Variation in bone mineral content and estimated body fat in young adult females

This study was designed to determine whether variability in bone mineral content (BMC) at the lumbar vertebrae (L2-4), radius shaft (RS), femoral neck, and distal radius can significantly contribute to the variability observed in body density (Db) among 89 females (age = 25.1 +/- 5.3 yr) of varying activity levels and menstrual status. Theoretical differences in Db were calculated at +/- 1 and +/- 2 standard deviations of BMC (SDBMC) for the population as well as for the subgroups: eumenorrheic inactive controls (C), recreational runners (RR), collegiate runners (CR), body builders (BB), swimmers (S), and amenorrheic runners (AR). Multiple regression to predict Db yielded significant coefficients (b) for BMC at L2-4 (b = 0.0190, P less than 0.001) and RS (b = 0.0425, P less than 0.01) when added separately to the sum of four skinfolds (subscapula, abdomen, thigh, calf). The differences in % BFHW at +/- 1 and +/- 2 SDBMC for the sample mean for RSBMC were +/- 1.0% and +/- 2.0%, respectively. Variability in L2-4 contributed differences of +/- 1.3% and +/- 2.6% at +/- 1 and +/- 2 SDBMC. The subgroup % BFHW differences (due to L2-4 and RS combined) ranged from an average overestimation of 1.3% for the AR to an average underestimation of 1.4% for the BB. Estimated mean errors for remaining groups were less than or equal to 0.5%. Individual differences ranged from a 3.3% underestimation (BB) to a 3.0% overestimation (AR).(ABSTRACT TRUNCATED AT 250 WORDS)     

髋关节置换术后假体周边骨密度测量的临床研究

目的 改良双用Ｘ线吸收法（ｄｕａｌ－ｅｎｅｒｇｙ Ｘ－ｒａｙ ａｂｓｏｒｐｔｉｏｍｅｔｒｙ,ＤＥＸＡ）并应用于临床研究。方法 随访近５年在本院行单侧非骨水泥型髋关节置换术患者４０例和髋关节翻修术患者６例,改良ＤＥＸＡ法测量双侧股骨上段骨密度常规摄Ｘ线片。结果 术侧术后第１年骨丢失最多,随时间延长,假体内侧和大转子区骨丢失最明显,假体柄外侧中、下部分次之,假体柄尖远端股骨干处骨丢失相对较少。患者本身     

应用定量CT测定胸椎骨矿密度

目的对行心脏CT检查的病人应用定量CT进行胸椎骨矿密度(BMD)测定,获得标准值,并将该值(来自各亚组)与行腰椎定量CT检查所获得的骨矿密度值进行比较。材     

Measurements of bone mineral density. Mineral density in metabolic bone disease.

Bone metabolism and thus bone remodelling and bone mineral content are profoundly influenced by many hormonal and metabolic factors. This review presents the state of the art procedures for bone mineral absorptiometry and examines the interactions of endocrine and metabolic diseases and bone mineral content. Preventive and therapeutic modalities of osteoporosis are discussed in this context.     

Strength training effects on bone mineral content and density in premenopausal women

PURPOSE: Mechanical loading, such as that seen with physical activity, is thought to be the primary factor influencing bone strength. Previous randomized studies that assessed the effect of strength training on bone in premenopausal women report inconsistent results. The analysis herein examines the effect of a strength training program following published guidelines (US Department of Health and Human Services) on bone mineral content (BMC) and areal bone mineral content (aBMD) in the proximal femur and lumbar spine in premenopausal women. METHODS: One hundred and forty-eight overweight, sedentary, premenopausal women aged 25-44 were randomized to progressive strength training (ST, n = 72) or standard care (CO, n = 76) for 2 yr. Measurements occurred at baseline, 1 yr, and 2 yr. Proximal femur and lumbar spine BMC and aBMD were measured by dual energy x-ray absorptiometry. Intention-to-treat analyses were completed, and repeated-measures ANCOVA adjusted for baseline height and weight was used to assess the effect of strength training on bone. RESULTS: aBMD showed little change and did not differ between groups at any site. Femoral neck BMC showed a significant difference in the slopes between ST and CO (P = 0.04) with no change in the ST group and a 1.5% decrease in the CO. There were no significant between-group differences at any other measurement site. CONCLUSION: Strength training had no effect on aBMD after 2 yr of strength training. Femoral neck BMC decreased in CO and had no change in ST. Because there was no change in aBMD, strength training may have influenced bone size. Research to better understand changes in bone dimensions and geometry with strength training in premenopausal women is warranted.     

Measurement of forearm bone mineral density in normal women by dual-energy X-ray absorptiometry.

We report the results of forearm measurements, without the use of a water bath, using dual-energy X-ray absorptiometry (DEXA) in 100 normal women aged 29-69 years (average age, 52 years). Studies were performed using the Hologic QDR-1000, with bone mineral density (BMD) measured at three sites in the non-dominant forearm: ultradistal, distal one-third and a region between these two. The precision of the technique was 0.74%, 0.55% and 0.58%, respectively. The normal range for forearm BMD and variation with age was established. BMD was also measured in the lumbar spine (L1-L4) and femoral neck. Linear regression analysis gave a range of correlation coefficients between forearm and axial sites of r = 0.49-0.67. Standard errors of the estimate (SEE) in predicting axial from peripheral measurements gave average values from the three forearm sites of 0.085 g/cm2 for the femoral neck and 0.118 g/cm2 for the spine. Forearm measurements using DEXA can now be reliably performed in air. DEXA produces a high-resolution image, is fast and simple to perform, and enables both cortical and trabecular sites to be examined in one measurement. Forearm and axial measurements can be performed using the same equipment, where centres possess a suitable DEXA system.     

西安地区人群骨密度检测及骨质疏松分析

目的:研究西安地区人群骨密度(BMD)变化规律及骨质疏松(OP)的发病状况,为OP的防治提供依据。方法:采用美国SXA3000骨密度分析仪对西安地区23~76岁的人群522人进行跟骨BMD检测。结果:男女骨峰值均在21~30岁年龄段,随年龄段增高BMD逐渐下降,50岁以上女性和60岁以上男性骨量呈快速下降(P<0.01);骨量减少发生率男女性各年龄段均较高,60岁以上年龄组骨量减少发生率男性高于女性(P<0.01);而严重骨质疏松发生率则女性显著高于男性(P<0.01)。结论:骨质疏松发病率与年龄和性别相关。从青年起定期监测骨密度,并尽早调治骨量减少是预防老年性骨质疏松的重要措施。     

Radiation exposure in bone mineral density assessment.

Osteoporosis is a systematic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue which leads to diminished biomechanical competence of the skeleton and low-trauma or atraumatic fractures. Due to increased awareness of the impact of osteoporosis on the elderly population, the use of bone densitometric techniques is becoming more widespread. Considerable progress has been made in the development of non-invasive methods for the assessment of the skeleton. While DXA and QCT are commonly used techniques, the popularity of other approaches such as RA, SXA and QUS is gaining grounds. QCT has an advantage over the other techniques in its ability to measure the true volumetric density of trabecular or cortical bone. We therefore present an overview of these current techniques for bone mineral density (BMD) measurements. In the second section we discuss the radiation doses incurred in BMD measurements by patients and methods for reducing patient and staff radiation exposure are given. Studies of radiation dose to patient from DXA confirms that patient dose is small (0.08-4.6 muSv) compared to that given by many other investigations involving ionizing radiation. Fan beam technology with increased resolution has resulted in increase patient dose radiation dose (6.7-31 muSv) but this is still relatively small. Carrying vertebral morphometry using DXA also incurs less radiation dose (< 60 muSv) than standard lateral radiographs QCT has radiation dose (25-360 muSv) comparable to simple radiological examination such as chest X-ray but lower than imaging CT. Radiation dose from other techniques such as RA and SXA are in the same order of magnitude as pencil beam DXA. For pencil beam DXA and SXA systems the time average dose to staff from scatter is very low even with the operator sitting as close as 1 m from the patient during measurement. However the scatter dose from fan beam DXA systems is considerable higher and approaches limits set by regulator bodies for occupational exposure.     

Current physical activity is related to bone mineral density in males but not in females

The purpose of the present study was to investigate the association between high-, medium-, and low-impact physical activity in males and females at the time of peak bone mineral density in young adulthood. The cohort consisted of 62 male medical students (aged 28.1 +/- 3.9) and 62 female medical students (aged 25.1 +/- 3.9). The bone mineral density (aBMD, g/cm (2)) of the total body, femoral neck, and lumbar spine, and the bone mineral content (BMC, grams) and area (cm (2)) of the femoral neck and lumbar spine was measured using dual energy X-ray absorptiometry. Volumetric BMD (vBMD, mg/cm (3)) of the femoral neck and lumbar spine was estimated. The total amount of physical activity per week, which was recorded in a questionnaire, was divided into high-impact, medium-impact, and low-impact activity. In the male cohort, hours of high-impact physical activity per week was associated with aBMD and BMC of all sites (r=0.27 - 0.53, p<0.05) and bone area of the femoral neck (r=0.38, p<0.01). Total amount of physical activity per week was associated with aBMD of the total body and femoral neck, BMC of femoral neck and lumbar spine, femoral neck vBMD, and the lumbar spine area (p<0.05 for all). Using multiple linear regression, high-impact physical activity was independently associated with aBMD (beta=0.27, p<0.05) and BMC (beta=0.34, p<0.01) of the femoral neck. In the female cohort there was no association between amount or type of physical activity to aBMD, BMC, vBMD, or the bone area of any site. Instead body weight, lean body mass, or fat mass were significantly related to aBMD and all BMC sites in this group. The results of the present study suggest that present physical activity level has a stronger relation to different aspects of bone mass in the male compared to the female adult skeleton.     

Precision of dual-energy x-ray absorptiometry in determining bone mineral density and content of various skeletal sites.

Repeated measurements of bone mineral density (BMD) by dual-energy x-ray absorptiometry (DEXA) reliably indicate changes in the bone mineral content (BMC) of the lumbar spine and proximal femur, but its applicability to other sites has not been properly determined. The in-vivo day-to-day precision of DEXA (Norland XR-26) for lumbar spine, femoral neck, distal femur, patella, proximal tibia, calcaneus and distal radius was evaluated for 15 subjects who were scanned three times for 2 wk. Intra- and interobserver errors were also determined for image analysis. For clearly defined regions of interest, the following precision values were obtained for BMD with low intra- and interobserver error: 1.7% (lumbar spine), 1.3% (femoral neck), 1.2% (distal femur), 1.0% (patella), 0.7% (proximal tibia), 1.3% (calcaneus) and 1.9% (distal radius). The precision for BMC was lower. The results indicate that DEXA can successfully and precisely measure BMD of sites not commonly assessed by this technique.     

Total and regional bone mineral content in healthy Spanish subjects by dual-energy X-ray absorptiometry

Design  This is an observational cross-sectional study. Objective  The aim of the present study was to describe and analyze patterns of change in total and regional bone mineral content in relation to age and gender in a sedentary Spanish sample population (from the Community of Madrid). The age range of the sample population was from birth to 80 years. Materials and methods  One thousand one hundred twenty healthy subjects were recruited and divided into 16 groups according to age. Each subject underwent whole-body densitometry using dual-energy X-ray absorptiometry. An analysis was made of the amount of bone mineral content (BMC) in the whole body and in different regions: the head, trunk, upper limbs, and lower limbs. Results  Gender differences in mean values for upper limbs and lower limbs are statistically significant between 16 and 70 years of age. For the head and trunk, the mean BMC values show the most significant gender differences between 16 and 25 years of age (p ≤ 0.001). Total bone mineral content (TBMC) and TBMC-to-height ratio show significant gender differences between 16 and 70 years of age. In females, TBMC values increase up to 20 years of age and in males up to 25 years of age. Conclusion  We have determined an evolutionary normal pattern of bone mineral content in urban Spanish people.     

High femoral bone mineral content and density in male football (soccer) players

PURPOSE: This investigation examined the effect that long-term football (soccer) participation may have on areal bone mineral density (BMD) and bone mineral content (BMC) in male football players. METHODS: Dual energy x-ray absorptiometry (DXA) scans were obtained in 33 recreational male football players active in football for the last 12 yr and 19 nonactive subjects from the same population. Both groups had comparable age (23 +/- 4 yr vs 24 +/- 3 yr), body mass (73 +/- 7 kg vs 72 +/- 11 kg), height (176 +/- 5 cm vs 176 +/- 8 cm), and calcium intake (23 +/- 10 mg.kg(-1).d(-1) vs 20 +/- 11 mg.kg(-1).d(-1) (mean +/- SD). RESULTS: The football players showed 8% greater total lean mass (P < 0.001), 13% greater whole-body BMC (P < 0.001), and 5 units lower percentage body fat (P < 0.001) than control subjects. Lumbar spine (L2-L4) BMC and BMD were 13% and 10% higher, respectively, in the football players than in the control subjects (P < 0.05). Furthermore, football players displayed higher femoral neck BMC (24%, 18%, 23%, and 24% for the femoral neck, intertrochanteric, greater trochanter, and Ward's triangle subregions, respectively, P < 0.05) and BMD (21%, 19%, 21%, and 27%, respectively, P < 0.05) than controls. BMC in the whole leg was 16-17% greater in the football players, mainly because of enhanced BMD (9-10%) but also because of bone hypertrophy, since the area occupied by the osseous pixels was 7% higher (867 +/- 63 cm2 vs 814 +/- 26 cm2, P < 0.05). Leg muscle mass was 11% higher in the football players than in the control subjects (20,635 +/- 2,073 g vs 18,331 +/- 2,301 g, P < 0.001). No differences were found between the legs in either groups for BMC, BMD, and muscle mass. Left leg muscle mass was correlated with femoral neck BMC and BMD (P < 0.001), as well as with lumbar spine (L2-L4) BMC and BMD (P < 0.001). CONCLUSION: Long-term football participation, starting at prepubertal age, is associated with markedly increased BMC and BMD at the femoral neck and lumbar spine regions.     

Recommendations for bone mineral density reporting in Canada.

OBJECTIVE: To propose a set of recommendations for optimal bone mineral density (BMD) reporting in postmenopausal women and older men and to provide clinicians with both a BMD diagnostic category and a useful tool to assess an individual's risk of osteoporotic fracture. OPTIONS: The current methods of BMD reporting were reviewed. In this document, we propose that an individual's 10-year absolute fracture risk, rather than BMD alone, be used for fracture risk categorization. Consequently, age, sex, BMD, fragility fracture history, and glucocorticoid use are the basis for the approach outlined in this document. OUTCOMES: An optimal BMD report as proposed in this document will provide clinicians with both a BMD diagnostic category and a useful tool to assess an individual's risk of osteoporotic fracture. A BMD report format, a checklist, and a patient questionnaire are meant to further encourage its use. EVIDENCE: All recommendations were developed using a consensus from clinicians and experts in the field of BMD testing and a standard method for the evaluation and citation of the supporting evidence. VALUES: These recommendations were developed by a multidisciplinary working group under the auspices of the Scientific Advisory Council of the Osteoporosis Society of Canada and the Canadian Association of Radiologists. BENEFITS, HARM, AND COSTS: Optimal BMD reports help the practitioner to assess an individual's risk for osteoporotic fracture and to decide whether medical therapy is warranted. RECOMMENDATIONS: The BMD report should include: patient identifiers. Dual-energy X-ray absorptiometry (DXA) scanner identifier. BMD results expressed in absolute values (g/cm2; 3 decimal places) and T-score (1 decimal place) for lumbar spine; proximal femur (total hip, femoral neck, and trochanter); and an alternate site (forearm BMD preferred: 1/3 radius, 33% radius or proximal radius) if either hip or spine is not valid. A statement about any limitations due to artifacts, if present. The fracture risk category (low, moderate, or high) as determined by using Tables 3 and 4 and by including major clinical factors that modify absolute fracture risk probability (with an indication of the corresponding absolute 10-year fracture risk of <10%, 10-20%, or >20%). A statement as to whether the change is statistically significant or not for serial measurements. The BMD centre's least significant change for each skeletal site (in g/cm2) should be included. VALIDATION: Recommendations were based on consensus opinion. Since these are the first Canadian recommendations integrating clinical risk factors in a quantitative fracture risk assessment, it is anticipated that these "Recommendations for BMD Reporting in Canada" will be a work in progress and will be updated periodically to accommodate advances in this field.     

中老年人群肝脏脂肪含量与骨密度的相关性研究

目的探讨中老年人群肝脏脂肪含量与腰椎骨密度的相关性。方法2016年3月至6月纳入184名北京社区中老年居民,其中男68名、女116名,对其进行腹部MRI mDIXON-Quant序列扫描和腰椎定量CT(QCT)扫描,测量肝脏脂肪含量和腰1~腰3椎体骨密度。根据肝脏脂肪含量的四分位数分为四组,采用单因素方差分析比较不同肝脏脂肪含量组间骨密度及身高、体重、体质量指数(BMI)、腰围、臀围等变量的差异,并对肝脏脂肪含量和骨密度做Spearman相关性分析和偏相关分析。结果随着肝脏脂肪含量的升高,BMI、腰围呈上升趋势,而腰椎骨密度逐渐降低。肝脏脂肪含量与腰椎骨密度呈低度负相关(r=-0.203,P=0.003),校正年龄、体重之后,仍呈负相关(r=-0.291,P<0.001),男性中r=-0.283(P=0.021),女性r=-0.210(P=0.025)。结论中老年人群肝脏脂肪含量与腰椎骨密度呈低度负相关。