Bone composition in the distal forearm

Prescreening for osteoporosis with forearm bone densitometry in health examination population

BACKGROUND

Early detection and timely prophylaxis can retard the progression of osteoporosis. The purpose of this study was to determine the validity of peripheral Dual Energy X-ray Absorptiometry (DXA) test for osteoporosis screening. We examined peripheral bone mineral density (BMD) using AKDX-09 W-I DXA densitometer. Firstly, we acquired BMD data from manufacturer-supplied density-gradient phantoms and 30 volunteers to investigate its accuracy and precision, then we measured BMD for 150 volunteers using both AKDX (left forearm) and Hologic Discovery Wi (left forearm, left hip and L1 - L4 vertebrae) simultaneously. Correlation relationship of BMD results acquired from two instruments was assessed by simple linear regression analysis, the Receiver Operating Characteristic (ROC) curves and Areas Under the Curves (AUCs) were evaluated for the diagnostic value of left forearm BMD measured by AKDX in detecting osteoporosis.

RESULTS

In vitro precision errors of AKDX BMD were 0.40, 0.20, 0.19%, respectively, on low-, medium-, and high-density phantom; in vivo precision was 1.65%. Positive correlation was observed between BMD measured by AKDX and Hologic at the forearm (r = 0.670), L1-L4 (r = 0.430, femoral neck (r = 0.449), and total hip (r = 0.559). With Hologic measured T-score as the gold standard, the sensitivity of AKDX T-score < - 1 for identifying suboptimal bone health was 63.0 and 76.1%, respectively, at the distal one-third radius and at any site, and the specificity was 73.9 and 90.0%, respectively; the AUCs were 0.708 and 0.879. The sensitivity of AKDX T-score ≤ - 2.5 for identifying osteoporosis at the distal one-third radius and at any site was 76.9 and70.4%, respectively, and the specificity was 80.4 and 78.0%, respectively; the AUCs were 0.823 and 0.778.

CONCLUSIONS

Peripheral DXA appears to be a reliable tool for prescreening for osteoporosis.

Multiscale Biofabrication of Articular Cartilage: Bioinspired and Biomimetic Approaches

Articular cartilage is the load-bearing tissue found inside all articulating joints of the body. It vastly reduces friction and allows for smooth gliding between contacting surfaces. The structure of articular cartilage matrix and cellular composition is zonal and is important for its mechanical properties. When cartilage becomes injured through trauma or disease, it has poor intrinsic healing capabilities. The spectrum of cartilage injury ranges from isolated areas of the joint to diffuse breakdown and the clinical appearance of osteoarthritis. Current clinical treatment options remain limited in their ability to restore cartilage to its normal functional state. This review focuses on the evolution of biomaterial scaffolds that have been used for functional cartilage tissue engineering. In particular, we highlight recent developments in multiscale biofabrication approaches attempting to recapitulate the complex 3D matrix of native articular cartilage tissue. Additionally, we focus on the application of these methods to engineering each zone of cartilage and engineering full-thickness osteochondral tissues for improved clinical implantation. These methods have shown the potential to control individual cell-to-scaffold interactions and drive progenitor cell differentiation into a chondrocyte lineage. The use of these bioinspired nanoengineered scaffolds hold promise for recreation of structure and function on the whole tissue level and may represent exciting new developments for future clinical applications for cartilage injury and restoration.

Mandibular bone structure, bone mineral density, and clinical variables as fracture predictors: a 15-year follow-up of female patients in a dental clinic

OBJECTIVE

To compare three mandibular trabeculation evaluation methods, clinical variables, and osteoporosis as fracture predictors in women.

STUDY DESIGN

One hundred and thirty-six female dental patients (35-94 years) answered a questionnaire in 1996 and 2011. Using intra-oral radiographs from 1996, five methods were compared as fracture predictors: (1) mandibular bone structure evaluated with a visual radiographic index, (2) bone texture, (3) size and number of intertrabecular spaces calculated with Jaw-X software, (4) fracture probability calculated with a fracture risk assessment tool (FRAX), and (5) osteoporosis diagnosis based on dual-energy-X-ray absorptiometry. Differences were assessed with the Mann-Whitney test and relative risk calculated.

RESULTS

Previous fracture, gluco-corticoid medication, and bone texture were significant indicators of future and total (previous plus future) fracture. Osteoporosis diagnosis, sparse trabeculation, Jaw-X, and FRAX were significant predictors of total but not future fracture.

CONCLUSION

Clinical and oral bone variables may identify individuals at greatest risk of fracture.

Bone mineral density measured by a portable X-ray device agrees with dual-energy X-ray absorptiometry at forearm in preschool aged children

Dual-energy X-ray absorptiometry (DXA) measures of bone mineral density (BMD) are generally not feasible in fieldwork. The present study determined the agreement between BMD measured by DXA and portable peripheral DXA in preschool aged children. Fifty-seven children (4.2 ± 1.0 yr) had their nondominant distal forearm scanned using a peripheral DXA scanner (PIXI; GE Medical Systems Lunar, Madison, WI) at their daycare and a DXA (4500A Discovery Series; Hologic Inc., Bedford, MA) at our research clinic. Correlation analysis, one-way analysis of variance, and Bland-Altman plots were performed to examine the agreement between measurements. Data were also divided into tertiles for cross-classification analysis and calculation of kappa coefficients. Distal forearm BMD measured by PIXI was significantly correlated with DXA measures of total forearm BMD (r > 0.51; p < 0.001), proximal 1/3 BMD (r > 0.41; p < 0.001), mid-BMD (r > 0.37; p < 0.001), and ultradistal (UD) BMD (r > 0.57; p < 0.001). Cross-classification in the same or adjacent tertile between measures (UD forearm: 96.5%; UD radius: 94.4%; total forearm: 87.7%; total radius: 84.2%) resulted in weighted kappa coefficients of 0.46, 0.58, 0.42, and 0.43, respectively. Bland-Altman plots further clarified these agreements as all had low bias (UD forearm: bias = 0.003 ± 0.002; UD radius: -0.015 ± 0.021; total forearm: -0.062 ± 0.027; total radius: -0.077 ± 0.026). These results demonstrate that portable DXA measures of forearm BMD agree moderately with DXA.

Prevalence of low forearm bone mineral density in Bulgarian men: a pilot study

OBJECTIVE

To determine the prevalence of osteoporosis at the distal forearm in a male cohort referred for bone density testing and to compare it to published data of Bulgarian women.

DESIGN AND SUBJECTS

315 consecutive Bulgarian men aged 20 to 84 years were included (mean age 53.74 +/- 14.67 years). 59% of them were self-referrals. The comparative female group consisted of 8869 Bulgarian women whose forearm bone mineral density (BMD) was measured in another study.

MEASUREMENTS

BMD was measured by single X-ray absorptiometry at the distal forearm (distal and ultradistal sites) in all men. T-scores were calculated from manufacturer-provided Danish male reference data.

RESULTS

The ratio of female to male patients was 28.2 (8869 to 315). Peak BMD was observed in men aged 30 to 39 years: 0.560 +/- 0.065 g/cm(2) (distal site) and 0.490 +/- 0.070 g/cm(2) (ultradistal site). A steady BMD decline followed reaching 0.492 +/- 0.064 g/cm(2) at the distal and 0.412 +/- 0.069 g/cm(2) at the ultradistal site in age group >70. Age had a rather weak negative impact on forearm BMD described by a linear model. In men aged over 50 years the prevalence of osteoporosis at the distal site was 21.19%, compared to 20.45% in women. Low bone mass was seen in 48.77% of men and 32.50% of women. Normal BMD was more frequent in women (47.05%) than in men (30.04%).

CONCLUSIONS

We found a high prevalence of forearm osteoporosis in Bulgarian men which is comparable to that already known in women.

Changes in the radiographic characteristics of the mandibular alveolar process in dentate women with varying bone mineral density: a 5-year prospective study

The association between skeletal bone mineral density (BMD) and mandibular alveolar bone mass has been reported to be rather weak, probably due to local functional factors. Many new investigations are therefore focused on assessing the mandibular bone structure. No long-term structural alterations have been reported in human mandibular bone with the exception of alveolar crest changes related to periodontal disease. The aim of this prospective study was to investigate dentate women to see if possible alterations in the radiographic characteristics of the mandibular alveolar bone are related to changes in BMD. The BMD of 131 women (initial age 22-75 years) was determined in the distal forearm with dual energy X-ray absorptiometry on two occasions separated by an interval of 5 years. Mandibular alveolar bone mass (MABM) was assessed both by the optical density and by the grey-level value on digitized, calibrated, periapical radiographs. The radiographic alveolar bone structure was evaluated with a visual index [Lindh C, Petersson A, Rohlin M. Assessment of the trabecular pattern before endosseous implant treatment: diagnostic outcome of periapical radiography in the mandible. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1996;82:335-43. ] and digitally by the alveolar bone texture. MABM decreased significantly during the 5-year period. Changes in MABM, evaluated by the mean grey-level value of a bone segment between the premolars, were correlated to changes in skeletal BMD (r = 0.33, P < 0.001). Changes in MABM, evaluated by the optical density, did not correlate to changes in skeletal BMD. The overall trabecular pattern did not change during the study period, but small changes in the bone texture were measured. The changes in the bone texture were correlated with BMD change (r = 0.39, P < 0.001). We conclude that changes in the mandibular alveolar bone do reflect changes in the skeletal BMD, and these may be estimated on periapical radiographs by changes in their grey-level value and their texture.

Bone status in primary hyperparathyroidism assessed by regional bone mineral density from the whole body scan and QUS imaging at calcaneus

To assess the bone mineral density status in primary hyperparathyroidism (PHPT), we studied 64 females with PHPT and 17 healthy women. Regional BMD (arms, trunk, legs) from the whole body scan and conventional sites (lumbar spine, femur, radius) were assessed by DXA. Quantitative ultrasound (QUS) imaging measurements were performed at calcaneus. Sixteen women had history of renal lithiasis, 11 had low impact fracture and 37 women had neither renal lithiasis nor fracture. In the entire group, the mean Z-scores were significantly decreased at all sites (lumbar spine, femur, radius). In all clinical subgroups, the mean Z-scores were significantly decreased at radius. The mean Z-scores in premenopausal women were significantly decreased comparatively to postmenopausal women at lumbar spine and femur. In a group of PHPT females matched to controls for age and BMI, only BMD values at radius were lower in PHPT patients than in control (P < 0.03). However, from the whole body scan data, all sites but no trunk were significantly involved in PHPT patients (P < 0.04). Using QUS measurements at calcaneus, the BUA but not SOS in PHPT females was significantly lower (P = 0.03) than in controls. Our results suggest that low BMD at lumbar spine and femur is encountered preferentially in premenopausal women. The BMD decrease predominates at limbs in PHPT with presumably a gradient from proximal to distal part of the limbs. Indeed, the distal part of the limbs are the most affected areas in PHPT whatever the amount of cortical or trabecular bone.

Physical activity in the post-pubertal period is associated with maintenance of pre-pubertal high bone density - a 5-year follow-up

OBJECTIVE

To evaluate the association between physical activity (PA) and skeletal growth in girls during adolescence.

DESIGN

A 5-year, observational, population-based study (Reykjavik, Iceland).

SUBJECTS

Seventy-eight Caucasian girls, mean age 13.4+/-1.0 (mean+/-SD) years at baseline.

METHODS

Bone mineral density (BMD, g/cm2) and bone width (cm) were measured in the forearm by single-photon absorptiometry at baseline and with dual-energy X-ray absorptiometry after 3 and 5 years, when lumbar spine, femoral neck (FN) and total body were also evaluated. Half of the physically active girls were compared with the other half of less active girls.

RESULTS

BMD in physically active girls was higher in the forearm at both baseline (P=0.001) and after 5 years (P=0.04) in comparison with less active girls. BMD was higher for the total body (P=0.0001), spine L2-L4 (P=0.02) and FN (P=0.002) in the active girls at age 18. The accrual of forearm BMD and bone width from age 13 to 18 was no different when comparing the two groups.

CONCLUSIONS

Pre-pubertal PA is associated with high BMD at age 13 and continued PA is associated with maintenance of high BMD until age 18.

Estudio de la masa ósea en el déficit de hormona de crecimiento

OBJECTIVES

To evaluate bone mineral density by radiogrametric study of metacarpal bone diameter and cortical thickness in patients with growth hormone deficiency (GHD) before and during treatment with growth hormone (GH).

PATIENTS AND METHODS

We studied 92 children with GHD (60 boys and 32 girls) divided into two groups: group I: 66 previously untreated patients (42 boys and 24 girls) aged between 3 and 14 years old; group II: 66 patients (42 girls and 24 boys) treated with GH and with a mean age of 10.2 +/- 3.1 years at treatment onset. Bone mass was studied indirectly by radiogrametry; the bone diameter and cortical thickness of the 2nd-3rd and 4th metacarpal bones were measured with a magnifying glass. As reference standards we used the Spanish longitudinal growth and development study (Andrea Prader Center, Zaragoza) in children aged between 0.5 and 9 years and the Swiss longitudinal standards in children aged 10 years of age and older. Statistical significance was set at p < 0.05.

RESULTS

Group I (spontaneous evolution): cortical thickness values were below the mean with statistically significant differences al 11, 12 and 13 years of age in girls and at 12, 13 and 14 years in boys. Bone diameter was diminished compared with controls in all the study periods and was significantly reduced at 8, 9, 10 and 11 years of age in girls and at 8, 10, 11, 12, 13 and 14 years in boys. Group II: (effect of GH treatment): cortical regression analysis showed a sharp increase in the first year of treatment with a subsequent moderate increase, which was statistically significant. Bone diameter showed a similar pattern with a significant increase which was more pronounced in the first period.

CONCLUSIONS

Children with GHD have decreased bone mass before initiation of treatment and therefore show deficient acquisition of peak bone mass, which in normal conditions occurs during in the first 4-5 years of life and during adolescence. GH replacement therapy leads to recovery of bone mass, which is more pronounced in the first year of treatment and prevents the progressive reduction that appears in untreated patients. Therefore, GH treatment plays an important role in peak bone mass acquisition in children with GHD.

Changes in the bucco-lingual thickness of the mandibular alveolar process and skeletal bone mineral density in dentate women: a 5-yr prospective study

After tooth extraction there is a great interindividual variation in the remodelling pattern of the alveolar process in edentulous areas, with some individuals losing little bone and others undergoing extensive resorption. However, little is known about possible longitudinal changes in the dentate region of the alveolar process of adults and if these are related to alterations in the skeletal bone mineral density (BMD). In a prospective study, on two occasions, 5-yr apart, the BMD of 117 women was determined in the distal forearm by using dual-energy X-ray absorptiometry, and the bucco-lingual thickness of the mandibular alveolar process was measured on dental casts by using a dial calliper. A decrease in the mean alveolar thickness, exceeding a cut-off value of 0.1 mm, was found in 60% of the women and an increase was found in 3% of the individuals. This decrease was 0.22 +/- 0.20 mm in the posterior region and 0.16 +/- 0.19 mm in the anterior region. The changes in alveolar thickness in the posterior region were significantly correlated to the BMD changes both on the mid-crestal level site and on the cervical level site. We conclude that the bucco-lingual thickness decreases with age in the dentate alveolar process, possibly owing to periosteal resorption related to skeletal bone loss.

Forearm single X-ray absorptiometry in the identification of postmenopausal women with osteoporosis at the hip and spine: a correlation study

The International Society for Clinical Densitometry (ISCD) has stated that forearm bone mineral density (BMD) testing combined with a thorough clinical evaluation may be an option for the diagnosis of osteoporosis when central bone density (CBD) testing is not available. This study assessed the performance of two different forearm sites in identifying subjects with spinal and femoral osteoporosis, and defined the 90% sensitivity point for the DTX-100 bone densitometer in the detection of central osteoporosis. Four hundred and two postmenopausal Bulgarian women between the ages of 50 and 81 yr (mean age 60.24 +/- 10.48 yr) participated in this study. Forearm BMD (distal and ultradistal forearm) was measured with a DTX-100 device (Osteometer Meditech, USA) and central BMD (lumbar spine and proximal femur) with a Hologic QDR 4500 A device. Linear T-score correlations among sites, sensitivity and specificity of the forearm site were analyzed. T-score correlations between the forearm and the central sites ranged from 0.32 to 0.69 (p < or = 0.05 for all correlations in age group 50-59). The forearm site sensitivity increased slightly with advancing age, but specificity decreased. When the distal forearm BMD cut point (0.340 g/cm2) was set to achieve 90% sensitivity to identify total hip osteoporosis, specificity was 40%; when the distal forearm BMD cut point (0.410 g/cm2) was set to achieve 90% sensitivity to identify spinal osteoporosis, specificity was 55.4%; when ultradistal forearm BMD cut points (0.280 and 0.320 g/cm2) were set to achieve 90% sensitivity to identify total hip and spinal osteoporosis, specificity was 40.8 and 59.2%, respectively. Forearm bone density measures may be useful to selectively screen for patients with central osteoporosis.

The association between the masseter muscle, the mandibular alveolar bone mass and thickness in dentate women

OBJECTIVE

Since muscle strength has been demonstrated to affect the bone in the long bones and spine, the possibility exists that the bone mass and dimension of the alveolar processes could be influenced by the function of the masticatory muscles. Therefore, the purpose of this study was to investigate whether two local factors (ultrasonographic masseter thickness, and occluding teeth) plus the skeletal bone mineral density (BMD) affect the mandibular alveolar bone mass (MABM) and the bucco-lingual alveolar thickness of the alveolar process.

DESIGN

The thickness of the masseter muscle was evaluated by ultrasound imaging in 62 dentate women (40-75 years) with no periodontal disease and no dental infection in the premolar region consecutively selected from the patients in a public dental clinic. MABM was evaluated using periapical radiographs. The bucco-lingual thickness of the alveolar process was measured on dental casts with a dial calliper. BMD of the forearm was determined with dual energy X-ray absorptiometry.

RESULTS

Multiple regression analyses demonstrated that masseter thickness and the number of occluding mandibular teeth in the lateral segment were significant determinants of MABM and of the interdental thickness, but BMD was not. The number of years after menopause and struma/gastro-intestinal disease influenced MABM but not the alveolar thickness.

CONCLUSION

The local factors played an important role in the posterior mandibular segment and their effect might partly explain the low correlation between MABM and skeletal BMD.

Universal standardization of forearm bone densitometry

As part of an effort to quantify device-dependent differences in forearm bone density, 101 women, aged 20-80 years (approximately 16 women in each age decade), were scanned on six forearm bone densitometers: the Aloka DCS-600EX, the Hologic QDR-4500A, the Lunar PIXI, the Norland pDEXA, the Osteometer DTX-200, and the Pronosco X-posure System. Regression statistics are reported for all similar regions of interest (ROIs). However, comparisons were confounded because of large differences in the ROI size and placement. The number of ROIs reported for a single scan by each device varied from 1 to 12. The correlation coefficients ranged from 0.7 < r < 0.97, with the highest correlation coefficients and lowest SEs for comparisons between the most similar ROIs. Standardized units of bone mineral density are derived for distal (sdBMD), mid-(smBMD), and proximal (spBMD) ROTs that allow for comparable mean bone densities to be derived for patient populations. Five phantoms were scanned and characterized on five of the devices and the precision and mean values were reported. These phantom values will aid in the in vitro cross-calibration between manufacturers to recreate the presented in vivo relationships. Care should be exercised when using these equations for cross-calibrating patient databases or pooling clinical data from different devices because the least significant differences detectable from measurements taken on two different machines can be increased substantially.

Assessment of forearm volumetric bone mineral density from standard areal densitometry data

The common bone density measurement procedures produce areal bone mineral density data (BMD) alone. Volumetric bone density is thought to offer a different diagnostic perspective and is usually measured by peripheral quantitative computed tomography. We developed a calculation procedure for radial and ulnar volumetric densities based on single X-ray absorptiometry. The study consisted of 418 healthy Bulgarian females (ages 20 83 yr). Forearm bone density was measured on a DTX-100 densitometer at the 8-mm distal site, and the total volumetric bone densities of radius and ulna were calculated. The accuracy error determined on cadaveric bones was 10 14%. The in vivo precision error was 1.0 1.1%. Age-matched reference curves for volumetric BMD (vBMD) were built. Peak values were registered in the age 30 34 group: 0.403 (radius) and 0.469 g/cm(3) (ulna). Ulnar volumetric density exceeded the radial one, representing an interesting finding to be further investigated. For the age 70 74 group, vBMD was reduced by approx 30% compared with the age 30 34 group. Our data confirmed the fact that volumetric density was much less affected by age and menopause. Correlations between forearm vBMD and axial BMD were moderate. The proposed calculation procedure could become an extra option in forearm bone densitometry to be applied in pediatric populations or adults of extremely large or small body size.

Separate assessment of forearm cortical and trabecular bone density from standard densitometry data

BACKGROUND

Cortical and trabecular bone are different bone components. Their mineral density cannot be measured directly by areal bone densitometry.

AIM

To introduce a method for assessment of pure radial cortical and trabecular bone density based on standard densitometry data.

METHOD

The study included 418 healthy females (aged 20-83 years, body mass index between 19 and 30) free of previous fractures and conditions or drugs affecting bone metabolism; as well as a group of 64 age-matched females with early menopause. Forearm bone density was measured by single X-ray absorptiometry and calculated separately for cortical and trabecular bone. Age-adjusted bone density curves were built.

RESULTS

Peak bone density was found to occur between 30 and 34 years of age and was 0.561 g/cm2 for cortical and 0.281 g/cm2 for trabecular bone. In comparison, lowest values were registered between 70 and 74 years of age; cortical bone density reduced by 26% and trabecular density by 44%. Both bone density profiles through life reflected the earlier peri- and postmenopausal (mainly trabecular) and later senile (cortical bone also involved) changes in bone mass. A step-wise pattern of trabecular bone reduction was registered with acceleration around 45, 55 and 65 years. The effects of early menopause on trabecular and cortical bone were tested in the prematurely menopausal women.

CONCLUSIONS

The ability of our model to discriminate between natural and premature menopause was moderate. Although hypothetical (based on calculations from integral densitometry data rather than on direct measurements), our method could differentiate between cortical and trabecular osteopenia and may prove helpful in assessing the type of osteoporosis, in making therapy choices and monitoring response to therapy based on forearm bone density.

Estimation of skeletal bone mineral density by means of the trabecular pattern of the alveolar bone, its interdental thickness, and the bone mass of the mandible

OBJECTIVE

We sought to evaluate the use of the alveolar trabecular pattern, the mandibular alveolar bone mass (MABM) measured by photodensitometry, and the interdental alveolar thickness for prediction of the skeletal bone mineral density (BMD).

STUDY DESIGN

MABM and the coarseness of trabeculation were assessed by using periapical radiographs in 80 dentate women. The interdental alveolar thickness was measured on casts, and BMD of the forearm with dual X-ray absorptiometry.

RESULTS

Significant correlations were found between skeletal BMD and MABM (r = 0.46, P <.001) as well as the coarseness of the trabeculation (r = 0.62, P <.001). The interdental alveolar thickness improved the correlation between skeletal BMD and MABM (R2 = 0.44, P <.001). Age, but not interdental thickness, improved the correlation between the coarseness of trabeculation and skeletal BMD (R2 = 0.52, P <.001).

CONCLUSION

Evaluation of the coarseness of trabeculation of the alveolar bone as seen on intraoral radiographs is a helpful clinical indicator of skeletal BMD and better than densitometric measurements of the alveolar bone. Dense trabeculation is a strong indicator of high BMD, whereas sparse trabeculation may be used to predict low BMD.

Diagnostic discrepancies between two closely related forearm bone density measurement sites

At the present time the diagnosis of osteoporosis is based on the use of T-scores. Measurements at different skeletal sites or of different regions of interest may result in diagnostic discrepancies. In this study, we tried to demonstrate that bone mineral density (BMD)values at the closely related forearm sites may lead to diagnostic uncertainty, and to assess the degree of site heterogeneity across different age groups. The study consisted of 2348 women (age 20-83) referred for bone densitometry. Forearm BMD was measured at the distal and ultradistal sites by single X-ray absorptiometry (DTX-100 device). T-scores were calculated from Bulgarian reference data. Diagnostic disagreement between sites was found in 19.3% of all women. In 7.7% of all cases, the difference between T-scores at the two sites exceeded 1. The discrepancies were more pronounced after age 60. This corresponds well to the different onset and rates of trabecular and cortical bone losses as well as to their different distribution along the forearm. We encourage the separate assessment of cortical and trabecular bone densities or measurements at axial sites in case forearm sites yield conflicting results or low-normal BMD values.

Cross-sectional and longitudinal assessment of pre- and postmenopausal bone loss with a portable forearm X-ray device: the Ofely study

The aim of our study was to describe cross-sectional and longitudinal bone mineral decrease in pre-, peri-, and postmenopausal healthy women using a monoenergy X-ray densitometer specifically designed for forearm assessement. Measurements were performed on the most distal part of the radius (ultradistal, 55% of trabecular bone and 45% of trabecular bone), and on the distal part (distal, 13% of trabecular bone and 87% of cortical bone). A specific trabecular-rich region of interest (nROI) comprising two trapezoids regions of interest located proximally to the endplates of the radius and ulna was also investigated. From a large prospective study (OFELY study), 455 women were measured once a year for 2 years (three measurements). The proportion of postmenopausal women classified as having osteoporosis (i.e., a T score <-2.5) was 33% for the distal region, 44% for the ultradistal region, and 45% for the nROI. No significant bone mineral decrease was found over the 2-year period in premenopausal women (n = 138). In perimenopausal (n = 48) women, a bone loss of 1% was found at the distal site. In the 269 postmenopausal women, a significant decrease was observed at all sites, ranging from 2.14% for the nROI to 2.68% for the ultradistal part. Bone loss was greater in the first 5 years after menopause in trabecular sites and decreased thereafter. For the distal site, bone loss remained stable during the postmenopausal period. We conclude that this small and portable forearm densitometer is suitable for the diagnosis of osteoporosis, and provides information on the rate of bone loss in peri- and postmenopausal women in trabecular and cortical compartments of bone.

Cervical thickness of the mandibular alveolar process and skeletal bone mineral density

Much effort has been devoted to finding methods for detecting individuals with low bone mass and risk of osteoporotic fractures. The aim of the present study was to investigate whether there is a relationship between the thickness of the alveolar process and the bone mineral density (BMD) of the distal forearm. In 24 women (38-65 years), the BMD of the distal forearm, obtained by dual X-ray absorptiometry, was correlated to the difference between two measures of the thickness of the mandibular alveolar process in the region of the first premolar. A highly significant correlation (r = 0.95, P< 0.001) was found. The method was cross-validated by using the equation obtained from the linear regression analysis above to predict BMD in two other groups. In both groups, the correlation between the measured BMD of the forearm and the predicted BMD was highly significant (r = 0.91, P< 0.001). The interdental thickness between the canine and the second incisor was also correlated to BMD, but with lower predictive value (r = 0.67, P<0.001). Measurements of the mandibular alveolar process can be used as one of several parameters to predict skeletal bone density.

Measurement of distal forearm bone mineral density: can different forearm segments be used interchangeably ?

Many different forearm sites have been used for the measurement of bone mineral density (BMD) and prediction of risk of future fracture among community dwelling populations. In populations where bone densitometry of peripheral sites may be the most cost effective and practical means of measuring BMD, such as the nursing home population, knowing the characteristics of forearm BMD measures would be beneficial. The purpose of this study was to assess the relationship of four common commercially available measures to each other and to estimate the inter- and intrarater reliability of the measures in a sample of nursing home residents as a first step toward identifying appropriate forearm measurement sites. These sites were the distal radius, the distal ulna, a composite of the distal radius and distal ulna, and the ultra distal radius. BMD measurements on 48 nursing home patients were obtained using single X-ray absorptiometry. Inter- and intrarater reliability was excellent at all four sites (interclass correlation coefficients > 0. 85). Moderate to high correlations (0.84-0.91) between the distal radius and ultra distal radius sites of the forearm suggest that these measures may be interchangeable. Although not directly assessed here, differences in bone composition among forearm sites may partially explain moderate rather than high correlations between sites and may affect the ability of each site to predict future fractures. Thus, different forearm sites may be used interchangeably for diagnostic purposes; however, the prognostic value of each site remains unknown.

T score of trabecular and cortical bone in normal postmenopausal women

OBJECTIVE

The T score of the cortical and trabecular bone compartments (T score of BMDTrab and T score of BMDCorti) was calculated in healthy postmenopausal women to determine which bone compartment loses more bone mass.

MATERIAL AND METHODS

A total 134 healthy postmenopausal women (mean age 55.1 +/- 6.4 years) and 67 healthy premenopausal women (mean age 36.0 +/- 8.6 years) were studied. Determinations were made using peripheral quantitative computed tomography (pQCT) of the nondominant forearm. The postmenopausal women were divided into groups by years since menopause (YSM): two early postmenopausal groups: < 5 YSM and 6-10 YSM; and two late postmenopausal groups: 11-20 YSM and > 20 YSM.

RESULTS

There was a significant correlation between the T score of BMDTrab and the T score of BMDCorti (P < 0.0001). Both correlated negatively and significantly with age (P < 0.001 and P < 0.0001, respectively) and neither correlated with weight. The Wilcoxon test showed no significant differences between the trabecular and cortical T scores in the overall group of women. By YSM, only the > 20 YSM group showed significant differences (P < 0.005). The ANOVA post hoc Bonferroni/Dunn test showed a significant difference in the T score of BMDTrab by YSM only in the < 5 YSM versus 11-20 YSM groups (P = 0.007) and in the < 5 YSM versus > 20 YSM groups (P < 0.0001). The T score of BMDCorti by YSM differed significantly only between the < 5 YSM versus 11-20 YSM groups (P < 0.0001) and between the 11-20 YSM and > 20 YSM groups (P < 0.005).

CONCLUSION

In contrast with what has been postulated in recent studies, our results showed that postmenopausal bone loss was similar in the cortical and trabecular bone compartments in the first 20 years after menopause. Trabecular bone loss was greater than cortical bone loss in late menopause (> 20 years).

Comparison of bone densitometry of the phalanges, distal forearm and axial skeleton in early postmenopausal women participating in the EPIC Study

We present baseline bone densitometry from the Early Postmenopausal Interventional Cohort study (EPIC, sponsored by Merck, Sharp & Dohme) for the first time, in which 1609 women from England, Oregon, Hawaii and Denmark are participating to investigate the efficacy of daily oral alendronate to prevent early postmenopausal bone loss. We compared radiographic absorptiometry (RA) of the phalanges for bone mineral density (BMD) measurement with single-energy X-ray absorptiometry (SXA) of the distal forearm, and dual-energy X-ray absorptiometry (DXA) of the lumbar spine, proximal femur and distal forearm. In a random subgroup of 308 women, aged 45-60 years, on average 6 years since menopause (YSM), bone densitometry was measured once at baseline by RA of the phalanges besides the mandatory measurements by DXA. Bone densitometry was furthermore measured by SXA at the Danish site (89 women). Sixty-eight of the women had duplicate measurements performed within 1-3 weeks to evaluate the short-term precision error (CV%). One hundred and one healthy premenopausal women, aged 25-48 years, were recruited at the Danish and Hawaiian sites to establish a reference group. The precision error was 1.5% for RA of the phalanges and in the range 1.0-2.2% for SXA and DXA. BMD by RA correlated with BMD measured by SXA and DXA in the range 0.45 < r < 0.72 (p < 0.001). In conclusion, bone densitometry by RA of the phalanges is highly correlated with bone densitometry by SXA and DXA. RA of the phalanges has a short-term precision error comparable to that of SXA and DXA.

Impact of soft tissue on in vivo accuracy of bone mineral measurements in the spine, hip, and forearm: a human cadaver study

The impact of soft tissue in vivo on accuracy of bone mineral density (BMD) measurements of the spine and hip by dual energy X-ray absorptiometry and of the forearm by single photon absorptiometry was assessed by use of 14 human cadavers. The in vivo accuracy errors (SEE%) were: forearm 3-5%, anteroposterior spine 5.3%, lateral spine 10-12%, and femoral greater trochanter, neck, total, intertrochanteric, and Ward's triangle 3%, 6.5%, 6.7%, 8%, and 11-13%, respectively. Except from the lateral spine and the greater trochanter, the slopes of the linear regressions of in vivo BMD against in vitro BMD were not significantly different from 1 (p > 0.05). The calculated random accuracy error of BMD measurements due to fat inhomogeneity was estimated to 3-4% for the anteroposterior spine and 9-14% for the lateral spine (from abdominal computed tomography in 26 healthy women). In conclusion, acceptable accuracy errors below 6-7% (of soft tissue in vivo) of BMD measurements were obtained in the anteroposterior spine, the forearm, and the neck, greater trochanter, and total proximal femur.

Single X-ray absorptiometry: performance characteristics and comparison with single photon absorptiometry

The aim of the present study was to evaluate a new device for measurement of forearm bone mass using the technique of single X-ray absorptiometry (SXA, DTX-100; Osteometer A/S, Rødovre, Denmark), and to compare the performance with the more traditional single photon absorptiometry (SPA, DT 100; Osteometer A/S, Rødovre, Denmark). The SPA phantom measurements showed a coefficient of variation of 0.43% and 0.42% for bone mineral content (BMC) and bone mineral density (BMD), respectively (39 months including seven source changes). The SXA precision errors were slightly lower with values of 0.30% and 0.30%, respectively. The patient measurements showed SPA coefficients of variation of 0.85% and 0.99% (BMC and BMD) and SXA coefficients of variation of 0.56% and 0.83%, respectively. The correlation between SPA and SXA values performed in 377 individuals yielded r values of 0.99 and 0.98 for BMC and BMD, respectively. The correlations between SXA measurements of the dominant and non-dominant forearm yielded an r-value of 0.95, with a slope of 0.949 (p < 0.001) and an intercept of 0.204 (p < 0.05). The non-dominant forearm thus had approximately 3% lower BMC than the dominant (the same was true for BMD). Correlations to spine and femur ranged from r = 0.48 to r = 0.75. In conclusion, the new single X-ray absorptiometry forearm bone densitometer described in this paper has performance characteristics which allows it to be used both for diagnostic purposes and for the follow-up of treatment.

Relation between calcium intake, grip strength and bone mineral density in the forearms of girls aged 13 and 15

OBJECTIVES

To evaluate whether there is an association between calcium intake in adolescent girls and bone mineral density (BMD). Also, the relationships between BMD, various anthropometric factors and grip strength were evaluated.

DESIGN

Cross-sectional comparison of BMD, calcium intake and grip strength in 13 and 15 year age groups, randomly selected.

SETTING

Ten secondary elementary schools in the Reykjavik area.

SUBJECTS

One hundred and ninety-seven Icelandic Caucasian girls aged 13 and 15. One hundred and seventy participated and 162 completed the study.

MAIN OUTCOME MEASURES

Single photon absorptiometry was used to measure BMD and bone mineral content (BMC) in both forearms. Consumption of milk and dairy products was assessed using a food frequency questionnaire. Height and weight were measured and grip strength was determined with a hand-held dynamometer.

RESULTS

Calcium intake was found to be significantly correlated to BMD in the older group after adjustment for menarcheal age and weight (r = 0.24; P < 0.05). Division into three subgroups yielded a significantly greater coefficient of correlation between calcium intake and BMD in the lowest calcium consumption group (r = 0.44; P < 0.05). No association was found in the younger age group. Significant positive correlations between grip strength and regional bone mineral density accounted for up to 16.8% of the variation in BMD (P < 0.001) and 38.4% of the variation in BMC.

CONCLUSIONS

This study is consistent with the hypothesis that a threshold effect of calcium intake on BMD might exist. Above this threshold (1000-1200 mg) no further effect on BMD was seen. The results show a strong association between grip strength, a measure representative of total body strength, and BMD.

Bone mineral density during long-term prophylaxis with heparin in pregnancy

OBJECTIVE

We studied the effect of long-term heparin treatment on bone mass during pregnancy.

STUDY DESIGN

Thromboprophylaxis with heparin was given to 39 women during pregnancy for a mean of 28 weeks and for an average of 6 weeks post partum. Bone mineral density measured with single-photon absorptiometry of the distal and ultradistal parts of the forearm was determined at the time of the start of heparin treatment (mean, twelfth week of gestation), immediately post partum, and on average 7 weeks post partum. The mean dosage of heparin was 17,300 IU/day. A control group of 34 normal pregnant women was studied for comparison.

RESULTS

In women treated with heparin, there was almost a 5% reduction in trabecular bone during pregnancy (p < 0.01) and an insignificant recovery post partum. There were no significant changes in bone mass during pregnancy or in the puerperium in the control group.

CONCLUSION

Long-term treatment with heparin during pregnancy is associated with bone loss, but indications of reversible changes are observed.

A computer-assisted method for the study of the trabecular bone of the distal radius on conventional radiographs

The procedure described is based on the acquisition and processing of x-rays of the distal radius obtained under standard conditions. An x-ray was obtained of the forearm together with an aluminum step wedge to automatically normalize the photometric values of the bone with respect to the photometric values of the reference aluminum wedge. Densitometric values for thickness (T) and a coarseness parameter (C) that depends on the trabecular bone pattern are measured on interactively selected rows and regions of interest (ROIs) of the digital image. Twenty-five women were examined and two different measurements were performed. The first measurement considers C in three sites of the radial epiphisis. The trabecular bone coarseness appears to increase from the distal to the very-very distal site and the value of C in the very distal site, which is located 1 cm distally to the distal one tenth of the radius, seems to be related to the pathological variations more than the value of C in the other sites. The second measurement is the C/T ratio of eight ROIs of 15 patients: five healthy and 10 osteoporotic women. This ratio is significantly different for the two groups in all the eight ROIs and the variations are particularly significant at 6 to 12 mm from the subchondral line.

Bone mineralisation, body fat and anthropometric measurement in mothers delivering preterm

Twenty mothers of preterm babies who had survived to 1 year old, were matched for age and parity of the mother and time of birth of the baby, with 20 mothers delivering fullterm. Bone mineral, body composition and anthropometric measurements were obtained for each mother and analysed using paired t-tests. The only significant difference (P < 0.01) between the groups was a lower fat-free mass in the preterm mothers calculated from skinfold thickness measurements.

Changes in calcanean bone mineral occurring spontaneously and during hormone replacement therapy in early post-menopausal women

The spontaneous calcanean bone loss occurring in healthy early post-menopausal women and the effect of two hormone replacement therapies (HRT's) were investigated in a longitudinal study. There was no difference between the right and left calcanean BMC or BMD (p > 0.15). The spontaneous bone loss was similar at all the skeletal sites measured, with a mean spontaneous loss in calcanean BMD of 1.6% over one year. Both HRT's significantly (p < 0.01) prevented the bone loss from all skeletal sites irrespective of the weight-bearing or content of trabecular bone, and (for the weight-bearing bones) there was even a gain in calcanean BMC and BMD and spinal BMD (p < 0.01). Bone mineral of the calcaneus and the spine correlated equally to body weight (r approximately 0.4, p < 0.001), whereas bone mineral in the forearm was not correlated to body weight. The correlations between the changes in bone mineral at the sites measured were all significant (r approximately 0.2-0.4).

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.

Discriminatory ability of bone mass measurements (SPA and DEXA) for fractures in elderly postmenopausal women

We investigated the discriminatory ability of forearm bone mineral content (BMCarm) measured by single photon absorptiometry (SPA) and spinal bone mineral density (BMDspine) measured by dual-energy X-ray absorptiometry (DEXA) in 387 elderly postmenopausal women. Of these, 22 had never sustained a fracture (normal), 91 had had less than three vertebral wedge fractures (mild), 51 had experienced a peripheral fracture (moderate), and 24 had had more than three vertebral wedge or compression fractures (severe). BMCarm exceeded BMDspine slightly in the ability to discriminate the mild and moderate groups (P less than 0.01-0.001), whether calculations were performed on raw values or the Z-scores compared with premenopausal women. Receiver operating (ROC) analysis showed that at every cutoff level BMCarm had a similar ability as BMDspine to discriminate between the vertebral fracture (mild and severe) groups and healthy premenopausal and nonfractured postmenopausal women (normal), whereas BMCarm had a significantly higher discriminatory ability of peripheral fractures (P less than 0.05) (moderate) group compared with premenopausal women. We conclude that SPA and DEXA are equally capable as diagnostic procedures in women with established osteoporosis.

Desogestrel in hormone replacement therapy: long-term effects on bone, calcium and lipid metabolism, climacteric symptoms, and bleeding

Seventy-three healthy, postmenopausal women, aged 45-54 years, were randomly assigned to one of three groups for 2 years of treatment: 17 beta-oestradiol 1.5 mg on days 1-12 and 17 beta-oestradiol 1.5 mg + desogestrel 150 micrograms on days 13-24 (E2/DG) or oestradiol valerate 2 mg on days 1-11 and oestradiol valerate 2 mg + medroxyprogesterone acetate 10 mg on days 12-21 (E2V/MPA) or placebo. Fifty-seven women (78%) completed the study. Bone mineral content of the distal regions of the forearms (measured by single photon absorptiometry, SPA) and bone mineral density of the spine (measured by dual energy X-ray absorptiometry, DXA) showed increases of 0.5-1% and 4-5%, respectively, in the hormone groups over 2 years. The placebo group exhibited a decrease in spinal bone density of 2% per year, and in the forearm of 2.5-3.5% per year. Biochemical estimates of bone turnover (serum alkaline phosphatase and fasting urinary calcium) decreased significantly to premenopausal levels in the hormone groups but remained unchanged in the placebo group. In both hormone groups total cholesterol decreased by about 9% (P less than 0.001), whereas low density lipoprotein cholesterol decreased by 16% in the E2/DG group and 20% in the E2V/MPA group (P less than 0.001). High density lipoprotein cholesterol showed only minor, insignificant changes in the hormone groups. The placebo group had virtually unchanged values. Climacteric symptoms, including hot flushes, were significantly reduced in both hormone groups. Bleeding occurred regularly in about 80% of the women.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone mass measured by photon absorptiometry: comparison of forearm, heel, and spine

We assessed bone mass quantification at different skeletal sites by single and dual photon absorptiometric (SPA and DPA) methods. Improved DPA measurement of spinal bone mineral density in young healthy subjects showed a short- and long-term precision of 1.2% and 1.6%. Compared to the conventional DPA method the imprecision was reduced by more than 50%. The appendicular measurements were more precise (0.5-1.2%). We present the intercorrelations and predictive errors between peripheral measurements and improved spinal and total body bone measurements in early postmenopausal women (n = 144) recruited in 1988. To compare the improved system with the conventional methods, we retrieved data on age-matched early postmenopausal women (n = 151) recruited in 1983. In the 1988 population all peripheral methods had similar predictive errors in estimation of spinal bone mineral density (SEE = 11-13%) and total body bone mineral density (SEE = 4-5%). Measurement of trabecular bone in the heel and distal forearm did not improve the validity of predicting spinal bone mass. In a cadaver study (n = 11) the predictive error in estimation of the spinal ash weight from forearm measurements was of the same magnitude (15%) as that in estimation of the spinal BMC from the forearm (16%). We conclude that the predictive error in estimation of spinal bone mass from peripheral bone measurements is more likely to be caused by intra-skeletal variation in bone mass than by precision errors. However, this does not reflect the inability of peripheral bone mass measurements to predict fracture risk.

Does a single local absorptiometric bone measurement indicate the overall skeletal status? Implications for osteoporosis and osteoarthritis of the hip

Regional bone mineral content (BMC) and density (BMD) (head, arms, chest, spine, pelvis, legs) of a total body dual photon 153Gd absorptiometry (DPA) scan were measured in 20 healthy postmenopausal women, 27 postmenopausal women with hip fracture, and 17 postmenopausal women with osteoarthritis of the hip. In addition, local BMC and BMD were measured in the proximal and distal regions of the distal forearm (BMCprox, BMDprox, BMCdist, BMDdist) by single photon absorptiometry (SPA); and in the lumbar spine (BMCL2-L4 and BMDL2-L4) by 153Gd DPA. The overall impression was a reduction of bone mass in hip fracture patients compared with healthy controls and an increase in the bone mass of osteoarthritic patients. These results were valid using both regional values of the total body scan, and local forearm and lumbar spine measurements, and statistically significant using one-way analysis of variance. There were, however, also significant within-group between-region differences (one-way analysis of variance), showing that the bone mass of the pelvis and legs in hip fracture patients was more reduced than in the remaining skeleton; in osteoarthritic patients it was not increased but rather unchanged or slightly reduced. The differences between the level of the three local measurements (BMDprox BMDdist BMDL2-L4), on the one hand, and the level of the six regional BMD values, on the other hand, were investigated by the two-way analysis of variance: local measurements = rows; regional values = columns. This analysis showed that none of the three local measurements was statistically better than the other two in predicting the overall level of skeletal bone mass as judged by the six regional values. We conclude that serious osteoporotic bone loss has a generalized nature, however, with a tendency towards lower values in the regions affected by fracture (viz: low bone mass in the legs of femoral neck fracture patients). Osteoarthritis may be associated with a high bone mass in most areas, but low values in the affected regions. Local lumbar spine measurement of bone mass by DPA is not superior to local forearm measurement of bone mass by SPA in predicting the nature of overall osteoporotic or osteoarthritic bone change.

Effect of salcatonin given intranasally on early postmenopausal bone loss

OBJECTIVE

To study the effect of salmon calcitonin (salcatonin) given intranasally on calcium and bone metabolism in early postmenopausal women.

DESIGN

Double blind, placebo controlled, randomised group comparison.

SETTING

Outpatient clinic for research into osteoporosis.

SUBJECTS

52 Healthy women who had had a natural menopause two and a half to five years previously.

INTERVENTIONS

The 52 women were allocated randomly to two years of treatment with either salcatonin 100IU given intranasally (n = 26) or placebo (n = 26). Both groups received a calcium supplement of 500 mg daily. Seven of the women receiving salcatonin and six of those receiving placebo left the study before its end.

MAIN OUTCOME MEASURES

Bone mineral content in the spine, the total skeleton, and the forearms after two years of treatment.

RESULTS

Bone mineral content in the spine was significantly higher in the women who had received salcatonin than in those who had received placebo both after one year and after two years of treatment. After one year the difference was 3.8% (95% confidence interval 0.0 to 7.6%) and after two years it was 8.2% (3.8 to 12.6%). In contrast, the bone mineral content in the distal and proximal forearms and in the total skeleton declined similarly in both groups by about 2% each year, and after two years of treatment the differences between the groups were not significant. Biochemical estimates of bone turnover were not affected by salcatonin.

CONCLUSION

The results suggest that salcatonin given intranasally in the dose used prevents bone loss in the spine of early post menopausal women but does not affect the peripheral skeleton.

Nasal calcitonin for treatment of established osteoporosis

Thirty-seven women with established osteoporosis completed a one-year double-blind, placebo-controlled study with the primary aim of examining the effect of nasal salmon calcitonin (200 IU daily) on bone and calcium metabolism. All the women received a daily calcium supplement of 500 mg. For comparison we also report data from an age-matched group of healthy women who did not receive calcium supplementation. The bone mineral measured in the forearm (single photon absorptiometry) and spine (dual photon absorptiometry) showed a similar pattern during treatment. The calcitonin group (n = 17) did not lose bone mineral in comparison with the placebo (n = 20) and the control groups (n = 19) (P less than 0.01). The biochemical estimates of both bone resorption and bone formation decreased highly significantly in the calcitonin group (P less than 0.001) and were unchanged in the control group, whereas the placebo (calcium) group showed intermediate values. Neither subjective nor objective side-effects occurred in any of the groups. We conclude that nasal calcitonin is a realistic treatment of established osteoporosis.

Treatment of postmenopausal osteoporosis: is the anabolic steroid nandrolone decanoate a candidate?

Thirty-nine postmenopausal women (aged 55-75 years) with at least one osteoporotic fracture were allocated to one year of treatment with the anabolic steroid nandrolone decanoate (50 mg i.m. every 3 weeks) or placebo injection. Both groups also received a daily intake of 500 mg calcium. Thirty-six women (92%) completed the study. In the nandrolone decanoate-treated group the fat corrected bone mineral content in the proximal part of the distal forearm (measured by single photon absorptiometry) showed a significant increase of 3% compared with placebo (P less than 0.01), and the same tendency was seen in the bone mineral content of the distal part of the distal forearm and density of the lumbar spine (measured by dual photon absorptiometry). However, this did not reach significance. In the placebo group all bone mineral measurements remained unchanged. The biochemical estimates of bone formation (plasma bone Gla protein (BGP), serum alkaline phosphatase) and whole body retention (WBR) of 99mTc-diphosphonates were not statistically significantly changed by the nandrolone decanoate therapy. We conclude that treatment with nandrolone decanoate does increase the bone mineral content; however, this may not be due to a direct increase in bone formation. The mechanism may theoretically be a combination of decreased bone resorption and increased muscle mass, which both play a beneficial role in conserving bone.

Discriminative ability of total body bone-mineral measured by dual photon absorptiometry

We investigated the discriminative ability of total body bone-mineral expressed as the total body bone-density (TBBD) measured by dual photon absorptiometry (DPA) in 79 healthy premenopausal women, 27 healthy postmenopausal women, and 120 female osteoporotic fracture patients presenting with either Colles' fracture, vertebral fracture or femoral neck-fracture. TBBD was compared to the bone-mineral density of the lumbar spine (BMDspine) also measured by DPA, and to the bone-mineral content of the forearms (BMCforearm) measured by single photon absorptiometry (SPA). TBBD, BMDspine and BMCforearm showed that all the fracture patient groups had significantly reduced bone-mass. Using receiver operating characteristic (ROC) analysis, we found that TBBD had a tendency towards better discriminative ability than BMDspine or BMCforearm with regard to the discrimination between healthy premenopausal women and the three types of osteoporotic fractures (not significant in spinal fracture patients). BMCforearm had an intermediate position, whereas BMDspine had the smallest discriminative ability. TBBD also discriminated better between healthy postmenopausal women and hip-fracture patients than BMDspine or BMCforearm, whereas there was no significant difference between the three methods regarding the discrimination between the healthy postmenopausal women and the Colles' and spinal fracture patients. We conclude that the TBBD measurement by DPA has a discriminative potential which is better than the local spine or forearm measurements.

The effect of hemiplegia on bone mass and soft tissue body composition

The content of bone mineral (BMC), lean tissue, and fat tissue were measured by single and dual photon absorptiometry in both the paretic and the non-paretic limbs of 15 patients, hemiplegic due to cerebrovascular accident 23-38 weeks earlier. Compared with the non-paretic arm, the paretic arm had approximately 10% lower (P less than 0.01) BMC. This difference was largest at the measuring site with the highest ratio of trabecular to compact bone. The paretic leg had a 4% (P less than 0.001) lower BMC than the non-paretic leg. For both the arms and the legs, the lean content was lower (P less than 0.05) and the fat content higher (P less than 0.01) in the paretic than in the non-paretic. This was relatively more pronounced in the arms than in the legs. We conclude that partial immobilization, owing to paresis after a cerebrovascular accident, results in characteristic changes in the affected limbs, with a marked decrease in the content of bone and lean tissue and a pronounced increase in fatty tissue.

Rates of bone loss in normal women: evidence of accelerated trabecular bone loss after the menopause

We have followed the changes in bone mass over 2 years in 42 premenopausal, seven perimenopausal and 76 postmenopausal women. The latter had passed a natural menopause between 6 months and 7 years previously. Bone mass was measured every 3 months at the proximal and distal forearm sites by single photon absorptiometry, and every 6 and 12 months in the lumbar spine and whole body by dual photon absorptiometry. The relative content of trabecular bone is approximately 15, 50, 60 and 20% at these four sites. Before the menopause there was a significantly low rate of bone loss from the two forearm sites and the whole body, whereas the spinal loss was insignificant. The rate of loss was five- to ten-fold higher at all sites after the menopause (P less than 0.001). With increasing menopausal duration the rate of loss declined at the two forearm sites and whole body (P less than 0.01). The distal forearm loss was larger than the proximal, both before and after the menopause (P less than 0.01). From the forearm results we thus conclude that a slightly larger loss of trabecular than cortical bone takes place both before and immediately after the menopause. The loss of both types of bone is, however, much larger after the menopause and this rapid bone loss seems to take place throughout the skeleton.

Lack of seasonal variation in bone mass and biochemical estimates of bone turnover

Three previous studies have indicated a seasonal variation in bone mineral content, with values during the summer being 1.7% to 7.5% higher than during the winter. We have examined the seasonal influence on both bone mass, biochemical estimates of bone turnover and vitamin D metabolites in 86 healthy women, aged 29-53 years. All participants were followed up for 2 years with examinations every 6 weeks or 3 months. Bone mineral content in the proximal and distal part of the forearm (single photon absorptiometry) did not reveal any significant seasonal variation, whereas bone mineral density of the lumbar spine (dual photon absorptiometry) indicated that the highest values occurred in winter. None of the biochemical parameters showed any statistically significant cyclical changes. Serum concentrations of 25-hydroxyvitamin D and 24,25-dihydroxyvitamin D3 showed a highly significant seasonal variation, whereas the serum 1,25-dihydroxyvitamin D concentration was virtually unchanged. We conclude that seasonal variation in bone mineral content and bone turnover should not be taken into account when interpreting data from longitudinal studies of healthy pre- and postmenopausal women on a sufficient vitamin D nutriture.

The diagnostic validity of local and total bone mineral measurements in postmenopausal osteoporosis and osteoarthritis

Assessment of different forms of prevention and treatment of bone mineral loss depends upon valid and precise methods to assess bone mass. We have here studied four groups of women: 45 healthy premenopausal women, 37 healthy postmenopausal women, 21 women with osteoarthritis and 20 with hip fractures. Bone mass was measured in the spine and total body by dual photon absorptiometry and in two forearm sites (proximal and distal bone mineral content (BMC) by single photon absorptiometry. The long-term (1 year) reproducibility was 1.2% for proximal BMC, 1.6% for distal BMC, 5.5% for spinal BMC, and 2.1% for total body bone mass (TBBM). In the early postmenopausal years bone mass was mainly reduced in areas with a high content of trabecular bone. In elderly postmenopausal women and women with hip fractures bone mass was almost identical in all four sites studied. The osteoarthritic patients had an 18% reduction of bone mass in the forearms and in TBBM, whereas the spinal bone mass was only reduced by 6%. In all subgroups TBBM could be predicted from the forearm measurements with standard errors of estimates of 9-13%. When the osteoarthritic women were excluded spinal bone mass could be predicted from both forearm measurements with a standard error of 15% (r = 0.74). The distal forearm BMC seems to be a more accurate estimate of spinal bone mass than does the proximal measurement. Of the 20 patients with hip fracture 16 had a distal forearm value below the premenopausal normal range, whereas spinal bone mass was subnormal in only eight (P less than 0.05). We conclude that bone loss is universal in patients with hip fracture and measurements of forearm bone mass will meet most clinical and research demands.

Is postmenopausal bone loss an age-related phenomenon?

Forearm bone mineral content (BMC), an index of skeletal mineralization, and lean body mass (LBM), an index of the muscle mass in the body, were calculated in 574 healthy, white subjects, aged 20-89 years. In women, there was no significant change in BMC with age until the menopause. Thereafter, a significant decline averaging 15% per decade was found up to the age of 70 years, after which it was 10% per decade. In men, there was a significant overall decline of about 4% per decade from the age of 20. When BMC was corrected for LBM, the age-related fall in men disappeared, while remaining without a significant trend in premenopausal women. This was, however, not the case in women after the menopause, where a significant decline of about 12% per decade was noted. These data clearly demonstrate that the major contribution to the well-known bone loss in postmenopausal women is not a simple age-related phenomenon. The development of osteoporosis must be due to some additional bone-diminishing effect on the female skeleton, most likely the absence of estrogen.