Bone mineral status in children with cow milk allergy

To investigate bone mineral status in children with verified cow milk allergy for more than 4 yr compared with a large reference population of 343 local healthy controls. Whole body bone mineral content (BMC), projected bone area and bone mineral density (BMD) were determined by dual energy x-ray absorptiometry in nine children (8-17 yr old, one girl and eight boys). All children had cow milk allergy for more than 4 yr. All children had asthma and was treated with corticosteroids. BMC and BMD were reduced for age (p < 0.01). Height for age was significantly reduced (p < 0.01), indicating 'short' bones. BMC for bone area was borderline reduced (p = 0.05), indicating reduced bone mineralization. The growth of the children was reduced compared with there parents and siblings (p < 0.01), and the bone age was retarded (mean 1.4 yr, p < 0.01). Calcium consumption calculated from food intake was about 25% of the recommended. All laboratory tests were normal. Short bones were the main reason for reduced BMC and BMD for age in children with cow milk allergy, but a borderline low BMC for bone area indicated reduced bone mineralization of the bones. A supplementation of calcium to children with cow milk allergy is recommended.     

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。     

Bone mineral density in children with neurofibromatosis 1

AIM: Our aim was to detect the status of bone mineral density (BMD) in children with NF1, and thus to help the management of the skeletal complications of NF1. METHODS: Dual-energy X-ray absorptiometry (DEXA) was performed in lumbar spine, total body, proximal femur and forearm in 31 children (3.1-18 years) with NF1. Correlations among the BMD values of four regions were calculated statistically. Z-scores of lumbar- and total body-BMD were also evaluated in 24 patients at and older than 5 years. RESULTS: Eleven children had skeletal findings, including mild scoliosis in 5 patients. No case with total body-Z score <-2 was detected. Lumbar-Z score was lower than -2 in 3 out of 24 cases. Patients with any skeletal involvement of NF1 were likely to have a lumbar-BMD lower than -2 in comparison with patients with no skeletal finding (odds ratio 4; 95% CI 0.01-4.62). Proximal femur-BMD values (g/cm(2)), yet forearm-BMDs, were correlated with both lumbar- and total body-BMD, regardless of skeletal involvements of NF1. CONCLUSIONS: Our findings suggest that lumbar- or proximal femur-DEXA, rather than forearm- or total body-DEXA, could reveal significantly decreased BMD in children with NF1, especially in those with skeletal involvement of NF1.     

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.     

Bone mineral metabolism changes in epileptic children receiving valproic acid

OBJECTIVE: The aim of this study was to evaluate bone mineral density (BMD) in epileptic children receiving valproic acid (VPA) and to determine differences between osteopenic and non-osteopenic children. METHODS: Thirty-three epileptic children, receiving VPA for at least 6 months, were compared with 33 healthy children for BMD. BMD was measured by dual-energy X-ray absorptiometry at lumbar vertebrae, femoral neck and greater trochanter. Serum calcium, phosphorus, alkaline phosphates, osteocalcin and VPA levels were also determined. RESULTS: Patient's osteocalcin levels were significantly higher (P = 0.02) and femur and trochanter BMD values were significantly lower (P = 0.04 and P = 0.03, respectively). Duration of VPA therapy was significantly longer and doses of VPA were significantly higher in seven osteopenic patients compared with 26 non-osteopenic patients. Osteopenic patients (4.6 +/- 2.4 years) were younger than non-osteopenic patients (7.8 +/- 3.2 years) (P = 0.01). CONCLUSION: Long-term and high dose VPA therapy may cause osteopenia, primarily in younger epileptic children. These patients should be followed closely by BMD measurements.     

Bone mineral density of the lumbar spine in very-low-birth-weight infants: a longitudinal study

To examine osteopenia in very low birth weight (VLBW) infants we used repeated dual-energy X-ray absorptiometry in a prospective study of lumbar spinal bone mineral density (BMD) in Japanese VLBW infants (birthweight 426–1498 g; n = 61, group 1) aged 40 weeks postconception to 3 years of age. Control subjects were Japanese infants with birthweight 1500–1999 g (group 2), 2000–2499 g (group 3), or more than 2500 g (group 4). BMD in group 1 during the early period after birth was very low, increased rapidly for 1 year, and then gradually increased until 3 years of age (r =  0.931, P < 0.0001). BMD at the age of 40 weeks postconception was 0.085 ± 0.026, 0.132 ± 0.039, 0.178 ± 0.042, and 0.196 ± 0.046 g/cm² in groups 1, 2, 3, and 4, respectively (P < 0.0001). However, at 1 and 2 years of age no differences were observed among the groups in BMD. Conclusion This study shows that lumbar spinal BMD in VLBW infants can normalize by the age of 2 years. Received: 12 May 1999 / Accepted: 11 October 1999     

Bone mineral content and collagen defects in osteogenesis imperfecta

Whole-body and spine dual-energy X-ray absorptiometry was done in 63 patients with osteogenesis imperfecta aged 5 to 63 y, and the results were compared with OI types and collagen defects. Bone mineral content (BMC)-for-age, bone area (BA)-for-age, bone mineral density (BMD)-­for-age, and BMC-for-BA were reduced, especially in patients with OI III/IV and/or in those with a qualitative collagen defect. BA-for-height was normal. Some patients with OI I and/or a quantitative collagen defect had BMD at or above -2 z-scores. We conclude (i) that both BMC and BMD differ significantly between OI types and collagen defects, (ii) that reduced BMC-for-age in OI patients is due mainly to reduced height (“short bones”) and reduced BMC-for-BA (“light bones”), whereas BA-for-height (“bone width”) is normal, (iii) that most OI patients have lower than average BMC, but in some mildly affected patients brittleness may exist with only small reductions in BMC.     

Reproducibility of DXA measurements of bone mineral density and body composition in children

Background  The technique of X-ray-based dual photon absorptiometry (DXA) is frequently used in children for the detection of changes in bone mass or body composition. Such changes can only be considered real if the uncertainties arising from the measurement technique are exceeded. Objective  Our objectives were twofold: (1) to determine the reproducibility of bone mineral density (BMD) measurements in children at the spine and the hip and from the whole body, as well as of whole-body measurements of mineral mass, lean body mass and fat mass in children; and (2) to estimate, from the measured precision, the time interval that needs to elapse before a statistically significant change in a DXA variable can be detected. Materials and methods  The reproducibility of techniques for the measurement of BMD and body composition using DXA was measured in 15 young children (9 girls and 6 boys) and 17 older children (9 girls and 8 boys). Results  Reproducibility was derived from the standard deviation of three repeated measurements of spine BMD, total hip BMD, whole-body BMD (WBBMD), whole-body bone mineral content (WBBMC), lean mass and fat mass. Technique precision was better than 0.01 g cm⁻² for spine BMD and for WBBMD. Hip BMD measurements were slightly less precise, particularly in younger children (0.013 g cm⁻²). For body composition variables, technique precision was 13 g for WBBMC, 201 g for lean body mass and 172 g for fat mass in younger children. Technique precision for older children was 18 g, 251 g and 189 g for the corresponding variables. Predictions showed that the absence of a normal increase in WBBMC in a small-for-age girl could be established after 12 months. For spine BMD, a significant increase should be observable after 6 months for boys over the age of 11 years. For younger boys, more than 12 months has to elapse before anticipated changes can be detected with confidence. Conclusion  The time intervals required to elapse before decisions can be made concerning the significance of observed differences between successive measurements of BMD or body composition in children depend upon the age of the child.     

Bone mineral status in ambulatory pediatric patients on long-term anti-epileptic drug therapy

BACKGROUND: For ambulatory pediatric outpatients,reports of abnormalities of bone metabolism associated with anti-epileptic drugs are inconsistent and may be difficult to interpret. METHODS: The effects of long-term anti-epileptic therapy (mainly valproic acid and/or carbamazepine) on bone mineral status were evaluated in ambulatory epileptic patients(seven males and 11 females) aged 5.5-15.9 years.Bone mineral density (BMD) at the lumbar spine was measured by dual-energy X-ray absorptiometry and markers of bone and mineral metabolism were determined. RESULTS: The mean BMD was decreased by 9% in our patients relative to the control, and five patients (all males)showed osteopenia, defined as BMD SD scores less than - 1.5.Serum levels of minerals, intact parathyroid hormone and 1alpha,25(OH)2 vitamin D were within the normal ranges. In most patients, serum levels of intact osteocalcin, carboxyterminal propeptide of type I procollagen and pyridinoline cross-linked telopeptide of type I collagen were reduced relative to the corresponding mean control values. The BB genotype by BsmI restriction fragment length polymorphism, associated with low BMD, was not found in our patients. The dietary calcium intake in the osteopenic patients was significantly lower than that of the non-osteopenic patients. CONCLUSIONS: Our results indicate that long-term anti-epileptic treatment induces a state of decreased bone turnover in children, resulting in osteopenia preferentially in males. The alterations may be due, at least in part, to direct effects of the drugs on bone cells; and that low calcium intake could be an aggravating factor for anti-epileptic-associated osteopenia.     

Bone mineral acquisition in adolescents with type 1 diabetes

OBJECTIVE: To track bone mineral acquisition in adolescents with type 1 diabetes (DM). STUDY DESIGN: Subjects were adolescents, ages 12 to 18 years, with DM (n=42) and a healthy regional reference (n=199). Measurements of tibia bone characteristics by peripheral quantitative computed tomography (pQCT) and spine and whole body (WB) by dual-energy x-ray absorptiometry (DEXA), anthropometrics, and lifestyle questionnaires were obtained during a 12-month period. Disease duration, insulin dose, renal function, and glycosylated hemoglobin (HbA1c) values for the previous 12 months were recorded. RESULTS: Body size and maturation were similar between groups. DM had lower tibia, spine, and WB bone characteristics but greater muscle mass (LBM) and lower bone mineral content (BMC)/LBM at baseline and 12 months. Annual gains for tibia cortical bone and WB BMC/LBM were lower and inversely related to HbA1c levels (R=-0.36 to -0.51), whereas spine area and density and WBLBM were greater and were predicted by pubertal-driven growth. Overall, the DM cohort had 8.5% less WB BMC/LBM, suggesting that bone mineral deposition was not adequately adapted to muscle gains. CONCLUSIONS: Adolescents with type 1 diabetes continue to have smaller bone mass and bone size despite normal growth and maturation. Poor metabolic control appears to negatively influence bone mineral acquisition.     

补充钙剂治疗儿童铅中毒效果的系统评价

目的系统评价补充钙剂治疗儿童铅中毒的疗效与安全性。方法检索相关文献数据库,并手工检索相关领域其他杂志。纳入以轻、中度铅中毒,年龄0～14岁儿童为研究对象,比较补充钙剂与其他疗法的疗效的随机对照试验,评价纳入研究的文献质量,并用RevMan5.0软件进行meta分析。结果共检索到633篇文献,最终筛选出4篇研究,共306例患儿。分析结果显示:当补充钙剂达到每日需要量时,补充钙剂组比对照组血铅降低值比较差异有统计学意义,其WMD及95%CI为:42.22(23.06～61.37);过量补充钙剂与钙剂充足的安慰剂对照组血铅下降无统计学意义,其MD及95%CI为:8(26.58～42.58)。结论足量补充钙剂能显著降低缺钙铅中毒儿童的血铅,如儿童钙剂摄入充足,过量补充钙剂能否降低儿童血铅尚证据不足。     

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.     

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 density in children with sickle cell anemia

PURPOSE: We evaluated bone mineral density (BMD) and risk factors for poor bone mineralization in children with sickle cell anemia (SCA). PATIENTS AND METHODS: Twenty-five children with severe manifestations of SCA (frequent hospitalizations, growth delay, or need for chronic red cell transfusions) were enrolled. Bone density was assessed at lumbar spine and proximal femur with dual-energy X-ray absorptiometry (DXA), and Z-scores were calculated by comparison with age, sex, and ethnicity-specific reference data. RESULTS: The median age of the study population was 12.8 years (10.2-19.8 years). Calcium intake was inadequate in 60%, and serum 25-hydroxy vitamin D (25-OHD) level <50 nM in 74% of patients. Median Z-scores for lumbar spine (-2.3) and proximal femur (-1.7) were markedly reduced, and 64% (95% confidence interval, 43%-82%) of patients had low bone density. Z-scores were not related to age, growth delay, chronic transfusions, or ferritin level. CONCLUSION: Our results suggest that children with severe manifestations of SCA have low BMD, and possess significant deficits in dietary calcium and circulating vitamin D.     

Determinants of low bone mineral density in children with epilepsy

Introduction

Children with epilepsy on long-term antiepileptic drugs (AEDs) are at risk of low bone mineral density (BMD). The aims of our study were to evaluate the prevalence and determinants of low BMD among Malaysian children with epilepsy.

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.     

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.     

Rate of radial bone mineral accretion in healthy children

Radial bone width and mineral content were measured in 392 healthy Cambridge children aged 6–12 years from a cohort of 420 children studied 2 years previously. The typical rate of bone mineral accretion was 0.044 g/cm/year for boys across the whole age range and 0.042 g/cm/year for girls up to a mean age of 9 years, rising rapidly thereafter in association with changes in body size. The factors best predicting bone mineral accretion rate were mean bone mineral content, mean height, height velocity, weight velocity and bone width velocity. After adjusting for anthropometry, age did not contribute to the model. These are the first available longitudinal reference data for the rate of radial bone mineral accretion in healthy children.