Prevalence and risk factors of osteoporosis detected by dual-energy X-ray absorptiometry among Chinese patients with primary biliary cholangitis

BACKGROUND Osteoporosis is an extrahepatic complication of primary biliary cholangitis(PBC)that increases the risk of fractures and mortality.However,Epidemiological studies of osteoporosis in patients with PBC in China and the Asia-Pacific region is lack.AIM To assess the prevalence and clinical characteristics of osteoporosis in Chinese patients with PBC.METHODS This retrospective analysis included consecutive patients with PBC from a tertiary care center in China who underwent bone mineral density(BMD)assessment using dual-energy X-ray absorptiometry between January 2013 and December 2021.We defined subjects with T-scores≤-2.5 in any sites(L1 to L4,femoral neck,or total hip)as having osteoporosis.Demographic,serological,clinical,and histological data were collected.Independent risk factors for osteoporosis were identified by multivariate logistic regression analysis.RESULTS A total of 268 patients with PBC[236 women(88.1%);mean age,56.7±10.6 years;163 liver biopsies(60.8%)]were included.The overall prevalence of osteoporosis in patients with PBC was 45.5%(122/268),with the prevalence of osteoporosis in women and men being 47.0%and 34.4%,respectively.The prevalence of osteoporosis in postmenopausal women was significantly higher than that in premenopausal women(56.3%vs 21.0%,P<0.001).Osteoporosis in patients with PBC is associated with age,fatigue,menopausal status,previous steroid therapy,body mass index(BMI),splenomegaly,gastroesophageal varices,ascites,Mayo risk score,histological stage,alanine aminotransferase,albumin,bilirubin,platelet and prothrombin activity.Multivariate regression analysis identified that older age,lower BMI,previous steroid therapy,higher Mayo risk score,and advanced histological stage as the main independent risk factors for osteoporosis in PBC.CONCLUSION Osteoporosis is very common in Chinese patients with PBC,allowing for prior screening of BMD in those PBC patients with older age,lower BMI,previous steroid therapy and advanced liver disease.

Association between body mass index and body fat measured by dual-energy X-ray absorptiometry (DXA) in China: a systematic review and meta-analysis

Objective:We examined the association between body mass index(BMI)and body fat percentage(BF%)measured by dual-energy X-ray absorptiometry(DXA)among adults and children in China.Methods:We searched four databases-PubMed,China National Knowledge Infrastructure,Wanfang,and Vip for studies published in the past 22 years.Meta-analysis was conducted using random-or fixed-effect models.Results:In total of 21 studies met inclusion criteria and were included in review,and 17 ot them in meta-analysis.They were conducted across China.Their sample size ranged from 62 to 5726,and participants'age ranged from 6-80 years.Meta-analysis revealed strong associations between BMI and BF% measured by DXA in adults(pooled r=0.71,95% CI:0.66 to 0.74)and children(pooled r=0.60,95% CI:0.52 to 0.68).The association was stronger in Northern China than in East China in children(β=-0.40,95%CI:-0.65 to-0.14)and in Central China in adults(β=-0.25;95% CI:-0.51 to-0.01).Urban children's BMI was strongly associated with BF%than rural(β=0.19;95%CI:0.04 to 0.35),whereas it was stronger in adults living in rural than in urban(β=-0.35;95% CI:-0.66 to-0.05).Conclusions:BMI was strongly associated with BF%measured by DXA,and the association in children and adults in China varied by residence and region.

Comparative Analysis of the Multi-Frequency Bio-impedance and Dual-energy X-ray Absorptiometry on Body Composition in Obese Subjects

To examine accuracy of body composition predicted by the Multi-Frequency Bioelectric Impedance Analysis （MF-BIA） compared with the Dual-energy X-ray Absorptiometry （DXA） in adults with obese. We measured body composition of 749 adults with obese both by the MF-BIA and DXA. The Lin＇s concordance correlation and the Bland-Altman plots were used to examine the consistency. The concordance correlation coefficient of %BF between the MF-BIA and DXA in men and women was 0.560, and 0.669, respectively. Compared with the DXA, the MF-BIA significantly underestimated %BF by 4.33% in men （P 〈 0.001）, however overestimated %BF by 0.50% in women （P 〈 0.001）. After corrected by the correction equations established in this study, the differences were significantly decreased. Therefore, the MF-BIA （TANITA MC-180） may need to be corrected in estimating body composition for adults with obese.

Reduced upper limb lean mass on dual energy X-ray absorptiometry predicts adverse outcomes in male liver transplant recipients

BACKGROUND Pre-transplant muscle wasting measured by computed tomography has been associated with adverse clinical outcomes after liver transplantation including increased rates of sepsis and hospitalisation days.Upper limb lean mass(LM)measured by dual-energy X-ray absorptiometry(DEXA)was recently identified as a novel predictor of sarcopenia-associated mortality in men waitlisted for transplantation.AIM To investigate the use of DEXA LM in predicting gender-stratified early posttransplant outcomes.METHODS Liver transplant recipients who underwent pre-transplant DEXA body composition imaging between 2002 and 2017 were included.Endpoints included posttransplant mortality and graft failure,bacterial infections,acute cellular rejection(ACR)and intensive care and total hospital length of stay.RESULTS Four hundred and sixty-nine patients met inclusion criteria of which 338 were male(72%).Median age was 55.0 years(interquartile range 47.4,59.7)and model for end-stage liver disease(MELD)score 16.Median time from assessment to transplantation was 7 mo(3.5,12).Upper limb LM was inversely associated with bacterial infections at 180 d post-transplant(hazard ratio=0.42;95%confidence interval:0.20-0.89;P=0.024)in males only.There was a negative correlation between upper limb LM and intensive care(τb=-0.090,P=0.015)and total hospital length of stay(τb=-0.10,P=0.0078)in men.In women,neither MELD nor body composition parameters were associated with post-transplant adverse outcomes or increased length of stay.Body composition parameters,MELD and age were not associated with 90-d mortality or graft failure in either gender.There were no significant predictors of early ACR.CONCLUSION Sarcopenia is an independent and potentially modifiable predictor of increased post-transplant bacterial infections and hospital length of stay in men with cirrhosis.DEXA upper limb LM provides a novel measure of muscle wasting that has prognostic value in this cohort.The lack of association in women requires further investigation.

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.

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.

Nutritional assessment in cirrhotic patients with hepatic encephalopathy

Hepatic encephalopathy(HE) is one of the worst complications of liver disease and can be greatly influenced by nutritional status. Ammonia metabolism, inflammation and muscle wasting are relevant processes in HE pathophysiology. Malnutrition worsens the prognosis in HE, requiring early assessment of nutritional status of these patients. Body composition changes induced by liver disease and limitations superimposed by HE hamper the proper accomplishment of exams in this population, but evidence is growing that assessment of muscle mass and muscle function is mandatory due to the role of skeletal muscles in ammonia metabolism. In this review, we present the pathophysiological aspects involved in HE to support further discussion about advantages and drawbacks of some methods for evaluating the nutritional status of cirrhotic patients with HE, focusing on body composition.

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.

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.

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.

Bone mineral density in lifelong trained male football players compared with young and elderly untrained men

Purpose: The purpose of the present controlled cross-sectional study was to investigate proximal femur and whole-body bone mineral density(BMD), as well as bone turnover profile, in lifelong trained elderly male football players and young elite football players compared with untrained age-matched men.Methods: One hundred and forty healthy, non-smoking men participated in the study, including lifelong trained football players(FTE, n = 35)aged 65—80 years, elite football players(FTY, n = 35) aged 18—30 years, as well as untrained age-matched elderly(UE, n = 35) and young(UY,n = 35) men. All participants underwent a regional dual-energy X-ray Absorptiometry(DXA) scan of the proximal femur and a whole-body DXA scan to determine BMD. From a resting blood sample, the bone turnover markers(BTMs) osteocalcin, carboxy-terminal type-1 collagen crosslinks(CTX-1), procollagen type-1 amino-terminal propeptide(P1NP), and sclerostin were measured.Results: FTE had 7.3%—12.9% higher(p < 0.05) BMD of the femoral neck, wards, shaft, and total proximal femur in both legs compared to UE,and 9.3%—9.7% higher(p < 0.05) BMD in femoral trochanter in both legs compared to UY. FTY had 24.3%—37.4% higher(p < 0.001) BMD in all femoral regions and total proximal femur in both legs compared to UY. The whole-body DXA scan confirmed these results, with FTE showing similar whole-body BMD and 7.9% higher(p < 0.05) leg BMD compared to UY, and with FTY having 9.6% higher(p < 0.001) wholebody BMD and 18.2% higher(p < 0.001) leg BMD compared to UY. The plasma concentration of osteocalcin, CTX-1, and P1NP were 29%,53%, and 52% higher(p < 0.01), respectively, in FTY compared to UY.Conclusion: BMD of the proximal femur and whole-body BMD are markedly higher in lifelong trained male football players aged 65—80 years and young elite football players aged 18—30 years compared to age-matched untrained men. Elderly football players even show higher BMD in femoral trochanter and leg BMD than untrained young despite an age difference of 47 years.

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.

Adiposity and spinal cord injury

The drastic changes in body composition following spinal cord injury(SCI) have been shown to play a significant role in cardiovascular and metabolic health. The pattern of storage and distribution of different types of adipose tissue may impact metabolic health variables similar to carbohydrate, lipid and bone metabolism. The use of magnetic resonance imaging provides insights on the interplay among different regional adipose tissue compartments and their role in developing chronic diseases. Regional adipose tissue can be either distributed centrally or peripherally into subcutaneous and ectopic sites. The primary ectopic adipose tissue sites are visceral, intramuscular and bone marrow. Dysfunction in the central nervous system following SCI impacts the pattern of distribution of adiposity especially between tetraplegia and paraplegia. The current editorial is focused primarily on introducing different types of adipose tissue and establishing scientific basis to develop appropriate dietary, rehabilitation or pharmaceutical interventions to manage the negative consequences of increasing adiposity after SCI. We have also summarized the clinical implications and future recommendations relevant to study adiposity after SCI.

Study on the Deactivation Kinetics of Pd(PPh_3)_2Cl_2 in the Monocarbonylation of Benzyl Chloride

The deactivation kinetics of Pd(PPh3)2Cl2 in the monocarbonylation of benzyl chloride to synthesize phenylacetic acid is studied in this paper. Solid 1-(2-pyridylazo)-2-naphthol (PAN) is used as the colouring agent, and the concentration of Pd(PPh3)2Cl2 in the system is measured through absorptiometry. The result shows that the optimum condition of the chromogenic reaction between Pd2+ and PAN is: 0.5 ml of 0.04% PAN added to 10 ml of Pd2+ solution (1.0×10-6-2.0×10-5 mol/L), and heated in a constant temperature water bath at 40℃ for about 30 min, with pH of the solution being about 3.0. The molar coefficient of absorption is 1.384×104 L/(mol·cm); the orders of the hydrolytic reaction to the concentration of Pd(PPh3)2Cl2, PPh3, phenylacetic acid and NaOH are 0.5, minus 0.8, 2 and 1.2, respectively. The activation energy (E) of the hydrolytic reaction is 75.59 kJ/mol, and the pre-exponential factor is 1.68×1012.

Deep Learning in DXA Image Segmentation

Many existing techniques to acquire dual-energy X-ray absorptiometry(DXA)images are unable to accurately distinguish between bone and soft tissue.For the most part,this failure stems from bone shape variability,noise and low contrast in DXA images,inconsistent X-ray beam penetration producing shadowing effects,and person-to-person variations.This work explores the feasibility of using state-of-the-art deep learning semantic segmentation models,fully convolutional networks(FCNs),SegNet,and U-Net to distinguish femur bone from soft tissue.We investigated the performance of deep learning algorithms with reference to some of our previously applied conventional image segmentation techniques(i.e.,a decision-tree-based method using a pixel label decision tree[PLDT]and another method using Otsu’s thresholding)for femur DXA images,and we measured accuracy based on the average Jaccard index,sensitivity,and specificity.Deep learning models using SegNet,U-Net,and an FCN achieved average segmentation accuracies of 95.8%,95.1%,and 97.6%,respectively,compared to PLDT(91.4%)and Otsu’s thresholding(72.6%).Thus we conclude that an FCN outperforms other deep learning and conventional techniques when segmenting femur bone from soft tissue in DXA images.Accurate femur segmentation improves bone mineral density computation,which in turn enhances the diagnosing of osteoporosis.

Leisure-time physical activity,anthropometrics,and body composition as predictors of quality of life domains after spinal cord injury:an exploratory cross-sectional study

The objective of the current work was to examine the relationships between quality of life(QOL)domains in persons with spinal cord injury(SCI)and their levels of weekly leisure-time physical activity(LTPA),anthropometric variables,and body composition variables.This exploratory cross-sectional study consisted of baseline data collected as part of a randomized clinical trial at a VA Medical Center and SCI center.A convenience sample of 36 community-dwelling persons with SCI participated in the current study.Outcome measures included the World Health Organization Quality of Life Short Form(WHOQOL-BREF),Leisure-Time Physical Activity Questionnaire for People with Spinal Cord Injury(LTPAQ-SCI),anthropomorphic measures(waist,hip,and abdominal circumference),and dual-energy x-ray absorptiometry(DXA)to quantify regional and total body composition.Multiple regression models suggested that engagement in LTPA accounted for 35.7%of the variance in physical health QOL,33.5%in psychological QOL,14.2%in social relationships QOL,and 38.2%in environmental QOL.Anthropometric measures accounted for 11.3%,3.1%,12.0%,and 6.7%of the variance in these QOL indices,respectively,and DXA indices accounted for 18.7%,17.5%,27.4%,and 21.9%.Within these models,the number of minutes of heavy LTPA per day uniquely predicted physical health QOL,the number of mild LTPA days per week uniquely predicted psychological QOL,and the amount of mild LTPA per day uniquely predicted environmental QOL.Bivariate analyses also suggested that android and trunk fat,as well as supine waist and abdominal circumferences,were positively associated with social relationships QOL.Encouraging individuals with SCI to engage in LTPA may robustly enhance multiple aspects of QOL while reducing the risk for cardiovascular and metabolic morbidities associated with SCI.Moreover,this may lead to a further understanding of how QOL may impact longitudinal intervention trials.The study protocol and procedures were reviewed and approved by the McGuire VA Research Institutional Review Board(IRB#02152,approval date August 9,2015;IRB#02375,approval date May 2,2018).

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.