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PubMed1977

Effect of estrogens and calcium carbonate on bone loss in postmenopausal women.

Sixty postmenopausal women were placed in three groups--control, sex hormone-treated, and CaCO3-treated--and followed for 2 years. Skeletal mass decreased by 1.18%/year in the control group, 0.15%/year in the hormone group, and 0.22%/year in the CaCO3 group by radiogrammetry; and 2.88%/year in the control group, 0.73%/year in the hormone group, and 1.83%/year in the CaCO3 group by photon absorptiometry. The treatment groups differed significantly from the control group except for photon absorptiometry in the CaCO3 group. Bone accretion and resorption decreased in the treatment groups as measured by calcium tracer kinetics, resorption more so than accretion. We conclude that [1] these techniques are sufficiently sensitive to detect age-related bone loss; [2] postmenopausal sex-hormone replacement measurably decreases age-related bone loss by suppressing bone turnover, resorption more than accretion; and [3] calcium supplements produce the same effect but at the dose we used were slightly less effective.

Absorptiometry, Photon↗

PubMed1991

Bone mass is related to creatinine clearance in normal elderly women.

We determined the relationship between bone mass and age, anthropometric variables, creatinine clearance (Ccr), and serum and urine biochemical variables in 77 normal white women (aged 41-86, mean = 67) living in their own homes. A total of 74 women were postmenopausal. Skeletal status was assessed in all subjects by x-rays of the hand with measurement of the mean combined cortical thickness (CCT) of the second metacarpal bones. In 53 women, bone mineral content of the radial shaft (RMBC) was also measured by single-photon absorptiometry (SPA) and lumbar bone mineral density (LBMD) was measured by dual-photon absorptiometry (DPA). Serum and urine biochemical variables were measured under standardized conditions on the sixth and seventh days of a controlled diet. There was a strong positive correlation between Ccr and bone mass. Although our subjects showed the expected linear decline in Ccr with age, we found that the relationship between Ccr and bone mass in the radius and lumbar spine was independent of age. On the other hand, the relationship between Ccr and CCT was not independent of age. We concluded that the relationship between Ccr and lumbar and radial bone mass is probably indicative of a relationship between glomerular filtration rate and bone mass, although this requires validation with a noncreatinine method for measurement of glomerular filtration rate. Age per se does not appear to be a cause of declining lumbar bone mass after the menopause.

Absorptiometry, Photon↗

PubMed1991

Pre-existing fractures and bone mass predict vertebral fracture incidence in women.

OBJECTIVE: To determine the independent contributions of bone mass and existing fractures as predictors of the risk for new vertebral fractures. SUBJECTS: Postmenopausal Japanese-American women. MEASUREMENTS: Baseline measurements of the distal radius, the proximal radius, and the calcaneus were obtained in 1981 using single-photon absorptiometry. Measurements of the lumbar spine were obtained in 1984 using dual-photon absorptiometry. Prevalent vertebral fractures were identified using dimensions measured on lateral radiographs; vertebral height values more than 3 SD below vertebra-specific means were considered to indicate fracture. Statistical models were used to evaluate the utility of bone mass and existing (prevalent) fractures to predict the risk for new fractures during an average follow-up of 4.7 years. MAIN RESULTS: Differences of 2 SD in bone mass were associated with fourfold to sixfold increases in the risk for new vertebral fractures. A single fracture at the baseline examination increased the risk for new vertebral fractures fivefold. Presence of two or more fractures at baseline increased the risk 12-fold. A combination of low bone mass (below the 33d percentile) and the presence of two or more prevalent fractures increased the risk 75-fold, relative to women with the highest bone mass (above the 67th percentile) and no prevalent fractures. Stature, body mass index, arm span, and spinal conditions such as scoliosis, osteoarthritis, and sacroiliitis did not predict fracture incidence (P greater than 0.05). Weight was marginally predictive (P = 0.04) of fracture incidence but became nonpredictive after adjusting for bone mass (P greater than or equal to 0.05). CONCLUSIONS: Both bone mass and prevalent vertebral fractures are powerful predictors of the risk for new vertebral fractures. Combining information about bone mass and prevalent fracture appears to be better for predicting new fractures than either variable alone. Physicians can use these risk factors to identify patients at greatest risk for new fractures.

Absorptiometry, Photon↗

PubMed1990

Broadband ultrasound attenuation in the os calcis: relationship to bone mineral at other skeletal sites.

1. We have examined the relationship between broadband ultrasound attenuation in the os calcis and measurements of bone mineral in the distal forearm and lumbar spine of normal and postmenopausal osteoporotic women. 2. Values of broadband ultrasound attenuation in postmenopausal women with vertebral osteoporotic fractures were significantly lower (35%) than in normal pre- and peri-menopausal women (55.4 +/- 3.8 and 79.6 +/- 0.8 dB/MHz, respectively). 3. Broadband ultrasound attenuation correlated significantly with bone mineral content measured in the distal forearm by single-photon absorptiometry (r = 0.77, P less than 0.0001) and with bone mineral content (r = 0.66, P less than 0.0001) and bone mineral density (r = 0.72, P less than 0.0001) measured in the lumbar spine by dual-photon absorptiometry. 4. Although significant, these correlations are not sufficiently close to be predictive. However, the accuracy of broadband ultrasound attenuation in discriminating between normal subjects and patients with vertebral fracture compared very favourably with direct measurements in the spine by dual-photon absorptiometry. 5. Broadband ultrasound attenuation, but not the other measurements, correlated significantly with age in the osteoporotic patients (r = 0.50, P less than 0.05). 6. These findings may reflect the partial dependence of broadband ultrasound attenuation on the intrinsic trabecular architecture of cancellous bone, the disruption of which contributes to an increase in fracture risk.

Absorptiometry, Photon↗

PubMed1992

Hypergonadotropic hypogonadic amenorrhea (World Health Organization III) and osteoporosis.

OBJECTIVE: To assess the bone mineral density in World Health Organization (WHO) III women after hormone replacement therapy. DESIGN: We studied the bone mineral density of 41 women with premature ovarian failure (hypergonadotropic hypogonadic amenorrhea--WHO III) before and during hormone replacement therapy. SETTING: All WHO III women were recruited from the Outpatient Department of the First Department of Gynecology and Obstetrics, University of Vienna Medical School, Austria, a public University Hospital. PATIENTS, PARTICIPANTS: Forty-one patients, 30 healthy women. INTERVENTIONS: Twenty-eight of 41 WHO III women received cyclic hormone replacement therapy consisting of 0.625 mg conjugated estrogen (days 1 to 30) and 5 mg medrogeston (days 20 to 30) in addition, with a 7-day interval. MAIN OUTCOME MEASURE: The bone mineral density was evaluated by single photon absorptiometry and dual energy x ray absorptiometry every 6 months (single photon absorptiometry six times, dual energy x ray absorptiometry four times). RESULTS: The bone mineral density in young women with hypergonadotropic hypogonadic amenorrhea (WHO III) was lower than in age-matched controls. Hormone replacement therapy produced an increase in bone mineral density in 28 WHO III women, whereas bone mineral density remained quite constant in the women without therapy. CONCLUSION: Hormone replacement therapy increases the bone mineral density of women with hypergonadotropic hypogonadic amenorrhea. Hormones should be substituted early and consistently in affected patients.

Adult↗

PubMed1987

Axial and appendicular bone mineral density in patients with long-term deficiency or excess of calcitonin.

Whether calcitonin deficiency causes and calcitonin excess prevents bone loss is controversial. We therefore measured plasma calcitonin levels and bone mineral density at the radius (by single photon absorptiometry) and lumbar spine (dual photon absorptiometry) in patients with an excess or deficiency of calcitonin. We studied 21 patients who had undergone subtotal thyroidectomy 6.8 to 29 years previously and had no calcitonin secretory reserve, and 11 patients who had received a diagnosis of medullary thyroid carcinoma 6.8 to 23 years previously and had chronic hypercalcitoninemia. Bone-density values, expressed as Z-scores (i.e., as the number of standard deviations above or below the normal means adjusted for age and sex), were indistinguishable from normal in the patients who had undergone thyroidectomy (means +/- SE: radius, 0.36 +/- 0.15; spine, 0.27 +/- 0.17). In the patients with medullary thyroid cancer, radial bone-density values were normal (-0.26 +/- 0.39), but spinal density was significantly reduced (-0.75 +/- 0.17, P less than 0.01). There were no significant correlations between the duration of calcitonin excess or deficiency and the bone density at either site. Bone mineral density was not affected by whether or not thyroxine replacement therapy was given. We conclude that skeletal mass is not affected by endogenous plasma calcitonin in adults.

Adult↗

PubMed1988

Ultrasonic transmission velocity and single photon absorptiometric measurement of metacarpal bone strength: an in vitro study in the horse.

Ten pairs of third metacarpal bones from Thoroughbred horses aged two to 12 years were used to estimate bone strength. Measurements of transverse cortical ultrasound velocity, cortical cross sectional area and bone mineral content were made using ultrasonic transmission velocity and single photon absorptiometry. These data were used to determine bone mineral density, compact bone density and modulus of elasticity. The results were compared with those measured by direct means or chemical analysis and satisfactory correlations were obtained between estimated and measured values. Single photon absorptiometry was found to be more accurate than dual photon absorptiometry. The estimated modulus of elasticity in the transverse direction correlated well with the measured longitudinal value obtained by compression testing. This investigation confirmed the value and precision of using a combined ultrasonic and photon absorptiometric technique for non-invasive measurement of bone strength.

Absorptiometry, Photon↗

PubMed1991

Clinical and anthropometric correlates of bone mineral acquisition in healthy adolescent girls.

We studied the acquisition of bone mineral in 45 healthy prepubertal and pubertal girls and related changes in bone mass to age, body mass, pubertal status, calcium intake, and exercise. A subgroup of 12 girls was followed longitudinally. Bone mineral content (BMC) of the lumbar spine, whole body, and femoral neck was measured by dual energy x-ray absorptiometry and that at the midradius by single photon absorptiometry. For comparison, spine and whole body mineral contents were also measured by dual photon absorptiometry. Bone mass was expressed in conventional terms of BMC and area density (BMD). However, we show that BMD fails to account for differences in bone thickness. Since bone size increases during adolescence, we present a new expression, bone mineral apparent density (BMAD), which is BMC normalized to a derived bone reference volume. This term minimizes the effect of bone geometry and allows comparisons of mineral status among bones of similar shape but different size. BMC increased with age at all sites. These increases were most rapid in the early teens and plateaued after 16 yr of age. When bone mineral values at all sites were regressed against age, height, weight, or pubertal stage, consistent relationships emerged, in which BMC was most strongly correlated, BMD was correlated to an intermediate degree, and BMAD correlated only modestly or without significance. Dietary calcium and exercise level did not correlate significantly with bone mass. From these relationships, we attribute 50% of the pubertal increase in spine mineral and 99% of the change in whole body mineral to bone expansion rather than to an increase in bone mineral per unit volume. In multiple regressions, pubertal stage most consistently predicted mineral status. This study emphasizes the importance of pubertal development and body size as determinants of bone acquisition in girls. BMAD may prove to be particularly useful in studies of bone acquisition during periods of rapid skeletal growth.

Absorptiometry, Photon↗

PubMed1993

Long-term fracture prediction by bone mineral assessed at different skeletal sites.

Bone mineral density (BMD) was measured at the lumbar spine and cervical and intertrochanteric regions of the proximal femur by dual-photon absorptiometry and bone mineral content was assessed at the distal and midradius by single-photon absorptiometry in an age-stratified random sample of 304 Rochester, Minnesota women aged 30-94 years. Over follow-up extending to 10 years (median 8.3 years), 93 women experienced 163 new fractures. After adjusting for age, these bone mineral measurements predicted the likelihood of any incident fracture due to moderate trauma, with relative hazards varying from 1.4 to 1.6 per SD decrease in baseline bone mineral. A 1 SD decrease in lumbar spine BMD increased the risk of a new vertebral fracture comparably to a 17 year increase in age; a 1 SD decrease in femoral BMD was comparable to a 13-14 year increase in age on the risk of a hip fracture. We conclude that bone mineral measurements made at a variety of skeletal sites can predict the occurrence for at least 8-10 years of moderate trauma fractures of the sort that might be related to osteoporosis.

Absorptiometry, Photon↗

PubMed1990

Interrelationships among bone densitometry sites in normal young women.

Interrelations among skeletal sites were examined in a population of up to 300 normal young white women aged 20-40 years. Measurements were done on the radius shaft, ultradistal radius, and ultradistal ulna using single-photon absorptiometry (SPA) and on the lumbar spine, proximal humerus, and proximal femur using dual-photon-absorptiometry (DPA). Because of the narrow range of intrapopulation variance in these normal young women, the intercorrelations among skeletal sites were not very high; the average correlation (r) was 0.43 for bone mineral content (BMC) and 0.45 for bone mineral density (BMD). The results at any one site predicted values at other sites with a standard error of estimate (SEE) of approximately 11% for BMD and 17% for BMC. Even in this relatively homogeneous sample, measurements at a single skeletal site could not be extrapolated to indicate skeletal status at other sites. BMC, and to a lesser extent BMD, were influenced by body size much as has been observed in both men and postmenopausal women. Bone results are preferably expressed as BMD, because (a) intrapopulation variability is lower (10% versus 15% for the lumbar spine), (b) intercorrelations among skeletal sites, and even among adjacent vertebrae, are higher for BMD, and (c) the influence of body size on BMD is lower (the average r for weight and BMD was 0.26 versus 0.33 for BMC).

Absorptiometry, Photon↗

PubMed1989

Interval bone mineral density with long-term gonadotropin-releasing hormone agonist suppression.

Twenty-six patients of mean age 37 +/- 4.8 (SD) years, who received a 6-month course of gonadotropin-releasing hormone (GnRH) analogue, were selected for study. Bone mineral density (BMD) was measured by dual-photon absorptiometry before initiation and after completion of agonist therapy. Mean BMD (g/cm2) by dual-photon absorptiometry at L2 to L4, femoral neck, Ward's triangle, and the trochanteric area did not change significantly (P = not significant [NS]) after 6 months of GnRH analogue suppression. Mean percent (%) expected density as standardized for age, weight, and sex remained in the range of 89.3% to 94.2% (P = NS). The interval detectable change in BMD after therapy was 0.05 +/- 0.06 g/cm2. These findings are reassuring with respect to the use of long-term GnRH analogue regimens to induce a hypoestrogenic state in the treatment of hormone-dependent conditions.

Absorptiometry, Photon↗

PubMed2000

Bone metabolism and mineral density following renal transplantation.

AIM: To study bone turnover following renal transplantation using a panel of biochemical markers and to correlate the results with both areal and volumetric bone mineral density (BMD). PATIENTS: A total of 31 patients aged 18.1 years were transplanted 5.4 years before this study. Control patients (n = 31) were age and gender matched. METHODS: In addition to measurement of biochemical markers, BMD was measured by single photon absorptiometry and peripheral quantitative computed tomography on the non-dominant radius. RESULTS: Patients had reduced glomerular filtration rate, raised concentrations of serum phosphate, serum procollagene type I carboxy terminal propeptide, osteocalcin, and serum procollagene type I cross linked carboxy terminal telopeptide. The differences were still significant if only patients with normal intact parathyroid hormone were considered. BMD single photon absorptiometry Z score for age was significantly decreased. Following standardisation for height the differences were no longer present. With volumetric techniques patients had normal trabecular but decreased cortical and total BMD compared to age matched controls, but there was no difference from height matched controls. CONCLUSION: Markers of bone turnover are increased following renal transplantation. However, the biochemical analysis did not allow conclusions to be drawn on the bone mineral content. BMD single photon absorptiometry Z score corrected for height and BMD measured by quantitative computed tomography compared to height matched controls were normal in paediatric renal transplantation patients. Height matched controls should be used in both areal and volumetric BMD measurements in states of growth failure.

Absorptiometry, Photon↗

PubMed1991

Demonstration that bone mass is greater in black than in white children.

Osteoporosis and hip fractures are less common and bone mass is greater in black than in white women. To determine if bone mass is greater in black than in white children, bone mineral density (BMD) of the midradius by single-photon absorptiometry and BMD of the lumbar spine (L1-L4), trochanter, and femoral neck by dual-photon absorptiometry were measured in 20 black boys, 18 black girls, 33 white boys, and 35 white girls between the ages of 7 and 12 years. Mean age (10.4 +/- 0.3 versus 10.2 +/- 0.2 years) and body weight (39 +/- 2 versus 38 +/- 2 kg) in the blacks and whites, respectively, were not different in the two groups, and the ages and weights of the boys and girls were not different from each other. BMD were significantly greater in black than in white children at each site, in the black than in white boys at the trochanter and femoral neck, and in the black than in white girls at each site. In both races, BMD varied directly with age and body weight. Multivariate analysis showed that BMD were greater at the midradius, lumbar spine, trochanter, and femoral neck in the black than in the white children, that BMD of the lumbar spine was greater in the girls than in the boys, and that BMD of the trochanter and femoral neck were greater in the boys than in the girls. There were significant partial correlations between race and BMD and between BMD and body weight at each site, between sex and BMD at the lumbar spine, trochanter, and femoral neck, and between age and BMD at the midradius, trochanter, and femoral neck. Race, sex, age, and body weight together accounted for 49-66% of the variation in bone mass. Thus, BMD of the midradius, spine, and hip are greater in black than in white children, body weight and age are important determinants of bone mass, and some sex differences in bone mass are present at this age.

Absorptiometry, Photon↗

PubMed1989

Bone densitometry of the peripheral skeleton with a new photon counting and imaging device.

We present a new method for the assessment of bone mineral content of the peripheral skeleton. The method employs a new photon counting and imaging area device, the multi-wire proportional counter. The system can work as a single photon absorptiometer at the energies of both I-125 and Gd-153. It can work also as a dual photon absorptiometer using one of the two pairs of isotopes (I-125, Gd-153) or (I-125, Am-241). Both the calcaneus and the forearm can be imaged in a few minutes, with either single or dual photon absorptiometry. To test this new method in a clinical environment we compared it with the standard dual photon absorptiometry of the forearm. The data collected in a cross-sectional study of bone mineral content and bone mineral density in a group of 76 patients show a good correlation between the two measurement techniques (r = 0.931). The multi-wire proportional counter, due to its imaging capabilities, has a much lower repositioning error. This allows its use in regions with a large gradient of bone mineral density, such as the calcaneus or the very distal site of the forearm, which recent data have indicated to be superior to more proximal measurements in identifying osteoporosis.

Absorptiometry, Photon↗

PubMed1982

Differential effects of endocrine dysfunction on the axial and the appendicular skeleton.

In 100 patients with various types of endocrine dysfunction, we measured bone mineral density (BMD) at the midradius (greater than 95% cortical bone) and distal radius (75% cortical and 25% trabecular bone) by single photon absorptiometry and at the lumbar spine (greater than 66% trabecular bone) using the new technique of dual photon absorptiometry. BMD in each endocrine disorder deviated in at least one site from the sex-specific age regression of 187 normal subjects. For patients with primary hyperparathyroidism, hypercortisolism, and hyperthyroidism this deviation was negative (suggesting bone loss), whereas for patients with secondary hyperparathyroidism due to chronic renal failure, acromegaly, and postsurgical hypoparathyroidism it was positive (suggesting bone gain). When all six states of endocrine dysfunction were compared concomitantly by multivariate analysis of variance, the profile of the changes in BMD differed significantly (P less than 0.001), indicating a nonuniform response of bone to the various hormonal alterations. When values for BMD at each of the three scanning sites were compared the midradius and distal radius did not differ significantly; either of the radius measurements, however, differed significantly (P less than 0.001) from the lumbar spine. Thus, the BMD of the axial skeleton cannot be reliably predicted from measurements made in the appendicular skeleton. We conclude that the effects of endocrine dysfunction on bone density are complex and are both disease and site specific.

Absorptiometry, Photon↗

PubMed1997

Lack of relationship between vitamin D receptor genotype and forearm bone gain in healthy children, adolescents, and young adults.

Recent studies have suggested that genetic effects on bone mineral density (BMD) are related to allelic variation in the vitamin D receptor (VDR) gene. We examined 1) allelic influences of the VDR gene on BMD of the forearm, spine, hip, and whole body; and 2) allelic influences of the VDR gene on forearm BMD gain. Two hundred and seventy-three healthy boys and girls, aged 8.2-16.5 yr, at baseline were eligible. Forearm BMD was assessed with single photon absorptiometry at baseline. BMD gain was calculated as the annual percent change in BMD measured by single photon absorptiometry from the baseline and after 3.8 +/- 0.1 (+/-SD) yr. Calcium intake and physical activity were assessed by a detailed questionnaire at baseline and after 1 yr. VDR alleles were determined by BsaMI endonuclease restriction fragment analysis after PCR amplification. No significant differences in forearm BMD gain or in BMD assessed at the forearm, spine, hip, and whole body were observed among the three VDR genotypes. These findings did not change after adjusting for environmental factors such as calcium intake and physical activity or age, weight, height, and changes in weight and height during the observation period. In conclusion, our data do not support the idea that VDR genotypes are related to BMD gain or to BMD at the forearm, hip, spine, and whole body in healthy boys and girls, aged 8-21 yr. VDR genotyping is probably of little use for the detection of individuals who would benefit from increased calcium and physical activity to increase their peak bone densities.

Absorptiometry, Photon↗

PubMed1991

Research note: current methods used in determination and evaluation of tibia strength: a correlation study involving birds fed various levels of cholecalciferol.

Tibiae were removed from 300 75-wk-old laying hens for tibia strength analysis using two methods, direct photon absorptiometry and tibia breaking strength. Left tibiae with flesh intact were used for bone density determination with direct photon absorptiometry. Right tibiae were cleaned and dried for determination of tibia weight and tibia breaking strength. Partial correlation coefficients were estimated among bone density, tibia breaking strength, tibia weight, and body weight. A significant correlation was observed between tibia breaking strength and bone density measurements (r = .66, P less than or equal to .0001). Tibia weight and tibia breaking strength were also significantly correlated (r = .62, P less than or equal to .0001), as well as bone weight and bone density (r = .71, P less than or equal to .0001). Tibia weight and BW were also significantly correlated (r = .66, P less than or equal to .0001), necessitating covariance adjustment for BW. Bone densitometry measurements are less variable than tibia breaking strength measurements, and bone densitometry does not require cleaning bones of flesh before measurement.

Absorptiometry, Photon↗

PubMed1975

Phonton absorptiometry and skeletal mass in the treatment of osteoporosis.

Thirty-six osteoporotic patients who underwent several therapeutic regimes were studied on two occasions by photon absorptiometry and total-body neutron activation analysis (TBNAA). These determinations were made at a mean interval of 8.9 plus or minus 0.8 months. The 8-cm radial site was chosen for the photon absorptiometry which was performed with the Norland-Instruments Densitometer. Mean initial bone mineral content (BMC) was 0.724 plus or minus 0.069 gm/cm and mean bone width was 1.235 plus or minus 0.072 cm. The mean percent change in BMC (%deltaBMC) was 1.02 plus or minus 4.2. The initial total-body calcium (TBCa) as determined by TBNAA was reduced when compared with values that would be expected from empirically derived formulas. The mean percent change in TB-Ca (%deltaTB-Ca) was -3.2 plus or minus 4.7. Most patients displayed a change in BMC and TB-Ca that was at least 2 s.d. greater than the precision of the methods used (%deltaTB-Ca greater than 2). No relationship was found between the deltaBMC and the deltaTB-Ca (r = 0.17). These findings suggest that changes in the radical BMC at the 8-cm site cannot be extrapolated to indicate changes in skeletal mass in response to treatment of osteoporosis. Whether photon absorptiometry at other sites or at multiple sites provides a closer relationship to changes in skeletal mass (TB-Ba) remains to be determined.

Activation Analysis↗