Change in hip bone mineral density and risk of subsequent fractures in older men

Low bone mineral density (BMD) increases fracture risk; how changes in BMD influence fracture risk in older men is uncertain. BMD was assessed at two to three time points over 4.6 years using dual‐energy X‐ray absorptiometry (DXA) for 4470 men aged ≥65 years in the Osteoporotic Fractures in Men (MrOS) Study. Change in femoral neck BMD was estimated using mixed effects linear regression models. BMD change was categorized as “accelerated” (≤?0.034 g/cm²), “expected” (between 0 and ?0.034 g/cm²), or “maintained” (≥0 g/cm²). Fractures were adjudicated by central medical record review. Multivariate proportional hazards models estimated the risk of hip, nonspine/nonhip, and nonspine fracture over 4.5 years after the final BMD measure, during which time 371 (8.3%) men experienced at least one nonspine fracture, including 78 (1.7%) hip fractures. Men with accelerated femoral neck BMD loss had an increased risk of nonspine (hazard ratio [HR] = 2.0; 95% confidence interval [CI] 1.4–2.8); nonspine/nonhip (HR = 1.6; 95% CI 1.1–2.3); and hip fracture (HR = 6.3; 95% CI 2.7–14.8) compared with men who maintained BMD over time. No difference in risk was seen for men with expected loss. Adjustment for the initial BMD measure did not alter the results. Adjustment for the final BMD measure attenuated the change in BMD‐nonspine fracture and the change in BMD‐nonspine/nonhip relationships such that they were no longer significant, whereas the change in the BMD‐hip fracture relationship was attenuated (HR = 2.6; 95% CI 1.1–6.4). Total hip BMD change produced similar results. Accelerated decrease in BMD is a strong, independent risk factor for hip and other nonspine fractures in men. © 2012 American Society for Bone and Mineral Research.     

中国男女性骨大小和体积骨密度的探讨

目的　确定中国北方人群在腰椎和股骨部位峰值骨大小和体密度的性别差异 ,并分析影响其大小的因子。方法　年龄 15至 4 0岁 2 5 6例健康男性和 30 9例健康女性 ,他们的腰椎和股骨颈的骨大小和体积骨密度用双能X线骨密度仪测量。椎体和股骨颈近似为圆柱体 ,骨体积V =π× (宽度 2 ) 2 ×高度 ,vBMD =BMC 体积。结果　椎体峰值BMC ,体积和vBMD女性在 30～ 4 0岁达到峰值 ,而男性 15～ 17岁达到峰值。椎体和股骨颈的BMC男性比女性高 18 1%～ 2 6 7% ,而骨体积相应高 2 8 5 %～ 32 0 % ,这样vBMD男性比女性低 4 0 %～ 8 3% (P <0 0 1)。初潮较晚 (≥ 15岁 )绝经前妇女比来潮较早者 (≤ 12岁 ) ,BMC低 10 % (P <0 0 5 )。男性抽烟者与非抽烟者骨大小和vBMD没有统计学差异。饮酒也没有观察到明显的效应。结论　中国男性比女性有较低的vBMD ,这可能部分地解释中国男性有较高骨折发生率的原因     

Attainment of peak bone mass at the lumbar spine,femoral neck and radius in men and women: relative contributions of bone size and volumetric bone mineral density

The age at which peak bone mineral content (peak BMC) is reached remains controversial and the mechanism underlying bone mass consolidation is still undefined. The aims of this study were to investigate; (1) the timing of peak BMC by studying bone size and volumetric BMD (vBMD) as separate entities and (2) to determine the relative contributions of bone size and vBMD to bone mass consolidation. A total of 132 healthy Caucasian children (63 boys and 69 girls, ages 11–19 years) and 134 healthy Caucasian adults (66 men and 68 women, ages 20–50 years) were studied. BMC was measured by DXA at the AP and lateral lumbar spine (LS) femoral neck (FN) and ultradistal radius (UDR). vBMD and bone volume (size) were estimated. Bone mass consolidation was examined between age 16 years to the age peak bone values were attained. During growth, BMC and bone size increased steeply with age and approximately 80–90% of peak values were achieved by late adolescence. vBMD at the spine and UDR (in women) increased gradually, but vBMD at the FN and UDR in men remained almost constant. During consolidation, bone size continued to increase with little change in vBMD. Peak vBMD at the lumbar spine was reached at 22 and 29 years in men and women, respectively, but earlier at the FN at 12 years. At the UDR peak vBMD was achieved at age 19 years in women, with little change in men. In conclusion, peak vBMD and bone size are almost fully attained during late adolescence. Although speculative, the lack of change in vBMD during consolidation implies that the continued increase in bone mass may primarily be due to increases in bone size rather than increases in either trabecular volume, cortical thickness or the degree of mineralisation of existing bone matrix (vBMD). Skeletal growth and maturation is heterogeneous, but crucial in understanding how the origins of osteoporosis may begin during childhood and young adulthood.Presented in part at the XXXVIIth European Symposium on Calcified Tissues, Tampere, Finland, 2000.     

Relationship of femoral neck areal bone mineral density to volumetric bone mineral density, bone size, and femoral strength in men and women

Summary

Using combined dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography, we demonstrate that men matched with women for femoral neck (FN) areal bone mineral density (aBMD) have lower volumetric BMD (vBMD), higher bone cross-sectional area, and relatively similar values for finite element (FE)-derived bone strength.

Introduction

aBMD by DXA is widely used to identify patients at risk for osteoporotic fractures. aBMD is influenced by bone size (i.e., matched for vBMD, larger bones have higher aBMD), and increasing evidence indicates that absolute aBMD predicts a similar risk of fracture in men and women. Thus, we sought to define the relationships between FN aBMD (assessed by DXA) and vBMD, bone size, and FE-derived femoral strength obtained from quantitative computed tomography scans in men versus women.

Methods

We studied men and women aged 40 to 90?years and not on osteoporosis medications.

Results

In 114 men and 114 women matched for FN aBMD, FN total cross-sectional area was 38% higher (P?P?Conclusions In this cohort of young and old men and women from Rochester, MN, USA who are matched by FN aBMD, because of the offsetting effects of bone size and vBMD, femoral strength and the load-to-strength ratio tended to be relatively similar across the sexes.     

Fracture prediction from bone mineral density in Japanese men and women.

In a cohort of 2356 Japanese elderly, after adjusting for age and prevalent vertebral fracture, baseline BMD predicted the risk of spine and hip fracture with similar RR to that obtained from previous reports in whites. The RR per SD decrease in BMD for fracture declined with age. INTRODUCTION: Low bone mineral density (BMD) is one of the most important predictors of a future fracture. However, we are not aware of any reports among Japanese in Japan. MATERIALS AND METHODS: We examined the association of BMD with risk of fracture of the spine or hip among a cohort of 2356 men and women aged 47-95 years, who were followed up by biennial health examinations. Follow-up averaged 4 years after baseline measurements of BMD that were taken with the use of DXA. Vertebral fracture was assessed using semiquantitative methods, and the diagnosis of hip fracture was based on medical records. Poisson and Cox regression analysis were used. RESULTS: The incidence was twice as high in women as in men, after adjusting for age. After adjusting for baseline BMD and prevalent vertebral fracture, however, the gender difference was no longer significant. Age, baseline BMD of spine and femoral neck, and prior vertebral fracture predicted vertebral fracture and hip fracture. Loss of absolute BMD of the femoral neck predicted spine fracture, after adjusting for baseline BMD; rates of change in percent BMD, weight, height, body mass index, and age at menopause did not. The predictive value of baseline BMD for vertebral fracture risk was similar in men and women. The relative risk (RR) for vertebral fracture and hip fracture per SD decrease in BMD declined with age, after adjustment for prevalent vertebral fractures. CONCLUSIONS: Baseline BMD, loss of femoral neck BMD, and prior vertebral fracture predict the risk of spine and hip fracture in Japanese with similar RR to that obtained from previous reports in whites. The RR per SD decrease in BMD for fracture declined with age, suggesting that factors other than BMD might play a greater role in the elderly.     

Correlates of trabecular and cortical volumetric bone mineral density at the femoral neck and lumbar spine: The osteoporotic fractures in men study (MrOS)

The objective of this cross‐sectional analysis was to examine the correlates of trabecular and cortical volumetric bone mineral density (vBMD) in 3670 community‐dwelling men, mean age 73.6 ± 5.9 years. vBMD was measured by quantitative computed tomography (QCT) and areal BMD by dual‐energy X‐ray absorptiometry (DXA). Demographic, historical, and lifestyle information was obtained by interview, and height, weight, and neuromuscular function were determined by examination. To express the strength of the associations, percent differences (95% confidence interval) were calculated from multivariable linear regression models using the formula 100 (β × unit/mean BMD). Units for continuous variables were chosen to approximate 1 standard deviation (SD). The multivariable linear regression models predicted 15%, 21%, and 20% of the overall variance in trabecular and cortical vBMD of the femoral neck and vBMD of the lumbar spine, respectively. Diabetes was associated with a 16.5% greater trabecular vBMD at the femoral neck and 11% at the lumbar spine but less than 2% for cortical vBMD. For femoral neck trabecular vBMD, the strongest negative correlates were past smoking (?9%), fracture history (?15%), kidney stones (?7%), corticosteroids (?11%), and insulin therapy (?26%). For cortical vBMD, the strongest negative correlate was use of thyroid medication (?2.8%). The strongest negative correlates for lumbar spine trabecular vBMD were fracture history (?5%), antiandrogen use (?19%), height (?8%), and thiazoliainedione use (?22%). Bioavailable estradiol and testosterone levels were positively related and sex hormone–binding globulin was negatively related to trabecular vBMD of the spine. There was no relationship between sex hormones and femoral neck trabecular vBMD. Our conclusion is that correlates of trabecular vBMD and cortical vBMD appear to differ in older men. © 2010 American Society for Bone and Mineral Research     

New or worsening lumbar spine vertebral fractures increase lumbar spine bone mineral density and falsely suggest improved skeletal status.

Changes in lumbar spine bone mineral density (BMD) are determined by follow-up dual-energy x-ray absorptiometry (DXA) assessments. Inclusion of new or worsening vertebral fractures in follow-up measurements may increase BMD. To test this hypothesis, we examined pooled data from the placebo groups of two clinical trials that involved postmenopausal women with osteoporosis. DXA measurements of lumbar spine BMD, bone mineral content (BMC), and area were obtained at baseline and at two years in the Multiple Outcomes of Raloxifene Evaluation (MORE) Trial and at baseline and study endpoint in the Fracture Prevention Trial. In these trials, fractured vertebrae identified by expert radiologists during posterioranterior (PA) spine DXA assessment were excluded from the BMD assessment. Lateral spine radiographs were graded using a semi-quantitative (SQ) scale. Most new or worsening vertebral fractures (84%) diagnosed from lateral spine radiographs were not identified by PA spine DXA. While the follow-up BMD of vertebrae without new or worsening fractures did not change significantly, each unit increase in SQ grade was associated with an approximate 7.0% increase in the BMD of affected vertebrae (p < 0.001). Increases in BMD were highly correlated with increases in BMC (r = 0.87, p < 0.001). Inclusion of new or worsening vertebral fractures increased PA spine BMD measurements at follow-up, with the impact being related to the magnitude of change in SQ score. It is difficult to reliably identify vertebral fractures from PA spine DXA assessments. Inclusion of new or worsening vertebral fractures in follow-up DXA measurements may falsely suggest an improvement in spine BMD. Our suggestion is to perform lateral spine imaging concurrently with any assessment of PA spine BMD in patients who, in the opinion of the health care provider, may have vertebral fractures.     

Association of volumetric bone mineral density with abdominal aortic calcification in African ancestry men

Summary

We tested for association between cortical and trabecular volumetric bone mineral density (vBMD) with abdominal aortic calcification (AAC) prevalence in 278 Afro-Caribbean men. AAC was present in 68.3 % of the men. Greater cortical, but not trabecular, vBMD was associated with significantly decreased odds of AAC independent of traditional risk factors.

Introduction

The aim of this study is to assess the prevalence and correlates of AAC in a sample of 278 Afro-Caribbean men (mean age 56) and to test for a largely unexplored association between cortical and trabecular vBMD with AAC prevalence.

Methods

Men were recruited consecutively as part of an ongoing prospective cohort study of body composition in men aged 40+. For this analysis, AAC was assessed by computed tomography of the abdomen from L3 to S1. Aortic calcium was scored using the Agatston method, and prevalence was defined as a score ≥10 to rule out false positives. Men also had BMD assessed using peripheral quantitative computed tomography at 4 % (trabecular vBMD) and 33 % (cortical vBMD) of the radius and tibia.

Results

Abdominal aortic calcification was present in 68.3 % of the men. Significant independent predictors of AAC prevalence were increased age, increased BMI, hypertension, and current smoking. Age was the strongest predictor, with each SD (7.8 year) increase in age conferring 2.7 times increased odds of having AAC (P?<?0.0001). A one SD greater cortical, but not trabecular, vBMD was associated with a significant decreased odds of AAC prevalence independent of other traditional risk factors (OR 0.65; 95 % CI 0.45–0.92).

Conclusions

Cortical vBMD is inversely associated with AAC presence. This finding suggests that there may be shared physiology between cortical bone compartment remodeling and vascular calcification.     

Correlates of trabecular and cortical volumetric bone mineral density of the radius and tibia in older men: The osteoporotic fractures in men study

Quantitative computed tomography (QCT) can estimate volumetric bone mineral density (vBMD) and distinguish trabecular from cortical bone. Few comprehensive studies have examined correlates of vBMD in older men. This study evaluated the impact of demographic, anthropometric, lifestyle, and medical factors on vBMD in 1172 men aged 69 to 97 years and enrolled in the Osteoporotic Fractures in Men Study (MrOS). Peripheral quantitative computed tomography (pQCT) was used to measure vBMD of the radius and tibia. The multivariable linear regression models explained up to 10% of the variance in trabecular vBMD and up to 9% of the variance in cortical vBMD. Age was not correlated with radial trabecular vBMD. Correlates associated with both cortical and trabecular vBMD were age (?), caffeine intake (?), total calcium intake (+), nontrauma fracture (?), and hypertension (+). Higher body weight was related to greater trabecular vBMD and lower cortical vBMD. Height (?), education (+), diabetes with thiazolidinedione (TZD) use (+), rheumatoid arthritis (+), using arms to stand from a chair (?), and antiandrogen use (?) were associated only with trabecular vBMD. Factors associated only with cortical vBMD included clinic site (?), androgen use (+), grip strength (+), past smoker (?), and time to complete five chair stands (?). Certain correlates of trabecular and cortical vBMD differed among older men. An ascertainment of potential risk factors associated with trabecular and cortical vBMD may lead to better understanding and preventive efforts for osteoporosis in men. © 2010 American Society for Bone and Mineral Research     

Effects of skeletal size of the lumbar spine on areal bone density,volumetric bone density,and the diagnosis of osteoporosis in postmenopausal women in China

To understand the effects of skeletal size of the lumbar spine on areal bone mineral density (aBMD), volumetric bone mineral density (vBMD), and the diagnosis of osteoporosis in postmenopausal women, we measured the projected bone area, bone mineral content (BMC), aBMD, and vBMD at the anteroposterior and lateral lumbar spines in a population of 1081 postmenopausal Chinese women, 42 to 86 years of age. The results indicated that, at the anteroposterior and lateral lumbar spine, there were significant positive correlations between bone area and both BMC (r = 0.606; P = 0.000 and r = 0.610; P = 0.000) and aBMD (r = 0.270; P = 0.000 and r = 0.182; P = 0.000), but not vBMD (r = –0.055; P = 0.000 and r = 0.000; P = 0.929). When bone area at the anteroposterior spine changed by ±1 SD, the BMC, aBMD, and vBMD correspondingly changed by 28.2%, 10.1%, and 1.69% on the basis of their respective means. When a variation of ±1 SD was observed in bone area at the lateral spine, BMC and aBMD, correspondingly changed by 25.9% and 6.18% on the basis of their respective means, while vBMD indicated no change. Through comparisons among large-, intermediate-, and small-bone area groups, significant differences were found in the means of subjects heights, weights, BMC, and vBMD at the anteroposterior and lateral lumbar spines, as well as in the detection rates of osteoporosis by aBMD (P = 0.000). Detection rates of osteoporosis by aBMD at the anteroposterior spine and by aBMD at the lateral spine, and by vBMD were 44.1%, 55.5%, and 49.7%, respectively, in the total population; 31.4%, 41.7%, and 53.7%, respectively, in the large-bone area group; 43.3%, 55.9%, and 50.5%, respectively, in the intermediate-bone area group; and 61.7%, 70.0%, and 42.5%, respectively, in the small-bone area group. No significant differences were found in the detection rates of osteoporosis by vBMD among the groups. The results of multiple linear regression revealed that the major factors influencing skeletal size and aBMD of the lumbar spine were height and weight. Therefore, in menopausal women of the same ethnic group and age, the skeletal size of the lumbar spine would have significant influence upon aBMD and the diagnosis of osteoporosis, i.e., the larger the spinal size, the greater the aBMD and the lower the osteoporosis detection rate, while, conversely, the smaller the skeletal size, the smaller the aBMD and the higher the osteoporosis detection rate. When we use aBMD of the lumbar spine to diagnose osteoporosis in a population with different body sizes, we need to take this body size difference into account. When we use vBMD to diagnose osteoporosis, the effect of body size on BMD will diminish.     

Fluoride pharmacokinetics and changes in Lumbar spine and hip bone mineral density

Debate about the use of fluoride for the treatment of vertebral osteoporosis has centered not only on whether fluoride treatment decreases vertebral fractures, but also the interindividual vertebral bone mineral density (BMD) response, the potential for nonvertebral fractures, as well as side effects and tolerability. These effects may be dose dependent and, in this study, we examin the pharmacokinetics of sodium monofluorophosphate (MFP) in osteoporotic patients and relate this to changes in BMD. Plasma fluoride absorption curves were measured from 0 to 6 h after ingestion of MFP at baseline and during long-term dosing in 21 patients with vertebral osteoporosis (T scores 2). BMD was measured at baseline and at 12 months at the lumbar spine (LS), femoral neck (FN), trochanter, and Ward's triangle. We found that fluoride elimination was inversely related to creatinine clearance. LS BMD increased from a median of 0.77 g/cm² (range 0.69 to 0.99) at baseline to 0.88 g/cm² (0.75 to 1.13) (p < 0.001) after 12 months. This equates to a median increase of 12% (range −1.2 to 37). Median femoral neck BMD decreased from 0.75 g/cm² (0.62 to 0.94) at baseline to 0.69 g/cm² (0.62 to 0.92) (p = 0.13) after 12 months. This equates to a decrease of −2% (−19 to 10). BMD at the other hip sites also decreased alightly. Changes in LS and FN BMD were not significantly related (r = 0.28, p = 0.29). The various pharmacokinetic parameters measured were not related to changes in LS BMD; however, there was an inverse relationship between trough fluoride concentration during long-term dosing and change in FN BMD. Further studies are required to see if this relationship can be used to monitor osteoporotic patients treated with fluoride and prevent significant decreases in FN BMD and possibly fractures at this site.     

Effect of concomitant vitamin D deficiency or insufficiency on lumbar spine volumetric bone mineral density and trabecular bone score in primary hyperparathyroidism

Summary

Lower vitamin D and higher parathyroid hormone (PTH) levels are associated with higher volumetric BMD and bone strength at the lumbar spine as measured by central quantitative computed tomography in primary hyperparathyroidism (PHPT), but there are no differences in bone microarchitecture as measured by trabecular bone score (TBS).

Introduction

The purpose of this study was to evaluate the association between 25-hydroxyvitamin D (25OHD) and volumetric bone mineral density (vBMD) and the TBS at the lumbar spine (LS) in PHPT.

Methods

This is a cross-sectional analysis of PHPT patients with and without low 25OHD. We measured vBMD with quantitative computed tomography (cQCT) and TBS by dual-energy X-ray absorptiometry (DXA) at the LS in 52 and 88 participants, respectively.

Results

In the cQCT cohort, those with lower vitamin D (<20 vs. 20-29 vs. ≥30 ng/ml) tended to be younger (p?=?0.05), were less likely to use vitamin D supplementation (p?<?0.01), and had better renal function (p?=?0.03). Those with 25OHD <20 ng/ml had 80 and 126 % higher serum PTH levels respectively vs. those with 25OHD 20–29 ng/ml (p?=?0.002) and 25OHD ≥30 ng/ml (p?<?0.0001). Covariate-adjusted integral and trabecular vBMD were higher in those with 25OHD 20–29 vs. those with 25OHD ≥30 ng/ml, but those with 25OHD <20 did not differ. Because there were few participants with 25OHD deficiency, we also compared those with vitamin D <30 vs. ≥30 ng/ml. Covariate-adjusted integral and trabecular vBMD were 23 and 30 % higher respectively (both p?<?0.05) in those with vitamin D <30 vs. ≥30 ng/ml. TBS was in the partially degraded range but did not differ by vitamin D status.

Conclusion

In mild PHPT, lower 25OHD is associated with higher PTH, but vitamin D deficiency and insufficiency using current clinical thresholds did not adversely affect lumbar spine skeletal health in PHPT. Further work is needed to determine if higher vBMD in those with lower vitamin D is due to an anabolic effect of PTH.

     

Muscle mass deficits are associated with bone mineral density in men with idiopathic vertebral fracture

Introduction and hypothesis The causes of idiopathic vertebral fractures (IVF) in men are poorly understood. We hypothesised that in IVF, areal bone mineral density (aBMD) deficits would be associated with reduced muscle mass. Methods In this case-control study, 48 men (61.5 ± 12.1 years old) presenting with symptomatic IVF were compared with 48 healthy controls matched for age (±5 years) and stature (±5 cm). The aBMD and soft-tissue body composition were determined by dual energy X-ray absorptiometry (DXA). Muscle mass was defined as the ratio of appendicular lean mass to the square of height (ALMI). Sex hormones, IGF-I and its binding protein IGFBP-3 were measured by immunoassay. Results ALMI was significantly lower in IVF patients (8.27 ± 0.90 vs 8.65 ± 0.88 kg/m², t = 2.193, df = 47, P = 0.033 by paired sample t-test). Hierarchical regression analysis revealed that for IVF patients, ALMI explained the greatest proportion of variance in BMD at the lumbar spine, femoral neck and total hip (R ² _change = 16.4–22.7%, P = 0.012–0.002) and only IGFBP-3 explained variance in ALMI (R ² _change = 19.9%, P = 0.006). Conclusions In men with IVF, ALMI was reduced and associated with IGFBP-3. ALMI was identified as a novel factor that explained a greater proportion of variance in BMD than either fat mass or serum biochemistry. Electronic Supplementary Material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

女性骨质疏松性髋部骨折的骨密度和髋部结构强度变化

目的观察女性骨质疏松性髋部骨折的骨密度和髋部结构强度变化。方法对95例骨质疏松性髋部骨折女性患者进 行双能X线骨密度检测和髋关节结构分析,年龄：76. 60 ±9. 36岁,体重指数：20. 88 ±3. 72 kg/m2 ;将63例年龄>50岁骨密度 正常的女性作为对照组。对照组女性年龄57. 24 ±5. 65岁,体重指数：26. 56 ±4. 82 kg/m2,比较二组股骨颈骨密度和结构强 度参数(包括骨横截面积、皮质厚度和屈曲应力比）。结果髋部骨折患者的股骨颈骨密度、股骨颈和转子间的骨横截面积和 皮质厚度均非常显著低于对照组;屈曲应力比非常显著高于对照组,87. 4%髋部骨折患者的股骨颈和转子间屈曲应力比均> 10;而84. 1%正常骨密度组患者的股骨颈和转子间屈曲应力比均< 10。结论髋部骨折患者的股骨颈骨密度及髋关节结构 强度均发生非常显著改变,骨强度降低,HSA提供的结构强度参数有助于预测髋部骨折风险。     

Factors associated with the lumbar spine and proximal femur bone mineral density in older men

Bone mass is a major determinant of fracture, but there have been few comprehensive studies of the correlates of bone mineral density (BMD) in older men. The objective of the current cross-sectional analysis was to determine the factors associated with BMD of the lumbar spine and proximal femur in a large population-based sample of older men enrolled in The Osteoporotic Fractures in Men Study, Mr.OS. We enrolled 5,995 men 65 years of age or older, 89% Caucasian, in Mr.OS at six US clinical centers. Demographic, medical and family history and lifestyle information was obtained by interview and physical function and anthropometric data by examination. Spine and hip BMD was measured using dual-energy X-ray absorptimetry. The multivariable linear regression models predicted 19 and 10% of the overall variance in BMD of the femoral neck and spine, respectively. African-American men had 6 to 11% higher BMD than Caucasian men independent of multiple factors. Hip BMD declined with advancing age, while spine BMD increased. Body weight (per 10 kg) and self report of diabetes were each associated with 2 to 4% higher BMD, while history of a non-trauma fracture and current use of selective serotonin reuptake inhibitors, but not other antidepressants, were associated with at least 4% lower BMD. Both maternal and paternal histories of fracture were associated with 1.4–1.7% lower BMD. Osteoarthritis, physical activity, grip strength, alcohol intake, and dietary calcium were positively related to BMD, while a history of chronic lung disease, prostate cancer, and kidney stones was associated with lower BMD. Smoking, caffeine intake, and thiazide diuretics were not related to BMD in older men. A number of lifestyle and behavioral characteristics and medical conditions were associated with BMD in older men. Identification of these correlates could improve methods to identify men at risk for fracture and improve our understanding of fracture etiology.The authors represent the Osteoporotic Fractures in Men (Mr.OS) Research Group. The Osteoporotic Fractures in Men (MrOS) Study is supported by National Institutes of Health funding. The following institutes provided support: the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), the National Institute on Aging (NIA), and the National Cancer Institute (NCI), under the following grant numbers: UO1 AG18197-02, UO1 AR45580-02, UO1 AR45614, UO1 AR45632, UO1 AR45647, UO1 AR45654, UO1 AR45583, and M01 RR00334.     

The effects of muscle-building exercise on bone mineral density of the radius,spine, and hip in young men

Summary We previously demonstrated that muscle-building exercise is associated with increases in serum Gla-protein, serum 1,25(OH)₂D, and urinary cyclic AMP. These studies were interpreted to mean that this form of exercise increases bone formation and modifies the vitamin D-endocrine system to provide more calcium for bone. The present investigation was carried out in normal young adult white men to determine the effects of exercise on bone mineral density at weight-bearing and nonweight-bearing sites. Twelve men who had regularly engaged in muscle-building exercises (use of weights, exercise machines, or both) for at least 1 year and 50 age-matched controls (aged 19–40 years) were studied. The body weights of the two groups were not different from each other (78±2 vs. 74±1 kg, NS). Bone mineral density (BMD) of the lumbar spine, trochanter, and femoral neck was measured by dual-photon absorptiometry, and BMD of the midradius was measured by single-photon absorptiometry. It was found that muscle-building exercise was associated with increased BMD at the lumbar spine (1.35±0.03 vs. 1.22±0.02 g/cm²,P<0.01), trochanter (0.99±0.04 vs. 0.86±0.02 g/cm²,P<0.01), and femoral neck (1.18 ±0.03 vs. 1.02±0.02 g/cm²,P<0.001) but not at the midradius (0.77±0.02 vs. 0.77±0.01 g/cm², NS). These studies provide additional evidence that muscle-building exercise is associated with increases in BMD at weight-bearing sites but not at nonweight-bearing sites.     

Bone structure in patients with low bone mineral density with or without vertebral fractures.

Vertebral fractures (VFX) are caused by low bone mass and microstructural deterioration of bone tissue. The latter is not well defined. We investigated bone structure in transiliac biopsy specimens from 88 volunteers. Biopsy specimens were obtained at baseline in the Multiple Outcomes of Raloxifene Evaluation trail, a prospective study in osteoporotic (BMD < or = -2.5 T score) postmenopausal women without or with VFX on standardized lateral spinal radiographs. Bone biopsy specimens were embedded in methylmethacrylate (MMA). Histomorphometry was done in 8 microns (U.S.A.) or 5 microns (Europe) Goldner stained sections. Vertebral fracture status (yes/no) was the outcome variable in logistic regression models adjusted for age and biopsy specimen origin (U.S.A. vs. Europe). Patients with and without VFX (26/62) were similar regarding age (69.2 +/- 5.2 years vs. 67.3 +/- 6.7 years), bone volume (BV/TV; 17.7 +/- 4.7% vs. 19.0 +/- 5.8%), and bone surface (BS/TV; 2.7 +/- 0.6 mm2/mm3 vs. 2.8 +/- 0.6 mm2/mm3). A lower cortical thickness (C.Th; 652 +/- 267 microns vs. 822 +/- 325 microns), total strut length (TSL; 826 +/- 226 microns/mm2 vs. 922 +/- 256 microns/mm2), node-to-loop (Nd-Lp) strut length (10.1 +/- 10.3% vs. 15.0 +/- 13.6%), together with a higher node-to-terminus (Nd-Tm) strut length (45.6 +/- 9.7% vs. 39.1 +/- 9.3%) were each associated with prevalent VFX (0.01 < p < 0.10). Differences in BV/TV did not explain these associations. In conclusion, cortical thinning and disruption of trabecular lattice are possible pathogenic mechanisms in patients with VFX.     

Vertebral fractures despite normal spine bone mineral density in a boy with nephrotic syndrome

Glucocorticoids (GCs) are associated with fragility fractures in children with various chronic illnesses. The impact of GCs on bone health in children with nephrotic syndrome (NS) is less well understood. Here we report skeletal findings in a 10-year-old boy with steroid-sensitive NS who presented with back pain due to vertebral fractures 5 years after NS diagnosis. Spine radiographs showed a Genant grade 2 fracture at T7 and a grade 1 fracture at T8. Dual-energy X-ray absorptiometry (DXA) revealed a lumbar spine areal bone mineral density (BMD) Z-score of −0.5 and a total body areal BMD Z-score of −0.4. Quantitative transiliac bone histomorphometry revealed low trabecular bone volume and cortical width but no osteomalacia. Our findings show the potential for significant bone morbidity due to osteoporosis in steroid-sensitive NS treated with intermittent GC therapy and emphasize that vertebral fractures may be an underrecognized complication. Furthermore, our report highlights that vertebral fractures can be associated with normal spine areal BMD in this context, suggesting that DXA-based, anteroposterior areal BMD should not be relied upon exclusively for assessing bone health and disease in children with steroid-sensitive NS.