摘要:

AbstractWe followed 130 postmenopausal women without evidence of vertebral deformity by lateral spine radiographs on entry into study for 2 years, and repeat spine radiographs were taken at the end of that time. Incident deformities occurring within this 2 year period were detected by two methods, a level‐specific radiogrammetric approach and visual inspection by skilled clinicians. Fourteen incident deformities were detected by the radiogrammetric method, and 19 by the clinicians. Ultrasound transmission velocity was measured at the patella in each subject on entry. Values for ultrasound velocity were significantly correlated with incident fracture occurrence, with individuals having velocity values more than one standard deviation below the mean for the group exhibiting from 3.3 to 4.6 times the probability of incident fracture as individuals with velocity values more than one standard deviation above the mean. Thus, low values for ultrasound transmission velocity at the patella detect yet‐unexpressed bony fragility at the spine and predict future fract

ISSN:0884-0431    

DOI:10.1002/jbmr.5650100302

出版商:John Wiley and Sons and The American Society for Bone and Mineral Research (ASBMR)    

年代:1995

数据来源: WILEY

摘要:

AbstractThe purpose of this study was to compare the ability of ultrasound velocity measurement with that of single photon absorptiometry to determine the odds of history of fracture since age 40, for a population‐based study. To do this we computed odds ratios and 95% confidence intervals for 809 women and 502 men, aged 50 years and older, who are participants in the prospective phase of the Saunders County Bone Quality Study. These participants received both the ultrasound and single photon absorptiometry bone measurements at the initiation of the study. In addition, a history of all fractures that had occurred to participants since age 40 was obtained. The two bone assessment methods were compared by examining the magnitude of the odds ratios, to determine which produces the highest estimate of the probability of odds of fracture, and by examining widths of the respective confidence intervals to show which estimate of odds ratio is the most precise. Ultrasound velocity estimates a higher probability of odds of both low‐trauma fractures and all fractures than distal radius and ulna bone mineral content, but lower than bone mineral density at the same sites for both women and men. However, the ultrasound measure is more precise than bone mineral density, but less precise than bone mineral content. We conclude that ultrasound velocity is as good as single photon absorptiometry in estimating odds of fract

ISSN:0884-0431    

DOI:10.1002/jbmr.5650100303

出版商:John Wiley and Sons and The American Society for Bone and Mineral Research (ASBMR)    

年代:1995

数据来源: WILEY

摘要:

AbstractQuantitative ultrasound is a promising technique to evaluate fracture risk. To test the hypothesis that reduction of one ultrasound measurement, broadband ultrasound attenuation (BUA), is associated with an increased risk of vertebral fracture in postmenopausal women, we performed a cross‐sectional analysis of 442 women aged 55–80 years enrolling in a clinical trial of alendronate. Prior to randomization, we obtained bone mineral density (BMD) measurements of the hip, spine, and whole body, radiographs of lateral lumbar and thoracic spine, and duplicate measurements of calcaneal BUA with a Walker Sonix UBA575. Vertebral fractures were defined by morphometry and semiquantitative reading by a radiologist. After adjustment for potential confounders, the relative risk of vertebral fracture was 1.8 (95% CI 1.4–2.3) for each standard deviation reduction in BUA; for each standard deviation reduction in BMD, the relative risk was 1.7 (95% CI 1.3–2.1) at the femoral neck, and 2.2 (95% CI 1.7–2.9) at the spine. Adjustment for hip, spine, or whole body BMD did not significantly alter the relation between BUA and vertebral fracture. For example, after adjusting for spine BMD, the relative risk of vertebral fracture was 1.5 (95% CI 1.1–2.0) for each standard deviation reduction in BUA. We conclude that low BUA is associated with the presence of vertebral fractures in postmenopausal women. The relation between BUA and vertebral fracture is similar to that observed for BMD and vertebral fractures. Furthermore, the relation between BUA and vertebral fracture persists after adjustment for BMD. Our findings suggest BUA measures qualities of bone that are in part independent of BMD, and thus may be useful alone or in combination with bone mass measurements in the prediction of vertebra

ISSN:0884-0431    

DOI:10.1002/jbmr.5650100304

出版商:John Wiley and Sons and The American Society for Bone and Mineral Research (ASBMR)    

年代:1995

数据来源: WILEY

摘要:

AbstractIn the United States, the higher prevalence of osteoporosis and the higher incidence of fractures in whites than in blacks may be attributed to the finding of lower bone density (BD) in both white children and adults. In South Africa, osteoporosis and fractures also occur more frequently in whites than in blacks. Appendicular BD has been found to be similar in black and white children in South Africa, but there is little information available on BD of adults in South Africa. This cross‐sectional study aimed to assess changes in BD with age in adult females in South Africa and to assess possible differences in peak BD and in the rate of postmenopausal bone loss between blacks and whites. Data for 180 black and 184 white female nurses aged 20–64 years were analyzed. The distal radius bone density (RBD) was measured by single photon absorptiometry. The lumbar spine bone density (SBD) and the femur bone density (FBD) were measured by dual‐energy X‐ray absorptiometry. Blacks were shorter than whites (p= 0.0001), and blacks' weight, body mass index, and skinfold thickness increased with age. Peak SBD and RBD were similar in blacks and whites, but peak FBD was higher in blacks (p= 0.0001). This ethnic difference in peak FBD became apparent in the fourth decade. Peak FBD was similar in black and white subjects with normal body mass indices (p= 0.09), but in overweight subjects peak FBD was higher in blacks than in whites (p= 0.0001). SBD (p= 0.03), RBD (p= 0.0002), and FBD (p= 0.04) in whites, but not in blacks, decreased after the menopause. Weight had a positive association with FBD in premenopausal blacks (R= 0.24,p= 0.0001) but not in whites. In the postmenopausal group, adiposity had a positive association with SBD and RBD in blacks and with FBD in both blacks and whites. These results suggest that weight‐bearing is important in the attainment of peak FBD and that adiposity may be important in decreasing postmenopausal bone loss. The finding of higher FBD in blacks than in whites may explain the lower rate of femoral fractures in black South Africans. However, the similarity in SBD between blacks and whites in this study suggests that factors other than bone density might contribute to the lower vertebral fracture rate in black compared with white South

ISSN:0884-0431    

DOI:10.1002/jbmr.5650100305

出版商:John Wiley and Sons and The American Society for Bone and Mineral Research (ASBMR)    

年代:1995

数据来源: WILEY

摘要:

AbstractMany studies have demonstrated significant differences in bone mineral density between various racial groups. Although it has been suggested that differences in body weight contribute to such interracial variation, the artifactual effect of the skeletal size inherent in projectional absorptiometry methods has been largely ignored. We have measured bone mineral density by dual‐energy X‐ray absorptiometry in the lumbar spine and at three femoral sites in 200 premenopausal women of Chinese, Indian, European, or Polynesian origin (50 of similar mean age in each group). In the Chinese and Indian women the measured bone mineral density measurements (g/cm) were similar, but significantly less, at all sites, than those of European women (p≤ 0.005). The European women were, however, significantly taller than both the Chinese and Indian women (p<0.0001), and when the scale artifact of absorptiometry was removed by dividing the measured bone mineral density either by the height of the subject, or by the square root of the area over which the X‐ray beam was projected, then the differences in mean bone mineral density between the Chinese, Indian, and European women were almost completely eliminated. The Polynesian women were significantly more obese (as judged from mean body mass index) than all the other groups (p<0.0001) and had significantly greater bone mineral density at all sites than all the other groups both before (p<0.0001) and after (p<0.0001) correcting for the scale artifact. Analysis of covariance suggested that 10–40% of the remaining increase in bone density could be accounted for by their greater obesity, the balance representing a true interracial difference. This effect was most obvious in the lumbar spine and least evident at the femoral sites. We conclude that there is a true interracial difference in bone mineral density between Polynesians and the other races studied, and that this is increased further by the greater body weight of Polynesians. The differences between Europeans and Asians are substantially attributable to a measurement artifact arising from the smaller skeletal dimensions of Asians. This needs to be borne in mind by clinicians assessing bone density in Asian

ISSN:0884-0431    

DOI:10.1002/jbmr.5650100306

出版商:John Wiley and Sons and The American Society for Bone and Mineral Research (ASBMR)    

年代:1995

数据来源: WILEY

摘要:

AbstractIn this cross‐sectional study of 55 women (mean age 73.54 ± 5.87), the magnitude of the relation between different indices of physical ability and confounding factors to bone density were determined. Physical fitness was assessed by direct measurement of maximal oxygen consumption (V̇O2 max), isokinetic muscle strength, and quadriceps and psoas muscle surfaces and densities using computed tomography. Anthropometry, chronological and gynecological ages, and dietary calcium intake were also recorded. The bone mineral density (BMD) was evaluated at the axial level (lumbar spine and proximal femur) and at the peripheral level (radius and tibia, cancellous and cortical compartments). Parameters related to physical ability proved to be the best predictors of BMD in radial and tibial cancellous compartments, spine, femoral neck, and trochanter, accounting for 15–27.5% of the total variance. The V̇O2 maxwas a major determinant of the femoral mineral density and one of the predictors of radial and tibial cancellous compartments. Psoas parameters were strongly related to spine mineral density and also constituted a predictor of radius (cancellous) and tibia mineral densities. The arm muscle strength could predict, though weakly, the BMD of axial skeleton, whereas thigh muscle strength only predicted the BMD of inferior limbs. No correlation was observed between current dietary calcium intake and BMD. Age‐postmenopause and fertile life remained predictive of BMD at mostly cancellous sites, whereas anthropometry exerted important effects on radial and tibial cortices. The study suggests distinct sets of relations between physical ability and the BMD variables. Subjects with greater and denser psoas muscles had greater spine BMD, and those with higher V̇O2 maxhad greater proximal

ISSN:0884-0431    

DOI:10.1002/jbmr.5650100307

出版商:John Wiley and Sons and The American Society for Bone and Mineral Research (ASBMR)    

年代:1995

数据来源: WILEY

摘要:

AbstractPotential determinants of bone mineral density (BMD) were studied cross‐sectionally in 115 healthy, sexually mature Caucasian women aged 18 years. Bone mineral density (Hologic QDR1000W) of the lumbar spine, proximal femur (five sites), and distal tibia and fibula; fasting blood and urine calcium biochemistry; serum sex hormone levels (follicular phase); nutrient intakes; aerobic fitness; trunk muscle strength; and habitual activity levels were measured. The effects of heredity were considered by measuring the BMD of 107 of the subjects' mothers. Simple and stepwise regression analysis were used to identify significant determinants of BMD at each of the regions studied. The analysis indicated that significant bivariate correlations exist between BMD at all sites and body weight (r= 0.23–0.47,p≤ 0.01), lean body weight (r= 034–0.46), trunk strength (r= 0.27–0.47), physical activity score (r= 0.20–0.25), and aerobic fitness (r= 0.29–0.45). Dietary calcium intake correlated significantly with BMD at the trochanter site only (r= 0.19), and none of the biochemical or hormonal indices measured correlated consistently with BMD at any site. Significant correlations between the BMD of mothers and daughters ranged fromr= 0.43 at lumbar spine tor= 0.34 at the intertrochanteric site. Pairedt‐tests showed the daughters had significantly (p<0.03) lower BMD than their mothers at the lumbar spine (98 ± 12% [mean ± SD]) and significantly higher (p<0.002) BMD at the femoral neck, trochanter, and total hip sites (110 ± 16%, 108 ± 17%, 103 ± 14%, respectively). When stepwise regression analysis includedweight‐corrected strength of the trunk flexor muscles(Corr Flex),weight‐corrected aerobic fitness(Corr VO2max),physical activity score, andbody weight, body weight was the only significant determinant of BMD at all sites. Corr Flex made significant contributions at all sites except the femoral neck, while Corr VO2maxmade additional contribution at the femoral neck, trochanter, total hip, and shaft of femur sites. These variables accounted for 13–27% of the variance in BMD. The addition of mother's BMD to these independent variables, in stepwise regression analysis, improved the prediction

ISSN:0884-0431    

DOI:10.1002/jbmr.5650100308

出版商:John Wiley and Sons and The American Society for Bone and Mineral Research (ASBMR)    

年代:1995

数据来源: WILEY

摘要:

AbstractA new slow‐release, neutral potassium phosphate salt (UroPhos‐K) has been formulated in order to minimize gastrointestinal side effects and avoid sodium‐induced calciuria. It was tested in a prospective randomized, double‐blind trial in a group of 21 kidney stone patients with absorptive hypercalciuria type I (AH). Twelve patients allocated to the UroPhos‐K group received four tablets twice daily with breakfast and an evening snack providing 1240 mg of phosphorus and 63.5 mEq of potassium daily. Nine patients assigned to the placebo group received placebo tablets of the same appearance containing excipient only. Subjects were studied during a 3‐day period in the hospital while consuming a constant metabolic diet containing 400 mg Ca, 100 mEq Na, and 800 mg P per day before and after 3 months of treatment. Treatment with UroPhos‐K did not cause any significant gastrointestinal side effects; nor did it raise fasting serum K or phosphorus, or reduce hemoglobin or creatinine clearance. It was associated with a rise in urinary K from 46 ± 7 to 98 ± 9 mEq per day and phosphorus from 744 ± 185 to 1535 ± 112 mg per day (p<0.001 each). UroPhos‐K treatment reduced urinary Ca from 288 ± 63 to 171 ± 49 mg/day (p<0.001), without altering oxalate excretion. It reduced the urinary saturation of calcium oxalate without altering that of brushite. Moreover, by increasing urinary excretion of inhibitors (citrate and pyrophosphate), it reduced the propensity for spontaneous nucleation of brushite (increased formation product of brushite) and inhibited crystal agglomeration of calcium oxalate. None of these changes were seen in the placebo‐treated group. It is concluded that treatment with UroPhos‐K reduces urinary stone‐forming potential without causing ga

ISSN:0884-0431    

DOI:10.1002/jbmr.5650100309

出版商:John Wiley and Sons and The American Society for Bone and Mineral Research (ASBMR)    

年代:1995

数据来源: WILEY

摘要:

AbstractBone morphogenetic protein‐6 (BMP‐6) is an osteoinductive factor that may have a regulatory role in the terminal differentiation of chondrocytes. We investigated the expression of BMP‐6 messenger RNA in freshly isolated newborn calf rib chondrocytes separated by density gradient centrifugation into five highly enriched subpopulations at different stages of maturation as assessed by cell size and alkaline phosphatase activity. Expression of BMP‐6 mRNA was compared with expression of type II collagen mRNA and type X collagen mRNA using Northern analysis. Type X collagen mRNA expression increased with increasing cell size whereas type II collagen mRNA varied little with cell size. BMP‐6 mRNA expression was highest in small cells and lowest in the largest cells, which were maximally expressing type X collagen mRNA. This suggests that up‐regulation of the BMP‐6 gene may precede chondrocyt

ISSN:0884-0431    

DOI:10.1002/jbmr.5650100310

出版商:John Wiley and Sons and The American Society for Bone and Mineral Research (ASBMR)    

年代:1995

数据来源: WILEY

摘要:

AbstractProstaglandins (PGs) have been postulated to amplify their own production by stimulating cyclic adenosine monophosphate activity, which in turn stimulates PG production. We examined regulation of messenger RNA levels for the inducible and constitutive prostaglandin G/H synthases, PGHS‐2 and PGHS‐1, in murine osteoblastic MC3T3‐E1 cells, which express both PGHS‐1 and PGHS‐2, and in rat osteoblastic Py1a cells, which express only PGHS‐2. Prostaglandins E2, F2α, and D2induced PGHS‐2 mRNA in both cell lines under serum‐free conditions and stimulated small increases in PGHS‐1 mRNA levels in MC3T3‐E1 cells. PGE2(1 μM) increased the transcription rate of PGHS‐2 mRNA 9‐fold at 2 h in serum‐free cells and also induced PGHS‐2 protein. In the presence of arachidonic acid or serum, PGs also increased medium PGE2. Both forskolin, a protein kinase A activator, and phorbol 12‐myristate 13‐acetate (PMA), a protein kinase C (PKC) activator, have previously been shown to induce PGHS‐2 mRNA in MC3T3‐E1 cells, but in the present study only PMA induced PGHS‐2 expression in Pyla cells. The induction of PGHS‐2 mRNA in Py1a cells by PGs was inhibited by chelerythrine, a PKC inhibitor, and blocked by 24 h of pretreatment with PMA. The 2 h serum stimulation of PGHS‐2 mRNA in MC3T3‐E1 cells was inhibited 40–50% by three structurally unrelated nonsteroidal anti‐inflammatory drugs (NSAIDs), suggesting that endogenous PGs also amplify PG production through induction of PGHS‐2. We conclude that the mechanism for autoamplification is in part transcriptional and may involve multiple pathways. We speculate that the induction of PGHS‐2 by PGs may be the means for expanding PG responses to small

ISSN:0884-0431    

DOI:10.1002/jbmr.5650100311

出版商:John Wiley and Sons and The American Society for Bone and Mineral Research (ASBMR)    

年代:1995

数据来源: WILEY