Relationship between body composition and bone mineral content in young and elderly women

Primary objective : To study the relationship between bone mineral content (BMC), lean tissue mass (LTM) and fat mass (FM) in a large sample of young and elderly women. Research design : Cross-sectional. Methods and procedures : BMC, LTM and FM were measured by dual-energy X-ray absorptiometry in 2009 free-dwelling Caucasian women aged 63 &#45 7 years (mean &#45 SD; range: 37-88 years). The majority of women were postmenopausal (96%). Results : LTM explained 13% more variance of BMC than FM ( R 2 adj = 0.39 vs 0.26, p < 0.0001) but weight (Wt) explained 5% more variance of BMC than LTM ( R 2 adj = 0.44, p < 0.0001). The prediction of BMC obtained from LTM and FM ( R 2 adj = 0.46, p < 0.0001) was only slightly better than that obtained from Wt. After the effects of age, Wt and height (Ht) on BMC were taken into account by multiple regression, the contribution of LTM and FM to BMC was just one-fifth of that of Wt ( R 2 adj for full models &#114 0.56, p < 0.0001). After a further correction for bone area (BA), the contribution of LTM and FM to BMC was just one-tenth of that of BA and not different from that of Wt and Ht on practical grounds ( R 2 adj for full models = 0.84, p < 0.0001). Thus, after inter-individual differences in age, Wt, Ht (and bone size) are taken into account, the relationship between body composition and BMC is substantially weakened. Conclusions : In Caucasian women, (1) LTM is a stronger predictor of BMC than FM, but (2) Wt is a better predictor of BMC than body composition for practical purposes, and (3) Wt and body composition are not able to explain more than 46% of BMC variance.     

Anthropometry fails in classifying bone mineral status in postmenopausal women

This study tested two hypotheses: (1) that simple anthropometric parameters can be used to identify patients at risk of decreased bone mineral content and (2) that an inverse relationship exists between waist:hip ratio (WHR) and bone mineral density (BMD). Bone mineral content (BMC) and BMD were evaluated by dual-energy X-ray absorptiometry in 1873 free-living women. Of these, 1819 (97%) were post-menopausal. One thousand and thirteen women (54%) had normal BMD, 705 (38%) osteopenia and 155 (8%) osteoporosis. Body weight (Wt), body mass index and arm muscle and fat areas were significantly lower in osteoporotics than osteopenics (p < 0.0001) and in these latter than controls (p < 0.0001). However, values of WHR were similar in all groups (p = ns). Body weight was the anthropometric parameter better correlated with BMC (rho = 0.650, p < 0.0001) and only Wt and age were identified as significant predictors of bone mineral status (normal-BMD/osteopenic/osteoporotic) at polytomous logistic regression (p = 0.0001 for each). However, Wt could not be employed as an indicator of bone mineral status at the individual level because of high variations in BMC for the same level of Wt. Under- (< 5th percentile) and normal-Wt (5th-95th percentile) women had the same frequency of osteopenia (39%) while it was lower in over-Wt (> 95th) women (13%). The frequency of osteoporosis was higher in under- than normal-Wt women (37 vs 7%) and none of the over-Wt women had osteoporosis. This study shows that: (1) simple anthropometric measurements cannot be used to select subjects at risk of decreased BMC and, (2) BMD does not vary with WHR.     

Anthropometry fails in classifying bonemineral status in postmenopausal women

This study tested two hypotheses: (1) that simple anthropometric parameters can be used to identify patients at risk of decreased bonemineral content and (2) that an inverse relationship exists between waist:hip ratio (WHR) and bonemineral density (BMD). Bonemineral content (BMC) and BMD were evaluated by dual-energy X-ray absorptiometry in 1873 free-living women. Of these, 1819 (97%) were post-menopausal. One thousand and thirteen women (54%) had normal BMD, 705 (38%) osteopenia and 155 (8%) osteoporosis. Body weight (Wt), body mass index and arm muscle and fat areas were significantly lower in osteoporotics than osteopenics (p &;lt; 0.0001) and in these latter than controls (p &;lt; 0.0001). However, values of WHR were similar in all groups (p = ns). Body weight was the anthropometric parameter better correlated with BMC (rho= 0.650, p &;lt; 0.0001) and only Wt and age were identified as significant predictors of bonemineral status (normal-BMD/osteopenic/osteoporotic) at polytomous logistic regression (p = 0.0001 for each). However, Wt could not be employed as an indicator of bone mineral status at the individual level because of high variations in BMC for the same level of Wt. Under- (&;lt; 5th percentile) and normal-Wt (5th-95th percentile) women had the same frequency of osteopenia (39%) while it was lower in over-Wt (&;gt; 95th) women (13%). The frequency of osteoporosis was higher in under- than normal-Wt women (37 vs 7%) and none of the over-Wt women had osteoporosis. This study shows that: (1) simple anthropometric measurements cannot be used to select subjects at risk of decreased BMC and, (2) BMD does not vary with WHR.     

Cross-calibration of eight-polar bioelectrical impedance analysis versus dual-energy X-ray absorptiometry for the assessment of total and appendicular body composition in healthy subjects aged 21-82 years

AIM: To calibrate eight-polar bioelectrical impedance analysis (BIA) against dual-energy X-ray absorptiometry (DXA) for the assessment of total and appendicular body composition in healthy adults. RESEARCH DESIGN: A cross-sectional study was carried out. SUBJECTS: Sixty-eight females and 42 males aged 21-82 years participated in the study. METHODS: Whole-body fat-free mass (FFM) and appendicular lean tissue mass (LTM) were measured by DXA; resistance (R) of arms, trunk and legs was measured by eight-polar BIA at frequencies of 5, 50, 250 and 500 kHz; whole-body resistance was calculated as the sum R of arms, trunk and legs. RESULTS: The resistance index (RI), i.e. the height(2)/resistance ratio, was the best predictor of FFM and appendicular LTM. As compared with weight (Wt), RI at 500 kHz explained 35% more variance of FFM (vs 0.57), 45% more variance of LTM(arm) (vs 0.48) and 36% more variance of LTM(leg) (vs 0.50) (p < 0.0001 for all). The contribution of age to the unexplained variance of FFM and appendicular LTM was nil or negligible and the RI x sex interactions were either not significant or not important on practical grounds. The percent root mean square error of the estimate was 6% for FFM and 8% for LTM(arm) and LTM(leg). CONCLUSION: Eight-polar BIA offers accurate estimates of total and appendicular body composition. The attractive hypothesis that eight-polar BIA is influenced minimally by age and sex should be tested on larger samples including younger individuals.     

Cross-calibration of eight-polar bioelectrical impedance analysis versus dual-energy X-ray absorptiometry for the assessment of total and appendicular body composition in healthy subjects aged 21-82 years

Aim: To calibrate eight-polar bioelectrical impedance analysis (BIA) against dual-energy X-ray absorptiometry (DXA) for the assessment of total and appendicular body composition in healthy adults. Research design: A cross-sectional study was carried out. Subjects: Sixty-eight females and 42 males aged 21-82 years participated in the study. Methods: Whole-body fat-free mass (FFM) and appendicular lean tissue mass (LTM) were measured by DXA; resistance ( R ) of arms, trunk and legs was measured by eight-polar BIA at frequencies of 5, 50, 250 and 500 kHz; whole-body resistance was calculated as the sum R of arms, trunk and legs. Results: The resistance index (RI), i.e. the height 2 /resistance ratio, was the best predictor of FFM and appendicular LTM. As compared with weight (Wt), RI at 500 kHz explained 35% more variance of FFM ( vs 0.57), 45% more variance of LTM arm ( vs 0.48) and 36% more variance of LTM leg ( vs 0.50) ( p < 0.0001 for all). The contribution of age to the unexplained variance of FFM and appendicular LTM was nil or negligible and the RI &#50 sex interactions were either not significant or not important on practical grounds. The percent root mean square error of the estimate was 6% for FFM and 8% for LTM arm and LTM leg. Conclusion: Eight-polar BIA offers accurate estimates of total and appendicular body composition. The attractive hypothesis that eight-polar BIA is influenced minimally by age and sex should be tested on larger samples including younger individuals.     

Effects of long-term tennis playing on the muscle-bone relationship in the dominant and nondominant forearms.

The relationship between muscle strength and bone mineral density illustrates the positive effect of mechanical loading on bone. But local and systemic factors may affect both muscle and bone tissues. This study investigated the effects of long-term tennis playing on the relationship between lean tissue mass and bone mineral content in the forearms, taking the body dimensions into account. Fifty-two tennis players (age 24.2 +/- 5.8 yrs, 16.2 +/- 6.1 yrs of practice) were recruited. Lean tissue mass (LTM), bone area, bone mineral content (BMC), and bone mineral density were measured at the forearms from a DXA whole-body scan. Grip strength was assessed with a dynamometer. A marked side-to-side difference (p < 0.0001) was found in favor of the dominant forearm in all parameters. Bone area and BMC correlated with grip strength on both sides (r = 0.81-0.84, p < 0.0001). The correlations were still significant after adjusting for whole-body BMC, body height, or forearm length. This result reinforced the putative role of the muscles in the mechanical loading on bones. In addition, forearm BMC adjusted to LTM or grip strength was higher on the dominant side, suggesting that tennis playing exerts a direct effect on bone.     

Relationships between blood pressure, anthropometric characteristics and blood lipids in high- and low-altitude populations from Central Asia

We studied the relationships between blood pressure, anthropometric characteristics and blood lipids in 72 low altitude (LA) Uighurs (600 m), 91 LA-Kirghizs (900 m), 117 medium altitude (MA) Kazakhs (2100 m) and 94 high altitude (HA) Kirghizs (3200 m). All subjects were male and had a similar age (p = ns, ANOVA; range for all 374 subjects: 18-66 yr). Body weight (Wt), body mass index (BM1) and the sum of four skinfolds (4SF) were significantly lower in HA-Kirghizs than the remaining groups (p < 0.0005, p < 0.0005 and p < 0.05 respectively, ANOVA). However, no difference was found in body fat distribution as detected by waist:hip circumference (WHR) and triceps:subscapular skinfold ratios (TSR; p = ns, ANOVA). Stage 1 hypertension was detected in 18% of LA-Uighurs, 2% of LA-Kirghizs, 4% of MA-Kazakhs and 1% of HA-Kirghizs; stage 2 hypertension was detected in 2% of LA-Uighurs and none of the remaining groups; no subject had stage 3 hypertension (The Joint National Committee on Prevention. Detection, Evaluation and Treatment of High Blood Pressure 1997). Blood cholesterol (CH) and triglycerides (TG) did not differ between groups (p = ns, ANOVA). The relationships between systolic (SBP) or diastolic (DBP) blood pressure and age, Wt, BMI, 4SF, WHR, TSR, CH and TG were independent from altitude (p = ns, ANCOVA). In the pooled sample (n = 374), age explained 1 and 3% of SBP (p < 0.05) and DBP (p < 0.005) variance respectively, Wt was the best predictor of SBP and DBP explaining 11 and 10% of their variance respectively (p < 0.0001) and CH explained 5% of DBP variance (p < 0.0001). In conclusion, hypertension is more frequent in LA- than MA- and HA-subjects from Central Asia. However, anthropometric characteristics and blood lipids do similarly contribute to explain blood pressure in these subjects.     

Fat mass influence on bone mass is mediated by the independent association between lean mass and bone mass among elderly women: A cross-sectional study

ObjectivesTo study the independent association of fat mass (FM) and lean mass (LM) with bone mass and to study the differences in bone mass by weight and fat status in 223 seniors (aged 65–89 years) from the city of Zaragoza (Spain), after controlling for age, height, physical activity (PA) and LM.Study designCross-sectional study.Main outcome measuresLM, FM, bone mineral content (BMC) and density (BMD) were measured with dual energy X-ray absortiometry. The relationships of FM and LM with bone-related variables (subtotal body, hip, femoral neck and lumbar spine) were analyzed by linear regression and differences between weight and fat status were analyzed by one-way analysis of covariance.ResultsIn men, there were no significant associations between FM and BMC or BMD. In women FM was positively associated with bone-related variables after adjustment for age, height and PA, whereas adjustment for LM removed all these significant associations. Overweight/obese elderly women had higher BMC and BMD than their non-overweight peers in all regions studied. Additional adjustment for PA did not change the differences between weight status groups, while adjusting for LM removed some of the associations. Overfat/obese men and women did not show higher levels of bone mass than their non-overfat peers. LM was positively associated with bone variables in both sexes. Additional adjustment for PA and FM did not alter the results.ConclusionThe association between fat mass and bone mass of elderly women is mediated by the independent association between lean mass and bone mass.     

An investigation of ethnic differences in bone mineral, hip axis length, calcium metabolism and bone turnover between West African and Caucasian adults living in the United Kingdom.

The aim of the study was to investigate factors relating to calcium and bone metabolism which might explain the low incidence of osteoporotic fracture among Africans. Adult bone mineral status, hip axis length and biochemical indices were investigated in 20 Caucasians (10 male, 10 female) and 19 Gambians (12 male, 7 female) living in the UK. Bone mineral content (BMC), bone mineral density (BMD) and BMC adjusted for bone area, body weight and height (size-adjusted BMC) were measured for the whole-body, lumbar spine, femoral neck, trochanter, radius shaft and radius wrist using dual-energy X-ray absorptiometry. There were no significant differences in whole body or regional BMC; values tended to be lower in the Gambians. Gambian men had higher size-adjusted BMC at the femoral neck (Gambian-British = 21%, 95% CI = 6 to 36%, p < 0.01), associated with a smaller bone area (Gambian-British = -11%, 95% CI = -20 to -2%, p = 0.02). BMD was affected similarly. No other significant differences in BMD or size-adjusted BMC were observed. Gambians had shorter hip axis length (Gambian British, after accounting for sex, = -5%, 95% CI = -9 to -1%, p = 0.02). There were no significant differences in bone turnover (osteocalcin, bone isoenzyme of alkaline phosphatase, urinary deoxypyridinoline) or calciotropic hormone levels (parathyroid hormone, 1,25-dihydroxyvitamin D, calcitonin). Gambian men had lower 25-hydroxyvitamin D concentrations (Gambian = 26.3 SD 12.0 nmol/L, British = 55.5 SD 13.9 nmol/L, p < 0.0001), a difference not seen among the women. Gambian men and women excreted significantly less phosphate and potassium than British subjects by 30-60%; urinary calcium and sodium excretion were similar in the two groups. This study revealed few ethnic differences that could account for the disparity in osteoporotic fracture rates between Africans and Caucasians, with the possible exception of anatomical differences in the hip.     

不同甲状腺功能绝经前女性血清饥饿素与全身骨量、肌肉量、体重的相关分析

目的:探讨不同甲状腺功能的绝经前女性血清饥饿素(ghrelin)水平与其身体成份骨量(BMC)、脂肪量(FM)、肌肉量(LM)的相互关系。方法:采用放射免疫分析法检测71例不同甲状腺功能的绝经前女性其中包括甲状腺机能亢进(甲亢)组33例、甲状腺机能减低(甲减)组18例、正常对照组20例的血清饥饿素水平,同时采用化学发光快速检测法检测其血清游离三碘甲状腺原氨酸(FT3)、游离甲状腺素(FT4)、灵敏促甲状腺激素(sTSH);并采用双能X线吸收法(DXA)测定其全身身体成份(骨量、脂肪量、肌肉量),同时记录体重(BW)。结果:(1)甲亢组血清饥饿素水平明显低于正常对照组(P0.01)和甲减组(P0.01),甲减组血清饥饿素水平与正常对照组之间无显著差别(P0.05)。血清饥饿素与其FT3(r=-0.318,P0.01)、FT4(r=-0.350,P0.01)呈负相关,与sTSH(r=0.281,P0.05)呈正相关。(2)血清饥饿素与全身骨量(r=0.284,P0.05)、肌肉量(r=0.259,P0.05)、体重(r=0.279,P0.05)存在正相关;与脂肪量不存在相关(P0.05)。结论:不同甲状腺功能的绝经前女性血清饥饿素可能影响其全身骨量、肌肉量、体重。     

Lower-limb and whole-body tissue composition assessment in healthy active older women

AIM: The study evaluated, in active elderly women, the accuracy and bias of anthropometry and bioelectrical impedance analysis (BIA) for lower-limb and whole-body tissue composition measures using dual-energy X-ray absorptiometry (DXA) as the criterion method. METHODS: Nineteen individuals (66.1 +/- 4.2 years) participated in the study. Whole-body fat mass (FM) and fat-free mass (FFM) were measured by anthropometry, BIA and DXA. Lower-limb volume (LLV) and lower-limb FFM (LLFFM) were assessed by anthropometry and DXA. RESULTS: LLV and LLFFM were significantly overestimated by anthropometry vs. DXA (p < 0.05 and p < 0.001, respectively) but significant relationships were observed [coefficient of determination (R(2)) > 0.25, p < 0.05]. No significant difference was observed between FM(A) (where (A) stands for anthropometry) vs. FM(DXA) and FFM(A) vs. FFM(DXA) and significant relationships were observed [R(2) = 0.93, p < 0.001, coefficient of variation (CV) = 7.3%; and R(2) = 0.85, p < 0.001, CV = 4.4%, respectively]. No significant difference was observed between FM(BIA) and FM(DXA) and a significant relationship was observed (R(2) = 0.80, p < 0.001, CV = 11.6%). FFM was significantly underestimated by BIA vs. DXA (p < 0.01). CONCLUSIONS: In active elderly women, (i) compared with DXA, anthropometry overestimates LLV and LLFFM; (ii) anthropometry can be an accurate method for assessing whole-body composition; and (iii) despite a non-significant bias for the FM measurement, the BIA tends to overestimate FM and underestimate FFM.     

Effects of silicone breast prostheses on the assessment of body composition by dual-energy X-ray absorptiometry.

We examined the influence of silicone breast prostheses on body composition as assessed by dual-energy X-ray absorptiometry (DXA). Eighteen women were measured with and without a pair of silicone breast prostheses placed on the upper part of the trunk simulating endogenous implants. Bone area, bone mineral content (BMC), areal bone mineral density (BMD), lean tissue mass (LTM) and fat tissue mass (FTM) of the total body and of the subregions of the body, i.e. the head, trunk, arms and legs, were measured by a Norland XR-36 DXA scanner. After application of the silicone prostheses, bone area, BMC and BMD of the total body significantly increased by an average of 3.7, 6.6 and 3.4% (P<0.0001), respectively. Total body LTM and FTM were not affected. In the trunk region, changes were more pronounced. Trunk BMC, for example, was overestimated by 17.9% (P<0. 0001). The prostheses also influenced measurements of truncal soft tissue composition, with a small but statistically significant overestimation of both LTM (1.1%) and FTM (2.1%) (P<0.05). No changes in bone mass and soft tissue composition were seen in the head, arms and legs. Activation of a high-density detection software utility provided by the manufacturer had no influence on any of the measurements. We conclude that silicone breast prostheses affect the assessment of body composition by DXA.     

Lean body mass and bone mineral density in physically exercising postmenopausal women

OBJECTIVES: To investigate whether the relative contribution of body composition (lean and fat mass component) to postmenopausal bone mineral density (BMD) differs between women participating in physical exercise and sedentary women. METHODS: Subjects were 45 postmenopausal women participating in regular physical exercise and 89 sedentary controls aged 50-60 years. Baseline characteristics included age, height, weight, body mass index (BMI, Wt/Ht(2)), age at menopause, and years since menopause (YSM). Body fat mass, percentage of body fat, lean body mass, and lumbar spine BMD (L2-4) were measured by dual-energy X-ray absorptiometry. RESULTS: Although age, height, weight, BMI, and YSM did not differ between the two groups, lean body mass and lumbar spine BMD were significantly higher (P<0.05 and <0.001, respectively), while body fat mass and percentage of body fat mass were significantly lower in exercising women than in sedentary controls (P<0.05 and <0.05, respectively). In exercising women, BMD was positively correlated with lean body mass (r=0.415, P<0.01) but not with body fat mass (r=0.155, NS). Conversely, in sedentary controls, BMD was correlated with body fat mass (r=0.251, P<0.05) and lean body mass (r=0.228, P<0.05). CONCLUSIONS: Lean body mass is a more significant determinant of postmenopausal BMD in physically exercising women than in sedentary women.     

Bone mineral density in older non-Hispanic Caucasian and Mexican-American women: relationship to lean and fat mass

PRIMARY OBJECTIVE: The prevalence of osteoporotic fracture is higher in non-Hispanic Caucasian (NHC) than Mexican-American (MA) women in the USA. The present study examined bone mineral density (BMD) in these two ethnic groups and the association between BMD and body composition. RESEARCH DESIGN: Cross-sectional. SUBJECTS: Sixty-two NHC and 54 MA women, aged 60-86 years, with a body mass index (kgm(-2)) of <30. METHODS: BMD (gcm(-2)) of the spine (L2-4), hip (femoral neck, trochanter, Ward's triangle) and whole body was determined by dual-energy X-ray absorptiometry (DXA). Bone mineral-free lean mass (LM) and fat mass (FM) and several ratios of body fat distribution were also assessed by DXA. RESULTS: There was no difference in age (NHC, 69.5+/-0.7; MA 69.5+/-0.9 years; mean +/- SEM) or body mass, but MA women were shorter with a higher truncal adiposity (p < 0.001). There was no significant difference in BMD between groups, however, adjusting for height resulted in higher hip and whole body BMD in MA women (p < 0.01). When volumetric bone density was calculated (bone mineral apparent density; BMAD, gcm(-3)), a trend for higher values in MA women was observed at the femoral neck (p = 0.018). LM contributed independently to BMD at the spine and hip in NHC women, with FM also contributing at the femoral neck. In MA women, LM was an independent contributor to lumbar spine and trochanter BMD, and both LM and FM contributed to whole body BMD. However, the effects of LM and FM were removed in both groups when BMD was adjusted for body or bone size, the only exception being at the trochanter in NHC women. CONCLUSIONS: These results indicate that MA women have higher bone density at the proximal femur than NHC women, which may partially account for their lower rate of hip fracture. Further, differences in bone density between the two ethnic groups do not appear to be dependent on soft-tissue composition.     

Early life and current determinants of bone in South African children of mixed ancestral origin

BACKGROUND: The influence of early life factors on the bone mineral density of children has been identified, however the contribution of these determinants may vary. AIM: The study investigated determinants of bone mineral content (BMC) in South African children of mixed ancestral origin. SUBJECTS AND METHODS: Early life data including birth weight, maternal alcohol consumption and smoking during pregnancy were collected on 9-year-old children of mixed ancestral origin (n = 64). Grip strength was measured, and physical activity, housing density and dietary data were collected. Whole body BMC (WB BMC), fat-free soft tissue and fat tissue were measured using dual energy X-ray absorptiometry. RESULTS: Maternal alcohol consumption during pregnancy was associated with WB BMC, however after adjusting for possible confounders, this was no longer significant. When combined with gender, gestational age and maternal BMC in a multiple regression, maternal alcohol consumption during pregnancy could explain 20% of the variance in the WB BMC, however when current height was included in the model, the contribution of the other factors was insignificant. There was however a significant correlation between current height and birth weight (r = 0.34; p < 0.01) and alcohol consumption during pregnancy (r = 0.34; p < 0.05). A model consisting of current factors such as age, weight, gender, grip strength and calcium intake was able to explain 81.5% of the variance. Housing density was negatively correlated with WB BMC (r =-0.11; p = 0.05). CONCLUSION: These data suggest that although early life factors may contribute indirectly to the bone mass of children of mixed ancestral origin, the contribution of current factors is greater. In addition, environmental factors such as housing density have a direct effect on bone mass, independent of body size.     

Assessment of bone tissue mineralization by conventional x-ray microcomputed tomography: comparison with synchrotron radiation microcomputed tomography and ash measurements

Assessment of bone tissue mineral density (TMD) may provide information critical to the understanding of mineralization processes and bone biomechanics. High-resolution three-dimensional assessment of TMD has recently been demonstrated using synchrotron radiation microcomputed tomography (SRmuCT); however, this imaging modality is relatively inaccessible due to the scarcity of SR facilities. Conventional desktop muCT systems are widely available and have been used extensively to assess bone microarchitecture. However, the polychromatic source and cone-shaped beam geometry complicate assessment of TMD by conventional muCT. The goal of this study was to evaluate muCT-based measurement of degree and distribution of tissue mineralization in a quantitative, spatially resolved manner. Specifically, muCT measures of bone mineral content (BMC) and TMD were compared to those obtained by SRmuCT and gravimetric methods. Cylinders of trabecular bone were machined from human femoral heads (n = 5), vertebrae (n = 5), and proximal tibiae (n = 4). Cylinders were imaged in saline on a polychromatic muCT system at an isotropic voxel size of 8 microm. Volumes were reconstructed using beam hardening correction algorithms based on hydroxyapatite (HA)-resin wedge phantoms of 200 and 1200 mg HA/cm3. SRmuCT imaging was performed at an isotropic voxel size of 7.50 microm at the National Synchrotron Light Source. Attenuation values were converted to HA concentration using a linear regression derived by imaging a calibration phantom. Architecture and mineralization parameters were calculated from the image data. Specimens were processed using gravimetric methods to determine ash mass and density, muCT-based BMC values were not affected by altering the beam hardening correction. Volume-averaged TMD values calculated by the two corrections were significantly different (p = 0.008) in high volume fraction specimens only, with the 1200 mg HA/cm3 correction resulting in a 4.7% higher TMD value. MuCT and SRmuCT provided significantly different measurements of both BMC and TMD (p < 0.05). In high volume fraction specimens, muCT with 1200 mg HA/cm3 correctionteg resulted in BMC and TMD values 16.7% and 15.0% lower, respectively, than SRmuCT values. In low volume fraction specimens, muCT with 1200 mg HA/cm3 correction resulted in BMC and TMD values 12.8% and 12.9% lower, respectively, than SRmuCT values. MuCT and SRmuCT values were well-correlated when volume fraction groups were considered individually (BMC R2 = 0.97-1.00; TMD R2 = 0.78-0.99). Ash mass and density were higher than the SRmuCT equivalents by 8.6% in high volume fraction specimens and 10.9% in low volume fraction specimens (p < 0.05). BMC values calculated by tomography were highly correlated with ash mass (ash versus muCT R2 = 0.96-1.00; ash versus SRmuCT R2 = 0.99-1.00). TMD values calculated by tomography were moderately correlated with ash density (ash versus muCT R2 = 0.64-0.72; ash versus SRmuCT R2 = 0.64). Spatially resolved comparisons highlighted substantial geometric nonuniformity in the muCT data, which were reduced (but not eliminated) using the 1200 mg HA/cm3 beam hardening correction, and did not exist in the SRmuCT data. This study represents the first quantitative comparison of muCT mineralization evaluation against SRnuCT and gravimetry. Our results indicate that muCT mineralization measures are underestimated but well-correlated with SRmuCT and gravimetric data, particularly when volume fraction groups are considered individually.     

Nandrolone decanoate treatment of post-menopausal osteoporosis for 2 years and effects of withdrawal

This study investigated the effects of nandrolone decanoate (ND) therapy (50 mg i.m. every 3 or 4 wk) on bone mass and soft tissue body composition in post-menopausal women. Twenty-two (22) women were followed up over a period of 30 mth, during which they received ND therapy for 12–24 mth and were treatment-free for the other 6–18 mth. While they were receiving treatment forearm bone mineral content (BMC) and lean body mass (LBM) increased, whereas fat mass (FM) decreased. After withdrawal of ND therapy the BMC, LBM and FM values all tended to return to pretreatment levels.

Serum high-density-lipoprotein cholesterol showed a non-significant decrease, while serum lowdensity-lipoprotein cholesterol and serum total cholesterol remained unchanged during therapy. It was concluded that ND therapy can achieve an increase in BMC in post-menopausal women, but this is maintained only for as long as therapy is continued.     

Validation of a dual energy X-ray absorptiometer: measurement of bone mass and soft tissue composition

We investigated the reproducibility of total and regional body composition measurements performed on a dual energy X-ray absorptiometer (DXA). A group of 38 women aged 21–81 (mean 52. 4) years was scanned twice with repositioning to determine intra-observer reproducibility of measurements of bone mineral density (BMD, g?·?cm^?2), bone mineral content (BMC, g), lean mass (LM, kg) and fat mass (FM, kg) of the total body and of the major subregions of the body. In addition, the ability of the DXA machine to detect changes in LM and FM (simulated by placing 11.1 and 22.3 kg porcine lard on the body of 11 subjects) was examined. Coefficients of variations calculated from the root mean square averages of individual standard deviations were as follows (BMD, BMC, FM, LM): 1.4%, 1.1%, 1.4%, 1.7% (total body), 2.2%, 2.1%,-,- (head), 2.8%, 2.8%, 2.0%, 2.2% (trunk), 3.6%, 3.9%, 4.0%, 4.9% (arms), 2.7%, 1.3%, 2.6%, 2.8% (legs). Percentage fat (%fat) of exogenous lard was 81.3 (SD 3.5)% as assessed by the absorptiometer which corresponded well with the result of chemical analysis (82.8%). Estimated %fat of exogenous lard was not influenced by initial body mass or percentage body fat. Percentages of expected mean values with 11.1 kg lard placed on the body were 99.9 (SD?0.3) for body mass, 100.5 (SD 2.1) for LM, and 99.5 (SD 3.5) for FM. BMD was overestimated by 3.2% (P?P?相似文献   

Relationship between bone mineral content and frequency of postmenopausal fractures

To elucidate the relationship between bone mineral content (BMC) and the frequency of postmenopausal fractures, we performed an epidemiologic investigation in a representative sample of 70-year-old women. Anamnestic data concerning postmenopausal fractures due to minor trauma were recorded and lateral X-rays of the spine were taken for evaluation of spinal fractures. BMC was measured by 125I photon absorptiometry. The 285 women studied were allocated into quintiles according to their BMC value. In 77 women, there were 131 definite osteoporotic fractures (i.e., spinal crush, and fracture of the hip, proximal humerus, and distal forearm), and in 48 women, there were 162 other non-violent fractures (i.e., spinal wedge and other long bone fractures). The frequencies of osteoporotic fractures varied inversely with the mean BMC values for each quintile (r = 0.959, p less than 0.01). The difference in frequency of osteoporotic fractures between the first and fifth quintiles was highly significant (p less than 0.001). In contrast, other non-violent fractures appeared to be unrelated to BMC. It is concluded that low BMC levels predispose to osteoporotic fractures.     

Determinants of one-year response of lumbar bone mineral density to alendronate treatment in elderly Japanese women with osteoporosis

The purpose of this study was to determine factors that could predict the one-year response of the lumbar bone mineral density (BMD) to alendronate treatment in elderly Japanese women with osteoporosis. Eighty-five postmenopausal women with osteoporosis, all of whom were between 55-88 years of age, were treated with alendronate (5 mg daily) for 12 months. Serum calcium, phosphorus, and alkaline phosphatase (ALP) and urinary NTX levels were measured at the baseline and 6 months, and lumbar (L1-L4) BMD was measured by dual energy X-ray absorptiometry at the baseline and 12 months. Multiple regression analysis was used to determine factors that were correlated with the percent change in lumbar BMD at 12 months. Lumbar BMD increased by 8.1 % at 12 months with a reduction in the urinary NTX level by 51.0 % at 6 months. Baseline lumbar BMD (R2=0.226, p < 0.0001) and percent changes in serum ALP and urinary NTX levels (R2=0.044, p < 0.05 and R2=0.103, p < 0.001, respectively) had a negative correlation with the percent change in lumbar BMD at month 12, while the baseline number of prevalent vertebral fractures (R2=0.163, p < 0.001), serum ALP level, and urinary NTX level (R2=0.074, p < 0.05 and R2=0.160, p < 0.001, respectively) had a positive correlation with it. However, baseline age, height, body weight, body mass index, years since menopause, serum calcium and phosphorus levels, and percent changes in serum calcium and phosphorus levels at 6 months did not have any significant correlation with the percent change in lumbar BMD at 12 months. These results suggest that lumbar BMD was more responsive to one-year of alendronate treatment in elderly osteoporotic Japanese women with lower lumbar BMD, more prevalent vertebral fractures, and higher bone turnover, who showed a greater decrease in bone turnover at 6 months, regardless of age, years since menopause, and physique. Alendronate may be efficacious in elderly Japanese women with evident osteoporosis that is associated with high bone turnover, and the percent changes in serum ALP and urinary NTX levels at 6 months could predict the one-year response of lumbar BMD to alendronate treatment.