Regional and total body bone mineral content,bone mineral density,and total body tissue composition in children 8–16 years of age

Summary Normative values for total body bone mineral content (TBBM) and total body bone mineral density (TBMD) were derived from measurements on 234 children 8–16 years of age. In addition, bone mineral content (BMC) and bone mineral density (BMD) values for selected regions of interest and soft tissue (bone free lean and fat) for the total body are presented. Bone mineral and soft tissue values were determined by dual energy X-ray absorptiometry (DXA) using a Hologic QDR-2000 in the array mode. Results of a stepwise multiple regression analysis revealed a significant correlation between bone-free lean tissue (BFLT) and BMD (r² = 0.80) in girls. Adding age to the equation accounted for an additional 2% of the variance (P < 0.05) and height accounted for another 1% of the variance (P < 0.05). Body weight and fat tissue (FT) did not account for any additional variance. In boys BFLT correlated significantly with BMD (r² = 0.75;P < 0.05); none of the other predictor variables accounted for additional variance. No significant differences were found in TBBM or TBMD between boys and girls at any age. There was a significant overall gender effect for only three regions of interest. Boys had greater BMC in the head region and had greater BMD in the upper limbs, but post hoc analysis revealed no significant differences for any specific age groups. Girls had greater overall BMD in the pelvis, but this difference was only significant at the 15–6-year age group. The changes in BFLT and FT over the age ranges were consistent with the growth literature.The normative values can be applied to the assessment of children and adolescents with health problems that may impact on the skeleton as well as to research studies investigating bone mineral development in children.     

体重体成分与骨密度的关系

为了研究体成分与骨密度（ＢＭＤ）之间的关系，因体重与ＢＭＤ显著相关，体成分各个组成相加等于体重，而体成分与ＢＭＤ的关系仍不清楚。方法随机选取２０６名１６～５２岁健康的男女性汉族人，用双能Ｘ射线吸收法（ＤＸＡ）测量ＢＭＤ与体成分，进行ＢＭＤ与体重，体成分的多元线性回归分析。结果体重，瘦组织（ＬＴＭ）与男女性的ＢＭＤ显著正相关，脂肪组织（ＦＴＭ）仅对女性全身，腰椎ＢＭＤ起显著性作用。结论影响男女性ＢＭＤ的体成分中，ＬＴＭ是主要因素，ＦＴＭ仅对女性ＢＭＤ有影响。本文较全面地研究了体成分与ＢＭＤ的关系。     

Bone density,body composition and menstrual history of sedentary female former gymnasts,aged 20–32 years

Few studies have examined the effects of retirement from sports involving regular, high impact and weight bearing activity on bone mass. This cross-sectional study compared total body and regional areal bone mineral density (aBMD, g/cm²) within female former gymnasts and women who had never participated in structured sport or exercise, and explored relations between aBMD of these former gymnasts and their duration of retirement. Eighteen sedentary female former gymnasts (GYM) and 18 sedentary controls (CON) were recruited. GYM displayed a broad range of duration of retirement (3–12 years) and a wide age range (20–32 years). GYM and CON were paired individually to match for age, body mass and stature. GYM had commenced training at least 3 years pre-menarche and had trained post-menarche for 2 or more years. They had trained continuously for 5–12 years and had retired between age 14 and 22 years. Measurements of aBMD and body composition were made using dual energy X-ray absorptiometry (DXA). Group mean values of physical and skeletal characteristics were compared using paired t-tests. Linear regression was used to explore possible relations of aBMD within GYM to duration of retirement. GYM displayed a higher aBMD than CON at all measurement sites, which ranged in magnitude from 6% for the total body (P=0.004), to 11% for the total femur (P=0.006). Elevations of aBMD within GYM equated to T-scores ranging from +0.8 (arms) to +1.7 (legs). There were no differences in body composition or age of menarche between groups, although 11 of 18 GYM reported a history of irregular menses. There was no significant decline of aBMD with increasing duration of retirement in GYM. The results suggested that an elevated bone mass in female former gymnasts was retained during early adulthood, in spite of a cessation of training for up to 12 years.     

Hypercalciuria in ex-preterm children, aged 7-8 years

In a previous study, 8 of 28 ex-preterm infants, aged 4–5 years, had increased urinary calcium excretion. The aim of this study was to confirm this finding and to determine if raised urinary calcium excretion is associated with reduced bone mineralisation. Forty-six ex-preterm children, aged 7–9 years, and 40 age- and sex-matched controls were recruited. The calcium excretion measured from 3 separate 24-h urine collections was recorded and a dietary assessment made from a diary record. Data were retrieved from the neonatal case notes and included aminoglycoside usage. Dual energy X-ray absorptiometry was used to measure bone mineral content and bone mineral density (BMD) in all children. The mean maximum 24-h urinary calcium was significantly higher in the preterm group than the term group (P=0.01). Increased calcium excretion was associated with raised neonatal aminoglycoside levels (P=0.0013). Height standard deviation score and hip BMD were significantly lower in the 21 preterm children with a 24-h urinary calcium above 4 mg/kg per day than term controls (P=0.04 and P=0.004, respectively). Urinary calcium excretion had a negative relationship with hip BMD in the preterm group (P=0.004). This difference in BMD was not observed in the 25 preterm children with normocalciuria. In the 10 preterm girls with hypercalciuria, hip BMD was lower than in control females (P=0.01). This difference in hip BMD between the 11 preterm boys with hypercalciuria and term boys was not significant (P=0.05). In conclusion, preterm children are shorter and have a lower hip BMD than those with normocalciuria. Further prospective studies are required to assess this risk and its influence on subsequent impaired bone mineralisation. Received: 28 September 2000 / Revised: 2 April 2001 / Accepted: 2 April 2001     

Correlations between leptin, body composition, bone mineral density, and bone metabolism in kidney transplant recipients

INTRODUCTION: In kidney transplant recipients leptin levels are often elevated and bone mineral density (BMD) decreased. However, to date there are no about correlations between leptin and BMD in this population. It has been suggested that leptin is a predictor of BMD in postmenopausal women. Moreover, leptin acts as a marker of fat stores. We examined the relationships between leptinemia, some markers of nutritional status, BMD, and bone metabolism in kidney transplant recipients. We also assessed whether leptin was a significant and independent predictor of BMD in this population. METHODS: BMD and fat content (global, percentage, trunk) were measured using dual-energy X-ray absorptiometry in 27 kidney allograft recipients. Markers of bone turnover and leptin were studied using commercially available kits. RESULTS: Leptin correlated with the percentage of body fat, trunk fat, lean body mass, serum creatinine, and urea. Insulin growth factor binding protein 1 was negatively related to waist-hip ratio and global and trunk fat, whereas BMD of the lumbar spine was correlated with the daily dose of prednisone, azathioprine, cyclosporine trough levels, serum calcium, as well as osteoprotegerin level. CONCLUSIONS: Leptin levels are associated with graft function and body fat in kidney allograft recipients. Leptin is not related to nutritional status, BMD, or bone metabolism in kidney allograft recipients, but is associated with the current dosage of immunosuppressants and the serum calcium.     

Weight,body composition,and bone density in postmenopausal women

Associations of body weight and body composition with bone mineral density (BMD) were examined in 261 postmenopausal women. BMD, body fat, and body nonfat soft tissue (NFST) were measured by dual-energy X-ray absorptiometry (DXA). A height-independent BMD variable (HIBMD) was calculated to correct for differences among individuals in bone thickness, a dimension that is ignored by DXA scanners. HIBMD was calculated as BMD divided by height at the spine and femoral neck, and BMD divided by the square root of height at the total body. Weight, fat, and nonfat soft tissue were all positively correlated with both BMD and HIBMD, but the magnitudes of regression and correlation coefficients were lower when HIBMD was the dependent variable. The weight-independent associations of body composition with HIBMD were examined by including weight and % NFST together in linear models. In these analyses, weight was positively associated with HIBMD at all three skeletal sites (r=0.22–0.26, P<0.05), % NFST was not associated with HIBMD at the spine or femoral neck (r=0.01–0.02), and there was only a weak inverse correlation of % NFST with total body BMD (r=-0.12, P<0.05). These findings are consistent with those of previous studies demonstrating positive associations between body weight and BMD. In addition, they demonstrate that once bone thickness and body weight are taken into account, body composition appears to have little if any independent effect on bone density at the skeletal sites measured. This finding is consistent with the hypothesis that the protective effect of body weight is brought about predominantly through its mechanical force on the skeleton.     

正常女性的身体组成成份与骨密度的关系

目的 研究体内的体脂含量(fat mass)和非脂质含量(lean mass)对正常女性骨密度的影响程度.方法 414例绝经前和1020例绝经后妇女参加本研究,采用美国Hologic Delphi A 双能X线骨密度仪测定腰椎、左股骨骨密度和全身骨密度以及fat mass和lean mass.结果 ①各部位脂肪含量和肌肉含量呈显著负相关;②在青年女性和绝经前妇女中,Lean mass是决定腰椎、股骨近端各部位和全身骨密度的主要因素;③在绝经后妇女中,fat mass起主要作用.结论 Fat mass和lean mass对骨密度起不同的作用.     

正常女性的身体组成成份与骨密度的关系

目的 研究体内的体脂含量(fat mass)和非脂质含量(lean mass)对正常女性骨密度的影响程度.方法 414例绝经前和1020例绝经后妇女参加本研究,采用美国Hologic Delphi A 双能X线骨密度仪测定腰椎、左股骨骨密度和全身骨密度以及fat mass和lean mass.结果 ①各部位脂肪含量和肌肉含量呈显著负相关;②在青年女性和绝经前妇女中,Lean mass是决定腰椎、股骨近端各部位和全身骨密度的主要因素;③在绝经后妇女中,fat mass起主要作用.结论 Fat mass和lean mass对骨密度起不同的作用.     

老年男性骨密度与身体成分相关性的研究

目的分析老年男性骨密度(bone mineral density,BMD)与身体成分的关系。方法记录166名80~94岁老年男性的年龄、身高、体重、BMI,检测L1-4、左侧股骨颈、Wards三角、大粗隆、左侧股骨上端的BMD及总肌肉含量(total lean mass,TLM)和总脂肪含量(total fat mass,TFM),根据BMD水平将受试者分为骨量正常组(n=50)、骨量低下组(n=91)和骨质疏松组(n=25)。结果 (1)骨量低下组及骨质疏松组的BMD均明显低于正常骨量组(P0.01),骨质疏松组又明显低于骨量低下组(P0.01);(2)骨质疏松组体重、TLM、TFM及BMI均明显低于正常骨量组(P0.01);(3)TLM与左侧股骨颈、Wards三角、左侧股骨上端的BMD相关系数分别为0.227、0.203及0.193(P0.05),TFM与腰椎1-4、左侧股骨颈、Wards三角、大粗隆、左侧股骨上端的BMD相关系数为0.269、0.222、0.206、0.246及0.242(P0.01)。结论大部分老年男性BMD与年龄呈显著负相关;与体重、BMI及TFM、TLM呈显著正相关,适当的运动和适度的肥胖,增强肌肉量和维持一定的脂肪量,保持健康的体重,可能有利于预防老年性骨质疏松症。     

Relationships between sex hormone levels in men over 50 years of age and body composition, bone quality, and quality of life

ObjetiveTo determine whether there was a relationship between sex hormone levels and body composition, bone health, and health-related quality of life in men over 50 years of age.Material and methodsTransversal study carried out in 230 Spanish male outpatients. Body composition was studied using direct anthropometric measures: height, weight, waistline circumference, dominant arm circumference, tricipital skinfold, dominant arm skinfold, subscapular skinfold. Calculated anthropometric parameters were obtained. Quantitative ultrasound measurements of the calcaneus were performed and bone turnover markers were determined (N-telopeptides urinary excretion and calcium/creatinine urinary rate). Quality of life was studied using the short form 36 questionnaire (SF-36). Blood tests included total testosterone, sex hormone binding-globulin, calculated free testosterone (cFT), dehydroepiandrosterone sulphate (DHEA-S), androstenedione, 17-β-estradiol and gonadotrophins.ResultscFT was associated with increased muscle and to decreased in fat content, even after adjusting for age (p < 0.05). Bone density was only related to estradiol and its bioavailable fraction (p < 0.05). DHEA-S and cFT were related (p < 0.05) to some SF-36 subscales.ConclusionscFT level is most associated with body changes that accompany aging. Androgen levels are not related to bone density. Decline in cFT and DHEA-s levels might be related to decreased quality of life.     

Comparisons of body size, composition, and whole body bone mass between North American and South African children.

We compared whole body BMC of 811 black, white, and mixed ancestral origin children from Detroit, MI; Johannesburg, South Africa; and Cape Town, South Africa. Our findings support the role of genetic and environmental influences in the determination of bone mass in prepubertal children. INTRODUCTION: Higher bone mass and lower fracture rates have been shown in black compared with white children and adults in North America. MATERIALS AND METHODS: We compared whole body BMC (WBBMC), whole body fat mass (WBFM), and whole body fat free soft tissue (WBFFST) data between three ethnic groups of children from Detroit, MI (n = 181 white, USW; n = 230 black, USB), Johannesburg, South Africa (n = 73 white, SAW; n = 263 black, SAB), and Cape Town, South Africa (n = 64 mixed ancestral origin, SAM). RESULTS: SAB and SAW groups were slightly older than USW and USB groups (9.5 +/- 0.3 versus 9.3 +/- 0.1 yr); however, USB and USW boys were significantly taller, were heavier, and had a higher BMI than SAM and SAB boys. USB girls were significantly taller than SAB girls and heavier than SAB and SAM girls. In South Africa and the United States, black children had a significantly higher WBBMC than white children, after adjusting for selected best predictors. After adjusting for age, weight, and height, WBBMC was significantly higher in the SAB and SAW boys than in USW and USB and in the SAM group compared with the USW and USB groups. WBFFST and WBFM made significant contributions to a best linear model for log(WBBMC), together with age, height, and ethnicity. The best model accounted for 79% of the WBBMC variance. When included separately in the model, the model containing WBFFST accounted for 76%, and the model containing WBFM accounted for 70%, of the variance in WBBMC. CONCLUSIONS: WBBMC is lower in children of European ancestry compared with African ancestry, irrespective of geographical location; however, South African children have significantly higher WBBMC compared with USB and USW groups, thereby acknowledging the possible contribution of environmental factors. Reasons for the significantly higher WBBMC in the children of mixed ancestral origin compared with the other groups need to be studied further.     

绝经妇女绝经后年限及年龄与骨量丢失率关系

目的探讨绝经后妇女的绝经年限及年龄与骨量丢失率关系。方法1999年5月-2003年4月,对已绝经的1467例妇女进行骨密度测定,并对不同绝经后妇女年龄、绝经年限与骨密度关系进行分析。结果1467例绝经后妇女中,以绝经1-5年期间和40-45岁时各部位骨密度作为基线值比较,绝经已超过35年或年龄大于80岁时各部位骨密度最低。其中按绝经年限腰椎、股骨颈、大转子、华氏三角区在绝经后6-10年间和超过35年时丢失速度最快;按年龄腰椎在56-65岁、股骨颈和华氏三角区在61-65岁、大转子在71-75岁及各部位大于80岁时丢失速度最快。结论绝经后妇女绝经年限及年龄增加,腰椎、股骨颈、粗隆、华氏三角区骨量丢失增加。绝经年限及年龄不同,各部位丢失速度不同。     

中年妇女年龄、月经状态、体重指数及体力活动对机体组成及脂肪分布的影响

目的 研究中年妇女年龄、月经状态、体重指数(body mass index,BMI)及体力活动对机体组成及脂肪分布的影响. 方法 横断面收集于北京协和医院体检中心体检的健康妇女,利用经过效度和信度检验的国际体力活动问卷短卷中文版调查研究对象的体力活动情况,利用双能X线吸收法(DEXA)测定机体组成及脂肪分布情况. 结果 共收集到162例妇女资料,年龄40～62岁、(52.81±5.31)岁.多元线性回归分析结果显示,全身脂肪组织百分比与BMI(标准化偏回归系数b=0.70)、月经状态(b=0.19,生育期赋值1,绝经过渡期赋值2,绝经后赋值3,下同)呈正相关,而与体力活动能量消耗呈负相关(b=-0.17),回归方程的决定系数R2-0.55.全身无脂肪组织含量(fat-free tissue)与BMI呈正相关(b=0.61)、与月经状态呈负相关(b=-0.14),回归方程的决定系数R2=0.39.躯干脂肪/全身脂肪比值与BMI(b=0.32)、月经状态(b=0.30)呈正相关,回归方程的决定系数R2=0.20.校正了BMI、月经状态及体力活动的影响后,年龄与全身脂肪组织百分比、全身无脂肪组织含量、躯干脂肪/全身脂肪比值均无明显相关性. 结论 月经状态对机体组成及脂肪分布具有独立影响,随着生殖衰老的进展,脂肪组织增加且趋于中心性分布,机体无脂肪组织含量降低.而年龄本身与机体组成及脂肪分布无直接关系.中年妇女应增加体力活动,保持适当的体重以降低绝经对脂肪组织所造成的不利变化.     

Relation between steroid dose, body composition and physical activity in renal transplant patients

BACKGROUND: Fat mass is increased in renal transplant (RTx) patients, which may have untoward metabolic and cardiovascular effects. The influence of steroids on body composition (BC), resting energy expenditure (REE), and substrate oxidation rates was assessed in stable RTx patients in a cross-sectional design. Also, the relation between physical activity and nutrient intake, respectively, and body composition was studied. METHODS: 77 RTx patients (42 males, 35 females) were studied. Twenty-one patients were on 10 mg and 27 patients on 5 mg maintenance steroid dose; 29 patients were receiving steroid-free immunosuppression. Assessed were BC (DEXA, anthropometry), REE and substrate oxidation (indirect calorimetry), physical activity (Baecke questionnaire), and nutrient intake (dietary records). RESULTS: BC was not different between the 0-, 5-, and 10-mg steroid group, and no relationship existed between cumulative dose of steroids and BC. REE and substrate oxidation also did not differ between the various groups, apart from a small increase in glucose and decrease in lipid oxidation in female patients using 5-mg steroids. Especially in females, leisure time physical activity was positively related with the percentage lean body mass (r=0.571, P=0.004) and inversely related with fat mass (r= -0.588, P=0.003). Nutrient intake and BC (corrected for physical activity) were not related. CONCLUSIONS: No relation was observed between daily and cumulative steroid dosage and BC and between daily steroid dose and REE and substrate oxidation in RTx patients. Especially in female patients, physical activity level and the percentage of lean body mass concluded and body fat were significantly related.     

南宁地区成年女性骨密度与年龄、体重指数关系的研究

目的 研究南宁地区成年女性骨密度(BMD)与年龄、体重指数(BMI)之间关系.方法 采用双能X线骨密度仪测量384例年龄20～87岁的女性腰椎正位和股骨近端的BMD;分别按年龄和BMI分组,分析各年龄组和各BMI组BMD和骨质疏松(OP)检出率的变化.结果 ①腰椎和股骨近端骨峰值均出现在30～39岁组;50岁后BMD明显降低,70岁后再次出现BMD降低加速.②OP在50岁后明显增加,并以每增加10岁OP增加20%以上的速度发展,80岁后OP发生率近100%.③与正常BMI和超BMI组相比,低BMI组BMD显著降低,OP显著增高.结论 南宁地区成年女性BMD峰值在30～39岁;绝经后、年龄70岁以上和低BMI是OP发生危险因素.     

中国围绝经期妇女体脂含量与骨密度关系的初步研究

目的探讨肌肉、脂肪含量与围绝经期骨质疏松妇女骨密度之间的关系。方法利用双能X线骨密度测量仪(美国,Hologic DiscoveryA型)测量门诊围绝经期妇女(90例,年龄:45~52岁(47.3±8.2))骨密度与体脂含量;同时测量登记受试者的年龄、身高、体重。结果结果显示,21%受试者腰椎和股骨骨量降低,全身脂肪含量(20675.129±5080.44)g与腰椎骨密度(0.91±0.177)g/cm2(P>0.05,r=-0.17)和髋部骨密度(0.99±0.102)g/cm2(P>0.05,r=0.158)没有相关性,肌肉含量(39790.80±6551.54)g与腰椎骨密度没有相关性(P>0.05,r=0.078),但是与髋部骨密度高度正相关(P<0.05,r=0.216)。体重(63.01±9.39)kg和腰椎(P<0.05,r=0.217)和髋部(P<0.05,r=0.305)骨密度高度正相关;BMI指数(24.6751±3.45637)与腰椎(P<0.05,r=0.244)和髋部(P<0.01,r=0.339)骨密度高度正相关。结论研究结果表明BMI指数和肌肉含量与围绝经期妇女髋部骨密度高度相关。     

Correlation between hand and total body bone density in normal Chinese children

Hand bone mineral density (BMD) in adults was found to be significantly correlated with various skeletal sites, including the total body. However, the relationships between hand and total body bone measurements have yet to be explored for children. We conducted a cross-sectional study of 892 normal Chinese children (511 males, 381 females) aged 5-14 years by measuring the BMD and bone mineral content (BMC) at the total hand, upper limb, subtotal body, and total body using dual-energy X-ray absorptiometry (DXA). We found that hand BMD and BMC increased with age for both genders. Female children had significantly higher hand BMD and BMC than males. Age explained more variance in hand BMD for females (R2=0.727) than for males (R2=0.596). For both genders, hand BMD and BMC correlated highly with age, weight, height, total body lean mass, and BMD and BMC at the upper limb, subtotal body, and total body (r=0.730-0.965, p<0.001) and moderately with body mass index and total body fat mass (r=0.525-0.701, p<0.001). Therefore, the hand DXA scan can potentially be a new tool for the clinical assessment of bone health in children.     

The role of lean body mass and physical activity in bone health in children

In the context of physical education curricula, markers of physical fitness (e.g., aerobic capacity, muscular strength, flexibility, and body mass index or body fat) are usually evaluated in reference to health standards. Despite their possible mediating role in the relationship between weight-bearing or muscle forces and features of bone tissue, these attributes of fitness may not be the most relevant to predict skeletal health. It is therefore important to analyze the relative contribution of these factors to the variability in bone tissue of different parts of the skeleton, and to analyze it by gender, as sensitivity to mechanical loading can diverge for boys and girls. We compared the effects of habitual physical activity (PA) and lean mass, as surrogates of weight-bearing and muscle forces, and of physical fitness (aerobic and muscle capacity of lower and upper limbs) on bone mineral content (BMC) and size of total body, lumbar spine, femoral neck, and 1/3 radius in 53 girls and 64 boys from 7.9 to 9.7 years of age. After controlling for bone age, body mass, body height, and calcium intake, lean mass was the most important predictor of bone size and/or mineral in both genders (p < 0.05), while habitual weight-bearing PA positively influenced BMC in boys (p < 0.05). The effect of muscle in bone was not determined by PA and fitness score did not explain bone variability. Femoral neck was the bone site more closely associated with mechanical loading factors; boys with a PA > 608 counts/min/day (~105 min/day of moderate and vigorous intensity) showed 13–20% more BMC than those with less physical activity, and girls with a lean mass >19 kg showed 12–19% more BMC than those with less lean mass. These findings suggest that lean mass was the most important predictor of bone size and/or mineralization in both genders, while habitual weight-bearing PA appears to positively impact on bone mineral in prepubertal boys and that both lean mass and PA need to be considered in physical education curricula and other health-enhancing programs.     

Pediatric reference data for bone mineral density in the calcaneus for healthy children 2, 4, and 7 years of age by dual-energy x-ray absorptiometry and laser.

Dual-energy X-ray absorptiometry and laser (DXL) Calscan measures bone mineral density (BMD) in the calcaneus. In the present study, the DXL Calscan device has been modified for use in pediatric practice. It includes a function for measuring calcaneal height, which makes it possible to calculate volumetric bone mineral apparent density (BMAD). The aims of the present study were to evaluate the method when used in children, to create pediatric reference values in healthy Swedish 2-, 4-, and 7-yr-old children for BMD, bone mineral content (BMC), and BMAD, and to study whether these parameters were related to auxological data. The method was well tolerated by all children. Intraindividual coefficients of variation for BMC and BMD decreased with increasing age. The mean BMD was 0.17+/-0.003 g/cm2 in 2-yr-old children, 0.22+/-0.003 g/cm2 in 4-yr-old children, and 0.30+/-0.005 g/cm2 in 7-yr-old children. This study provides normative data as percentile values for BMD, BMC, and BMAD in young children measured with DXL Calscan. BMD was significantly correlated with age (p<0.001), height (p=0.001), weight (p<0.001), and body mass index standard deviation score (p<0.001). Seven-year-old girls showed significantly higher BMD than boys.