Correlation of Femoral and Lumbar DXA and Calcaneal Ultrasound, Measured In Situ with Intact Soft Tissues, with the In Vitro Failure Loads of the Proximal Femur

The objective of this study was to determine experimentally the sex-specific correlation of femoral and lumbar DXA and calcaneal ultrasound, measured in situ, with the in vitro failure loads of the proximal femur. Fifty-eight cadavers with intact skin and soft tissues (34 male, aged 81.2 ± 8.7 years; 24 female, aged 83.7 ± 10.6 years) were examined. The bone mass of the proximal femur and the lumbar spine were determined using dual-energy X-ray absorptiometry and the ultrasonic properties of the calcaneus with quantitative ultrasound. Afterwards, the right femora were excised 18 cm distal to the minor trochanter, and their load to failure determined with a material testing machine. Femoral fracture loads were significantly higher in males than in females, both before and after correcting for body height and weight. Femoral neck bone mineral density (BMD) was significantly correlated with femoral failure loads (r= 0.65 all specimens, 0.57 males (0.64 after excluding trochanteric fractures) and 0.77 females; p <0.001). The correlations with the ultrasonic Stiffness Index of the calcaneus were in a similar range (r= 0.67 all specimens, 0.48 males (0.64 after excluding trochanteric fractures) and 0.65 females; p <0.001). The correlations between femoral failure loads and the spinal BMD were lower (r= 0.40, p <0.01), particularly in males (r= 0.30, not significant). In contrast to previous experimental investigations on excised bones, our results are consistent with clinical studies that have reported that ultrasound and femoral DXA have a similar ability to predict the risk of hip fracture. Received: 13 November 1997 / Revised: 4 March 1998     

In Situ Femoral Dual-Energy X-ray Absorptiometry Related to Ash Weight, Bone Size and Density, and its Relationship with Mechanical Failure Loads of the Proximal Femur

The objective of this study was to directly compare in situ femoral dual-energy X-ray absorptiometry (DXA) and in vitro chemical analysis (ash weight and calcium) with mechanical failure loads of the proximal femur, and to determine the influence of bone size (volume) and density on mechanical failure and DXA-derived areal bone mineral density (BMD, in g/cm²). We performed femoral DXA in 52 fixed cadavers (age 82.1 ± 9.7 years; 30 male, 22 female) with intact skin and soft tissues. The femora were then excised, mechanically loaded to failure in a stance phase configuration, their volume measured with a water displacement method (proximal neck to lesser trochanter), and the ash weight and calcium content of this region determined by chemical analysis. The correlation coefficient between the bone mineral content (measured in situ with DXA) and the ash weight was r= 0.87 (standard error of the estimate = 16%), the ash weight allowing for a better prediction of femoral failure loads (r= 0.78; p<0.01) than DXA (r= 0.67; p<0.01). The femoral volume (r= 0.61; p<0.01), but not the volumetric bone density (r= 0.26), was significantly associated with the failure load. The femoral bone volume had a significant impact (r= 0.35; p< 0.01) on the areal BMD (DXA), and only 63% of the variability of bone volume could be predicted (based on the basis of body height, weight and femoral projectional bone area. The results suggest that accuracy errors of femoral DXA limit the prediction of mechanical failure loads, and that the influence of bone size on areal BMD cannot be fully corrected by accounting for body height, weight and projected femoral area. Received: 26 April 1999 / Accepted: 25 October 1999     

Effects of Cigarette-Smoking on Bone Mass as Assessed by Dual-Energy X-ray Absorptiometry and Ultrasound

In order to elucidate the influence of nicotine smoking on bone mass in elderly women, bone mass was cross-sectionally assessed by dual energy X-ray absorptiometry (DXA) in total body, hip and lumbar spine, as well as with ultrasound of calcaneus and phalanges of the hand. Subjects were 1,042, 75-year old women, recruited on a population basis (Osteoporosis Prospective Risk Assessment (OPRA) study). We found bone mineral density (BMD) to be lower in hip (0.71 vs. 0.76 g/cm², p<0.0001 for femoral neck) and total body (0.96 vs. 1.02 g/cm², p<0.0001) in current smokers compared to never-smokers. There was no difference in BMD of the lumbar spine between current smokers and never-smokers. Bone mass as assessed by ultrasound of the calcaneus was lower for speed of sound (p<0.01), broadband ultrasound attenuation (p<0.0001) and stiffness (p<0.0001) in current smokers than in never-smokers. No differences were found for ultrasound measurements of the phalanges between smokers and never-smokers. Also, weight and current physical activity as assessed by a questionnaire differed significantly between current smokers and never-smokers.  There was no evident difference between former smokers and never-smokers in any of the skeletal regions assessed by DXA or ultrasound.  After correcting for differences in weight and physical activity, current smokers had lower BMD in all hip sites (p<0.05) and total body (p<0.01) compared to never-smokers. Ultrasound and BMD spine did not differ between these two groups after correction for weight and physical activity.  We conclude that nicotine smoking has a negative influence on bone mass independent of differences in weight and physical activity. This difference is detected by DXA but not by ultrasound measurements of the calcaneus or the phalanges. The present data are encouraging since no bone mass differences were found between former and never-smokers. Received: 29 March 2002 / Accepted: 2 July 2002     

Regular Physical Exercise and Bone Mineral Density: A Four-Year Controlled Randomized Trial in Middle-aged Men. The DNASCO Study

The aim of the study was to investigate the effects of regular aerobic exercise training on bone mineral density (BMD) in middle-aged men. A population based sample of 140 men (53–62 years) was randomly assigned into the exercise and reference groups. BMD and apparent volumetric BMD (BMD_vol) of the proximal femur and lumbar spine (dual-energy X-ray absorptiometry, DXA) and anthropomorphic measurements were performed at the randomization and 2 and up to 4 years later. The participation rate was 97% and 94% at the second and third BMD measurements, respectively. As another indication of excellent adherence and compliance, the cardiorespiratory fitness (aerobic threshold) increased by 13% in the exercise group. The 2% decrease in the reference group is regarded as an age-related change in cardiorespiratory fitness. Regardless of the group, there was no association between the increase in aerobic threshold and change in BMD. In the entire group, age-related bone loss was seen in the femoral neck BMD and BMD_vol (p<0.01). BMD and BMD_vol values increased with age in L2–L4 (p<0.004). An increased rate of bone loss at the femoral neck was observed in men with a low energy-adjusted calcium intake (p = 0.003). Men who increased their alcohol intake during the intervention showed a decrease in the rate of bone loss at the femoral neck (p = 0.040). A decrease in body height associated with decreased total femoral BMD (r= 0.19, p = 0.04) and the change in body height was a predictor of bone loss in the femoral neck (β= 0.201). Long-term regular aerobic physical activity in middle-aged men had no effect on the age-related loss of femoral BMD. On the other hand, possible structural alterations, which are also essential for the mechanical strength of bone, can not be detected by the DXA measurements used in this study. The increase seen in lumbar BMD reflects age-related changes in the spine, thus making it an unreliable site for BMD follow-up in men. Received: August 2000 / Accepted: November 2000     

Hormonal and Anthropometric Predictors of Bone Mass in Healthy Elderly Men: Major Effect of Sex Hormone Binding Globulin, Parathyroid Hormone and Body Weight

Osteoporosis in men is a significant health problem, and factors associated with bone mass are being investigated. Although osteoporosis is a typical feature of hypogonadism, the influence of testosterone levels and other hormonal factors on bone mass of eugonadal males is unknown. Our aim was to identify several anthropometric and hormonal predictors that could be responsible for the variability in bone mineral density (BMD) in healthy men. One hundred elderly men (age 68 ± 7 years) were investigated in this cross-sectional study. BMD was measured by dual-energy X-ray absorptiometry (DXA) at the lumbar spine and femoral sites (femoral neck, Ward’s triangle, trochanter, intertrochanter and total femur). Anthropometric measures were obtained including: weight, height, body mass index (BMI), waist–hip ratio and testicular volume. Hormonal data measures were total, free and bioavailable testosterone, dihidrotestosterone, estradiol, sex hormone binding globulin (SHBG), insulin-like growth factor I (IGF-I), intact parathyroid hormone (iPTH) and 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃). One subject was excluded because primary hypogonadism was found. SHBG levels were increased in 53.5% of men, and 8% showed a mild increase in iPTH levels. Twenty-eight subjects had densitometric criteria of osteoporosis (T-score ≤−2.5). All BMD sites were positively correlated with body weight (r= 0.29–0.48, p<0.001) and BMI (r= 0.24–0.47, p<0.001). A negative correlation between SHBG levels and intertrochanter (IT) and total femur (TL) BMD was found (r=−0.24 and r=−0.22, p<0.05). After adjusting for age and BMI, SHBG and IGF-I levels were negatively correlated (r=−0.33, p<0.001). In multiple linear regression analysis independent predictors of bone mass were body weight, SHBG and iPTH levels. The best predictive model accounted for 24–40% of the observed variability of BMD. However, most of the BMD variability was explained by body weight. In conclusion, in our study body weight, SHBG and iPTH levels were predictors of BMD in healthy elderly men. Received: 9 June 2000 / Accepted: 27 September 2000     

Quantitative Ultrasound Measurements of the Tibia and Calcaneus in Comparison with DXA Measurements at Various Skeletal Sites

The performance of quantitative ultrasound (QUS) measurements of the tibia and calcaneus was studied in 109 elderly people (age range 65–87 years). Broadband ultrasound attenuation (BUA) and speed of sound (SOS) were measured at the calcaneus and SOS was assessed at the tibia. Short-term precision of tibial QUS was studied in 16 volunteers. The coefficient of variation (CV) was 0.4% and the standardized CV (sCV) was 4.4%. We compared the calcaneal and tibial QUS measurements with bone mineral density (BMD) measurements of the lumbar spine, femoral neck, trochanter and total body assessed by dual-energy X-ray absorptiometry (DXA). Calcaneal QUS correlated better with BMD at various skeletal sites than tibial QUS. Calcaneal BUA showed higher correlations with BMD values of the lumbar spine, femoral neck, trochanter and total body than calcaneal and tibial SOS (r= 0.48–0.64, r= 0.30–0.47, r= 0.35–0.47, respectively; p<0.001). Body weight modified the relationships between calcaneal and tibial QUS and BMD measurements of the hip. Higher body weight was associated with higher BMD values at the femoral neck and trochanter for the same calcaneal and tibial QUS values. After adjustments for body weight correlations of tibial and calcaneal QUS with BMD improved and were very similar. This suggests that correction for body weight is important and could add to the predictive value of QUS measurements. Received: 16 July 1997 / Accepted: 8 July 1998     

The Effect of Weight Change on DXA Scans in a 2-Year Trial of Etidronate Therapy

Variation in soft tissue composition is a potential cause of error in dual X-ray absorptiometry (DXA) measurements of bone mineral density (BMD). We investigated the effect of patients' change of weight on DXA scans in 152 women enrolled in a 2-year trial of cyclical etidronate therapy. Scans of the spine, hip, and total body were performed at baseline, 1 and 2 years on a Hologic QDR-2000. The study was completed by 135 subjects (64 on etidronate, 71 on placebo). Results were expressed as the percentage change in BMD (spine, femoral neck, total body) or bone mineral content (BMC) (total body only) at 2 years. Total body scans were analyzed using the manufacturer's `standard' and `enhanced' algorithms. Analysis was performed using multivariate regression with percentage change in BMD or BMC as the dependent variable, and treatment group and percentage change in weight as the independent variables. Weight change varied between −14.4% and +16.7%. All DXA variables showed a statistically significant treatment effect. Standard total body BMD and BMC and enhanced total body BMC all showed a significant dependence on weight change (P < 0.01, P < 0.001 and P < 0.01, respectively). No effect of weight change was seen on spine, femoral neck, or enhanced total body BMD. In order to investigate the effects of weight on long-term precision, patients were allocated to two groups according to baseline body mass index (BMI <25 and >25 kg/m², respectively). For femoral neck BMD the root mean square (RMS) residual percentage change was statistically significantly larger in the high BMI group (P < 0.05) but all other bone density variables showed no significant difference. With patients allocated to two groups according to their absolute percentage change in weight (<5% and >5%, respectively) the RMS residual percentage changes in the bone density variables were statistically significantly larger in the large weight change group for femoral neck BMD (P < 0.05) and for standard and enhanced total body BMC (P < 0.01 and P < 0.05, respectively). With the exception of the standard total body algorithm, weight change in a longitudinal study of postmenopausal women was not found to cause systematic errors in the results of DXA studies but may adversely affect precision. Received: 22 November 1996 / Accepted: 30 April 1997     

Evolution of Lumbar Bone Mineral Content During Adolescence and Adulthood: A Longitudinal Study in 395 Healthy Females 10–24 Years of Age and 206 Premenopausal Women

In a longitudinal study of 395 normal 10- to 24-year-old female volunteers, 105 of whom were initially premenarcheal, lumbar bone mineral density (BMD) and content (BMC) were measured by dual-energy X-ray absorptiometry (DXA) at inclusion and after a 2-year interval. The mean age of menarche was 13.1 t 1.1 years (n = 395). In a multiple regression analysis the BMD and BMC relative gains were highly correlated with the height and weight relative gains and with the time since menarche (r= 0.91 and r= 0.93, respectively). The mean relative annual increments in body height, in L2–4 vertebral height, in BMD and in BMC peaked respectively at 1.5, 1.0, 0.6 and 0.7 years before menarche. The four perimenarcheal years, beginning with the first pubertal clinical signs, are essential for bone acquisition, since 46.7% of adult BMC is acquired during this period. Two years after menarche, BMC is 85% of the adult value. Seven years after menarche no further significant variation in BMC is observed. In 206 menstruating women 27–47 years old, a DXA lumbar measurement was also performed after a 4-year interval. There was a small but significant increase of 0.3 %/year in BMD and 0.7 %/year in BMC, contrasting with the results in the young population. This could be explained by a volumetric expansion with aging, which is supported by a small increase in L2–4 area (0.4 %/year). In conclusion, this longitudinal study on the lumbar site emphasizes the importance of the pre- and perimenarcheal period, when half of lumbar adult BMC is acquired. This suggests that greater attention must be paid to this period regarding nutrition and physical activity. Received: 15 May 1998 / Accepted: 19 October 1998     

PIXImus Bone Densitometer and Associated Technical Measurement Issues of Skeletal Growth in the Young Rat

The PIXImus dual-energy X-ray absorptiometer (DXA) is designed to measure body composition, bone mineral content (BMC), area (BA), and density (BMD) in mice and rats. The aims of this study were to longitudinally measure BMC, BA, and BMD in growing rats and to identify potential technical problems associated with the PIXImus. Total femur and lumbar DXA measurements, body weight, and length of initially 3-week-old rats (n = 10) were taken at weeks 5, 9, and 14. BMC and BMD of femoral metaphyseal and diaphyseal regions rich in trabecular and cortical bone, respectively, were obtained. Results showed significant increases in body weight, total femur BMC and BMD, lumbar area, length, BMC, and BMD at each time point. There was a significant positive correlation between body weight and total femur BMD (r = 0.97, P < 0.001) as well as lumbar BMD (r = 0.99, P < 0.001). BMD values for the femoral metaphyseal region and the lumbar spine were also positively correlated (r = 0.96, P < 0.01). Several technical issues (e.g., positioning of animals), difficulties (e.g., in analysis of images), and limitations (e.g., inability to detect underdeveloped calcified bone in growing animals and bone edge detection) of the software pertinent to the PIXImus were evident. In conclusion, despite limitations in the software, the PIXImus is a valuable tool for studying skeletal development of growing rats.     

Determinants of Bone Loss in Elderly Men and Women: A Prospective Population-Based Study

While several studies have described the rate and pattern of involutional bone loss in women, far less information is available for men. Furthermore, the roles of lifestyle and body build in determining bone loss rate in both sexes have been largely extrapolated from cross-sectional studies. We addressed this issue in a population-based longitudinal study which sought to ascertain rates of bone loss at the femoral neck and lumbar spine in a cohort of men and women aged 60–75 years at baseline, and to relate this loss to anthropometric and lifestyle variables. We additionally investigated the capacity of biochemical markers of bone turnover to predict bone loss rates in these subjects. Women lost bone at all sites; this ranged from 0.20%/year at the lumbar spine to 1.43%/year at the femoral trochanteric region. By contrast, men lost only 0.20%/year at the trochanteric region, and gained at the lumbar spine (0.33%/year) and at Ward’s triangle (0.27%/year) over the 4-year period. Anthropometric measurements were associated with bone loss in both sexes; lower baseline body mass index (BMI) and a greater rate of loss of adiposity over the follow-up period were both associated with greater bone loss at all proximal femoral sites. These attained statistical significance after Bonferroni correction at the total proximal femur among both men (r= 0.29), p<0.01) and women (r= 0.31, p<0.05). Lifestyle factors associated with lower rates of bone loss (after adjustment for BMI) included alcohol consumption at the femoral neck among women (p= 0.007) and physical activity at the lumbar spine among men (p = 0.05). Serum parathyroid hormone, 25-hydroxyvitamin D and biochemical markers of bone turnover did not predict bone loss after adjustment for adiposity. Received: 8 December 1998 / Accepted: 8 April 1999     

Continuous Loss of Bone During Chronic Immobilization: A Monozygotic Twin Study

Acute immobilization is associated with rapid loss of bone. Prevailing opinion, based on population cross-sectional data, assumes that bone mass stabilizes thereafter. In order to address whole-body and regional skeletal mass in long-term immobilization, monozygotic twins were studied, one of each twin pair having chronic spinal cord injury (SCI) of a duration ranging from 3 to 26 years. The research design consisted of the co-twin control method using 8 pairs of identical male twins (mean ± SD age, 40 ± 10 years; range 25–58 years), one of each set with SCI. The twins were compared by paired t-tests for total and regional bone mineral content (BMC) and bone mineral density (BMD) measured by dual-energy X-ray absorptiometry. Linear regression analyses were performed to determine the associations of age or duration of injury with the differences between twin pairs for total and regional skeletal bone values. In the SCI twins, total-body BMC was significantly reduced (22%± 9%, p<0.001), with the predominant sites of reduction for BMC and BMD being the legs (42%± 14% 35%± 10%, p<0.0001), and pelvis (50%± 10% and 29%± 9%, p<0.0001). Duration of SCI, not age, was found to be linearly related to the degree of leg bone loss in SCI twins (BMC: r ²= 0.60, p<0.05; BMD: r ²= 0.70, p<0.01). Our findings suggest that pelvic and leg bone mass continues to decline throughout the chronic phase of immobilization in the individual with SCI, and this bone loss appears to be independent of age. Received: 28 September 1998 / Accepted: 28 December 1998     

Changes in Bone Mass and Bone Turnover Following Ankle Fracture

Bone loss and increased bone turnover are recognized local changes after a fracture, but the exact patterns of these changes after different fractures are unclear. We aimed to investigate the changes in bone density and biochemical markers following ankle fracture. Fourteen subjects (7 postmenopausal women and 7 men, mean age 63 years) were recruited following fracture of the distal tibia and fibula. Bone mineral density (BMD) of the ankle and proximal femur were measured by dual-energy X-ray absorptiometry (DXA) and quantitative ultrasound (QUS) of the calcaneus at 0, 6, 12, 26 and 52 weeks after fracture. Serum and urine samples were collected at 0, 3 and 7 days and at 2, 4, 6, 12, 26 and 52 weeks after fracture to measure markers of bone turnover. For bone formation we measured: bone alkaline phosphatase (iBAP), osteocalcin (Oc), procollagen type I N-terminal propeptide (PINP); and for bone resorption: tartrate-resistant acid phosphatase (TRAcP), deoxypyridinoline (iFDpd), N-telopeptides of type I collagen (NTx). We used the nonfractured limb to calculate values for baseline BMD and QUS. There was a significant decrease in BMD at the ultradistal ankle (p<0.001), the trochanteric region of the hip (p<0.01) and QUS of the heel after ankle fracture. This bone loss was maximal for ultradistal ankle BMD by 6 weeks at 13% (p<0.001) and for the trochanter by 26 weeks at 3% (p<0.01). The ankle BMD returned to baseline at 52 weeks but the trochanter BMD did not. Velocity of sound (VOS) decreased at 6 weeks by 2% (p<0.01) and broadband ultrasound attenuation (BUA) by 15% (p<0.01). VOS recovered completely by 52 weeks, but BUA did not return to baseline. Bone formation markers increased significantly between 1 and 4 weeks by 11–78% (p<0.01), and iBAP returned to baseline at 52 weeks but PINP and Oc remained elevated. Bone resorption markers did not increase and NTx was decreased at 52 weeks. We conclude that BMD decreased distal and immediately proximal to the fracture line when measured with DXA and QUS. Ankle BMD and heel VOS recovered at 52 weeks (trochanteric BMD and heel BUA did not) and the bone turnover markers returned toward baseline. Received: 27 January 1999 / Accepted: 19 April 1999     

The Effect of Weight Change on Total Body Dual-Energy X-ray Absorptiometry: Results from a Clinical Trial

In the past decade dual-energy X-ray absorptiometry (DXA) scanning has assumed an important role in the evaluation of new treatments for osteoporosis. Although the spine and hip are the sites usually chosen for monitoring bone mineral density (BMD) changes, total body DXA is also of interest because of the comprehensive view it gives of the whole skeleton. However, recent studies have reported anomalies in total body DXA in subjects undergoing weight change, suggesting that the technique may not be valid in this circumstance. The present study evaluated total body DXA in a trial of cyclical etidronate therapy in which many subjects underwent significant weight change. The study population was 152 postmenopausal women who had spine, hip and total body DXA scans performed at baseline, 1 and 2 years. The total body scans were analyzed using two software options referred to as “standard” and “enhanced”. The following variables were studied: total body BMD, total body bone mineral content (BMC), and subregional BMD values for the following seven sites: lumbar spine, thoracic spine, pelvis, head, ribs, arms and legs. The percentage change from baseline was analyzed in a multivariate regression analysis to derive the treatment effect (defined as the difference in changes between the etidronate and placebo groups) and a coefficient that described the effect of weight change on the total body DXA variable. Mean weight change after 2 years was +1.1 kg (range −9.3 to +16.8 kg). Results for the weight change coefficient were significantly different from zero for five of nine total body variables using the standard analysis and seven of nine for the enhanced analysis with values (and standard errors) that varied from +0.67 (0.04) %/kg for standard total body BMC to −0.32 (0.11) %/kg for enhanced arm BMD. Results for the treatment effect at 2 years were significantly different from zero for total body BMD, total body BMC and for the lumbar spine, thoracic spine and pelvis BMD subregions, but were not significant for head, rib, arm or leg BMD. Findings for the standard and enhanced analyses agreed closely and the size of the treatment effect was related to the proportion of trabecular bone at the measurement site. We conclude that in a randomized study the effects of weight change can be corrected and total body DXA can give useful information about the response to treatment across the whole skeleton. Received: 18 February 2000 / Accepted: 12 April 2000     

Birth Weight as a Predictor of Adult Bone Mass in Postmenopausal Women: The Rancho Bernardo Study

Understanding the determinants of adult bone mass may help to identify women for prevention of osteoporosis. We postulated that birth weight would predict low adult bone mass in old age. Subjects were 305 postmenopausal Caucasian women (mean age 70 years). Bone mineral content (BMC) and bone mineral density (BMD) were measured at the wrist, forearm, hip and lumbar spine. Birth weight was assessed by self-report. Birth weight was positively correlated with BMC at the forearm (r= 0.15), hip (r= 0.12) and lumbar spine (r= 0.18), and the age-adjusted mean BMC increased significantly from the lowest to the highest birth weight tertile. Adjusting for adult weight diminished this association at the forearm and hip, but not at the spine. Adjustment for multiple other covariates, including height, did not materially change these associations. Adult weight and height were significantly correlated with birth weight (r= 0.19 and r= 0.24, respectively). Birth weight was not independently correlated with BMD. Birth weight was thus positively correlated with adult weight and BMC 70 years later. These findings suggest that low birth weight may be a marker for future low bone mass and that different mechanisms exist for establishing the adult bone envelope (estimated by BMC) versus its density (estimated by BMD). Received: 18 August 1999 / Accepted: 21 January 2000     

Bone Mineral Density and Body Composition in Underweight and Normal Elderly Subjects

The importance of malnutrition as a risk factor in osteoporosis is emphasized by the evidence that patients with fractures of the proximal femur are often undernourished. In this study, nutritional status, bone mineral mass and its association with body composition were investigated in underweight and normal weight elderly subjects. Moreover the hypothesis that malnutrition in elderly is associated with a higher risk of osteoporosis was tested. The participants were 111 elderly subjects divided into two groups according to body mass index (BMI): 51 patients were underweight (BMI < 22 kg/m²) while in 60 subjects BMI ranged from 22 to 30 kg/m². In all patients anthropometric parameters and blood indices of malnutrition and of bone turnover were measured. Fat-free soft mass (FFSM), fat mass (FM), bone mineral content (BMC) and bone mineral density (BMD) ‘total body’ and at the hip were obtained by dual-energy X-ray densitometry. Dietary intake was evaluated with the diet history method, while resting energy expenditure (REE) was measured by indirect calorimetry. Underweight subjects had other signs of malnutrition, such as low visceral proteins, sarcopenia, and an inadequate energy intake. Moreover they showed a significant reduction of BMC and BMD compared with normal subjects. In men with BMI <22 kg/m², T-score was below −2.5 (−3 at femoral neck and −2.7 at total hip) while men in the control group had normal bone mineral parameters. T-score at different sites was lower in underweight women than in underweight men, always showing values under −3.5, with clear osteoporosis and a high fracture risk. In healthy women the T-score values indicated the presence of mild osteoporosis. In underweight subjects, low levels of albumin (< 35 g/l) were associated with higher femoral bone loss. Using a partial correlation model, BMC, adjusted for age, bone area, knee height and albumin showed a significant association with FM in women (r= 0.48; p < 0.01) and with FFSM in men (r= 0.48; p < 0.05). Albumin, when adjusted for other variables, was significantly correlated (r= 0.52; p < 0.05) with femoral neck BMC only in women. In conclusion, the underweight state in the elderly is associated with malnutrition and osteoporosis; other factors occurring in malnutrition, besides body composition changes, such as protein deficiency, could be involved in the association between underweight and osteoporosis. Moreover bone mineral status seems to be related to fat-free soft mass tissue in men while in women it is much more closely associated with total body fat. Received: 3 January 2000 / Accepted: 3 July 2000     

High Bone Mineral Density in Male Elite Professional Volleyball Players

The aim of this study was to assess bone mass in male elite athletes participating in an impact loading sport (volleyball) and, in particular, to determine whether the asymmetric nature of this sport leads to differences in the skeletal tissue composition of the limbs. Fifteen male volleyball players (VP) (26 ± 4 years, 192 ± 6 cm, 87 ± 9 kg; mean ± SD) and 15 non-active control subjects (25 ± 2 years, 177 ± 8 cm, 72 ± 11 kg; mean ± SD) were studied. VP training sessions (3–6 days/week) included a variety of jumping and weightlifting exercises. The VP were taller and heavier than the control subjects (p<0.001). Whole-body bone mineral content (BMC) and lean mass were higher in VP after adjustment for body mass and height (p<0.001). Axial skeleton and limb BMC and bone mineral density (BMD) were higher in VP than in control subjects (p<0.05). Adjusted lumbar spine (L2–4) BMD was 14% higher in VP than in control subjects (p<0.05). Similarly, a much greater adjusted BMD was observed in the femoral neck of VP (24%, 20%, 27% and 20% for the femoral neck, intertrochanteric, greater trochanter and Ward’s triangle subregions respectively; p<0.05). The dominant arm was slightly heavier (≈3%) and had 4% more muscle mass than the contralateral arm in both the VP (p<0.05) and control subjects (p<0.05). Greater BMC values (9%), BMD (7%) values and the area occupied by osseous pixels (5%) were recorded in the dominant arm as compared with the nondominant arm in VP (p<0.05). No differences between arms were observed in control subjects. Right and left leg BMC and BMD values were similar in control subjects while 4% higher BMC values were recorded for the left leg in the VP group (p<0.05). A close relationship between left leg muscle mass and BMD was observed in the femoral neck subregions of all the subjects (r= 0.81, 0.81, 0.78 and 0.79 for the femoral neck, intertrochanteric, greater trochanter and Ward’s triangle subregions respectively; p<0.001; n= 30). These findings clearly demonstrate a considerably high BMC and BMD in professional volleyball players which seems to be related to the loading type of exercise they perform. Received: 26 October 1998 / Accepted: 26 May 1999     

A Prospective Study of Bone Loss in Menopausal Australian-Born Women

Two hundred and twenty-four women (74 pre-, 90 peri-, 60 post-menopausal), aged 46–59 years, from a population-based cohort participated in a longitudinal study of bone mineral density (BMD). BMD was measured by dual-energy X-ray absorptiometry (DXA) at the lumbar spine and femoral neck and the time between bone scans was on average 25 (range 14–41) months. The aim of the study was to assess changes in BMD in relation to changes in normal menopausal status. During the study period women who were between 3 and 12 months past their last menstrual period (n= 22, late perimenopausal) at the time of the second bone scan had a mean (SE) annual change in BMD of 70.9% (0.4%) at the lumbar spine and 70.7% (0.6%) at the femoral neck (both p50.05 compared with women who remained premenopausal). In the women who became postmenopausal (n= 42) the mean annual changes in BMD were 72.5% (0.2%) at the lumbar spine and 71.7% (0.2%) at the femoral neck (both p50.0005), and in the women who remained postmenopausal (n= 60) they were 70.7% (0.2%) per year and 70.5% (0.3%) per year respectively (both p50.05), compared with women who remained premenopausal. In the 1–3 years after the final menstrual period (FMP) there was greater bone loss from the lumbar spine than the femoral neck (p50.05). In women who were menstruating at the time of the second bone scan and whose FMP could be dated prospectively (n= 35), higher baseline oestradiol levels were associated with less lumbar spine bone loss (p50.005). In the women who remained postmenopausal there was an association between baseline body mass index (BMI) and percentage change per year in femoral neck BMD (p50.05), such that women with higher BMI had less bone loss. In conclusion, during the time of transition from peri- to post-menopause, women had accelerated BMD loss at both the hip and spine. Received: 23 June 1997 / Accepted: 5 November 1997     

Comparison of Quantitative Ultrasound Measurements in Calcaneus with DXA and SXA at Other Skeletal Sites: A Population-Based Study on 280 Children Aged 11–16 Years

We performed ultrasound measurements (QUS) of the calcaneus in a population-based setting on 280 healthy children, aged 11–16 years, from a small urban area in southern Sweden. The results are compared with dual-energy X-ray absorptiometry (DXA) measurements in the total body, the lumbar spine and the hip, as well as single-energy X-ray absorptiometry (SXA) of the forearm. Normative data and correlations between the three different techniques were determined. We found significant correlations between QUS and age (r= 0.34–0.54), height (r= 0.13–0.56) and weight (r= 0.30–0.60), and between QUS and bone mineral density (BMD) measurements (r= 0.44–0.70). Boys increased all their bone mineral variables with age, whereas girls showed a decreasing trend from age 15 years. QUS had a significantly higher increase in standardized value with age than Ward's triangle BMD, but a significantly lower increase in standardized value with age than distal radius (cortical site) BMD. At other BMD sites we did not find any significant differences compared with QUS regarding changes with age. The measurements obtained by QUS, DXA and SXA, respectively, were divided into quartiles. Of all subjects in the lowest quartile for QUS measurements, only 34–50% were also in the lowest quartiles for DXA and SXA measurements. In conclusion, QUS measurements of the calcaneus in children show similar results as for adult regarding the correlation with DXA and SXA; they also have a significant correlation with anthropometric data. QUS did not identify the same individuals with low bone mass as the X-ray techniques. Received: 23 June 1997 / Accepted: 21 January 1998     

The Contribution of Cortical and Cancellous Bone to Dual-Energy X-ray Absorptiometry Measurements in the Female Proximal Femur

Dual-energy X-ray absorptiometry (DXA) is the most common method for determining bone mineral density (BMD) in the proximal femur. However, there remain questions concerning the contribution of cortical and cancellous bone to this technology in the proximal femur. The purpose of this investigation was to identify structural and compositional characteristics of human bone in the proximal femur that significantly influence DXA BMD measurements. Twenty-four femora were obtained at autopsy from Caucasian females ranging in age from 17 to 92 years (mean ± SD, 61 ± 25 years). DXA scans were performed on each specimen with a Hologic QDR-2000 densitometer. Direct measurements were determined from proximal femoral sections for cancellous bone (volume fraction, ash fraction, cancellous cross-sectional area and percent cancellous cross-sectional area), cortical bone (thickness, ash fraction, porosity, cortical cross-sectional area and percent cortical cross-sectional area) and anteroposterior thickness. These parameters were compared with the associated DXA measurements by means of simple and multiple regressions. Cancellous volume fraction was the best predictor of variability of DXA measurements for both the neck and trochanter, with an R ² of 0.87 and 0.76, respectively (p<0.0001). There was only a minor influence of cortical factors such as thickness (neck and trochanter R ²= 0.51 and 0.42, respectively, p<0.001) and trochanteric cross-sectional area (R ²= 0.21, p<0.05). Although the accuracy for determining specific components of the proximal femur was low, the DXA BMD measurement was a strong predictor of cancellous bone factors, but not cortical bone factors that have been shown to change significantly with age. Received: 2 February 2000 / Accepted: 7 September 2000     

The Association between Parathyroid Hormone, Vitamin D and Bone Mineral Density in 70-Year-Old Icelandic Women

Parathyroid hormone (PTH) may be an important determinant of cortical bone remodeling in the elderly. Vitamin D status is one of the determining factors in this relationship. The aim of this study was to quantify the relationship between serum PTH, vitamin D and bone mineral density (BMD) in elderly women in Reykjavik (64° N), where daily intake of cod liver oil is common and mean calcium intake is high. ln PTH correlated inversely with 25(OH)D (r=−0.26, p<0.01). In multivariate analysis PTH correlated inversely with whole body BMD (mostly cortical bone) (R ²= 2.2%, p = 0.04) but not with the lumbar spine BMD, reflecting more cancellous bone. No association was found between 25(OH)D levels and BMD at any site in univariate or multivariate analysis. Osteocalcin, a measure of bone turnover, was negatively associated with BMD and this association remained significant when corrected for PTH levels. In summary, in this fairly vitamin D replete population with high calcium intake, PTH was negatively associated with total body BMD. We infer that suppression of PTH may reduce cortical bone loss, but other factors are likely to contribute to age-related bone remodeling and osteoporosis. Received: 3 January 2000 / Accepted: 10 April 2000