.0 and no vertebral fracture, age- and aBMD-matched to group 1 (n = 34); group 3, aBMD score > - 1 and no vertebral fracture, age-matched to group 1 (n = 37). Lumbar spine aBMD was measured by DXA. BMAD was calculated using the DXA scan results. TBS was derived following DXA scan image reanalysis. Lumbar spine vBMD was assessed by quantitative computed tomography and Mindways Pro software. Differences in variables between groups 1, 2 and 3 were examined using general linear univariate modelling approaches. Area under the receiver operating characteristic (ROC) curve was calculated for BMAD, TBS and vBMD to determine the ability of lumbar spine measurement variables to discriminate between group 1 and group 2. A comparison of ROCs was performed.
    RESULTS: Lumbar spine BMAD and TBS measurement variables were similar for groups 1 and 2. However, vBMD was significantly lower in group 1 and could discriminate between those women with low aBMD with (group 1) and without vertebral fractures (group 2).
    CONCLUSIONS: We conclude that lumbar spine vBMD may discriminate well between postmenopausal women with low aBMD with and without vertebral fractures as it provides a 3D measure of bone mineral density, excludes the posterior elements of the vertebrae and takes into account bone size. A unique feature of the SHATTER study is that groups 1 and 2 were matched for aBMD, thus our study findings are independent of aBMD. Furthermore, we observed that neither BMAD nor TBS could distinguish between women with low aBMD with and without vertebral fractures. The knowledge gained from the SHATTER study will influence clinical and therapeutic decision-making, thereby optimising the care of patients with and without vertebral and other fragility fractures.
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  • 文章类型: Journal Article
    The currently available clinical tools have limited accuracy in predicting hip fracture risk in individuals. We investigated the possibility of using normalized cortical bone thickness (NCBT) estimated from the patient\'s hip DXA (dual energy X-ray absorptiometry) as an alternative predictor of hip fracture risk. Hip fracture risk index (HFRI) derived from subject-specific DXA-based finite element model was used as a guideline in constructing the mathematical expression of NCBT. We hypothesized that if NCBT has stronger correlations with HFRI than the single risk factors such as areal BMD (aBMD), then NCBT can be a better predictor. The hypothesis was studied using 210 clinical cases, including 60 hip fracture cases, obtained from the Manitoba Bone Mineral Density Database. The results showed that, in general HFRI has much stronger correlations with NCBT than any of the single risk factors; the strongest correlation was observed at the superior side of the narrowest femoral neck with r2 = 0.81 (p < 0.001), which is much higher than the correlation with femoral aBMD, r2 = 0.50 (p < 0.001). The capability of aBMD, NCBT, and HFRI in discriminating the hip fracture cases from the non-fracture ones, expressed as the area under the curve with 95% confidence interval, AUC (95% CI), is respectively 0.627 (0.593-0.657), 0.714 (0.644-0.784) and 0.839 (0.787-0.892). The short-term repeatability of aBMD, NCBT, and HFRI, measured by the coefficient of variation (CV, %), was found to be in the range of (0.64-1.22), (1.93-3.41), (3.10-4.16), respectively. We thus concluded that NCBT is potentially a better predictor of hip fracture risk.
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  • 文章类型: Journal Article
    A number of factors may have effects on hip fracture, for example, bone mineral density (BMD), body weight and height, femur length, femoral neck length, etc. It is not clear which factor(s) has the dominant effect on hip fracture. Therefore, the factors were investigated by a previously developed DXA (dual energy X-ray absorptiometry) based finite element model. The finite element model is patient-specific, as all information required in constructing the model was extracted from the patient\'s hip DXA image. DXA images of 180 patients were obtained from the Manitoba Bone Mineral Density Database. For each patient, a finite element model was constructed and fracture risk indices (FRI) were calculated at the three critical locations on the hip, i.e. the femoral neck, the intertrochanter and the subtrochanter. Possible correlations between the fracture risk indices and the factors were then investigated. The obtained results indicated that, for hip fractures resulted from lateral fall, areal BMD and patient\'s body weight are two dominant factors, but effects from the other factors are not trivial. The study suggested that hip fracture is the result of combined effects from all the factors. Therefore, use of areal BMD alone in clinical assessment of fracture risk is not reliable.
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