BMD at multiple sites and risk of fracture of multiple types: long-term results from the Study of Osteoporotic Fractures

Perspective on post-menopausal osteoporosis: establishing an interdisciplinary understanding of the sequence of events from the molecular level to whole bone fractures

Current drug treatments for post-menopausal osteoporosis cannot eliminate bone fractures, possibly because the mechanisms responsible for bone loss are not fully understood. Although research within various disciplines has significantly advanced the state of knowledge, fundamental findings are not widely understood between different disciplines. For that reason, this paper presents noteworthy experimental findings from discrete disciplines focusing on post-menopausal osteoporosis. These studies have established that, in addition to bone loss, significant changes in bone micro-architecture, tissue composition and micro-damage occur. Cellular processes and molecular signalling pathways governing pathological bone resorption have been identified to a certain extent. Ongoing studies endeavour to determine how such changes are initiated at the onset of oestrogen deficiency. It emerges that, because of the discrete nature of previous research studies, the sequence of events that lead to bone fracture is not fully understood. In this paper, two sequences of multi-scale changes are proposed and the experimental challenges that need to be overcome to fully define this sequence are outlined. Future studies must comprehensively characterize the time sequence of molecular-, cellular- and tissue-level changes to attain a coherent understanding of the events that ultimately lead to bone fracture and inform the future development of treatments for post-menopausal osteoporosis.

Proton-pump inhibitor use is not associated with osteoporosis or accelerated bone mineral density loss

BACKGROUNDS & AIMS

Recent studies have shown an association between proton-pump inhibitor use (PPI) and hip fracture. The mechanism by which PPI use promotes the development of hip fracture is uncharacterized. Therefore, we sought to determine whether PPI use is associated with osteoporosis or accelerated bone mineral density (BMD) loss.

METHODS

We used the Manitoba Bone Mineral Density Database to determine the relationship between chronic PPI use and osteoporosis on an initial assessment of BMD and on BMD loss between successive assessments of BMD. In the cross-sectional study, cases with osteoporosis at the hip or lumbar vertebrae (T-score < or =-2.5) were matched to 3 controls with normal BMD (T-score > or =-1.0). In the longitudinal analysis, the change in BMD among PPI users and nonusers between successive BMD assessments was assessed. Conditional logistic regression and multivariate linear regression were used to obtain estimates of the association between PPI use and osteoporosis and of the annualized change in BMD associated with PPI use.

RESULTS

PPI use was not associated with having osteoporosis at either the hip (OR, 0.84; 95% CI, 0.55-1.34) or the lumbar spine (OR, 0.79; 95% CI, 0.59-1.06) for PPI use >1500 doses over the previous 5 years. In the longitudinal study no significant decrease was observed in BMD at either site attributable to PPI use.

CONCLUSIONS

PPI use does not appear to be associated with either the presence of osteoporosis or accelerated BMD loss. The association between PPI use and hip fracture is probably related to factors independent of osteoporosis.

Genes influencing spinal bone mineral density in inbred F344, LEW, COP, and DA rats

Previously, we identified the regions of chromosomes 10q12-q31 and 15p16-q21 harbor quantitative trait loci (QTLs) for lumbar volumetric bone mineral density (vBMD) in female F2 rats derived from Fischer 344 (F344) x Lewis (LEW) and Copenhagen 2331 (COP) x Dark Agouti (DA) crosses. The purpose of this study is to identify the candidate genes within these QTL regions contributing to the variation in lumbar vBMD. RNA was extracted from bone tissue of F344, LEW, COP, and DA rats. Microarray analysis was performed using Affymetrix Rat Genome 230 2.0 Arrays. Genes differentially expressed among the rat strains were then ranked based on the strength of the correlation with lumbar vBMD in F2 animals derived from these rats. Quantitative PCR (qPCR) analysis was performed to confirm the prioritized candidate genes. A total of 285 genes were differentially expressed among all strains of rats with a false discovery rate less than 10%. Among these genes, 18 candidate genes were prioritized based on their strong correlation (r (2) > 0.90) with lumbar vBMD. Of these, 14 genes (Akap1, Asgr2, Esd, Fam101b, Irf1, Lcp1, Ltc4s, Mdp-1, Pdhb, Plxdc1, Rabep1, Rhot1, Slc2a4, Xpo4) were confirmed by qPCR. We identified several novel candidate genes influencing spinal vBMD in rats.

Heritability of lumbar trabecular bone mechanical properties in baboons

Genetic effects on mechanical properties have been demonstrated in rodents, but not confirmed in primates. Our aim was to quantify the proportion of variation in vertebral trabecular bone mechanical properties that is due to the effects of genes. L3 vertebrae were collected from 110 females and 46 male baboons (6-32 years old) from a single extended pedigree. Cranio-caudally oriented trabecular bone cores were scanned with microCT then tested in monotonic compression to determine apparent ultimate stress, modulus, and toughness. Age and sex effects and heritability (h(2)) were assessed using maximum likelihood-based variance components methods. Additive effects of genes on residual trait variance were significant for ultimate stress (h(2)=0.58), toughness (h(2)=0.64), and BV/TV (h(2)=0.55). When BV/TV was accounted for, the residual variance in ultimate stress accounted for by the additive effects of genes was no longer significant. Toughness, however, showed evidence of a non-BV/TV-related genetic effect. Overall, maximum stress and modulus show strong genetic effects that are nearly entirely due to bone volume. Toughness shows strong genetic effects related to bone volume and shows additional genetic effects (accounting for 10% of the total trait variance) that are independent of bone volume. These results support continued use of bone volume as a focal trait to identify genes related to skeletal fragility, but also show that other focal traits related to toughness and variation in the organic component of bone matrix will enhance our ability to find additional genes that are particularly relevant to fatigue-related fractures.

Serum 25-hydroxyvitamin D and the risk of hip and nonspine fractures in older men

The association between vitamin D levels and incident fractures in older men is uncertain. To test the hypothesis that low serum 25-hydroxyvitamin D [(25(OH)D] levels are associated with an increased risk of fracture, we performed a case-cohort study of 436 men with incident nonspine fractures, including 81 hip fractures, and a random subcohort of 1608 men; average follow-up time 5.3 years. Serum vitamin D(2) and vitamin D(3) were measured on baseline sera using mass spectrometry and summed for total vitamin D. Modified Cox proportional hazards models were used to estimate the hazard ratio (HR) of fracture with 95% confidence intervals (CIs). Multivariable models included age, clinic, season, race, height, weight, and physical activity. The mean (SD) total 25(OH)D was 24.6 (7.8) ng/mL in nonspine fracture subjects, 21.5 (7.9) ng/mL in hip fracture subjects, and 25.2 (7.8) ng/mL in controls (nonspine fracture subjects versus nonpatients, p = .14; hip fracture subjects versus controls, p < .0001). 25(OH)D levels were unrelated to nonspine fractures. One SD decrease in total 25(OH)D was associated with an increased risk of hip fracture (multivariate HR = 1.60; 95% CI 1.18-2.17). Compared with men in the top quartile of total 25(OH)D (> or =28), the HR of hip fracture was 2.36 (95% CI 1.08-5.15) for men in the lowest quartile (<20) (p = .009 for trend). Adjusting for hip bone mineral density attenuated the association by more than 50% (p = .065 for trend). Low serum 25(OH)D concentrations are associated with a higher risk of hip fracture in older men. Measurement of 25(OH)D may be useful in identifying men at high risk of hip fracture.

Lasofoxifene in postmenopausal women with osteoporosis

BACKGROUND

The effects of lasofoxifene on the risk of fractures, breast cancer, and cardiovascular disease are uncertain.

METHODS

In this randomized trial, we assigned 8556 women who were between the ages of 59 and 80 years and had a bone mineral density T score of -2.5 or less at the femoral neck or spine to receive once-daily lasofoxifene (at a dose of either 0.25 mg or 0.5 mg) or placebo for 5 years. Primary end points were vertebral fractures, estrogen receptor (ER)-positive breast cancer, and nonvertebral fractures; secondary end points included major coronary heart disease events and stroke.

RESULTS

Lasofoxifene at a dose of 0.5 mg per day, as compared with placebo, was associated with reduced risks of vertebral fracture (13.1 cases vs. 22.4 cases per 1000 person-years; hazard ratio, 0.58; 95% confidence interval [CI], 0.47 to 0.70), nonvertebral fracture (18.7 vs. 24.5 cases per 1000 person-years; hazard ratio, 0.76; 95% CI, 0.64 to 0.91), ER-positive breast cancer (0.3 vs. 1.7 cases per 1000 person-years; hazard ratio, 0.19; 95% CI, 0.07 to 0.56), coronary heart disease events (5.1 vs. 7.5 cases per 1000 person-years; hazard ratio, 0.68; 95% CI, 0.50 to 0.93), and stroke (2.5 vs. 3.9 cases per 1000 person-years; hazard ratio, 0.64; 95% CI, 0.41 to 0.99). Lasofoxifene at a dose of 0.25 mg per day, as compared with placebo, was associated with reduced risks of vertebral fracture (16.0 vs. 22.4 cases per 1000 person-years; hazard ratio, 0.69; 95% CI, 0.57 to 0.83) and stroke (2.4 vs. 3.9 cases per 1000 person-years; hazard ratio, 0.61; 95% CI, 0.39 to 0.96) Both the lower and higher doses, as compared with placebo, were associated with an increase in venous thromboembolic events (3.8 and 2.9 cases vs. 1.4 cases per 1000 person-years; hazard ratios, 2.67 [95% CI, 1.55 to 4.58] and 2.06 [95% CI, 1.17 to 3.60], respectively). Endometrial cancer occurred in three women in the placebo group, two women in the lower-dose lasofoxifene group, and two women in the higher-dose lasofoxifene group. Rates of death per 1000 person-years were 5.1 in the placebo group, 7.0 in the lower-dose lasofoxifene group, and 5.7 in the higher-dose lasofoxifene group.

CONCLUSIONS

In postmenopausal women with osteoporosis, lasofoxifene at a dose of 0.5 mg per day was associated with reduced risks of nonvertebral and vertebral fractures, ER-positive breast cancer, coronary heart disease, and stroke but an increased risk of venous thromboembolic events. (ClinicalTrials.gov number, NCT00141323.)

Unusual mid-shaft fractures during long-term bisphosphonate therapy

BACKGROUND

Bisphosphonates are the most commonly prescribed medications for the treatment of osteoporosis. Although existing evidence supports a good safety profile, there is concern that chronic administration of these agents could result in severe suppression of bone turnover with increased risk of nonvertebral fractures.

OBJECTIVE

The objective of this study was to report the clinical presentation, selected bone histomorphometry and X-ray images of patients who developed mid-shaft long bone fractures during bisphosphonate therapy, six of whom had bone biopsy for histomorphometery.

RESULTS

Of the 13 patients who sustained atraumatic mid-shaft fractures, 10 were on alendronate and three were on risedronate therapy before the fractures. In addition to bisphosphonates, three patients were on oestrogen and two on tamoxifen concomitantly. Four patients with glucocorticoid-induced osteoporosis were on alendronate for 3-11 years along with glucocorticoid therapy. Bone histomorphometry showed severe suppression of bone turnover in five patients and low bone turnover in one patient.

CONCLUSION

Long-term bisphosphonate therapy may increase the risk of unusual long bone mid-shaft fractures. This is probably due to prolonged suppression of bone turnover, which could lead to accumulation of microdamage and development of hypermineralized bone. At present, the scope of this complication in the larger context of patients receiving bisphosphonate therapy remains unknown, but appears to be small.

Urinary levels of pentosidine and the risk of fracture in postmenopausal women: the OFELY study

The aim of the study was to investigate prospectively whether the levels of urinary pentosidine could predict fractures in postmenopausal women from the OFELY cohort. The results of the study suggest that urine pentosidine concentration is not an independent risk factor for fractures in postmenopausal women from a French cohort.

INTRODUCTION

Pentosidine has been described as an independent risk factor for hip and vertebral fracture in postmenopausal Japanese women. We investigated the prediction of urinary pentosidine on all fragility fracture risk in healthy untreated postmenopausal women from the OFELY cohort.

METHODS

Urinary pentosidine was assessed at baseline in 396 healthy untreated postmenopausal women aged 63.3 +/- 8.4 years from the OFELY cohort using high-performance liquid chromatography method. Incident clinical fractures were recorded during annual follow-up and confirmed by radiographs, and vertebral fractures were assessed on radiographs performed every 4 years. Multivariate Cox's regression analysis was used to calculate the risk of urinary pentosidine levels after adjustment for age, prevalent fractures, and total hip bone mineral density (BMD).

RESULTS

During a mean follow-up of 10 years, 88 of the 396 postmenopausal women have undergone incident vertebral (n = 28) and peripheral (n = 60) fractures. Fracture risk was higher in postmenopausal women with pentosidine in the highest quartile (p = 0.02), but it did not remain significant after adjustment for age, BMD, and prevalent fracture.

CONCLUSIONS

Urine pentosidine concentration is not an independent risk factor of osteoporotic fracture in healthy postmenopausal women from the OFELY cohort.

Age curves of bone mineral density at the distal radius and calcaneus in Koreans

This study evaluated age-related changes in bone mineral density (BMD) and identified the peak bone mineral density (PBMD) in Koreans. We recruited 2929 subjects, ranging in age from 5 to 86 years, from three regions: Seoul, Siwha, and Gwangyang. The BMD at the distal radius and calcaneus were measured with dual-energy X-ray absorptiometry, and anthropometric measures were also obtained. PBMD was calculated from the highest mean in each age group. The PBMD at the distal radius was 0.514 +/- 0.06 g/cm(2) in females and 0.598 +/- 0.07 g/cm(2) in males. Peak ages for both sexes were the thirties. For the calcaneus, PBMD was 0.509 +/- 0.09 g/cm(2) in females and 0.629 +/- 0.09 g/cm(2) in males. Peak ages were the thirties for females and the twenties for males. These results could facilitate international or interracial comparisons and be used as reference data to screen for osteoporosis in Koreans.

High systemic bone mineral density increases the risk of incident knee OA and joint space narrowing, but not radiographic progression of existing knee OA: the MOST study

OBJECTIVES

Previous studies suggest that high systemic bone mineral density (BMD) is associated with incident knee osteoarthritis (OA) defined by osteophytes but not with joint space narrowing (JSN), and are inconsistent regarding BMD and progression of existing OA. The association of BMD with incident and progressive tibiofemoral OA was tested in a large prospective study of men and women aged 50-79 years with or at risk for knee OA.

METHODS

Baseline and 30-month weight-bearing posteroanterior and lateral knee radiographs were scored for Kellgren-Lawrence (K-L) grade, JSN and osteophytes. Incident OA was defined as the development of K-L grade > or =2 at follow-up. All knees were classified for increases in grade of JSN and osteophytes from baseline. The association of gender-specific quartiles of baseline BMD with risk of incident and progressive OA was analysed using logistic regression, adjusting for covariates.

RESULTS

The mean (SD) age of 1754 subjects was 63.2 (7.8) years and body mass index was 29.9 (5.4) kg/m(2). In knees without baseline OA, higher femoral neck and whole body BMD were associated with an increased risk of incident OA and increases in grade of JSN and osteophytes (p<0.01 for trends); adjusted odds were 2.3-2.9-fold greater in the highest compared with the lowest BMD quartiles. In knees with existing OA, progression was not significantly related to BMD.

CONCLUSIONS

In knees without OA, higher systemic BMD was associated with a greater risk of the onset of JSN and K-L grade > or =2. The role of systemic BMD in early knee OA pathogenesis warrants further investigation.

Updated fracture incidence rates for the US version of FRAX

On the basis of updated fracture and mortality data, we recommend that the base population values used in the US version of FRAX be revised. The impact of suggested changes is likely to be a lowering of 10-year fracture probabilities.

INTRODUCTION

Evaluation of results produced by the US version of FRAX indicates that this tool overestimates the likelihood of major osteoporotic fracture. In an attempt to correct this, we updated underlying fracture and mortality rates for the model.

METHODS

We used US hospital discharge data from 2006 to calculate annual age- and sex-specific hip fracture rates and age-specific ratios to estimate clinical vertebral fracture rates. To estimate the incidence of any one of four major osteoporotic fractures, we first summed these newly derived hip and vertebral fracture estimates with Olmsted County, MN, wrist and upper humerus fracture rates, and then applied 10-20% discounts for overlap.

RESULTS

Compared with rates used in the current FRAX tool, 2006 hip fracture rates are about 16% lower, with greatest reductions observed among those below age 65 years; major osteoporotic fracture rates are about one quarter lower, with similar reductions across all ages.

CONCLUSIONS

We recommend revising the US-FRAX by updating current base population values for hip fracture and major osteoporotic fracture. The impact of these revisions on FRAX is likely to be lowering of 10-year fracture probabilities, but more precise estimates of the impact of these changes will be available after these new rates are incorporated into the FRAX tool.

Low bone mineral density at femoral neck is a predictor of increased mortality in elderly Japanese women

This study aimed to determine whether low bone mineral density (BMD) at the femoral neck independently predicts all-cause mortality in elderly Japanese women. A prospective cohort study of 271 women aged 67-89 years was conducted. A Cox proportional hazard model was used to examine independent associations between BMD and total mortality. During a 12-year follow-up period, the mortality risk (as measured by hazard ratio [HR]) was significantly increased in the three categories of baseline BMD (diagnostic criteria of osteoporosis, tertile of BMD, and quartile of BMD). After adjusting for major potential confounding variables for mortality, significantly increased mortality risks were found in subjects with osteoporosis (HR = 2.17, p = 0.032), in subjects in the lowest tertile (HR = 2.57, p = 0.007), and in subjects in the lowest quartile (HR = 3.13, p = 0.014], respectively. Our findings suggest that preventive strategies should be considered to increase and maintain high BMD at the femoral neck in the elderly women not only to prevent hip fractures but also probably to reduce mortality risk.

INTRODUCTION

Several longitudinal studies with Caucasian subjects have suggested that osteoporosis is associated with increased mortality. This study aimed to determine whether low bone mineral density (BMD) at the femoral neck independently predicts all-cause mortality in elderly Japanese community-dwelling women.

METHOD

A prospective cohort study of 271 women aged 67-89 years was conducted. A Cox proportional hazard model was used to examine independent associations between BMD at both the femoral neck and the trochanter and total mortality.

RESULTS

During a 12-year follow-up period, 81 of 271 women (29.9%) died. An independent and significant relationship was found between baseline BMD at the femoral neck and mortality risk. The mortality risk (as measured by HR) was increased by 2.80-fold (95% confidence interval [CI] 1.55-5.06; p < 0.01) in the subjects with osteoporosis or by 2.94-fold (95% CI 1.64-5.26; p < 0.001) in subjects in the lowest tertile or by 3.61-fold (95% CI 1.77-7.41; p < 0.001) in subjects in the lowest quartile of BMD, respectively. After adjusting for major potential confounding factors for mortality such as age, body mass index, blood pressure, blood variables, medical history, alcohol drinking, and smoking status, those in the subjects with osteoporosis (HR = 2.17 [95% CI 1.07-4.41], p = 0.032), in the lowest tertile (HR = 2.57 [95% CI 1.29-5.15], p = 0.007), or in the lowest quartile (HR = 3.13 [95% CI 1.26-7.73], p = 0.014] had a significantly increased risk of mortality. BMD measurement at the trochanter showed similar but weaker results.

CONCLUSIONS

Our findings suggest that preventive strategies should be considered to increase and maintain high BMD at the femoral neck in elderly subjects not only to prevent osteoporosis and its associated fractures but also probably to reduce mortality risk.

Association analyses of vitamin D-binding protein gene with compression strength index variation in Caucasian nuclear families

This study was conducted to test whether there exists an association between vitamin D-binding protein (DBP) gene and compression strength index (CSI) phenotype. Candidate gene association analyses were conducted in total sample, male subgroup, and female subgroup, respectively. Two single-nucleotide polymorphisms (SNPs) with significant association results were found in males, suggesting the importance of DBP gene polymorphisms on the variation in CSI especially in Caucasian males.

INTRODUCTION

CSI of the femoral neck (FN) is a newly developed phenotype integrating information about bone size, body size, and bone mineral density. It is considered to have the potential to improve the performance of risk assessment for hip fractures because it is based on a combination of phenotypic traits influencing hip fractures rather than a single trait. CSI is under moderate genetic determination (with a heritability of approximately 44% found in this study), but the relevant genetic study is still rather scarce.

METHODS

Based on the known physiological role of DBP in bone biology and the relatively high heritability of CSI, we tested 12 SNPs of the DBP gene for association with CSI variation in 405 Caucasian nuclear families comprising 1,873 subjects from the Midwestern US. Association analyses were performed in the total sample, male and female subgroups, respectively.

RESULTS

Significant associations with CSI were found with two SNPs (rs222029, P = 0.0019; rs222020, P = 0.0042) for the male subgroup. Haplotype-based association tests corroborated the single-SNP results.

CONCLUSIONS

Our findings suggest that the DBP gene might be one of the genetic factors influencing CSI phenotype in Caucasians, especially in males.

Gait variability detects women in early postmenopause with low bone mineral density

BACKGROUND

Women in early postmenopause and with low bone mineral density (BMD) may exhibit early markers for physical frailty as a result of sarcopenia and osteopenia.

OBJECTIVE

The purpose of this study was to determine whether women in early postmenopause and with low BMD exhibit decreased physical performance and differences in gait variability and fall and fracture rates.

DESIGN

This study was an observational cohort design with participants assigned to groups on the basis of BMD status.

METHODS

Fifty-four women, 31 with low BMD and 23 with normal BMD, participated. This study was conducted in a university research facility. Physical performance was measured by assessment of dynamic balance (timed backward tandem walk test), strength (handheld dynamometry of isometric quadriceps muscle force production), and free gait speed. Gait variability was assessed on the basis of the coefficient of variation for temporal-spatial gait characteristics. Falls and fractures were assessed for the year after initial testing.

RESULTS

Significant between-group differences were found for step time and stance time variability.

LIMITATIONS

The limitations of this study included group assignment on the basis of the results of the most recent bone density scan within the preceding 2 years.

CONCLUSIONS

Women in early postmenopause and with low BMD exhibited increased gait variability in step time and stance time but did not exhibit differences in balance, strength, or gait speed. Gait variability may be more sensitive for detecting differences in women in early postmenopause and with or without low BMD than more typical measures of physical performance.

Variation in risk factors for fractures at different sites

Fractures in older people are important medical problems. Knowledge of risk factors is essential for successful preventive measures, but when fracture sites of diverse etiology are combined, risk factors for any one site are difficult to identify and may be missed entirely. Among older people, incidence rates of hip, proximal humerus, and vertebral fractures increase with age, but not rates of distal forearm and foot fractures. Low bone mineral density is strongly associated with hip, distal forearm, vertebral, and proximal humerus fractures, but not foot fracture. Most fractures of the hip, distal forearm, and proximal humerus result from a fall, whereas smaller proportions of fractures of the foot and vertebrae follow a fall. Frail people are likely to fracture their hip or proximal humerus, while healthy, active people tend to fracture their distal forearm. We strongly recommend that studies identify risk factors on a site-specific basis.

The prevalence of significant left-right hip bone mineral density differences among black and white women

SUMMARY

In a cross-sectional retrospective study, we examined the prevalence of significant opposite hip bone mineral density difference among white and black women. Left-right hip bone mineral density difference was a common finding in both races, raising the possibility that osteoporosis can be missed if only one hip is imaged.

INTRODUCTION

We examined the prevalence of significant left-right hip bone mineral density (BMD) difference among black and white female subjects and its implications on the diagnosis of osteoporosis.

METHODS

This was a retrospective review of dual energy X-ray absorptiometry (DXA) data in black and white subjects age 50 years and older. One thousand four hundred seventy-seven scans obtained using a GE Lunar Prodigy scanner in dual hip mode were analyzed (24% black, 76% white). Significant left-right hip BMD difference was considered present when the subregion least significant change (LSC) was exceeded. Its prevalence was determined, along with consequences on the diagnosis of osteoporosis.

RESULTS

Significant differences in BMD were common in both races; the LSC was exceeded in 47% of the patients at the total hip, 37% at the femoral neck, and 53% at the trochanter. Diagnostic agreement was lower when the LSC was exceeded than when it was not. The LSC was exceeded in a statistically significant number of black and white patients with normal or osteopenic spines and unilateral hip osteoporosis.

CONCLUSIONS

Significant left-right hip BMD difference is a common finding among black and white women and can result in osteoporosis being missed if only one hip is imaged.

Automated simulation of areal bone mineral density assessment in the distal radius from high-resolution peripheral quantitative computed tomography

SUMMARY

An automated image processing method is presented for simulating areal bone mineral density measures using high-resolution peripheral quantitative computed tomography (HR-pQCT) in the ultra-distal radius. The accuracy of the method is validated against clinical dual X-ray absorptiometry (DXA). This technique represents a useful reference to gauge the utility of novel 3D quantification methods applied to HR-pQCT in multi-center clinical studies and potentially negates the need for separate forearm DXA measurements.

INTRODUCTION

Osteoporotic status is primarily assessed by measuring areal bone mineral density (aBMD) using 2D dual X-ray absorptiometry (DXA). However, this technique does not sufficiently explain bone strength and fracture risk. High-resolution peripheral quantitative computed tomography (HR-pQCT) has been introduced as a method to quantify 3D bone microstructure and biomechanics. In this study, an automated method is proposed to simulate aBMD measures from HR-pQCT distal radius images.

METHODS

A total of 117 subject scans were retrospectively analyzed from two clinical bone quality studies. The distal radius was imaged by HR-pQCT and DXA on one of two devices (Hologic or Lunar). Areal BMD was calculated by simulation from HR-pQCT images (aBMD(sim)) and by standard DXA analysis (aBMD(dxa)).

RESULTS

The reproducibility of the simulation technique was 1.1% (root mean-squared coefficient of variation). HR-pQCT-based aBMD(sim) correlated strongly to aBMD(dxa) (Hologic: R (2) = 0.82, Lunar: R (2) = 0.87), though aBMD(sim) underestimated aBMD(dxa) for both DXA devices (p < 0.0001). Finally, aBMD(sim) predicted aBMD at the proximal femur and lumbar spine with equal power compared to aBMD(dxa).

CONCLUSION

The results demonstrate that aBMD can be simulated from HR-pQCT images of the distal radius. This approach has the potential to serve as a surrogate forearm aBMD measure for clinical HR-pQCT studies when axial bone mineral density values are not required.

Degeneration of the lumbar spine and dual-energy X-ray absorptiometry measurements in patients without osteoporosis

AIM

The aim of this study was to evaluate the effects of degenerative findings on the accuracy of readings obtained by dual-energy X-ray absorptiometry (DXA) in patients without osteoporosis.

METHODS

Twenty-four female patients who had undergone both DXA and lumbar magnetic resonance imaging were included in the study.

CONCLUSION

This study has demonstrated that degenerative radiologic changes, especially in the osteophyte area, affect bone mineral density measurements, so degeneration should be considered in the evaluation of this measurement.

Self-reported frailty is associated with low calcaneal bone mineral density in a multiracial population of community-dwelling elderly

INTRODUCTION

Low bone mineral density (BMD) is associated with frailty assessed using performance-based measures. However, the latter can be cumbersome and difficult to standardize. We examined whether an easily obtained self-reported frailty measure also predicted low BMD.

METHODS

In 230 elderly (82% female, 58% African-American), calcaneal BMD was measured by DXA and frailty evaluated using the VES-13 questionnaire. In addition to the original scoring, we developed a modified scoring system which provided a broader assessment of frailty and excluded age, which is a known independent predictor of BMD. A telephone interview conducted 6 years later ascertained interval fragility fractures and survival status.

RESULTS

A higher modified frailty score was associated with lower BMD (p = 0.002), even after adjusting for age, weight, sex, and race and was more predictive of death at 6 years (p = 0.009) than the original score (p = 0.08). Based on our model, a subject with the highest frailty score differed from an otherwise similar subject with the lowest score by a calcaneal BMD of 1.4 T-score units, corresponding to 2-3 times higher fracture risk.

CONCLUSION

Self-reported frailty is associated with low calcaneal BMD and can be used to identify subjects with a greater risk of osteoporosis than expected from traditional risk factors.

Prediction of hip and other osteoporotic fractures from hip geometry in a large clinical cohort

SUMMARY

Incident hip fractures and non-hip osteoporotic fractures were studied in 30,953 women during mean 3.7 years of observation. Hip axis length (HAL) and strength index (SI) made a small but statistically significant contribution to hip fracture prediction that was independent of age and hip bone density.

INTRODUCTION

It is uncertain whether bone geometric measures improve fracture prediction independent of conventional areal bone mineral density (BMD).

METHODS

Women aged > or =50 years with hip dual-energy x-ray absorptiometry were identified from the regionally based database in the Province of Manitoba, Canada. Scans were reprocessed to derive parameters of hip bone geometry. Incident hip fractures (N = 270) and non-hip osteoporotic fractures (N = 1,347) were identified during mean 3.7 years of observation.

RESULTS

HAL was greater in both hip and non-hip fracture cases than in non-fracture cases, whereas cross-sectional moment of inertia, cross-sectional area, and femoral SI were all significantly less. After adjustment for total hip BMD, HAL [hazard ratio (HR) 1.22 per SD increase, 95% CI 1.07-1.38] and SI (HR 1.21 per SD decrease, 95% CI 1.07-1.37) were independent predictors of hip fractures but not of non-hip fractures. When both HAL and SI were added to a model containing age and total hip BMD, there was a small improvement in hip fracture prediction (ROC area under the curve 0.832 +/- 0.013 vs 0.823 +/- 0.013; P = 0.001).

CONCLUSIONS

HAL and SI made a small but statistically significant contribution to hip fracture prediction that was independent of age and BMD measurement.

Combination of nanoindentation and quantitative backscattered electron imaging revealed altered bone material properties associated with femoral neck fragility

Osteoporotic fragility fractures were hypothesized to be related to changes in bone material properties and not solely to reduction in bone mass. We studied cortical bone from the superior and inferior sectors of whole femoral neck sections from five female osteoporotic hip fracture cases (74-92 years) and five nonfractured controls (75-88 years). The typical calcium content (Ca(Peak)) and the mineral particle thickness parameter (T) were mapped in large areas of the superior and inferior regions using quantitative backscattered electron imaging (qBEI) and scanning small-angle X-ray scattering, respectively. Additionally, indentation modulus (E) and hardness (H) (determined by nanoindentation) were compared at the local level to the mineral content (Ca(Ind)) at the indent positions (obtained from qBEI). Ca(Peak) (-2.2%, P = 0.002), Ca(Ind) (-1.8%, P = 0.048), E (-5.6%, P = 0.040), and H (-6.0%, P = 0.016) were significantly lower for the superior compared to the inferior region. Interestingly, Ca(Peak) as well as Ca(Ind) were also lower (-2.6%, P = 0.006, and -3.7%, P = 0.002, respectively) in fracture cases compared to controls, while E and H did not show any significant reduction. T values were in the normal range, independent of region (P = 0.181) or fracture status (P = 0.551). In conclusion, it appears that the observed femoral neck fragility is associated with a reduced mineral content, which was not accompanied by a reduction in stiffness and hardness of the bone material. This pilot study suggests that a stiffening process in the organic matrix component contributes to bone fragility independently of mineral content.

Trabecular bone analysis in CT and X-ray images of the proximal femur for the assessment of local bone quality

Currently, conventional X-ray and CT images as well as invasive methods performed during the surgical intervention are used to judge the local quality of a fractured proximal femur. However, these approaches are either dependent on the surgeon's experience or cannot assist diagnostic and planning tasks preoperatively. Therefore, in this work a method for the individual analysis of local bone quality in the proximal femur based on model-based analysis of CT- and X-ray images of femur specimen will be proposed. A combined representation of shape and spatial intensity distribution of an object and different statistical approaches for dimensionality reduction are used to create a statistical appearance model in order to assess the local bone quality in CT and X-ray images. The developed algorithms are tested and evaluated on 28 femur specimen. It will be shown that the tools and algorithms presented herein are highly adequate to automatically and objectively predict bone mineral density values as well as a biomechanical parameter of the bone that can be measured intraoperatively.

Factors predicting osteoporosis treatment initiation in a regionally based cohort

Osteoporosis treatment initiation was assessed during the year after baseline BMD testing in 8,689 previously untreated women. Treatment initiation increased progressively as BMD T-scores decreased, but there was a gradient response rather than step increases at conventional T-score intervention thresholds.

INTRODUCTION

Bone mineral density (BMD) testing is used to identify those at high fracture risk and guide osteoporosis treatment (OTx) initiation. Clinical guidelines have used the World Health Organization T-score diagnostic cutoffs as thresholds for treatment intervention. Our objective was to assess whether OTx initiation tracks these T-score cutoffs.

METHODS

Eight thousand six hundred and eighty-nine women age > or = 50 years who had not been dispensed any OTx medication in the year prior to baseline BMD were identified from a regionally based database in the Province of Manitoba, Canada, and OTx initiation rates were analyzed.

RESULTS

Forty-four percent of women were dispensed OTx in the year after BMD. OTx initiation increased progressively as BMD T-scores decreased (8.2% normal, 41.0% osteopenic, 78.5% osteoporotic, p-for-trend < 0.0001). There was a gradient response to OTx initiation, rather than step increases at conventional T-score intervention thresholds. BMD was strongly associated with OTx (p < 0.0001) while age, weight, and fracture in the last year were not.

CONCLUSIONS

Physicians rely heavily on BMD T-score to decide on OTx initiation. Although guidelines suggest using clinical risk factors to guide decision making, we did not see evidence of this. More explicit methods of reporting fracture risk may help physicians select patients who are likely to derive the largest benefit from OTx.

Denosumab in men receiving androgen-deprivation therapy for prostate cancer

BACKGROUND

Androgen-deprivation therapy is well-established for treating prostate cancer but is associated with bone loss and an increased risk of fracture. We investigated the effects of denosumab, a fully human monoclonal antibody against receptor activator of nuclear factor-kappaB ligand, on bone mineral density and fractures in men receiving androgen-deprivation therapy for nonmetastatic prostate cancer.

METHODS

In this double-blind, multicenter study, we randomly assigned patients to receive denosumab at a dose of 60 mg subcutaneously every 6 months or placebo (734 patients in each group). The primary end point was percent change in bone mineral density at the lumbar spine at 24 months. Key secondary end points included percent change in bone mineral densities at the femoral neck and total hip at 24 months and at all three sites at 36 months, as well as incidence of new vertebral fractures.

RESULTS

At 24 months, bone mineral density of the lumbar spine had increased by 5.6% in the denosumab group as compared with a loss of 1.0% in the placebo group (P<0.001); significant differences between the two groups were seen at as early as 1 month and sustained through 36 months. Denosumab therapy was also associated with significant increases in bone mineral density at the total hip, femoral neck, and distal third of the radius at all time points. Patients who received denosumab had a decreased incidence of new vertebral fractures at 36 months (1.5%, vs. 3.9% with placebo) (relative risk, 0.38; 95% confidence interval, 0.19 to 0.78; P=0.006). Rates of adverse events were similar between the two groups.

CONCLUSIONS

Denosumab was associated with increased bone mineral density at all sites and a reduction in the incidence of new vertebral fractures among men receiving androgen-deprivation therapy for nonmetastatic prostate cancer. (ClinicalTrials.gov number, NCT00089674.)

Denosumab for prevention of fractures in postmenopausal women with osteoporosis

BACKGROUND

Denosumab is a fully human monoclonal antibody to the receptor activator of nuclear factor-kappaB ligand (RANKL) that blocks its binding to RANK, inhibiting the development and activity of osteoclasts, decreasing bone resorption, and increasing bone density. Given its unique actions, denosumab may be useful in the treatment of osteoporosis.

METHODS

We enrolled 7868 women between the ages of 60 and 90 years who had a bone mineral density T score of less than -2.5 but not less than -4.0 at the lumbar spine or total hip. Subjects were randomly assigned to receive either 60 mg of denosumab or placebo subcutaneously every 6 months for 36 months. The primary end point was new vertebral fracture. Secondary end points included nonvertebral and hip fractures.

RESULTS

As compared with placebo, denosumab reduced the risk of new radiographic vertebral fracture, with a cumulative incidence of 2.3% in the denosumab group, versus 7.2% in the placebo group (risk ratio, 0.32; 95% confidence interval [CI], 0.26 to 0.41; P<0.001)--a relative decrease of 68%. Denosumab reduced the risk of hip fracture, with a cumulative incidence of 0.7% in the denosumab group, versus 1.2% in the placebo group (hazard ratio, 0.60; 95% CI, 0.37 to 0.97; P=0.04)--a relative decrease of 40%. Denosumab also reduced the risk of nonvertebral fracture, with a cumulative incidence of 6.5% in the denosumab group, versus 8.0% in the placebo group (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01)--a relative decrease of 20%. There was no increase in the risk of cancer, infection, cardiovascular disease, delayed fracture healing, or hypocalcemia, and there were no cases of osteonecrosis of the jaw and no adverse reactions to the injection of denosumab.

CONCLUSIONS

Denosumab given subcutaneously twice yearly for 36 months was associated with a reduction in the risk of vertebral, nonvertebral, and hip fractures in women with osteoporosis. (ClinicalTrials.gov number, NCT00089791.)

The clinical role of dual energy X-ray absorptiometry

Dual energy X-ray absorptiometry (DXA) measurements of hip and spine bone mineral density (BMD) have an important role in the evaluation of individuals at risk of osteoporosis, and in helping clinicians advise patients about the appropriate use of anti-fracture treatment. Compared with alternative bone densitometry techniques, hip and spine DXA examinations have a number of advantages that include a consensus that BMD results can be interpreted using the World Health Organisation (WHO) T-score definition of osteoporosis, a proven ability to predict fracture risk, proven effectiveness at targeting anti-fracture therapies, and the ability to monitor response to treatment. This review discusses the evidence for these and other clinical aspects of DXA scanning, including its role in the new WHO algorithm for treating patients on the basis of their individual fracture risk.

Association analyses of RANKL/RANK/OPG gene polymorphisms with femoral neck compression strength index variation in Caucasians

Femoral neck compression strength index (fCSI), a novel phenotypic parameter that integrates bone density, bone size, and body size, has significant potential to improve hip fracture risk assessment. The genetic factors underlying variations in fCSI, however, remain largely unknown. Given the important roles of the receptor activator of the nuclear factor-kappaB ligand/receptor activator of the nuclear factor-kappaB/osteoprotegerin (RANKL/RANK/OPG) pathway in the regulation of bone remodeling, we tested the associations between RANKL/RANK/OPG polymorphisms and variations in fCSI as well as its components (femoral neck bone mineral density [fBMD], femoral neck width [FNW], and weight). This was accomplished with a sample comprising 1873 subjects from 405 Caucasian nuclear families. Of the 37 total SNPs studied in these three genes, 3 SNPs, namely, rs12585014, rs7988338, and rs2148073, of RANKL were significantly associated with fCSI (P = 0.0007, 0.0007, and 0.0005, respectively) after conservative Bonferroni correction. Moreover, the three SNPs were approximately in complete linkage disequilibrium. Haplotype-based association tests corroborated the single-SNP results since haplotype 1 of block 1 of the RANKL gene achieved an even more significant association with fCSI (P = 0.0003) than any of the individual SNPs. However, we did not detect any significant associations of these genes with fBMD, FNW, or weight. In summary, our findings suggest that the RANKL gene may play an important role in variation in fCSI, independent of fBMD and non-fBMD components.

Tibial or hip BMD predict clinical fracture risk equally well: results from a prospective study in 700 elderly Swiss women

SUMMARY

In a randomly selected cohort of Swiss community-dwelling elderly women prospectively followed up for 2.8 +/- 0.6 years, clinical fractures were assessed twice yearly. Bone mineral density (BMD) measured at tibial diaphysis (T-DIA) and tibial epiphysis (T-EPI) using dual-energy X-ray absorptiometry (DXA) was shown to be a valid alternative to lumbar spine or hip BMD in predicting fractures.

INTRODUCTION

A study was carried out to determine whether BMD measurement at the distal tibia sites of T-EPI and T-DIA is predictive of clinical fracture risk.

METHODS

In a predefined representative cohort of Swiss community-dwelling elderly women aged 70-80 years included in the prospective, multi-centre Swiss Evaluation of the Methods of Measurement of Osteoporotic Fracture risk (SEMOF) study, fracture risk profile was assessed and BMD measured at the lumbar spine (LS), hip (HIP) and tibia (T-DIA and T-EPI) using DXA. Thereafter, clinical fractures were reported in a bi-yearly questionnaire.

RESULTS

During 1,786 women-years of follow-up, 68 clinical fragility fractures occurred in 61 women. Older age and previous fracture were identified as risk factors for the present fractures. A decrease of 1 standard deviation in BMD values yielded a 1.5-fold (HIP) to 1.8-fold (T-EPI) significant increase in clinical fragility fracture hazard ratio (adjusted for age and previous fracture). All measured sites had comparable performance for fracture prediction (area under the curve range from 0.63 [LS] to 0.68 [T-EPI]).

CONCLUSION

Fracture risk prediction with BMD measurements at T-DIA and T-EPI is a valid alternative to BMD measurements at LS or HIP for patients in whom these sites cannot be accessed for clinical, technical or practical reasons.

Race and sex differences in bone mineral density and geometry at the femur

INTRODUCTION

Differences in osteoporotic hip fracture incidence between American whites and blacks and between women and men are considered to result, in part, from differences in bone mineral density and geometry at the femur. The aim of this study was to quantify differences in femoral bone density and geometry between a large sample of healthy American white and black women and men.

SUBJECTS AND METHODS

Healthy American white (n=612) and black (n=164) premenopausal women, aged 23 to 57 years, and healthy American white (n=492) and black (n=169) men, aged 20 to 63 years, had volumetric bone mineral density (vBMD) and geometry variables measured at the femur by computerized tomography (CT), and areal bone mineral density (aBMD) at femoral neck measured by dual X-ray absorptiometry (DXA).

RESULTS

American blacks had higher vBMD at the femoral neck and femoral shaft cortex than American whites whereas femoral axis length and femoral neck area were not different. Men had lower vBMD at the femoral neck and femoral cortex than women but had greater femoral axis length and femoral neck area than women. The higher aBMD in American blacks than whites persisted after correction for measured area whereas the higher aBMD in men than women disappeared.

CONCLUSIONS

At the femoral neck, American whites have lower bone density than American blacks but similar geometry. Women have higher bone density than men in both races but have smaller geometry variables. The differences in bone density may account in part for the differences in hip fracture incidence between American blacks and whites, whereas the differences in femur size may account for the differences in hip fracture rates between men and women.

Ultrasound backscatter imaging provides frequency-dependent information on structure, composition and mechanical properties of human trabecular bone

The strength as well as the acoustic properties of trabecular bone are determined by its structure and composition. Consequently, tissue structure and compositional properties also affect the ultrasound propagation in bone. The diagnostic potential of ultrasound has not been fully exploited in clinical quantitative ultrasound devices. The aim of this study was to investigate the ability of quantitative ultrasound pulse-echo imaging, conducted over a broad range of frequencies (1 to 5 MHz), to predict the mechanics, composition and microstructure of trabecular bone. Ultrasound reflection and backscatter parameters correlated significantly with the ultimate strength of the trabecular bone and the bone volume fraction (r=0.76-0.90, n=20, p<0.01). Ultrasound backscatter associated significantly (independently of bone structure or mineral content) with the collagen content of the bone matrix (r=0.75, r(adjusted)=0.66, p<0.01). Interestingly, the applied ultrasound frequency seemed to relate the sensitivity of ultrasound backscatter to different properties of trabecular bone. At frequencies ranging from 1 to 3.5 MHz, the ultrasound backscatter associated significantly with the tissue mechanical and structural parameters. At 5MHz, the composition of the bone matrix was a more significant determinant of the measured backscatter. This study provides useful information for optimizing the use of pulse-echo measurements, and thereby further emphasizes the diagnostic potential of the ultrasound backscatter measurements of trabecular bone.

High Prevalence of Asymptomatic Vertebral Fractures in Chinese Women with Systemic Lupus Erythematosus

Objective.

To investigate the prevalence of vertebral fractures and to identify risk factors associated with vertebral fractures in Chinese women with systemic lupus erythematosus (SLE).

Methods.

One hundred fifty-two consecutive patients with SLE were recruited in this cross-sectional study. Bone mineral density (BMD) measurements of the hip and spine were performed using the same dual energy X-ray absorptiometry (DEXA). Lateral radiographs of the spine (T5–L4) were assessed for vertebral fractures using a method described by Genant. Inflammatory and biochemical markers included C-reactive protein, receptor activator of nuclear factor-κB ligand, serum ß-CrossLaps assay for C-terminal telopeptides of type 1 collagen, and osteoprotegerin (OPG).

Results.

Asymptomatic vertebral fractures occurred in 20.4% of patients with SLE. Univariate analyses of variables associated with fractures were older age, higher body mass index (BMI), lower BMD spine, lower BMD hips, higher serum C3 and C4, longer estrogen exposure, higher levels of OPG, and the use of sunscreen. Multivariate analysis showed older age (p = 0.017), higher BMI (p < 0.036), and lower BMD of the spine were significantly associated with vertebral fractures in the thoracic and/or lumbar spine (odds ratio 1.068, 1.166, 0.005; p = 0.018, p = 0.025, p = 0.003, respectively).

Conclusion.

Asymptomatic vertebral fractures occur in 20.4% of patients with SLE and 30% of these patients have normal BMD. The current method using DEXA to predict the presence of vertebral fracture has limited value and there is a need for assessment of bone quality. Vertebral morphometry in patients with SLE is recommended and early therapeutic intervention is necessary to prevent vertebral fractures in patients with SLE.

Variation in bone mineral density by anatomical site in patients with proximal humeral fractures

Low-energy fractures of the proximal humerus indicate osteoporosis and it is important to direct treatment to this group of patients who are at high risk of further fracture. Data were prospectively collected from 79 patients (11 men, 68 women) with a mean age of 69 years (55 to 86) with fractures of the proximal humerus in order to determine if current guidelines on the measurement of the bone mineral density at the hip and lumbar spine were adequate to stratify the risk and to guide the treatment of osteoporosis. Bone mineral density measurements were made by dual-energy x-ray absorptiometry at the proximal femur, lumbar spine (L2-4) and contralateral distal radius, and the T-scores were generated for comparison. Data were also collected on the use of steroids, smoking, the use of alcohol, hand dominance and comorbidity.

The mean T-score for the distal radius was −2.97 (sd 1.56) compared with −1.61 (sd 1.62) for the lumbar spine and −1.78 (sd 1.33) for the femur. There was a significant difference between the mean lumbar and radial T scores (1.36 (1.03 to 1.68); p < 0.001) and between the mean femoral and radial T-scores (1.18 (0.92 to 1.44); p < 0.001). The inclusion of all three sites in the determination of the T-score increased the sensitivity to 66% compared with that of 46% when only the proximal femur and lumbar spine were used. This difference between measurements in the upper limb compared with the axial skeleton and lower limb suggests that basing risk assessment and treatment on only the bone mineral density taken at the hip or lumbar spine may misrepresent the extent of osteoporosis in the upper limb and the subsequent risk of fracture at this site.

The assessment of osteoporosis must include measurement of the bone mineral density at the distal radius to avoid underestimation of osteoporosis in the upper limb.

Bivariate whole-genome linkage scan for bone geometry and total body fat mass

To quantify the genetic correlations between total body fat mass (TBFM) and femoral neck geometric parameters (FNGPs) and, if possible, to detect the specific genomic regions shared by them, bivariate genetic analysis and bivariate whole-genome linkage scan were carried out in a large Caucasian population. All the phenotypes studied were significantly controlled by genetic factors (P < 0.001) with the heritabilities ranging from 0.45 to 0.68. Significantly genetic correlations were found between TBFM and CSA (cross-section area), W (sub-periosteal diameter), Z (section modulus) and CT (cortical thickness) except between TBFM and BR (buckling ratio). The peak bivariate LOD scores were 3.23 (20q12), 2.47 (20p11), 3.19 (6q27), 1.68 (20p12), and 2.47 (7q11) for the five pairs of TBFM and BR, CSA, CT, W, and Z in the entire sample, respectively. Gender-specific bivariate linkage evidences were also found for the five pairs. 6p25 had complete pleiotropic effects on the variations of TBFM & Z in the female sub-population, and 6q27 and 17q11 had coincident linkages for TBFM & CSA and TBFM & Z in the entire population. We identified moderate genetic correlations and several shared genomic regions between TBFM and FNGPs in a large Caucasian population.

Trend in incidence of osteoporosis-related fractures among 40- to 69-year-old women: analysis of a large insurance claims database, 2000-2005

OBJECTIVE

To determine the trend in incidence of fractures among perimenopausal and postmenopausal women during the periods immediately before and after publication of the Women's Health Initiative and Heart and Estrogen/Progestin Replacement Study (HERS) II data.

DESIGN

This was an ecological study using a claims database for multiple healthcare plans. The cohort of women aged 40 to 69 years was included. Diagnostic codes for fractures likely to be osteoporosis related and prescriptions for hormone therapy and other bone-modifying medications were identified. Annual incidence rates and trends in incidence over time for fractures and prescriptions were determined for the period 2000 through 2005.

RESULTS

Enrollment among women aged 40 to 69 years increased from 919,389 in 2000 to 2,872,372 in 2005. A total of 43,017 new fractures were identified. There was a significant increasing trend in age-adjusted rates of radius and ulna, vertebra, ribs, hip, pelvis, multiple, and pathologic fractures during the period from 2003 through 2005 (P < 0.03). The incidence of each fracture type was significantly greater during 2004 to 2005 than 2000 to 2001 (P < 0.04). The use of estrogen, estrogen plus progestin, and other hormones declined over the period from 2000 to 2003, whereas the use of other bone-modifying drugs increased from 2003 through 2005.

CONCLUSIONS

The incidence of fractures among perimenopausal and postmenopausal women increased significantly in the 3 years after publication of Women's Health Initiative and Heart and Estrogen/Progestin Replacement Study II results. This trend followed a decline in the use of hormone therapy, concurrent with an increase in the use of other bone-modifying agents.

Estimates of the proportion of older white women who would be recommended for pharmacologic treatment by the new U.S. National Osteoporosis Foundation Guidelines

The new U.S. National Osteoporosis Foundation Clinician's Guide to Prevention and Treatment of Osteoporosis includes criteria for recommending pharmacologic treatment based on history of hip or vertebral fracture, femoral neck (FN), or spine BMD T-scores <or=-2.5 and presence of low bone mass at the FN or spine plus a 10-yr risk of hip fracture >or=3% or of major osteoporotic fracture >or=20%. The proportion of women who would be recommended for treatment by these guidelines is not known. We applied the NOF criteria for treatment to women participating in the Study of Osteoporotic Fractures (SOF). To determine how the SOF population differs from the general U.S. population of white women >or=65 yr of age, we compared women in SOF with women who participated in the National Health and Nutrition Examination Survey (NHANES) III on criteria included in the NOF treatment guidelines that were common to both cohorts. Compared with NHANES III, women in SOF had higher FN BMD and were younger. Application of NOF guidelines to SOF data estimated that at least 72% of U.S. white women >or=65 yr of age and 93% of those >or=75 yr of age would be recommended for drug treatment. Application of the new NOF Guidelines would result in recommending a very large proportion of white women in the United States for pharmacologic treatment of osteoporosis.

Effect of increasing vertebral marrow fat content on BMD measurement, T-Score status and fracture risk prediction by DXA

Quantitative examination of iliac crest bone biopsies shows that as subjects become older bone and functional marrow are replaced by adipose tissue. Studies of vertebral marrow fat using nuclear magnetic resonance spectroscopy ((1)H-MRS) show that subjects with lower spine T-scores have significantly higher marrow fat content. These findings suggest that the ability of DXA scans to determine fracture risk may be partly explained by the effect of increased marrow fat on BMD. However, a proper evaluation of the relationship between WHO spine T-score status and marrow fat content requires that the BMD data are first corrected for the bias caused by a selection effect in which subjects with higher marrow fat are more likely to be identified as having osteoporosis. In this study we have therefore reanalysed previously published data for 185 elderly Hong Kong Chinese subjects (103 women, mean age 73 y; 82 men, mean age 73 y) who had spine DXA scans and (1)H-MRS measurements of L3 marrow fat. The effect of varying marrow fat on BMD was modelled using vertebral body thicknesses measured in 50 men and women. Spine T-scores in each individual were adjusted for the measured marrow fat. Subjects were assigned to WHO categories based on their corrected T-scores, and the relationship between marrow fat and T-score status evaluated using regression analysis and analysis of variance. The average change in percent marrow fat per T-score unit was used to infer the fraction of the spine BMD fracture discrimination explained by marrow composition. The mean (SD) of the L1-L4 vertebral body thickness was 30.2 (2.1) mm for Hong Kong women and 33.4 (2.5) mm for men. A change in marrow fat content from 0 to 100% was estimated to produce a BMD decrease of 0.14 g/cm(2) (1.3 T-score units) in women and 0.16 g/cm(2) (1.3 T-score units) in men. Although adjusting spine BMD for marrow fat reduced the significance of the correlation, there was still a trend for marrow fat to increase with decreasing T-score with a slope of -1.2+/-0.7% per T-score unit (p=0.078) for women and -1.4+/-0.6% per T-score unit (p=0.023) for men. When the effect of marrow composition on fracture discrimination was evaluated the results showed that the higher vertebral marrow fat content found in osteoporotic subjects made a negligible contribution to the ability of spine BMD measurements to predict fracture risk.

Finite element analysis of the proximal femur and hip fracture risk in older men

Low areal BMD (aBMD) is associated with increased risk of hip fracture, but many hip fractures occur in persons without low aBMD. Finite element (FE) analysis of QCT scans provides a measure of hip strength. We studied the association of FE measures with risk of hip fracture in older men. A prospective case-cohort study of all first hip fractures (n = 40) and a random sample (n = 210) of nonfracture cases from 3549 community-dwelling men > or =65 yr of age used baseline QCT scans of the hip (mean follow-up, 5.6 yr). Analyses included FE measures of strength and load-to-strength ratio and BMD by DXA. Hazard ratios (HRs) for hip fracture were estimated with proportional hazards regression. Both femoral strength (HR per SD change = 13.1; 95% CI: 3.9-43.5) and the load-to-strength ratio (HR = 4.0; 95% CI: 2.7-6.0) were strongly associated with hip fracture risk, as was aBMD as measured by DXA (HR = 5.1; 95% CI: 2.8-9.2). After adjusting for age, BMI, and study site, the associations remained significant (femoral strength HR = 6.5, 95% CI: 2.3-18.3; load-to-strength ratio HR = 4.3, 95% CI: 2.5-7.4; aBMD HR = 4.4, 95% CI: 2.1-9.1). When adjusted additionally for aBMD, the load-to-strength ratio remained significantly associated with fracture (HR = 3.1, 95% CI: 1.6-6.1). These results provide insight into hip fracture etiology and demonstrate the ability of FE-based biomechanical analysis of QCT scans to prospectively predict hip fractures in men.

Risk factors of vertebral fractures in women with systemic lupus erythematosus

The aim of the current study was to analyze the role of traditional and systemic lupus erythematosus (SLE)-related risk factors in the development of vertebral fractures. A cross-sectional study was performed in women with SLE attending a single center. A vertebral fracture was defined as a reduction of at least 20% of vertebral body height. Two hundred ten patients were studied, with median age of 43 years and median disease duration of 72 months. Osteopenia was present in 50.3% of patients and osteoporosis in 17.4%. At least one vertebral fracture was detected in 26.1%. Patients with vertebral fractures had a higher mean age (50 +/- 14 vs. 41 +/- 13.2 years, p = 0.001), disease damage (57.1% vs. 34.4%, p = 0.001), lower bone mineral density (BMD) at the total hip (0.902 +/- 0.160 vs. 982 +/- 0.137 g/cm(2), p = 0.002), and postmenopausal status (61.9% vs. 45.3%, p = 0.048). Stepwise logistic regression analysis revealed that only age (p = 0.001) and low BMD at the total hip (p = 0.007) remained as significant factors for the presence of vertebral fracture. The high prevalence of vertebral fractures in the relatively young population implies that more attention must be paid to detect and treat vertebral fractures.

Examination of femoral-neck structure using finite element model and bone mineral density using dual-energy X-ray absorptiometry

BACKGROUND

Research regarding femoral-neck fractures has mainly focused on bone mineral density and limited studies have been performed on relationship between the femoral-neck structure and its fracture.

METHODS

Finite element models were established to estimate stress distributions across the femoral neck with various femoral-neck angle from 115 degrees to 140 degrees. The bone mineral density measurements across the femoral-neck region using dual-energy X-ray absorptiometry were taken from 89 healthy and 10 patients with a femoral-neck fracture. Femoral neck angles were determined on radiographs from a separate group of participants.

FINDINGS

The results showed that the bone mineral density of the fracture patients was significantly smaller in all examined areas around femoral neck, especially in the ward's triangle. Under a same loading condition, the stress level may easily reach its intensity limit and therefore cause a fracture. The modeling results indicated that the posteromedial side of the femoral neck experienced the highest stress and was inversely related with the femoral-neck angle. As the angle decreased below 125 degrees, the stress around the femoral neck increased significantly and therefore increases risk of fracture at the site.

INTERPRETATIONS

It is recommended that if the femoral-neck angle is below 125 degrees and is accompanied by low bone mineral density, the patient should be considered a high risk candidate for femoral-neck fracture. In addition, if the femoral-neck angle of one hip is significantly smaller than the other side and 125 degrees, the hip should be also considered as high risk.

Postoperative Protocol in the Prevention of Fragility Fractures in Patients with Osteoporosis-Related Fractures

Osteoporosis is a multifactorial disorder that requires advanced diagnostic evaluation tools. It should not be considered to be an inevitable disease entity or as a logical consequence of the physiological ageing process. Osteoporosis can be diagnosed and - more importantly - properly treated. It is therefore incomprehensible that most of the patients with diagnosed osteoporosis do not receive a specific pharmacotherapeutic treatment. Since orthopedic trauma surgeons most often see a patient with an osteoporosis-associated fracture on a first-hand basis, they, after providing adequate treatment of the fracture, must play a key role in initiating the primary diagnostics and therapy according to national or international guidelines for patients with previous osteoporotic fractures. Treatment should be closely coordinated with general practitioners so that a continuation of the therapy initiated in the hospital can be guaranteed. Basic measures for fracture prevention, including dietary supplements of calcium and vitamin D, should be recommended and implemented for all patients, whereas only those patients with the diagnosis of a manifest osteoporosis should receive a specific pharmacotherapy. Antiresorptive and anabolic drugs that are licensed for the treatment of men or postmenopausal women with osteoporosis have been shown to effectively reduce the incidence of vertebral and non-vertebral fractures. An evaluation of the treatment efficiency should also be performed, such as routine clinical re-evaluation and the measuring of the bone mineral density by dual X-ray absortiometry, every 18-24 months after the initiation of the pharmacotherapy.

Assessment of osteoporotic fracture risk in community settings: a study of post-menopausal women in Australia

The healthcare cost of managing osteoporotic fractures is projected to rise because of the change in population demographics. To reduce the fracture epidemic, strategies are needed to identify those at risk early to allow preventative intervention to be implemented. The aim of this study was to investigate if low-cost community-based assessments, such as calcaneal ultrasound and falls risk assessments, can discriminate a group of elderly women at risk of osteoporotic fracture from those at lower risk. Over the period of 2002-2003, 104 community-dwelling women (mean age 71.3, standard deviation 5.8) were recruited via various modes including advertisements in community newspaper and community centres. These women underwent dual-energy X-ray absorptiometry bone mineral density (BMD) and calcaneal quantitative ultrasound (QUS) measurements; spinal radiography; and performance-based assessment of strength, mobility and balance. The women were classified into a 'high risk' (osteoporotic) group, based on low BMD (T-score of </= -2.5) and/or a history of a fragility fracture, or a 'low risk' (non-osteoporotic) group. Multiple stepwise logistic regression identified decreased speed of sound (SOS), a QUS variable, and poor mobility [slower performance in the timed 'up and go' (TUG) task], as significant discriminators, adjusted for age [SOS: adjusted odds ratio (OR) = 2.96, 95% confidence interval (CI) = 1.64-5.12, P < 0.001; TUG: adjusted OR = 1.69, 95% CI = 1.04-2.73, P = 0.031]. This result suggests that there may be a potential role for primary healthcare practitioners to use calcaneal QUS and functional mobility assessment (TUG) to screen for post-menopausal women at risk of osteoporotic fracture in community settings.

Falls: epidemiology, pathophysiology, and relationship to fracture

Falls are common in the elderly, and frequently result in injury and disability. Most falls result from an interaction between individual characteristics that increase an individual's propensity to fall and acute mediating risk factors that provide the opportunity to fall. Predisposing risk factors include age-associated changes in strength and balance, comorbidities such as osteoarthritis, visual impairment and dementia, psychotropic medications, and certain types of footwear. Fewer studies have focused on acute precipitating factors, but environmental and situational factors are clearly important to fall risk. Approximately 30% of falls result in an injury that requires medical attention, with fractures occurring in approximately 10%. In addition to the risk factors for falls, the fall descent, fall impact, and bone strength are all important determinants of whether a fall will result in a fracture. In recent years, numerous studies have been directed toward the development of effective fall and fall-related fracture prevention interventions.

Assessment of clinical risk factors to validate the probability of osteoporosis and subsequent fractures in Korean women

This cross-sectional, observational study was designed to identify clinical risk factors of osteoporosis and fractures in Korean women to validate the probability of osteoporosis and subsequent fractures. A total of 1541 Korean women were recruited nationally. Fracture history of any site, risk factors of osteoporosis, and fall-related risk factors were surveyed and physical performance tests were conducted. Peripheral dual-energy X-ray absorptiometry was used to measure calcaneus bone mineral density (BMD). The number of positive responses on the modified 1-min osteoporosis risk test was related to the risk of osteoporosis. The frequency of osteoporosis was higher in those with a height reduction of >4 cm and a reduced body mass index (BMI). Multivariate analysis showed that older age and lower BMI were related to higher relative risk of osteoporosis. Time required to stand up from a chair and questions related to fall injury were significantly related to clinical fracture history of any site. Multivariate analysis showed that the relative risk of fractures at any site was higher in older subjects with a lower T-score and parental hip fracture history. This study shows that age and BMI are the most significant clinical risk factors for osteoporosis and that age, BMD, and parental history of hip fracture are highly applicable risk factors for validating the probability of osteoporotic fractures in Korean women.