Influence of stocking density on growth, body composition and energy budget of Atlantic salmon Salmo salar L. in recirculating aquaculture systems

Atlantic salmon Salmo salar were reared at four stocking densities--high density D1 （final density -39 kg/m^3）, medium densities DE （-29 kg/m^3） and D3 （~19 kg/m^3）, and low density D4 （-12 kg/m^3）- for 40 days to investigate the effect of stocking density on their growth performance, body composition and energy budgets. Stocking density did not significantly affect specific growth rate in terms of weight （SGRw） but did affect specific growth rate in terms of energy （SGRe）. Stocking density significantly influenced the ration level （RLw and RLe）, feed conversion ratio （FCRw and FCRe） and apparent digestibility rate （ADR）. Ration level and FCRw tended to increase with increasing density. Fish at the highest density D~ and lowest density D4 showed lower FCRe and higher ADR than at medium densities. Stocking density significantly affected protein and energy contents of the body but did not affect its moisture, lipid, or ash contents. The expenditure of energy for metabolism in the low-density and high-density groups was lower than that in the medium-density groups. Stocking density affected energy utilization from the feces but had no effect on excretion rate. The greater energy allocation to growth at high density and low density may be attributed to reduced metabolic rate and increased apparent digestibility rate. These findings provide information that will assist selection of suitable stocking densities in the Atlantic-salmon-farming industry.

Dosimetric Impact of Tumor Position and Lung Density Variations in Lung Stereotactic Body Radiotherapy

Purpose of this study was to evaluate the variation of the dose to gross tumor volume (GTV) related to tumor position and lung density for lung stereotactic body radiotherapy (SBRT) using a virtual phantom. The density of the equivalent lung surrounding the GTV (10 mm diameter) was defined as 0.10, 0.15, 0.25, 0.35, and 0.45 g/cm3. A planning target volume (PTV) was generated by adding a uniform 8 mm margin to the internal target volume (ITV). We defined that the 99% of the GTV should be covered by 100% of the prescribed dose using Monte Carlo (MC) calculation. The GTV structure was replicated from ITV to the PTV periphery at 1 mm intervals. Planned dose to the GTV was defined as the predicted dose in the replicated GTV structure. Simulated dose to the GTV was defined as the calculated dose in the replicated GTV structure taking into account the tumor position error. D99 of the planned dose to the GTV at the 8 mm shift position was 78.1%, 81.6%, 87.3%, 91.4% and 94.4% at equivalent lung densities of 0.10, 0.15, 0.25, 0.35, and 0.45 g/cm3, respectively. D99 of the simulated dose to the GTV at the 8 mm shift position was 96.9%, 95.3%, 94.2%, 95.1 % and 96.3% at equivalent lung densities of 0.10, 0.15, 0.25, 0.35, and 0.45 g/cm3, respectively. Planned dose to GTV is strongly dependent on lung density and tumor position errors, while simulated dose to GTV does not show any significant dependence.

Bone mineral density in Iranian patients: Effects of age, sex, and body mass index

Introduction: Osteoporosis is a multifactorial skeletal disease that is characterized by reduced bone mineral density (BMD). BMD values depend on several factors such as age, sex and age at menopause. The purpose of this study was to determine the prevalence and changes in bone mineral density in Iranian patients. Methods: Three hundred patients were selected through random sampling technique in 2009. BMD was assessed by Norland (Excell) technique at the lumbar and femoral neck. Weight and height were measured through standard methods. A thorough history was taken from each patient. The data was analyzed using SPSS software version 13.0. P-values less than 0.05 were considered statistically significant. Results: From among the 300 studied patients, 86.6% were female. their mean age was 52.7 years. Their average body mass index (BMI) was 28.14 kg/m2. Mean T-Score at lumbar spine and femoral neck was -1.07 ±1.19 and -1.75 ± 1.33 respectively. Mean BMD value at lumbar spine and femoral neck was 0.92 ± 0.19 and 0.77 ± 0.16 respectively. The prevalence of osteoporosis at lumbar spine and femoral neck was 33.7% and 16.7, respectively. There was a significant correlation between age, BMI and BMD values (P-Value Conclusion: This study shows that ageing and low BMI are risk factors associated with bone loss. it is recommended to measure BMD and implement prevention programs for high-risk people.

Effect of Stocking Density on Growth Performance, Production Trait, Food Utilization and Body Composition, of Meagre (Argyrosomus regius)

A 10-week rearing trial was conducted in cages with average initial weight of 9.15 ± 0.2 g/fish and average initial length of 9.2 ± 0.02 cm/fish of meagre, Argyrosomus regius, to examine the effect of three stocking density on growth performances, production traits, feed utilization and body composition. Nine cages 24 m3 each (4 × 6 × 1.5 m, long, width and height) were stocked with either 1200, 3600 and 6000 fish for each cage to give a stocking rate of 50, 150, and 250 fish/m3 respectively and fish fed daily, slightly in excess of satiation to eliminate the possibility of food supply being a limiting factor to growth. The results revealed that, mean final weight (g/fish), gain in weight, SGR (%per day), feed conversion ratio, protein efficiency ratio and total feed intake (g/fish) were significantly (P ≤ 0.01) influenced. The best at the lowest stocking density, while, the total production and net production exhibited significantly the opposite trend. Harvest and production estimates increased with increasing stocking density. Fish body composition% of moisture, protein, fat and ash were significantly (P ≤ 0.01) influenced by stocking density. From the above results and the economic information of the study, it can be concluded that stocking density of 50 fish/m3 of meagre exhibited the highest net profit and would seem to be the most desirable density in the system studied.

Effect of Stocking Density on Water Quality and(Growth, Body Composition and Plasma Cortisol Content) Performance of Pen-Reared Rainbow Trout(Oncorhynchus mykiss)

The goal of the study was to examine the effect of stocking density on the water quality of culture area, as well as the growth, body composition and cortisol content of rainbow trout(Oncorhynchus mykiss). Pen-reared trout were stocked in densities of 40, 60, 80 fish individuals m^(-3)(4.6, 6.6, 8.6 kg m^(-3), SD1, SD2 and SD3 groups, respectively) for 300 days. Compared to the water from SD1 and SD2, that from SD3 exhibited significantly higher NH_4^+-N content and COD(chemical-oxygen-demand), and a significant reduction of dissolved oxygen in day 180(40.6 kg m^(-3)). Stocking density was significantly associated with body weight, standard length, VSI(viscerosomatic index), CF(condition factor) and FC(food coefficient) in group SD3, particularly in day 240 and day 300(45 or 49.3 kg m^(-3)). Increased crude fat and decreased crude protein were displayed in high density group when the density reached to 36 kg m^(-3). As a cumulative effect of density-related stress, VSI, CF, FC, moisture, and crude protein content varied over time in each density group(SD1, SD2, and SD3). In summary, trout exhibited a better growth performance in low density(26.3 kg m^(-3)) than those reared in high densities(36 and 45 kg m^(-3)). The results indicate that rainbow trout(114.44 g ± 6.21 g, 19.69 cm ± 0.31 cm) initially stocked in 6.6 or 8.6 kg m^(-3) should be lightened to less than 36 kg m^(-3) after an intensive rearing for 240 days.

Quantitative Evaluation of Fat Composition in Lumbar Vertebral Body and Paraspinal Muscle by Proton Density Fat Fraction with MRI

Purpose: Bone marrow and muscle adiposity have been considered to correlate with osteoporosis and Sarcopenia. Proton Density Fat Fraction (PDFF) can be measured by Magnetic Resonance Imaging (MRI). The purpose of the present study was to measure PDFF in the lumbar spine, paraspinal muscle and subcutaneous fat tissue. Methods: Participants were comprised of 30 patients (18 males, 12 females;age range, 14 - 87 years) who underwent MRI due to low back symptoms. PDFFs for the body of the fourth lumbar vertebra (L4), paraspinal muscle, and subcutaneous fat were measured. Results: PDFFs of the vertebral body and subcutaneous fat were significantly higher than that of paraspinal muscle (p < 0.001). PDFF was significantly higher for subcutaneous fat than for the vertebral body (p < 0.001). Although no significant differences in PDFF of the vertebral body, paraspinal muscle, and subcutaneous fat between females and males, PDFFs of the vertebral body and paraspinal muscle were significantly higher in older subjects (>63 years) than in younger subjects (Conclusions: PDFF of the vertebral body was significantly higher than that of paraspinal muscle. PDFFs of the vertebral body and paraspinal muscle were significantly lower in younger subjects than in older subjects.

Reduced one-body density matrix of Tonks-Girardeau gas at finite temperature

With thermal Bose–Fermi mapping method, we investigate the Tonks–Girardeau gas at finite temperature. It is shown that at low temperature, the Tonks gas displays the Fermi-like density profiles, and with the increase in temperature, the Tonks gas distributes in wider region. The reduced one-body density matrix is diagonal dominant in the whole temperature region, and the off-diagonal elements shall vanish rapidly with the deviation from the diagonal part at high temperature.

利用DXA评估系统性红斑狼疮患者中肌少症的现患率

目的评估系统性红斑狼疮(systemic lupus erythematosus,SLE)患者中肌少症的现患率,分析SLE共病肌少症患者的体成分变化,探讨SLE患者肌少症发生的危险因素。方法共纳入114例SLE患者(病例组)和114例健康对照者(对照组)。采用双能X线吸收法(dual energy X-ray absorptiometry,DXA)测量两组的肌肉质量,通过握力和步速分别评估患者的肌力和体能。根据欧洲老年人肌少症工作组及亚洲肌少症工作组诊断标准对SLE患者进行肌少症诊断及分期,将SLE患者分为肌少症组及非肌少症组,比较组间患者的体成分及骨密度等指标的差异,分析SLE患者共病肌少症的影响因素。结果SLE患者的平均病程为(79.6±72.8)个月。45.6%(n=52)的SLE患者共病肌少症,其中22.8%(n=26)的患者为肌少症前期,16.7%(n=19)的患者为肌少症期,6.1%(n=7)的患者为严重肌少症期。肌少症组患者的体重、体质指数、脂肪质量指数、全身瘦组织含量、瘦质量指数、全身去脂体重、去脂体重指数均低于非肌少症组和对照组。肌少症组的骨矿物质含量、腰椎和股骨骨密度明显低于对照组。多因素回归分析显示,体质指数(OR=0.61,P<0.001,95%CI:0.49~0.75)和职业劳动强度(OR=2.0,P=0.009,95%CI:1.19~3.34)是SLE患者共病肌少症的影响因素。结论SLE患者中约半数共病肌少症,共病肌少症SLE患者的脂肪、肌肉含量和重要部位骨密度下降,其中体质指数和职业劳动强度是SLE患者出现肌少症的影响因素。

身体质量指数联合三酰甘油与高密度脂蛋白胆固醇比值预测2型糖尿病风险

目的利用体检指标中身体质量指数(BMI)和三酰甘油与高密度脂蛋白胆固醇比值(triglyceride to high-density lipoprotein cholesterol,TG/HDL-C)联合预测2型糖尿病(type 2 diabetes mellitus,T2DM)发病风险。方法基于瑞慈医疗集团2010—2016年体检人群的数据库,通过Cox比例风险模型观测不同BMI的人群基线TG/HDL-C对随访期间T2DM风险的影响,并分析TG/HDL-C与BMI是否存在交互作用。结果在随访期间,13685例研究对象中共有315例最终诊断为T2DM。以BMI=24 kg/m^(2)为界,将所有研究对象分成两个亚组。BMI<24 kg/m^(2)的亚组共有8238例研究对象,96例在随访结束时患T2DM,对潜在的混杂因素进行调整后,升高的TG/HDL-C导致T2DM事件的风险较高[HR 95%CI=1.47(1.23,1.74),P<0.001]。与最低五分位数(Q1)相比,升高的TG/HDL-C五分位数(Q2~Q5)T2DM发病率增加[HR 95%CI分别为:0.73(0.28,1.93)、2.75(1.29,5.85)、2.81(1.28,6.20)和3.91(1.51,10.11)]。BMI≥24 kg/m^(2)的亚组共有5447例研究对象,219例在随访结束时患T2DM。在两个亚组中,随着TG/HDL-C的增加,T2DM患病风险均呈非线性增加,这一变化在BMI<24 kg/m^(2)的亚组更为明显。绘制两个亚组TG/HDLC与3年和5年T2DM发病的ROC曲线,在BMI<24 kg/m^(2)的亚组中,ROC曲线下面积分别为0.72和0.77。在BMI≥24 kg/m^(2)的亚组中,ROC曲线下面积则分别为0.55和0.57。结论在BMI<24 kg/m^(2)的人群中,TG/HDL-C的升高提示T2DM患病风险显著增加。

绝经后2型糖尿病患者BMI、腰围与骨密度的相关性及其骨密度的影响因素

目的:探讨绝经后2型糖尿病(T2DM)患者BMI、腰围与骨密度的相关性及其骨密度的影响因素。方法:选取我院内分泌科2022年11月至2024年2月收治的130例绝经后T2DM患者为研究对象,根据BMI分级标准将患者分为肥胖组、超重组、正常组;根据腰围大小分为腹型肥胖组及腰围正常组。比较不同BMI及腰围组间临床资料及骨密度差异,研究BMI、腰围与骨密度的相关性,分析骨密度的影响因素。结果:BMI与腰围、体重及各部位骨密度均呈正相关(P<0.05)。腰围与年龄、体重及各部位骨密度均呈正相关(P<0.05)。多元线性回归分析显示,仅体重是各部位骨密度的影响因素(P<0.05)。结论:绝经后T2DM患者BMI及腰围与骨密度呈正相关,其骨密度受体重的影响,体重低者,骨密度也低,故T2DM患者在绝经后需避免体重过轻。

疏松砂岩多层气藏钻井难点及优化对策

涩北气田是典型的疏松砂岩气藏,具有纵向气层多、储层疏松非均质性强、敏感性矿物多等地质特征。利用大量的气藏地质、动态监测和钻录测资料,剖析钻井施工中存在的问题和技术难点,开展优化对策研究。结果表明:1)储层疏松、薄互层多、矿化度高和开发后期纵向压力系统紊乱是影响优快钻井施工的主要因素;2)针对钻井施工中井控风险大、井身结构确定困难的问题,通过优化研究确定了不同气藏、不同深度、不同部位井的井身结构;3)针对比较突出的井漏问题,研发适宜的低伤害、能有效抑制黏土膨胀的MEG (甲基葡萄糖苷)钻井液体系;4)针对固井质量难以保证的问题,采用纳米基低密度水泥浆、工艺改进和精细施工等措施得以解决。认为,优化技术对策应用效果明显,解决了钻井技术难点,实现了疏松砂岩多层气藏快速安全钻井。

中老年男性体检人群良性前列腺增生关联因素研究

背景寻找良性前列腺增生(benign prostatic hyperplasia,BPH)发生的影响因素有助于对BPH进行早期预防。目的探讨中老年男性体检人群临床指标与前列腺体积的相关性,寻找BPH的关联因素。方法回顾性分析2021年6月—2023年6月某三甲医院体检中心行健康检查的中老年男性的资料,以前列腺总体积(total prostate volume,TPV)为分组标准,TPV>25 cm3为BPH组,TPV≤25 cm3为健康对照组,采用Spearman相关性分析和多因素Logistic回归分析与TPV相关的因素。结果共纳入6732例45~89岁中老年男性,其中BPH组3972例,健康对照组2760例。与健康对照组相比,BPH组年龄[M(IQR):56(51~60)岁vs 53(49~58)岁,P<0.001]、体质量指数(body mass index,BMI)[M(IQR):26.41(24.64~28.36)kg/m^(2) vs 25.76(24.06~27.80)kg/m^(2),P<0.001]、空腹胰岛素(insulin,INS)[M(IQR):10.67(7.27~15.53)mmol/L vs 10.25(6.90~14.93)mmol/L,P=0.005]、总前列腺特异性抗原(total prostate specific antigen,tPSA)[M(IQR):1.01(0.66~1.63)ng/L vs 0.75(0.51~1.10)ng/L,P<0.001]较高,高密度脂蛋白胆固醇(high density lipoprotein-cholesterol,HDL-C)[M(IQR):1.18(1.00~1.37)mmol/L vs 1.19(1.01~1.40)mmol/L,P=0.004]、游离前列腺特异性抗原(free prostate specific antigen,fPSA)/tPSA[M(IQR):0.31(0.23~0.41)vs 0.32(0.24~0.42),P=0.016]较低。相关性分析显示,TPV与年龄(r=0.24,P<0.001)、tPSA(r=0.33,P<0.001)、fPSA(r=0.36,P<0.001)均呈显著正相关。多因素Logistic回归分析结果显示,随着年龄(OR=1.051,95%CI:1.042~1.060,P<0.001)、BMI(OR=1.095,95%CI:1.076~1.116,P<0.001)和tPSA(OR=1.775,95%CI:1.647~1.913,P<0.001)的增长或升高,BPH的发病风险升高,但高HDL-C男性发生BPH的概率较低(OR=0.790,95%CI:0.665~0.945,P=0.009)。结论tPSA、年龄、BMI、HDL-C与前列腺增生发生有关。

升力体缝隙模型红外测热试验及分析

针对升力体缝隙模型在中国空气动力研究与发展中心的Φ0.3 m高超声速低密度风洞中开展了红外测热试验,试验马赫数12、总温668 K、总压4.731 MPa、攻角0°和35°,获取了模型的红外热图结果,并开展了相应的数值仿真分析。在此基础上,研究了选取不同帧次的红外热图进行数据处理对热流密度结果的影响,分析了缝隙干扰引起的热流密度增量。结果表明:投放后模型抖动对数据处理存在明显影响,建议在数据处理中采用模型投放稳定后(约1.2 s)的红外热图结果;“T”字型缝干扰区的热流密度增量需要引起重视,攻角35°情况下的峰值热流密度能达到无缝隙时热流密度的8倍以上;红外测热试验数据与CFD数据吻合较好,两者仅在很小的峰值干扰区域存在差异。下一步需要在CFD建模倒角处理、红外方案优化等方面开展工作。

基于定量CT分析维持性血液透析患者腰椎骨密度与体质成分的相关性

目的:采用定量CT技术(QCT),分析维持性血液透析(MHD)患者的腰椎骨密度(BMD)与体成分及其他相关指标的关系。方法:回顾性分析弋矶山医院2014年7月-2022年8月维持性血液透析患者共106例,使用QCT测量患者的L1、L2的BMD,L3中心层面的体成分信息,包括内脏脂肪(VAT)、皮下脂肪(SAT)、总脂肪(TAT)、腰3水平横断面肌肉面积(L3-SMA),腰3水平肌肉内的脂肪含量(L3-IMAT),同时记录患者的年龄、性别、透析时长及血液生化指标,采用Pearson相关分析MHD患者腰椎BMD与各指标的相关性。依据BMD测量结果,将106例MHD患者分为骨量正常组(n=61)及骨量异常组(n=45),比较两组间体成分及各个临床指标的差异,并采用多因素logistic回归分析MHD患者骨量异常的危险因素。结果:106名MHD患者中57.55%(61例)骨量正常,42.45%(45例)骨量异常,其中26.41%(28例)骨量减少,16.04%(17例)骨质疏松。骨量异常组的年龄、TC、LDL-C、P、VAT、SAT、TAT、L3-SMA及L3-IMAT均高于骨量正常组,差异具有统计学意义(P<0.05),两组间的性别、透析龄、TG、HDL-C、ALB及Ca水平差异无统计学意义(P>0.05)。MHD患者腰椎BMD与L3-SMA呈正相关(r=0.264,P<0.05),与年龄、VAT、SAT、TAT、L3-IMAT及TC呈负相关(P<0.05)。未发现MHD患者腰椎BMD与透析龄、TG、HDL-C、LDL-C、ALB、Ca及P存在相关性(P>0.05),多因素logistic回归显示高血磷、高龄及高L3-IMAT是MHD患者发生骨量异常的危险因素。结论:MHD患者腰椎BMD与体成分、年龄及TC有相关性,高血磷、高龄及高L3-IMAT是MHD患者发生骨量异常的独立危险因素。

人体成分与跟骨骨密度因果关联:一项孟德尔随机化研究

目的采用孟德尔随机化方法研究人体成分与跟骨骨密度的因果关系。方法利用全基因关联分析数据,暴露因素为全身脂肪量、全身水分量和去脂体质量,结局变量为跟骨骨密度。采用IVW法、MR-Egger法、加权中位数法、简单模式法、加权模式法进行孟德尔随机化分析,并行异质性、敏感性、多效性分析以检验结果可靠性。结果IVW法显示全身脂肪量与跟骨骨密度存在正向因果关系(β=1.10,95%CI 1.05~1.15,P<0.001),MR-Egger法、加权中位数法、加权模式法与IVW法结果一致,敏感性分析显示单核苷酸多态性无异质性和水平多效性;IVW法显示全身水分量与跟骨骨密度因果关系无统计学意义(β=0.96,95%CI 0.91~1.02,P>0.05);IVW法显示去脂体质量与跟骨骨密度之间因果关系无统计学意义(β=0.97,95%CI 0.91~1.03,P>0.05)。结论人体全身脂肪量与跟骨骨密度存在正向因果关系。

军事基础体能训练期间男性青年学员体成分状况及对称性研究

目的:研究军事基础体能训练期间男性青年学员体成分状况及对称性的变化,为日常训练提供依据。方法:对25名健康男性受试者进行为期4个月军事基础体能,采用双能X射线骨密度仪进行体成分检测。研究结果:右臂骨面积、骨矿含量、和骨密度显著高于左臂(P<0.05);左右臂脂肪含量不存在差异(P>0.05)。右臂消瘦质量,整体质量显著高于左臂(P>0.05);右臂肌肉含量和整体质量显著高于左臂(P<0.01)。但右臂脂肪百分比显著低于左臂(P<0.01)。左右下肢骨面积、骨矿含量、骨密度、脂肪含量、肌肉含量、脂肪百分比不具有显著性差异(P>0.05)。整体Z评分的分布2~-1占76.9%%,-1~-2占19.2%,<-2占3.8%。研究结论:基础体能训练期间男性学员上肢体成分肢体间存在差异,下肢体成分肢体不存在差异,整体上对称性较好,但整体Z评分处在中风险和高风险比例较高,提示存在能量可利用性低的情况。应采取有效的应对措施,预防长期不利于骨骼健康的影响。

肌少症病人超声参数与体质指数、骨密度及骨骼肌质量指数的关系

目的:探究肌少症病人超声参数与体质指数、骨密度及骨骼肌质量指数的关系。方法:选取山西医科大学第二医院2023年1月1日—2024年1月1日收治的60例肌少症病人为研究组,选取同期来院体检的50名性别、年龄匹配的健康志愿者为对照组。两组均接受超声检查,记录腓肠肌肌肉厚度、肌肉最大横截面积、肌肉硬度(收缩及舒张时杨氏模量值)及双能X线吸收法检查,记录骨密度、四肢肌肉量并计算骨骼肌质量指数及体质指数。对比两组上述指标差异,使用Logistic回归分析筛选肌少症影响因素,使用受试者工作特征(ROC)曲线分析超声参数对肌少症诊断效能,使用Pearson相关系数分析研究组超声参数与体质指数、骨密度及骨骼肌质量指数的相关性。结果:Logistic回归分析结果显示:腓肠肌肌肉厚度、肌肉最大横截面积、收缩及舒张时杨氏模量值、体质指数、骨密度及骨骼肌质量指数是肌少症的独立影响因素(P<0.05);腓肠肌肌肉厚度、肌肉最大横截面积、收缩、舒张时杨氏模量值诊断肌少症ROC曲线下面积分别为0.908,0.958,0.909,0.932;Pearson相关分析结果显示,肌少症病人腓肠肌肌肉厚度、肌肉最大横截面积、收缩及舒张时杨氏模量值与体质指数、骨密度及骨骼肌质量指数均呈正相关(P<0.05)。结论:超声参数有助于筛查诊断肌少症,超声参数、腓肠肌肌肉厚度、肌肉最大横截面积、肌肉硬度与体质指数、骨密度及骨骼肌质量指数存在明显关联。

长期军事体能训练对男性青年学员体成分、骨密度产生的影响研究

目的:研究长期军事体能训练对男性青年学员体成分、骨密度产生的影响,为日常训练提供依据。方法:选取经过短期训练21学员为对照组,经过长期训练33学员为实验组,采用双能X射线骨密度仪进行体成分检测。结果:实验组整体脂肪质量、全身脂肪百分比、肥胖指数/体重显著低于对照组(P<0.05),而腹臀比、躯干脂肪比/腿部脂肪比、躯干/四肢脂肪质量比不存在差异(P>0.05);整体消瘦质量、消瘦指数,左侧上、下肢消瘦质量比(%)、右侧上、下肢消瘦质量比(%)不具有显著性差异(P>0.05);整体骨密度、年龄匹配Z-评分不具有显著性差异(P>0.05)。结论:长期体能训练可显著降低脂肪,但对骨密度影响不大,训练方案中应增加一些成骨训练,以促进骨健康。

围绝经期及绝经后期女性人体体成分与腰椎骨密度的相关分析

目的探讨围绝经期及绝经后期女性人体体成分与腰椎骨密度(bone mineral density,BMD)之间的关系,进一步分析该人群骨量减少的影响因素。方法招募2021年10月至2024年3月于首都医科大学附属北京妇产医院内分泌科就诊的围绝经期及绝经后期女性300例为研究对象。采用定量电子计算机断层扫描技术(quantitative computed tomography,QCT)测量腰椎骨密度,根据测量结果分为骨量正常组和骨量减少组,采用肌肉功能分析仪测定所有受试者的体质量、脂肪、下肢肌肉、膝关节活动等人体成分情况,采用更年期症状全面评估量表采集所有研究对象的年龄、绝经状态及活动类型。采用单因素方差分析比较骨量正常组和骨量减少组的人体体成分之间的差异性,采用多因素Logistic回归分析探讨骨量减少的危险因素。结果300例研究对象中,围绝经期女性148例(49%),平均年龄(51.40±5.03)岁;绝经后期女性152例(51%),平均年龄(53.59±6.04)岁。绝经后期女性的骨密度低于围绝经期女性,差异有统计学意义(P<0.05)。骨量减少组118例(39%),骨量正常组182例(61%)。骨量减少组女性年龄、脂肪百分比、绝经后期占比和无锻炼占比均高于骨量正常组,差异有统计学意义(P<0.05);而下肢肌肉分布系数、下肢肌力和有锻炼占比均低于骨量正常组,差异有统计学意义(P<0.05)。Spearman相关性分析结果表明围绝经期和绝经后期女性BMD与年龄、脂肪百分比、绝经后期占比均呈显著负相关(r=-0.492、-0.125、-0.287,P<0.05),而与下肢肌肉分布系数、下肢肌力、有锻炼占比均呈显著正相关(r=0.143、0.180、0.193,P<0.05)。二元Logistic回归分析结果显示,年龄大、脂肪百分比大、下肢肌肉分布少、锻炼少是骨量减少的危险因素(P<0.05)。结论与围绝经期女性相比,绝经后期女性的腰椎骨密度明显降低,围绝经期及绝经后期女性腰椎骨密度与人体体成分及活动类型密切相关,其中年龄大、脂肪百分比大、下肢肌肉分布少、锻炼少是骨量减少的危险因素(P<0.05)。建议临床医生关注此时期女性的腰椎骨密度及人体体成分的变化,以便通过及时合理的干预措施来提高她们的生活质量,预防骨质疏松的发生。

肥胖和骨质疏松之间的关联:一项两样本双向孟德尔随机化分析

背景:多项临床研究观察表明肥胖与骨质疏松症之间存在密切关系,但肥胖与骨质疏松症之间是否存在遗传因果效应尚不清楚。目的:利用大规模全基因组关联研究的汇总数据,通过孟德尔随机化分析探究肥胖和骨质疏松之间的关联。方法:肥胖数据来自人体特征遗传调查(GIANT)和英国生物样本库(UKBB)的汇总统计数据。骨质疏松症的数据来自从骨质疏松症遗传因素联盟(GeFOS)获得的2种骨密度表型:全身骨密度和跟骨骨密度。逆方差加权法为主要分析方法,基于Egger回归的孟德尔随机化法(Mendelian randomization method based on Egger regression,MR-Egger)和加权中位数法作为补充方法来计算肥胖遗传变异与骨质疏松症之间的因果关联。采用敏感性分析来验证结果的可靠性,利用Cochran’s Q检验分析结果的异质性,利用MR-Egger截距检验分析结果的水平多效性,留一法评估合并的逆方差加权法估计值是否具有潜在影响的单核苷酸多态性。结果与结论:①肥胖对骨质疏松症的影响:除身体质量指数与前臂骨密度外,身体质量指数、腰臀比、经身体质量指数调整的腰臀比与全身骨密度、跟骨骨密度、前臂骨密度、腰椎骨密度及股骨颈骨密度两两之间呈正向因果关系;进一步Meta分析显示,肥胖会增加骨密度的风险(OR=1.08,95%CI:1.05-1.11,P<0.01);②骨质疏松症对肥胖的影响:除了前臂骨密度、腰椎骨密度作为暴露因素对肥胖有因果关系外,其他数据集均显示全身骨密度、跟骨骨密度、股骨颈骨密度与肥胖之间不呈现因果效应;进一步Meta分析显示,骨密度并不会增加肥胖的风险(OR=0.99,95%CI:0.98-1.01,P<0.01)。③结果证实:肥胖与骨质疏松之间存在因果关系,即肥胖可能是骨质疏松症的危险性因素,但未发现骨质疏松症对于肥胖的因果关联。