BONE MINERAL ANALYSIS OF WHOLE BODY IN 292 NORMAL SUBJECTS ASSESSED BY DUAL X-RAY ABSORPTIOMETRY

Objective. To study the whole body bone mineral changes in normal subjects.Methods. Bone mineral was measured by dual X-ray absorptiometry(DXA) in 292 normal subjectsaged 10～79 years, including 152 females and 140 males. They were divided into age-groups by decade.Results. In males, the ages with peak value of total bone mineral content (TBMC), total bone min-eral density (TBMD), anteroposterior spine BMD(L2-4 BMD) were in the 30～39,20～39, 20～29 age-groups respectively. In females, they were all in the 30～39 age-group. Peak values of TBMC, TBMD,L2-4 BMD were higher in males than those in females. Loss of bone mineral for females was more pro-nounced than that for males. Loss of L2-4 BMD was more pronounced than TBMD.Conclusion. This study provides the normal bone mineral data of whole body for males and females,and the characteristic of changes.

Prevalence and outcome of sarcopenia in non-alcoholic fatty liver disease

BACKGROUND Nonalcoholic fatty liver disease(NAFLD)includes a spectrum of conditions,progressing from mild steatosis to advanced fibrosis.Sarcopenia,characterized by decreased muscle strength and mass,shares common pathophysiological traits with NAFLD.An association exists between sarcopenia and increased NAFLD prevalence.However,data on the prevalence of sarcopenia in NAFLD and its impact on the outcomes of NAFLD remain inconsistent.AIM To analyze the prevalence and outcomes of sarcopenia in patients with NAFLD.METHODS We conducted a comprehensive search for relevant studies in MEDLINE,Embase,and Scopus from their inception to June 2023.We included studies that focused on patients with NAFLD,reported the prevalence of sarcopenia as the primary outcome,and examined secondary outcomes,such as liver fibrosis and other adverse events.We also used the Newcastle-Ottawa scale for quality assessment.RESULTS Of the 29 studies included,the prevalence of sarcopenia in NAFLD varied widely(1.6%to 63.0%),with 20 studies reporting a prevalence of more than 10.0%.Substantial heterogeneity was noted in the measurement modalities for sarcopenia.Sarcopenia was associated with a higher risk of advanced fibrosis(odd ratio:1.97,95%confidence interval:1.44-2.70).Increased odds were consistently observed in fibrosis assessment through biopsy,NAFLD fibrosis score/body mass index,aspartate aminotransferase to alanine aminotransferase ratio,diabetes(BARD)score,and transient elastography,whereas the fibrosis-4 score showed no such association.Sarcopenia in NAFLD was associated with a higher risk of steatohepatitis,insulin resistance,cardiovascular risks,and mortality.CONCLUSION This systematic review highlights the critical need for standardized diagnostic criteria and measurement methods for sarcopenia in NAFLD patients.The variability in study designs and assessment methods for sarcopenia and liver fibrosis may account for the inconsistent findings.This review demonstrates the multidimensional impact of sarcopenia on NAFLD,indicating its importance beyond liver-related events to include cardiovascular risks,mortality,and metabolic complications.

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.

类风湿关节炎患者破骨细胞分化情况及其与骨破坏的关系

目的:观察类风湿关节炎(RA)患者破骨细胞(OC)的分化情况,并分析其与RA骨破坏的关系。方法:采用密度梯度离心法分离12例RA患者和10例健康志愿者外周血单个核细胞(PBMC),经核因子κB受体活化因子配体(RANKL)和巨噬细胞集落刺激因子(M-CSF)诱导培养为OC,进行抗酒石酸酸性磷酸酶(TRAP)染色并计数阳性细胞数,分别通过甲苯胺蓝染色及扫描电镜观察骨吸收陷窝;对RA组患者进行Sharp评分及骨密度(BMD)检测,将RA组外周血生成的OC数量与Sharp评分、BMD(T值)进行相关性分析。结果:RA组和对照组生成的OC形态相似; RA组TRAP阳性细胞数(个/10个视野)为127. 67±6. 96,较对照组79. 40±3. 86显著升高(P<0. 05); RA组OC骨吸收功能较对照组明显增强; RA组OC数量与Sharp评分呈显著正相关(r=0. 810,P=0. 001),与BMD(T值)呈显著负相关(r=-0. 685,P=0. 014)。结论:RA患者PBMC向OC分化的能力明显增强,RA患者OC的分化能力与RA骨破坏密切相关。

绝经后妇女前臂骨骨量丢失的相关危险因素研究

目的探讨绝经后妇女前臂骨骨量丢失的相关危险因素。方法采用美国NORLAND-Stratec周围型双能X线骨矿测量仪(pDXA)测量了183例绝经1年以上的女性健康志愿者非优势侧前臂远端桡+尺骨(distal radius+ulna)、近端桡+尺骨(proximal radius+ulna)以及近端桡骨(proximalradius)的BMD值,以问卷调查方法收集研究对象的一般情况,并测定了尿吡啶酚、血清雌二醇、甲状旁腺激素、骨钙素和碱性磷酸酶等指标。结果绝经后妇女前臂骨不同测量部位的BMD值均随年龄增长和绝经年限的延长呈加速下降,尤其是绝经后头十年内下降速度明显,此后逐步趋向缓和,其趋势与中轴骨测量结果一致。绝经早、绝经年限长、怀孕次数多和哺乳时间长等因素是绝经后女性骨丢失和骨质疏松症发生的重要危险因素。此外,与非OP的绝经后健康妇女相比,绝经后患OP妇女的雌激素水平明显下降、血钙水平较低,血PTH和尿Pyd/Cr等明显升高,表现为高骨转换型。使用雌激素替代治疗可减缓绝经后早期骨量丢失,但使用人数比例仅为9.3%。结论妇女绝经后前臂骨骨量丢失规律同中轴骨改变,可采用周围型双能X线骨矿测量仪测量前臂骨BMD用于社区高危人群筛查。绝经年限、生育状况和雌激素使用情况等是影响绝经后妇女骨量值的重要因素。

上海地区女性前臂骨峰值骨量的建立及其影响因素研究

目的建立女性前臂骨不同测量部位的峰值骨量和标准差值,并探讨其可能影响因素,为周围型DEXA测定开展OP研究提供基础数据。方法对上海市区365例21～59岁社区女性健康志愿者,采用美国NORLAND-Stratec周围型双能X线骨矿测量仪(pDEXA)测量了非优势侧(左侧)前臂远端桡骨和尺骨(Distal radius and ulna,Dist.R+U)、近端桡骨和尺骨(Proximal radius and ulna,Prox.R+U)和近端桡骨(Proximal radius,Prox.R)的BMD值,并分析了其年龄分布,建立了女性前臂骨不同测量部位的峰值骨量和标准差值。同时,以问卷调查了可能影响因素。结果前臂骨各部位的BMD值均符合正态分布,可以采用均数±标准差(-x±s)的形式表示,OP的骨量诊断标准也可以用骨量峰值的算术均数降低标准差的形式建立。45岁以前女性前臂骨不同测量部位的BMD值均随年龄增加而逐步上升,但不同年龄段BMD值的差异并不显著(P>0.05),45岁以后BMD值明显下降。前臂骨不同测量部位的骨量峰值均出现在40～44岁年龄段,前臂远端桡+尺骨(Dist.R+U)、近端桡+尺骨(Prox.R+U)和近端桡骨(Prox.R)的骨量峰值及标准差分别为(0.3717±0.0423)g/cm2、(0.7958±0.0771)g/cm2和(0.7802±0.0671)g/cm2。此外,体重和怀孕次数对峰值骨量的形成有较大影响,体重过轻和怀孕次数过多均不利于峰值骨量的形成。结论建立女性前臂骨不同部位的骨量峰值和标准差,可为周围型DEXA测定开展OP研究提供基础数据,尤其是用于高危人群筛查以确定是否需进一步开展中轴骨测量或进行药物干预。

前臂骨骨密度测定诊断骨质疏松标准的研究

目的探讨女性前臂骨骨量的年龄分布规律,为建立周围骨骨密度的骨质疏松诊断标准积累数据。方法采用美国NORLAND-Stratec周围型双能X线骨矿测量仪(pDXA)测量了452名20～79岁女性健康志愿者非优势侧前臂远端桡骨和尺骨(distal radius+ulna)、近端桡骨和尺骨(proximal radius+ulna)以及近端桡骨(proximal radius)的BMD值,以问卷调查方法收集研究对象的一般情况,分析前臂骨不同测量部位BMD变化的年龄分布规律。结果前臂骨不同测量部位的BMD数据均符合正态分布规律。健康女性峰值骨密度出现在40～44岁年龄段,此后随年龄增加而下降,在50～59岁和70岁以上年龄段出现快速骨丢失,尤其是前臂远端骨丢失速率较快,55～59岁年龄段女性骨累积丢失率达25%,与DXA测定中轴骨的骨量丢失规律一致。前臂远端桡+尺骨的骨质疏松(OP)检出率较高,是围绝经期妇女OP检出的敏感部位。50～54岁年龄段女性低骨量发生率为57.6%,骨质疏松的发生率为25.8%(以低于PBM-2.0s为诊断标准)和12.1%(以低于PBM-2.5s为诊断标准);55～59岁年龄段女性低骨量发生率上升至80.9%,骨质疏松的发生率上升至50.0%和30.9%。60岁以后,低骨量和骨质疏松发生率的增加速度趋缓,但70岁以后低骨量和骨质疏松的发生率再次上升。结论前臂骨骼BMD测定可以作为骨质疏松高危人群筛查的有效工具。将前臂远端桡+尺骨为BMD主要检测部位,以低于PBM-2.0s为骨质疏松诊断标准,是筛查骨质疏松人群和评估干预措施较适宜的标准。

Hand bone mass in rheumatoid arthritis:A review of the literature

Rheumatoid arthritis(RA) is a common chronic inflammatory disease and periarticular osteoporosis or osteopenia of the inflamed hand joints is an early feature of RA Quantitative measurement of hand bone loss may be an outcome measure for the detection of joint destruction and disease progression in early RA. This systematic review examines the published literature reporting hand bone mass in patients with RA, particularly those using the dual X-ray absorptiometry(DXA) methods The majority of the studies reported that hand bone loss is associated with disease activity, functional statusand radiological progression in early RA. Quantitative measurement of hand bone mineral density by DXA may be a useful and practical outcome measure in RA and may be predictive for radiographic progression or functional status in patients with early RA.

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.

影像学技术在骨质疏松症中的应用

骨质疏松症是一种全身性骨病,其是由于多种原因导致的骨密度和骨质量下降,骨微结构破坏,造成骨脆性增加,因此患者容易发生骨折。因此,骨密度和骨质量的诊断性评估和监测对于骨质疏松症患者至关重要。目前,双能X射线吸收法(DXA)、高分辨率外周定量计算机断层扫描(HR-pQCT)、定量超声骨密度仪检测(QUS)、磁共振成像(MRI)等影像学技术可以测量骨密度和骨质量,为临床诊断和治疗提供依据。本文对影像学技术诊断骨质疏松症的应用进展进行综述,分析每种影像学技术的优势和劣势,以期为临床诊断骨质疏松症提供更优的诊断方法,达到早诊断早治疗的目的。

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.

Competitive trampolining influence trabecular bone structure,bone size,and bone strength

Background：Trampolining is a form of gymnastics that has increased in popularity over the last decade and due to its concurrence with the formative years of bone development,it may have an important impact on bone health.However,bone density,microarchitecture,and bone strength of competitive trampolinists have not been explored.Therefore,the purpose of this cross-sectional study was to investigate the relationship between trampolining participation and（1） bone density,area,and microarchitecture;and（2） estimated bone strength and the role of muscle and impact loading in young female adults.Methods：We recruited 29 female participants aged 16–29 years for this study（n=14 trampolinists;n=15 controls）.Skeletal parameters were assessed using dual X-ray absorptiometry,high-resolution peripheral quantitative computed tomography（HR-pQCT）,and finit element analysis（FEA）.Muscle strength was measured using dynamometers.Results：Trampolinists had higher bone density at the hip and spine,greater trabecular density and thicker trabeculae at the tibia,as well as larger bones at both the tibia and radius than controls（p〈0.05）.Trampolinists also had higher muscle strength than controls at the lower body with no difference between groups in the upper body.Estimates of bone strength using FEA were greater for trampolinists than controls at both the radius and tibia.Conclusion：This is the firs study to investigate bone density,area,and microarchitecture in female trampolinists using HR-p QCT.Trampolinists had greater bone density,area,microarchitecture,and estimated bone strength than controls.

Bone mass in axial spondyloarthritis:A literature review

AIM: To review the published literature reporting bone loss in patients with axial spondyloarthritis(SpA) particularly those studies using dual X-ray absorptiometry(DXA) methods. METHODS: This literature review examines the reported bone mass in patients with ax-SpA, particularly those using the DXA methods. The MEDLINE, Web of Science and Scopus databases were searched for relevant articles published between September 1992 and November 2013. Some of used search terms were ankylosing spondylitis(AS), SpA, spondyloarthropathy, bone loss, bone mass, osteopenia, bone mineraldensity, osteoporosis(OP), densitometry. Studies in which bone loss was investigated by using DXA in patients with Sp A were eligible. Each article was reviewed and the key elements were noted.RESULTS: There were 286 hits on MEDLINE, 200 on Web of Science and 476 on Scopus. After applying inclusion and exclusion criteria, we identified 55 articles in our systematic search. The sample size of the studies varied from 14 to 332 patients with SpA. The reported age range varied from 25 to 56 years in the reviewed studies. The symptom duration of patients with axS pA varied from 1.6 to 49 years. There were more males than females in these studies. Most of the recruited females were premenopausal women. Reported HLA-B27 positivity changed between 19% to 95%. The prevalence of OP and osteopenia in patients with Sp A varied from 3%-47% to 5%-88%, respectively, in the included studies. In particular, the prevalence of OP and osteopenia ranged from 2.0%-47.0% and 5.0%-78.3%, respectively, in patients with AS. There are conflicting results regarding the relationship among disease activity, acute phase response and bone mass. Some studies suggest good correlation of bone mass with disease activity and acute phase reactants.CONCLUSION: Bone loss may be determined in patients with ax Sp A at the lumbar spine or proximal femur even in the early phase of the disease and may be associated with inflammation(bone marrow edema) at the vertebral colon.

Risk assessment instruments for screening bone mineral density in a Mediterranean population

AIM To evaluate the power of six osteoporosis-screening instruments in women in a Mediterranean country.METHODS Data concerning several osteoporosis risk factors were prospectively collected from 1000 postmenopausal women aged 42-87 years who underwent dual-energy X-ray absorptiometry(DEXA) screening. Six osteoporosis risk factor screening tools were applied to this sample to evaluate their performance and choose the most appropriate tool for the study population.RESULTS The most important screening tool for osteoporosis status was the Simple Calculated Osteoporosis Risk Estimation, which had an area under the curve(AUC)of 0.678, a sensitivity of 72%, and a specificity of 72%, with a cut-off point of 20.75. The most important screening tool for osteoporosis risk was the Osteoporosis Self-assessment Tool, which had an AUC of 0.643, a sensitivity of 77%, and a specificity of 46%,with a cut-off point of-2.9.CONCLUSION Some commonly used clinical risk instruments demonstrate high sensitivity for distinguishing individuals with DEXA-ascertained osteoporosis or reduced bone mineral density.

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.

晋城地区健康人群前臂骨峰值骨量的建立

目的：建立晋城地区健康人群前臂骨密度（ BMD）的峰值骨量和标准差值，为开展周围型双能X线骨密度仪测定及骨质疏松症研究提供基础数据。方法采用韩国产双能X线骨矿测量仪（ EXA－3000）对晋城地区1400例21～55岁的健康体检人群进行左侧前臂骨密度测定，进行非优势侧（左侧）前臂远端尺桡骨的BMD值测定，并分析其年龄分布，建立晋城地区健康人群前臂远端骨密度的峰值骨量和标准差值。骨质疏松的骨量诊断以骨量峰值的均数＆#177;标准差的形式建立，均数的计算采用三次方回归方程模型进行拟合。结果男、女性前臂骨的BMD值均符合正态分布，可采用均数＆#177;标准差（ xˉ＆#177;s）的形式表示。40岁以前男、女性前臂骨的BMD值均随年龄增加而逐步上升，且各年龄段BMD值的差异有统计学意义（P＜0．05）。45岁以后男、女性前臂骨的BMD值开始下降，且50岁以后下降明显（ P＜0．05）。男、女性前臂骨的骨量峰值均出现在41～45岁年龄段。男、女性前臂远端尺桡骨的骨量峰值及标准差分别为（0．5682＆#177;0．0647）g／cm2、（0．4209＆#177;0．0689）g／cm2。结论建立了晋城地区健康人群男、女性前臂骨的骨量峰值和标准差，为周围型双能X线骨密度仪测定并开展骨质疏松症的研究提供基础数据，尤其是用于高危人群筛查，以便确定是否需要进一步开展中轴骨测量或进行药物治疗。

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.

Assessment of bone marrow changes in postmenopausal women with varying bone densities： magnetic resonance spectroscopy and diffusion magnetic resonance imaging

Background Recent studies suggest that bone marrow adipose tissue might play a role in the pathogenesis of osteoporosis. There are inconsistent findings on the relationship among marrow fat content, bone mineral density and apparent diffusion coefficient （ADC）. This study aimed to prospectively explore the efficacy of MR spectroscopy （MRS） and diffusion-weighted MR imaging （DWl） in detecting vertebral marrow changes in postmenopausal women with varying bone densities. Methods Both MRS and DWl of the lumber spine were performed in 102 postmenopausal women （mean age, （67.3±6.5） years; range, 55-83 years）, who underwent dual X-ray absorptiometry. Marrow fat content and ADC were compared and correlated among three groups： 24 with normal bone density, 31 with osteopenia and 47 with osteoporosis. Results Vertebral marrow fat content was significantly increased in the osteoporotic group （（65.60±7.68）%, P 〈0.001） and the osteopenic group （（57.68±6.45）%, P 〈0.001）, when compared with the normal bone density group （（51.67±3.27）%）. ADC values were significantly decreased in the osteoporotic group （（0.39±0.03）×10^-3mm^2/s, P 〈0.001） and in the osteopenic group （（0.42±0.02）×10^-3mm^2/s, P 〈0.001）, when compared with the normal bone density group （（0.47±0.03）×10^-3mm^2/s）. The marrow fat content negatively correlated with both bone density （r=-0.731, P 〈0.001） and marrow ADC （r=-0.572, P 〈0.001）. The bone density positively correlated with the ADC values （r=0.802, P 〈0.001）. Conclusions Postmenopausal women experience a corresponding increase in vertebral marrow fat content as the bone density decreases. Marrow fat content and ADC correlate to the bone density. MRS and DWl may indirectly assess the early bone marrow changes in postmenopausal women.