Validation of quantitative computed tomography-derived areal bone mineral density with dual energy X-ray absorptiometry in an elderly Chinese population

Background The performance of computed tomography X-ray absorptiometry （CTXA） against the dual energy X-ray absorptiometry （DXA） as standard has not been studied in Chinese population. The aim of this study was to evaluate the precision of this measurement and validate the value of quantitative computed tomography （QCT） by comparing CTXA results with DXA results in an elderly Chinese population. Methods One hundred and three females of 46 to 76 years old and 49 males of 52 to 76 years old were recruited from the Prospective Urban Rural Epidemiology study. All subjects underwent hip scans by both QCT and DXA on the same day. For precision determination, 30 subjects had duplicate DXA hip scans. The hip QCT data of a subset of 27 subjects were separately analyzed by two observers and reanalyzed by one observer at a different time. The inter- and intra-observer variations of CTXA measurement were assessed, and the difference and correlation between CTXA and DXA results were analyzed. Results The inter- and intra-observer variations of CTXA were 0.070 and 0.024 g/cm^2 in the femoral neck （FN）, and 0.030 and 0.012 g/cm2 in the total hip （TH）, which were comparable to the DXA inter-scan variations （0.013 g/cm2 for FN and 0.014 g/cm2 for TH）. The results of CTXA bone mineral density （BMD） were highly correlated with those of DXA （R2 = 0.810 for FN and R2 = 0.878 for TH）. The BMD values of CTXA in FN and TH were lower than those of DXA by 21.0% and 17.8% （P〈0.05）, respectively. However, after appropriate transformation, the difference was eliminated and a comparable T score could be obtained. Conclusions CTXA shows good agreement with DXA for the measurement of BMD in the proximal femur, which makes QCT suitable for the quantification of bone mineral content in the hip and helpful for the diagnosis of osteoporosis.

两种常用品牌双能X线骨密度仪应用标准化中国库的检出率对比

目的回顾分析某三甲医院两种常用品牌双能X线吸收测量仪(dual energy X-Ray absorptiometry,DXA)应用标准化中国库(依据近期研究成果,首次试用)前后的骨质疏松检出率差异,以验证该标准化数据库的使用效果。为实现不同品牌DXA T值标准化提供理论和数据支持。方法收集2021年6月11日-2022年10月20日GE-Prodigy以及2021年10月1日-2022年9月9日Hologic Horizon-W测量的门诊30岁以上中国患者的骨密度结果。分别获得腰椎(L_(1~4))和单侧髋应用“中国库”和“标准化中国库”的T值,并依据T值计算两种品牌DXA应用标准化数据库前后的检出率。结果两种品牌DXA应用标准化数据库前后的L_(1~4)检出率分别相差136.99%和4.58%;单侧髋检出率分别相差58.69%和22.99%。结论GE-Prodigy与Hologic Horizon-W对骨质疏松的检出率差异较大,标准化中国库的应用降低了这两种国内常用品牌DXA的检出率的差异,将很大程度上提高骨质疏松诊断的同质性。

271例3～11岁儿童骨密度分析

目的：探讨儿童时期全身及身体各部位骨密度的变化规律，方法：选择济南市区无任何内外科疾病、未出现第二性征的271例3—11岁儿童作为研究对象，采用美国LUNAR公司生产的DPX—NT型双能X线骨密度仪测量全身及各部位（包括头、上肢、下肢、躯干、肋骨、骨盆和脊柱）的骨密度。结果：儿童时期骨密度值随年龄增长而增加，身体各部位的骨密度存在显著的性别及年龄差异。尽管骨的发育因躯体部位、性别、年龄而异，但男、女童均在6～8岁年龄段增长较快，9～11岁时增长缓慢。结论：骨的发育因性别、年龄和部位不同而呈现不同规律，在评价骨密度时应予以考虑。

97例5～7岁儿童身体成分分析

目的：了解5～7岁儿童身体成分，比较正常儿童与肥胖儿童、男童与女童身体的脂肪组织、肌肉组织、骨密度、骨矿物质含量之间的差异。方法：对97例（男童49例，女童48例）5～7岁儿童，按照体重指数（BMI）分为正常组和脂肪超量／肥胖组，BMI≤18为正常，BMI〉18为超重／肥胖。采用双能X射线骨密度仪（DXA），测量全身骨密度、骨矿物质含量、肌肉组织含量、脂肪组织含量及其百分比、躯干脂肪含量及其与全身脂肪含量的比值，并对其结果进行比较。结果：①正常组女童全身的脂肪含量、脂肪百分含量、躯干脂肪含量均明显高于男童，男童肌肉组织含量明显高于女童，差异有显著性（P〈0．05）；②脂肪超量／肥胖组男童与女童脂肪含量及肌肉组织含量差异无显著性（P〉0．05）；③骨密度、骨矿物质含量男女比较差异无显著性。结论：正常发育的儿童脂肪组织含量及肌肉组织含量男女之间存在差异，骨密度差异无显著性，运动对减少脂肪含量、增加肌肉含量有益，应鼓励儿童特别是女童增加户外活动。

沈阳市5岁以上儿童骨密度分析研究

目的研究沈阳地区5岁以上儿童骨密度变化规律，了解该地区儿童骨密度的正常参考范围。方法选择2003～2007年在沈阳市儿童医院儿保门诊进行体检的5～15岁健康儿童及青少年为研究对象，利用美国LUNAR公司生产的DPX．NT型双能X线骨密度仪进行检测。结果各年龄纽儿童骨密度与其年龄（r=0.997，P〈0．001）、身高（r=0．983，P〈0．001）呈显著正相关，在青春期前（8～12岁）男女骨密度有显著性差异（P〈0．01）。结论骨密度受年龄、性别影响，可作为儿童期钙营养的判定指标。

双能X线吸收仪测定骨密度对骨质疏松症的诊断价值

目的:应用双能X线吸收仪(DEXA)测定腰椎L2～4前后位(anterior鄄post,A鄄P正位)和侧位的骨密度(BMD),以界定L2～4前后位和侧位男、女患者骨质疏松症(OP)的诊断临界值。方法:测定2115例患者L2～4的BMD,其中前后位1018例,侧位1097例。以T值≤-2.0s和≤-2.5s为诊断标准进行OP检出率分析。结果:按T值≤-2.0s、≤-2.5s计算,其中女性L2～4前后位的OP检出率分别为32.5%和14.5%,侧位分别为59.0%和33.4%;男性L2～4的前后位OP检出率分别为17.6%和6.4%,侧位分别为45.9%和17.8%。无论男女,以T值≤-2.0s为标准时,L2～4前后位与侧位的OP检出率差异显著(P<0.01)。L2～4前后位以T值≤-2.0s为标准的OP检出率和侧位以T值≤-2.5s为标准的OP检出率一致(P>0.05)。结论:男、女性L2～4前后位BMD测定可参考以T值≤-2.0s作为OP的诊断标准,侧位可参考以T值≤-2.5s作为诊断标准。

应用双能X线骨密度仪测定131名健康妇女骨密度变化

应用双能X线骨密度仪 (DEXA)测定 1 3 1名不同年龄和绝经年限妇女骨密度 (BMD)变化 ,并观察外周血液中雌二醇 (E2 )、卵泡刺激素 (FSH)、碱性磷酸酶 (AKP)、骨钙素 (BGP)、血钙、血磷等指标 ,探讨BMD和E2 、AKP、BGP、Ca、P的相互关系。结果表明 ,妇女随着年龄及绝经年限增加 ,BMD及E2 水平逐年下降 ,BMD和E2 呈正相关 ;绝经后各组BGP和AKP明显高于绝经前各组 ,BMD和AKP、BGP呈负相关 ;血钙水平于绝经早期有一过性增加 ,以后略有下降 ,并保持在一相对稳定水平 ;血磷各组变化不大。由此可见 ,DEXA是一种理想的骨密度测定仪。BMD测定和E2 、AKP、BGP等生化指标可以早期诊断绝经后骨质疏松症 。

昆明地区女性腰椎双能X线骨密度调查分析

目的 调查昆明成年女性腰椎骨密度变化及其相关因素。方法 采用双能X线骨吸收仪前后位测量腰椎骨密度 (BMD) ,受检女性 345名 ,年龄 2 0～ 90岁 ,排除影响骨代谢疾病。结果 BMD值L1 <L2 <L3 L4 ,各椎体骨峰值均在 2 0～ 2 9岁。BMD随增龄下降 ,5 0～ 5 9岁下降最快 ,年均失骨 1 31% ,是绝经前的 6倍 ;80岁后累积失骨 32 0 6 %。BMD与体重极显著正相关 (P <0 0 0 1) ,BMD与年龄、绝经年限、生育胎次极显著负相关P均 <0 0 0 1。腰椎压缩变形占 70岁以上妇女的 5 8 4 9% ,其中 1 4BMD呈假性增高。结论 女性腰椎骨密度在 30岁前上升 ,5 0岁后加速下降 ,终生失骨近 1 3,失骨的决定性因素是增龄和绝经。未发现高海拔对骨量积累产生负面影响。

颅骨牵张术中新骨骨密度的定量评价

目的:探讨颅骨牵张术修复骨缺损过程中新骨骨密度的评价方法。方法:成年健康山羊18只,颅顶区制备25mm×10mm全层颅骨缺损,随机分为实验组和对照组,实验组15只建立牵张术修复颅骨缺损的动物模型,于牵张结束后2,4,6周分别处死5只动物,对照组3只动物与实验组牵张后6周动物同期处死,QCT、DEXA两种方法测量新骨骨密度,比较两种测量方法骨密度值(BMD)及相关性。结果:实验组QCT测量牵张间隙各兴趣区BMD值较前一时段对应BMD值明显增加(P<0.05),同一牵张间隙内各固定时段两端(R2、R3)较中央(R1)BMD值明显高(P<0.05),R2、R3之间无明显差别(P>0.05);DEXA测量固定期4周,各兴趣区BMD值较固定2周对应BMD值明显增加(P<0.05),而固定期6周,仅牵张间隙中央(R1)较固定4周对应BMD值增加有统计学意义(P<0.05),同一牵张间隙内固定期2,4周两端(R2、R3)较中央(R1)BMD值明显高(P<0.05);两种检测方法测得平均骨密度值在各时段均存在正相关(P<0.005);对照组缺损区QCT、DEXA检测未显示有新骨形成。结论:两种检测方法均能反映牵张过程新骨骨密度变化,QCT不受解剖结构和牵张器形状的影响,更适于颅面骨牵张术新骨形成的监测评价。

股骨近端骨密度的测量

双能X线骨密度仪检测骨密度是诊断骨质疏松症和疗效随访的金标准,特别是髋部骨密度的测量对于骨折的预测尤其测定部位本身骨折的预测作用较大。由于脊柱部位的骨密度测量值易受到脊柱退行性疾病的病理改变如退行性侧凸、骨赘增生、腰椎间盘突出等影响,测量的准确性下降。因而近年来欧美国家临床试验也好或者骨质疏松诊疗也好,大都以股骨近端的BMD测定为标准。本文就股骨近端解剖特点、骨密度测量的意义、方法以及测量的注意点作一个综述,以期帮助临床医生或技术员全面评估股骨近端骨密度测定的意义。

Cerebral artery evaluation of dual energy CT angiography with dual source CT

Background Conventional computed tomography angiography （CTA） is time consuming, user-dependent and has poor image quality in skull base region. This study assessed the feasibility of a new method, dual energy CTA for depicting the cerebral artery.Methods Phantom scan was done with head CTA sequences on dual source CT and 64 spiral CT for radiation dose calculation. Dual energy CTA was done with dual source CT on 36 patients who were suspected of having cerebral vascular disease. Three series axial images in 0.75 mm thick, 0.4 mm increment were acquired, which were named with 80 kV, 140 kV and merged images; 80 kV and 140 kV images were transferred into dual energy software, and maximum intensity projection （MIP） image was generated quickly by dual energy bone remove （DEBR group）; merged images were transferred into In Space software to acquire MIP image through manual conventional bone remove （CoBR group）. Post processing time and reading time were compared. Image qualities of the two groups were compared, mainly focusing on skull base segments of internal carotid artery and bone subtraction. ANOVA and SNK tests were applied for radiation dose comparison. Student＇s t test and Wilcoxon rank sum test were applied for assessing differences between data for significance. Cohen＇s kappa was used for interobserver agreement. Results Radiation dose of phantom scan showed dual energy CTA was between digital bone subtraction and conventional CTA. The post processing time and reading time were much shorter in DEBR than CoBR, and image quality in skull base was much higher in DEBR than CoBR （P〈0.01）. There was no significant difference for suprasellar vessels between two groups （P〉0.5）. Interobserver agreement for all vessel segments was excellent （kappa=0.97）. Conclusions Dual energy CTA is a reliable, new modality for depicting cerebral artery, overcoming the limitation of conventional CTA in the skull base region. It can save much time in post processing and reading than conventional CTA.

A Low-Cost Dual Energy CT System with Sparse Data

Dual Energy CT （DECT） has recently gained significant research interest owing to its ability to discriminate materials, and hence is widely applied in the field of nuclear safety and security inspection. With the current technological developments, DECT can be typically realized by using two sets of detectors, one for detecting lower energy X-rays and another for detecting higher energy X-rays. This makes the imaging system expensive, limiting its practical implementation. In 2009, our group performed a preliminary study on a new low-cost system design, using only a complete data set for lower energy level and a sparse data set for the higher energy level. This could significantly reduce the cost of the system, as it contained much smaller number of detector elements. Reconstruction method is the key point of this system. In the present study, we further validated this system and proposed a robust method, involving three main steps： （1） estimation of the missing data iteratively with TV constraints; （2） use the reconstruction from the complete lower energy CT data set to form an initial estimation of the projection data for higher energy level; （3） use ordered views to accelerate the computation. Numerical simulations with different number of detector elements have also been examined. The results obtained in this study demonstrate that 1 ＋ 14% CT data is sufficient enough to provide a rather good reconstruction of both the effective atomic number and electron density distributions of the scanned object, instead of 2 sets CT data.

Managing osteoporosis in ulcerative colitis: Something new?

The authors revise the latest evidence in the literature regarding managing of osteoporosis in ulcerative colitis (UC), paying particular attention to the latest tendency of the research concerning the management of bone damage in the patient affected by UC. It is wise to assess vitamin D status in ulcerative colitis patients to recognize who is predisposed to low levels of vitamin D, whose deficiency has to be treated with oral or parenteral vitamin D supplementation. An adequate dietary calcium intake or supplementation and physical activity, if possible, should be guaranteed. Osteoporotic risk factors, such as smoking and excessive alcohol intake, must be avoided. Steroid has to be prescribed at the lowest possible dosage and for the shortest possible time. Moreover, conditions favoring falling have to been minimized, like carpets, low illumination, sedatives assumption, vitamin D deficiency. It is advisable to assess the fracture risk in all UC patient by the fracture assessment risk tool (FRAX® tool), that calculates the ten years risk of fracture for the population aged from 40 to 90 years in many countries of the world. A high risk value could indicate the necessity of treatment, whereas a low risk value suggests a follow-up only. An intermediate risk supports the decision to prescribe bone mineral density (BMD) assessment and a subsequent patient revaluation for treatment. Dual energy X-ray absorptiometry bone densitometry can be used not only for BMD measurement, but also to collect data about bone quality by the means of trabecular bone score and hip structural analysis assessment. These two indices could represent a method of interesting perspectives in evaluating bone status in patients affected by diseases like UC, which may present an impairment of bone quality as well as of bone quantity. In literature there is no strong evidence for instituting pharmacological therapy of bone impairment in UC patients for clinical indications other than those that are also applied to the patients with osteoporosis. Therefore, a reasonable advice is to consider pharmacological treatment for osteoporosis in those UC patients who already present fragility fractures, which bring a high risk of subsequent fractures. Therapy has also to be considered in patients with a high risk of fracture even if it did not yet happen, and particularly when they had long periods of corticosteroid therapy or cumulative high dosages. In patients without fragility fractures or steroid treatment, a medical decision about treatment could be guided by the FRAX tool to determine the intervention threshold. Among drugs for osteoporosis treatment, the bisphosphonates are the most studied ones, with the best and longest evidence of efficacy and safety. Despite this, several questions are still open, such as the duration of treatment, the necessity to discontinue it, the indication of therapy in young patients, particularly in those without previous fractures. Further, it has to be mentioned that a long-term bisphosphonates use in primary osteoporosis has been associated with an increased incidence of dramatic side-effects, even if uncommon, like osteonecrosis of the jaw and atypical sub-trochanteric and diaphyseal femoral fractures. UC is a long-lasting disease and the majority of patients is relatively young. In this scenario primary prevention of fragility fracture is the best cost-effective strategy. Vitamin D supplementation, adequate calcium intake, suitable physical activity (when possible), removing of risk factors for osteoporosis like smoking, and avoiding falling are the best medical acts.

Adipokines and C-reactive protein in relation to bone mineralization in pediatric nonalcoholic fatty liver disease

AIM: To investigate bone mineral density (BMD) in obese children with and without nonalcoholic fatty liver disease (NAFLD); and the association between BMD and serum adipokines, and high-sensitivity C-reactive protein (HSCRP). METHODS: A case-control study was performed. Cases were 44 obese children with NAFLD. The diagnosis of NAFLD was based on magnetic resonance imaging (MRI) with high hepatic fat fraction (≥ 5%). Other causes of chronic liver disease were ruled out. Controls were selected from obese children with normal levels of aminotransferases, and without MRI evidence of fatty liver as well as of other causes of chronic liver diseases. Controls were matched (1-to 1-basis) with thecases on age, gender, pubertal stage and as closely as possible on body mass index-SD score. All participants underwent clinical examination, laboratory tests, and whole body (WB) and lumbar spine (LS) BMD by dual energy X-ray absorptiometry. BMDZ-scores were calcu- lated using race and gender specific LMS curves. RESULTS: Obese children with NAFLD had a significantly lower LS BMDZ-score than those without NAFLD [mean, 0.55 (95%CI: 0.23-0.86) vs 1.29 (95%CI: 0.95-1.63); P < 0.01]. WB BMD Z-score was also decreased in obese children with NAFLD compared to obese children with no NAFLD, though borderline significance was observed [1.55 (95%CI: 1.23-1.87) vs 1.95 (95%CI: 1.67-2.10); P = 0.06]. Children with NAFLD had significantly higher HSCRP, lower adiponectin, but similar leptin levels. Thirty five of the 44 children with MRI-diagnosed NAFLD underwent liver biopsy. Among the children with biopsy-proven NAFLD, 20 (57%) had nonalcoholic steatohepatitis (NASH), while 15 (43%) no NASH. Compared to children without NASH, those with NASH had a significantly lower LS BMD Z-score [mean, 0.27 (95%CI: -0.17-0.71) vs 0.75 (95%CI: 0.13-1.39); P < 0.05] as well as a significantly lower WB BMD Z-score [1.38 (95%CI: 0.89-1.17) vs 1.93 (95%CI: 1.32-2.36); P < 0.05]. In multiple regression analysis, NASH (standardized β coefficient, -0.272; P < 0.01) and HSCRP (standardized β coefficient, -0.192; P < 0.05) were significantly and independently associated with LS BMD Z-score. Similar results were obtained when NAFLD (instead of NASH) was included in the model. WB BMD Z-scores were significantly and independently associated with NASH (standardized β coefficient, -0.248;P < 0.05) and fat mass (standardized β coefficient, -0.224;P < 0.05). CONCLUSION: This study reveals that NAFLD is associated with low BMD in obese children, and that systemic, low-grade inflammation may accelerate loss of bone mass in patients with NAFLD.

Green coffee bean extract improves obesity by decreasing body fat in high-fat diet-induced obese mice

Objective:To evaluate possible lipid catabolism and body fat regulation effects of 3-caffeoylquinic acid in Green coffee bean extract(GCBE) in high-fat diet(HFD)-induced obese mice.Methods:Obesity was induced in mice using a HFD for four weeks.Then,mice were fed only HFD or HFD with GCBE at 50,100,and 200 mg/kg.Fatty acid synthesis mechanism regulation of body fat was investigated through real-time PCR and Western blot assay.Body fat reduction was measured through dual-energy X-ray absorptiometry.Results:In HFD-induced obese mice,GCBE treatment significantly decreased body weight gain,liver weight and white adipose tissue weights with regulation of adipose tissue lipolysis hormones,like adiponectin and leptin.GCBE treatment decreased mR NA expression levels of adipogenesis and adipocyte metabolism related genes in adipose tissues and the liver,and decreased the corresponding protein expression.Dual energy X-ray absorptiometry measurements were used to compare body fat between mice on high-fat and those treated with GCBE.GCBE treated mice had a lower fat mass compared to HFD alone fed mice and relative body weight and fat mass were markedly decreased.Conclusions:GCBE has a potential anti-obesity effect with lowering body fat accumulation by regulating adipogenesis and lipid metabolism-related genes and proteins in WAT and liver.

OSTC在2型糖尿病性骨质疏松症筛查中的作用

目的探讨中国大陆地区妇女骨质疏松筛查工具(OSTC)与双能X线吸收检测法(DXA)诊断2型糖尿病性骨质疏松症的一致性。方法收集404例2型糖尿病绝经后妇女的临床资料,应用双能X线骨密度仪测量腰椎(L1~4)和股骨颈骨密度,利用公式计算OSTC得分。将OSTC分值与DXA测定的不同部位骨密度进行比较。结果随年龄增长,受试者腰椎、股骨颈骨密度逐渐下降,各组间股骨颈骨密度差异有统计学意义(P <0.05)。应用DXA在腰椎(L1~4)、股骨颈的骨质疏松检出率分别为22.5%、21.8%。OSTC有危险组中达到骨质疏松诊断标准的比例为21.5%。以股骨颈为检测部位,OSTC识别骨质疏松症受试者工作特征曲线下面积为0.78(P=0.000)。OSTC诊断腰椎(L1~4)和股骨颈骨质疏松症的最佳截点均为-25.5,敏感度分别为63.7%、86.4%,特异度分别为48.9%、42.7%。结论 OSTC可用于早期筛查2型糖尿病性骨质疏松症,最佳截点是-25.5。

不同DEXA测量股骨头骨矿的比较

目的 评估不同双能X线吸收测量仪(DEXA)的准确性及不同扫描条件对测量值的影响。方法 取6个人体切除的股骨头作为实验标本。分别以Hologic QDR-2000及Aloka DCS-3000 DEXA,在不同的扫描条件下(分别在4cm的有机玻璃板上、水深5cm、10cm、15cm、20cm、25cm及30cm)对实验标本进行骨矿测量。最后将股骨头标本放入马福炉内,在700℃高温下焚化24 h。取出灰化的6个标本,分别称重。并与其DEXA测量值做比较性研究。结果 BMC值与灰重的相关关系显示,在无水条件下,Hologic及Aloka双能X线吸收测量仪BMC测量值与灰重都明显相关。Hologic QDR-2000机(r=0.965～0.996)优于Aloka DCS-3000(r=0.823～0.964),尤其是随水深增加,前者的优越性就更为突出。结论 两种不同厂家生产的DEXA都可为骨矿定量提供可靠的准确性。Hologic QDR-2000机测量股骨头BMC值与灰重明显相关,其优越性大于Aloka DCS-3000 DEXA。随水深增加,前者较后者测量的准确性就更为明显。

Non Destructive 3D, 4D Microscopy and Mineral Phase Characterization in Industrial Minerals, Composites to Construction Materials

Conventional electron and optical microscopy techniques require the sample to be sectioned, polished or etched to expose the internal surfaces for imaging. However, such sample preparation techniques have traditionally prevented the observation of the same sample over time, under realistic three-dimensional geometries and in an environment representative of real-world operating conditions. X-ray microscopy (XRM) is a rapidly emerging technique that enables non-destructive evaluation of buried structures within hard to soft materials in 3D, requiring little to no sample preparation. Furthermore in situ and 4D quantification of microstructural evolution under controlled environment as a function of time, temperature, chemistry or stress can be done repeatable on the same sample, using practical specimen sizes ranging from tens of microns to several cm diameter, with achievable imaging resolution from submicron to 50 nm. Many of these studies were reported using XRM in synchrotron beamlines. These include crack propagation on composite and construction materials; corrosion studies; microstructural changes during the setting of cement; flow studies within porous media to mention but a few.

Relationship between peak oxygen uptake and regional body composition in Japanese subjects

Purpose： To investigate the link between peak oxygen uptake and regional body composition by dual energy X-ray absorptiometry （DEXA） in Japanese subjects. Methods： A total of 93 men （42.2 ± 12.3 years old） and 106 women （43.5 ± 12.3 years old） were enrolled in this cross-sectional investigation study. Peak oxygen uptake was measured by the breath-by-breath method. Regional body composition i.e., body fat mass, lean body mass, and body fat percentage was evaluated using DEXA. In addition, metabolic risk parameters were also evaluated. Results： Peak oxygen uptake was 37.6± 8.7 mL/kg/min in men and 31.1 ± 6.4 mL/kg/min in women, and decreased with age in both genders. Peak oxygen uptake was significantly correlated with total body fat percentage （men： r = -0.684, p 〈 0.0001; women： r = -0.681, p 〈 0.0001）. These associations remained even after adjusting for age and total lean body mass. However, peak work rate was positively and significantly correlated with leg lean body mass. Conclusion： Peak oxygen uptake was closely correlated with total body fat percentage in both genders. Aerobic exercise as well as leg resistance training might be useful for improving peak oxygen uptake in Japanese subjects. Copyright

Body composition of healthy Spanish children

This paper shows the distribution of the body compartments, and the age and gender related changes in Spanish children. Subjects and Methods: A total of 231 healthy children from Madrid (Spain) were recruited and divided into 3 groups according to age (birth-5, 6-10, 11-15y). Body compartments (fat mass, lean mass and bone mass) measures were obtained from dual energy X-ray absorptiometry (DXA) scans. Total and regional body compositions were evaluated. Results: There were gender differences for TBFM (total body fat mass) in 11 - 15 year age group and for TLBM (total lean body mass) in all age groups except for the 6 - 10 year age group. TBMC (total bone mineral content) shows significant gender differences form birth. Conclusions: Contrary to boys, girls showed from early infancy a smaller proportion of muscle mass and a higher proportion of body fat (from the age of 10), with fat deposits being mostly peripheral. Bone mass and muscle mass values were higher in boys.