评价儿童青少年骨体重负荷的意义及指标选择(英文)

目的　探讨儿童青少年骨体重负荷对腰椎和髋部骨矿含量 (BMC)、骨密度 (BMD)的影响 ,并比较两指标的优次。方法　应用DXAQDR - 4 5 0 0A型扇形束骨密度仪测量长沙地区 5 4 7例 6～ 15岁儿童青少年腰椎前后位 ,仰卧侧位及髋部股骨近端的骨量。结果　不论男女 ,儿童青少年体重、体块指数 (BMI)、腰椎及髋部BMC和BMD随年龄增加而增加 (P <0 .0 5或 0 .0 1) ;体重与BMC的相关性较体重与BMD的相关性更密切 ;髋部及腰椎各部位体重标准化BMC随年龄增加而增大 ,而髋部和腰椎各部位体重标准化BMD随年龄增加反而减小。结论　 6～ 15岁儿童青少年腰椎及髋部BMC指标判断骨强度优于BMD ,尤以髋部及腰椎侧位BMC为佳。     

Measured and predicted bone mineral content in healthy boys and girls aged 6–18 years: adjustment for body size and puberty

Dual-energy X-ray absorptiometry (DEXA) is a rapid and precise technique for the assessment of bone mineralization in children. Interpretation of the results in growing children is complex as results are influenced by age, body size (height and weight) and puberty. Conventionally, bone mineral data derived from DEXA have been presented as an areal density [BMD; bone mineral content (BMC, g)/projected bone area (BA, cm²)], yet this fails to account for changes in BMC that result from changes in age, body size or pubertal development. Measurement of BMC and BA of the whole body, lumbar spine and left hip were made in 58 healthy boys and girls using DEXA. The relationship between BMC and BA was curvilinear, with the best fit being that of a power model (BMD = BMC/BA^λ, where λ is the exponent to which BA is raised in order to remove its influence on BMC). The value of λ changed when measures of body size and puberty were taken into account (e.g. for lumbar spine from 1.66 to 1.49). Predictive formulae for BMC were produced using regression analysis and based on the variables of age, body size and pubertal development. This provides a method for interpreting the measured BMC which is independent of such variables and a constant reference range for children aged 6-18 y.     

Lumbar bone mineral content measured by dual energy X-ray absorptiometry in newborns and infants

Dual energy X-ray absorptiometry (DXA), a non-invasive method for measuring small amounts of mineral, was used to assess the bone mineral content (BMC) and bone mineral density (BMD) of the lumbar spine (5 vertebrae) in 57 newborns (on day 1-2) and 22 infants (1-24 months of age). A modified high-resolution program (Hologic) allowed us to assess BMC and BMD with a precision higher than 2.4% and 1.5%, respectively. In newborns, BMC and BMD correlated positively with birth weight, body area, length and gestational age: r = 0.73, 0.71, 0.63 and 0.60, respectively, for BMC; and r = 0.59, 0.58, 0.54 and 0.53, respectively, for BMD. In infants, both BMC and BMD were highly correlated with weight, age, length and body area over two years (r = 0.94 or better in each instance). The data provide normal values for lumbar spine BMC and BMD in newborns (gestational age 31-40) and infants up to two years of age; DXA appears to be an excellent and safe tool for pediatric bone mineral measurements.     

Determinants of bone mineral density in prematurely born children aged 6–7 years

The aim of this study was to assess the long-term effects of prematurity and growth during the first year on bone mineralization in prematurely born children. The study group consisted of 38 prematurely born Finnish children (17M, 21F) examined at the age of 6-7 y. After birth, all children were fed with banked human milk until discharge from hospital. Thereafter, 27 children were partially breastfed until the age of 5–7 months. Infants with gestational age (GA) <33 weeks ( n = 25) received calcium 45-50 mg/100 kcal, phosphorus 40-45 mg/100 kcal, vitamin A 1000 IU/d, vitamin C 2 mg/d and vitamin D 400 IU/d until 2.5 kg. Infants born > 33 weeks received only vitamin D 400 IU/d. Bone mineral density (BMD) and bone mineral content (BMC) were measured by dual energy X-ray absorptiometry (DXA) of the lumbar spine (L2-L4) at 6-7 y of age. At examination, all children had normal height and weight. BMD values were within the confidence interval of the Finnish reference values. In regression analysis bone area, present weight, GA and weight at 1 y were the most significant factors explaining 77.1% of the variance of BMC. After adjusting for other independent variables the prematurely born children who were thinner at 1 y of age subsequently had higher BMC values when examined at the age of 6-7 y. This study shows that growth patterns during the first year of life have long-term effects on bone mineralization.     

Total body mineral mass measured with dual photon absorptiometry in healthy children

Using dual photon absorptiometry, bone mineral content (BMC) and bone mineral density (BMD) of the total body and the lumbar spine were assessed in 97 healthy, Caucasian children aged 3–14 years. Excellent correlations were found between BMC and BMD on the one hand and age, body height and body weight on the other. No differences were found between boys and girls. There was a strong correlation between lumbar spine measurement as compared to those of the total body. Regression equations for total body and the different parts of the skeleton were calculated with either BMC or BMD as the dependent variable, and age, body height and body weight as independent variables. High variation coefficients were obtained in these multiple regressions, except for the head. For total body BMC and total body BMD, growth charts were constructed using Tanner and Whitehouse data on body height and body height and body weight.The increase in total body mineral content is an important feature of normal growth. Normal data for BMC and BMD in childhood are essential for bone mineralistation abnormalities in paediatric patients.     

Bone mineral status in 134 patients with cystic fibrosis

AIM—To investigate bone mineral status in patients with cystic fibrosis (CF).
PATIENTS AND METHODS—Whole body bone mineral content (BMC), projected bone area, and bone mineral density (BMD) were determined by dual energy x ray absorptiometry in 134 patients with CF and compared with 396 healthy controls.
RESULTS—In patients ⩽ 19 years of age, BMD for age was normal in boys and marginally reduced in girls, whereas BMC for age was significantly reduced in both sexes. Height for age and bone area for height were significantly reduced, indicating "short" and "narrow" bones, whereas BMC for bone area was increased, indicating increased size corrected BMC. In patients > 19 years of age, BMD and BMC for age were significantly reduced.
CONCLUSION—Short and narrow bones were the main reasons for reduced BMC for age in patients ⩽ 19 years of age, indicating that treatment to prevent osteoporosis in younger patients should be directed at increasing bone size, whereas conventional treatment with calcium and vitamin D supplementation alone might not be as effective. Because of the significant decrease in BMD and BMC in adult patients, we fear that these patients may develop osteoporotic fractures prematurely.

     

Whole body bone mineral content in healthy children and adolescents

Data from healthy children are needed to evaluate bone mineralisation during childhood. Whole body bone mineral content (BMC) and bone area were examined by dual energy x ray absorptiometry (Hologic 1000/W) in healthy girls (n = 201) and boys (n = 142) aged 5-19 years. Centile curves for bone area for age, BMC for age, bone area for height, and BMC for bone area were constructed using the LMS method. Bone mineral density calculated as BMC/bone area is not useful in children as it is significantly influenced by bone size. Instead, it is proposed that bone mineralisation is assessed in three steps: height for age, bone area for height, and BMC for bone area. These three steps correspond to three different causes of reduced bone mass: short bones, narrow bones, and light bones.     

The diagnostic value of skin prick testing in children with food allergy

The diagnostic accuracy of the skin prick test (SPT) in food allergy is controversial. We have developed diagnostic cut-off levels for SPT in children with allergy to cow milk, egg and peanut. Based on 555 open food challenges in 467 children (median age 3.0 yr) we defined food-specific SPT weal diameters that were '100% diagnostic' for allergy to cow milk (>or=8 mm), egg (>or=7 mm) and peanut (>or=8 mm). In children < 2 yr of age, the corresponding weal diameters were >or=6 mm, >or=5 mm and >or=4 mm, respectively. These SPT cut-off levels were prospectively validated in 90 consecutive children 相似文献   

肥胖儿童瘦素水平的变化及其与骨密度的关系

目的：探讨长沙市肥胖儿童血清瘦素水平的变化及与骨密度（BMD）、身体成分的关系,为预防和治疗儿童肥胖及骨质疏松提供科学依据。方法：从长沙市5所小学随机抽取119例肥胖儿童和103例正常儿童,采用双能X线骨密度仪（DEXA）进行全身扫描,测定骨密度及身体成分;采用酶联免疫吸附试验（ELISA）测定血清瘦素水平。结果：①肥胖儿童的身高、体重、体重指数（BMI）、腰围和腰臀比均显著高于正常儿童（P<0.01）。②肥胖儿童的全身骨密度、骨矿物质含量、瘦组织含量、脂肪组织含量、体脂百分比(%BF)及血清瘦素水平均显著高于正常儿童（P<0.01）。③血清瘦素水平与儿童全身骨密度、骨矿物质含量、瘦组织含量、脂肪组织含量均呈显著正相关（r=0.528~0.903）,其中瘦素水平与脂肪组织含量呈高度正相关（男：r=0.883,女：r=0.903）。多元逐步回归分析显示,BMI及%BF是儿童血清瘦素水平的独立影响因素。结论：肥胖儿童血清瘦素水平升高,血清瘦素水平与骨密度及身体成分显著相关,BMI、%BF是儿童血清瘦素水平的独立影响因素。［中国当代儿科杂志,2009,11（9）：745-748］     

Risk of inadequate bone mineralization in diseases involving long-term suppression of dairy products

BACKGROUND: Eighty percent of peak bone mass should be achieved from birth through adolescence. An adequate calcium intake is essential, and it is advisable that 60% of the recommended calcium allowance be dairy calcium. This study was conducted to examine bone mineral content (BMC) in patients with diseases that usually involve long-term suppression of dairy products. METHODS: Thirty patients, aged 2 to 14 years (mean, 7 years), 10 with late-onset, genetically induced lactose intolerance, 7 with cow's milk protein allergy, 3 with short-bowel syndrome, and 10 with hypercholesterolemia were involved in the study. They were receiving various dietary regimens for periods longer than 2 years: 14 patients received special formulas for children (lactose-free cow's milk formula, highly hydrolyzed cow's milk protein formula, soy protein isolate formula), 4 patients received liquid soy beverages, 6 patients received skim milk (1% fat), and 6 patients had exclusion of dairy products. Bone mineral density (BMD) was assessed by dual-energy x-ray absorptiometry. RESULTS: Nine patients had osteoporosis, 6 had osteopenia, and 15 had results within normal ranges. Overall, the group had a standard deviation score of -1.3 (osteopenia). The statistical correlation between the BMD value and the percentage intake of recommended daily allowance (RDA) of dairy (or substitute) calcium (in milligrams per day) was highly significant (P < 0.0001, r = 0.89). CONCLUSIONS: All patients with diseases involving total or partial withdrawal from milk products for a prolonged period are a group at potential risk of defective bone mineralization and should be monitored through BMD assessment.     

Influence of weight, age and puberty on bone size and bone mineral content in healthy children and adolescents

The biology of bone mineralization during growth is important for peak bone mass. The aim of the study was to examine how body size, age and puberty influence bone size and bone mineral density. Whole body bone area (BA) and bone mineral content (BMC) were examined by dual-energy X-ray absorptiometry (Hologic 1000/W) in healthy girls ( n = 201) and boys ( n = 142) aged 5–19 y. The influence of height, weight, age and puberty on bone mineralization was examined by multiple regression. Main determinants of BA were height and weight. Bone width, approximated by BA corrected for height, increased highly significantly with weight and depended weakly significantly on pubertal stage. Main determinants of BMC were BA, height, age and pubertal stages. Bone mineral density, approximated by BMC corrected for BA and height, depended on age and pubertal stage, but not on weight. Thus skeletal size is mainly determined by body size, while bone density is determined by age and pubertal stage.     

Pegylated interferon α/ribavirin therapy enhances bone mineral density in children with chronic genotype 4 HCV infection

Background:The impact of chronic hepatitis C (CHC) on bone mineral density (BMD) has been well studied in adults with a relative paucity of data in children,especially concerning effect of treatment with pegylated interferon (PEG-IFN) plus ribavirin (RV).In the current work,we assessed prospectively changes in BMD in children with CHC before,during,and after treatment.Methods:Forty-six consecutive children with noncirrhotic genotype 4 CHC were subjected to dual-energy X-ray absorptiometry at baseline,24 weeks,48 weeks of therapy and 24 weeks after treatment.BMD,bone mineral content (BMC),and Z score of lumbar spine (L2-L4) were reported.Tanner pubertal stage,viral load,liver function tests,serum calcium,phosphorus,alkaline phosphatase,parathyroid hormone,and liver histopathology were assessed in all included children.Results:Thirty (65.2％) patients had normal BMD,10 (21.7％) were at risk for low BMD,and 6 (13.1％) had low BMD for chronological age.Patients with low BMD were significantly older (P=0.001),with higher frequency of delayed puberty than other groups (P=0.002).Baseline densitometric parameters (BMD & BMC) were significantly positively correlated with patients' age,weight,height,body mass index and hemoglobin level;while they were insignificantly correlated with basal viral load,histopathology activity index and fibrosis score.Densitometric parameters improved significantly on PEG-IFN plus RV treatment,this improvement was found to be sustainable 24 weeks after therapy.Conclusions:Low BMD is detectable in a proportion of CHC children.Antiviral therapy leads to a sustainable increase in BMD.     

Whole body bone mineral content in healthy children and adolescents

Accepted 23 July 1996
Data from healthy children are needed to evaluate bone mineralisation during childhood. Whole body bone mineral content (BMC) and bone area were examined by dual energy x ray absorptiometry (Hologic 1000/W) in healthy girls (n=201) and boys (n=142) aged 5-19 years. Centile curves for bone area for age, BMC for age, bone area for height, and BMC for bone area were constructed using the LMS method. Bone mineral density calculated as BMC/bone area is not useful in children as it is significantly influenced by bone size. Instead, it is proposed that bone mineralisation is assessed in three steps: height for age, bone area for height, and BMC for bone area. These three steps correspond to three different causes of reduced bone mass: short bones, narrow bones, and light bones.

     

Bone mineral density and metabolism in children with congenital hypothyroidism after prolonged l-thyroxine therapy

Abstract The effect of long-term l -thyroxine (LT4) replacement therapy on bone mineral density and on biochemical markers of bone turnover were studied in children with congenital hypothyroidism (CH). Forty-four children and adolescents (mean age 8.5 ± 3.5 years) with primary CH who began LT4 replacement therapy within the first month of life were studied. Bone mineral density (BMD) of the lumbar vertebrae and the upper femoral bone was measured by dual energy X-ray absorptiometry. Serum osteocalcin (OC) and bone alkaline phosphatase were measured as markers of bone formation and urinary deoxypyridinoline was taken as a marker of bone resorption. Bone mineral densities of CH children were not different from those in age-matched controls. The biochemical markers of bone turnover were normal except for the serum OC levels which were found to be higher than in controls and positively correlated with the free thyroid hormone levels (for FT4 r = 0.42, p = 0.02). Eight CH children demonstrated low BMD values (below -1 SDS) at - 2 ± 0.7 SDS for the lumbar spine and - 1.6 ± 0.5 SDS for the femoral site. These eight children showed lower mean weight ( p < 0.05) and their dietary calcium intake tended to be less ( p < 0.06) than that seen in the normal BMD group. In conclusion, our results show that LT4 replacement therapy for 8 years is not detrimental to the skeletal mineralization of CH children. As in a healthy population, weight and current intake of calcium seem to be major determinants of bone density. Dietary recommendations, especially when calcium intake is below the recommended dietary allowance, may have to be reconsidered.     

Bone mineral content in black pre-schoolers: Normative data using single photon absorptiometry

Fifty-nine children aged 18 to 47 months with normal and elevated blood lead levels had bone mineral density (BMD in gm/cm2) and bone mineral content (BMC in gm/cm) measured using the technique of single photon absorptiometry of the radius shaft. No normative data are available for black children of this age group. Moderate elevations of blood lead were not found to influence bone mineralization. The BMC of the study children was significantly higher than the published values for white children of the same age. We found no statistical difference between the bone mineral density of males and females in this age group.     

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目的 分析肥胖儿童骨密度(BMD)及其影响因素,为早期预防骨质疏松提供科学依据.方法 2007年1-12月从长沙市开福区5所小学7～12岁学龄儿童中,按照体质指数(BMI)法诊断单纯性肥胖,随机抽取119例单纯性肥胖儿童及103名正常儿童.采用双能X线骨密度仪(DEXA)全身扫描,测量BMD和身体成分.结果 单纯性肥胖儿童的身高、体重、BMI、腰围和腰臀比均显著高于正常儿童.单纯性肥胖儿童的各部位瘦组织含量(LM)、脂肪组织含量(FM)、体脂百分比(PBF)及躯干脂肪组织百分比均显著高于正常儿童,但四肢FM百分比却显著低于正常儿童.肥胖儿童各部位BMD和骨矿物质含量(BMC)均大于正常儿童.控制FM后,BMD(或BMC)与LM呈显著正相关:控制LM后,BMC与FM亦呈正相关.多元逐步回归分析显示,影响儿童BMD的主要因素是LM.结论 肥胖儿童BMD高于正常儿童,LM对儿童成长中骨的BMD起重要作用.     

Risk factors for reduced areal bone mineral density in young adults with stem cell transplantation in childhood

Slightly, but significantly, reduced bone mineral density (BMD) has been detected as a late effect after stem cell transplantation (SCT) performed in childhood. The aim of the study was to evaluate the risk factors of reduced BMD after SCT in childhood. We evaluated areal BMD of 16 young adults (six males, 10 females), aged 21 yr (range 15-34) by dual-energy X-ray absorptiometry at the lumbar spine, at the femoral neck, in the total hip, and in the total body. Bone turnover rate was evaluated by markers of bone formation and resorption. Six of the 16 patients had reduced BMD with a Z-score of < or = -1 at least at one measurement site. Factors associated with reduced BMD were prepubertal status at transplant (p = 0.03), delayed pubertal growth (p = 0.03), pubertal onset gonadal hormone insufficiency (p = 0.02), and female sex (p = 0.02). Surprisingly, height in SDs and lumbar spine BMD correlated negatively (p = 0.008) in those with reduced bone mass, indicating that low areal density could not be due the small size of the vertebrae. Bone turnover markers were similar for those with normal and reduced BMD. In conclusion, 38% of the SCT long-term survivors had reduced areal BMD. Prepubertal status at transplant with pubertal onset gonadal hormone insufficiency and female sex predisposed to reduced bone mass after SCT performed in childhood.     

Bone densitometry by dual-energy X-ray absorptiometry (DXA) in preterm newborns compared with full-term peers in the first six months of life

ObjectivesTo longitudinally assess bone mineral content (BMC), bone mineral density (BMD), and whole-body lean mass obtained through bone densitometry by dual-energy X-ray absorptiometry (DXA) in preterm newborns (PTNs) and compare them with full-term newborns (FTNs) from birth to 6 months of corrected postnatal age.MethodsA total of 28 adequate for gestational age (AGA) newborns were studied: 14 preterm and 14 full-term newborns. DXA was used to determine BMC, BMD, and lean mass in three moments: 40 weeks corrected post-conceptual age, as well as 3 and 6 months of corrected postnatal age. PTNs had gestational age ≤ 32 weeks at birth and were fed their mother's own milk or milk from the human milk bank.ResultsAll infants had an increase in BMC, BMD, and lean body mass values during the study. PTNs had lower BMC, BMD, and lean mass at 40 weeks of corrected post-conceptual age in relation to FTNs (p < 0.001, p < 0.001, p = 0.047, respectively). However, there was an acceleration in the mineralization process of PTNs, which was sufficient to achieve the normal values of FTNs at 6 months of corrected age.ConclusionsThis study suggests that bone densitometry by dual-energy X-ray absorptiometry is a good method for the assessment of body composition parameters at baseline, and at the follow-up of these PTNs.     

Bone mineral assessment by dual energy X-ray absorptiometry in children with inflammatory bowel disease: evaluation by age or bone area

BACKGROUND: Abnormal linear growth and deficient bone mineral acquisition may coexist in children with inflammatory bowel disease (IBD). Traditionally, bone mineral assessment by dual energy x-ray absorptiometry (DXA) involves comparison to age- and gender-matched reference ranges, and these studies in children with IBD show a high prevalence of osteopenia. AIMS: To compare the prevalence of osteopenia using two methods of interpretation; one adjusted for age and gender and the other adjusted for bone size and gender. PATIENTS: Forty-seven patients with Crohn disease (CD) and 26 patients with ulcerative colitis (UC) with a median age of 13.5 years (range, 5.5-18.2 years) were evaluated. METHODS: Lumbar spine (LS) and total body (TB) bone mineral content (BMC) were measured by DXA and converted to bone mineral density (BMD, g/cm) corresponding to BMC divided by the bone area. Age and gender-matched BMD standard deviation scores (SDS) were based on reference data providing age- and gender-matched BMC and bone area. These data also allowed calculation of percentage of predicted bone area for age and gender (ppBone Area) and percentage of predicted BMC for Bone Area (ppBMC). RESULTS: Patients with CD were shorter than those with UC (median height, SDS, -0.9 v 0, P < 0.05). Median ppBone Area for LS and TB for the whole group was 85% (10th centile, 68; 90th centile 99) and 81% (10th centile 66; 90th centile, 97), respectively. The ppBone Area at both sites was directly related to height SDS and BMI SDS (r > 0.5; P < 0.005). Median BMD SDS for LS and TB was -1.6 (10th centile -3.6; 90th centile, -0.2) and -0.9 (10th centile, -2.4; 90th centile, 0.4), respectively. Median ppBMC for LS and TB was 98% (10th centile, 84%; 90th centile, 113%) and 101% (10th centile 94%; 90th centile, 107%), respectively. The ppBMC showed no relationship to ppBone Area (r = 0.1, NS). Failure to account for bone area led to a label of moderate or severe osteopenia in 65% of cases. After adjustment for bone area, the proportion of children with osteopenia fell to 22%. CONCLUSIONS: The data suggest that children with IBD often have small bones for age because they have growth retardation. When DXA data are interpreted with adjustment for bone size, most children were found to have adequate bone mass. Correct interpretation of DXA is important for identifying children who may be at a real risk of osteoporosis.