Provision of High Protein Foods Slows the Age-Related Decline in Nutritional Status in Aged Care Residents: A Cluster-Randomised Controlled Trial

OBJECTIVES

Malnutrition, particularly protein insufficiency, is common in institutionalised older adults and increases morbidity, mortality, and costs. We aimed to determine whether 12 months supplementation using high-protein foods (milk, cheese, yoghurt) prevents malnutrition in older adults.

DESIGN

Cluster randomised control study.

SETTING

Sixty Australian aged care facilities.

PARTICIPANTS

Older adults living in aged care homes (n=654, mean age 86.7±7.2 years, 72% females). Intervention Facilities randomly allocated to a high-protein (n=30 intervention) or regular (n=30 controls) menu.

MEASUREMENTS

Nutritional status assessed using the Mini Nutrition Assessment (MNA) tool and fasting morning blood samples (n=302) assayed for haemoglobin (Hb) and albumin. Food intake was monitored 3-monthly using visual plate waste assessment. Measurements at baseline and month 12 were analysed using random effects model accounting for clustering (facility), repeated measure and confounders.

RESULTS

Addition of 11g of protein as 1.5 servings of high-protein foods daily preserved nutritional status that deteriorated in controls [MNA screen (-0.68, 95%CI: -1.03, -0.32, p<0.001) and total (-0.90, 95%CI: -1.45, -0.35, p=0.001) scores], resulting in group differences in MNA screen (0.62, 95%CI: 0.17, 1.06, p=0.007) and total (0.81, 95%CI: 0.11, 1.51, p=0.023) scores and group difference in Hb (3.60g/L, 95%CI: 0.18, 7.03, p=0.039), the net result of preservation with intervention (0.19g/L, 95%CI: -2.04, 2.42, p=0.896) and a decline in controls (-3.41g/L, 95%CI: -6.01, -0.82, p=0.010). No group differences were observed for serum albumin.

CONCLUSION

Consumption of high-protein foods is a pragmatic approach to maintaining nutritional status in older adults in aged-care.

Sex differences in recovery of quality of life 12 months post-fracture in community-dwelling older adults: analyses of the Australian arm of the International Costs and Utilities Related to Osteoporotic Fractures Study (AusICUROS)

In this study of 695 Australian older adults (aged ≥50 years), we found that men and women had a similar trajectory of health-related quality of life (HRQoL) recovery following fragility fracture at any skeletal site. These results provide us with critical knowledge that improves our understanding of health outcomes post-fracture.

INTRODUCTION

Mortality is higher in men than that in women following a fragility fracture, but it is unclear whether recovery of patient-reported outcomes such as health-related quality of life (HRQoL) differs between sexes. This study aimed to identify sex differences in HRQoL recovery 12 months post-fracture.

METHODS

Data were from the Australian arm of the International Costs and Utilities Related to Osteoporotic Fractures Study (AusICUROS). Participants recruited to AusICUROS were adults aged ≥50 years who sustained a fragility fracture. HRQoL was measured using the EQ-5D-3L at three time-points post-fracture: within 2 weeks (including pre-fracture recall) and at 4 and 12 months. Multivariate logistic regression analyses were undertaken, adjusting for confounders including age, education, income, and healthcare utilization post-fracture.

RESULTS

Overall, 695 AusICUROS participants (536 women, 77.1%) were eligible for analysis with fractures at the hip (n = 150), distal forearm (n = 261), vertebrae (n = 61), humerus (n = 52), and other skeletal sites (n = 171). At the time of fracture, men were younger, reported a higher income, and were more likely to be employed, compared with women. For all fracture sites combined, there were no differences between men and women in recovery to pre-fracture HRQoL at 12-month follow-up (adjusted OR = 1.09; 95% CI: 0.75-1.61). When stratified by fracture site, no significant sex differences were seen for hip (OR = 1.02; 95% CI: 0.42-2.52), distal forearm (OR = 1.60; 95% CI: 0.68-3.78), vertebral (OR = 2.28; 95% CI: 0.61-8.48), humeral (OR = 1.62; 95% CI: 0.16-9.99), and other fractures (OR = 1.00; 95% CI: 0.44-2.26).

CONCLUSION

Community-dwelling men and women who survived the 12 months following fragility fracture had a similar trajectory of HRQoL recovery at any skeletal site.

Effect of dietary sources of calcium and protein on hip fractures and falls in older adults in residential care: cluster randomised controlled trial

OBJECTIVE

To assess the antifracture efficacy and safety of a nutritional intervention in institutionalised older adults replete in vitamin D but with mean intakes of 600 mg/day calcium and <1 g/kg body weight protein/day.

DESIGN

Two year cluster randomised controlled trial.

SETTING

60 accredited residential aged care facilities in Australia housing predominantly ambulant residents.

PARTICIPANTS

7195 permanent residents (4920 (68%) female; mean age 86.0 (SD 8.2) years).

INTERVENTION

Facilities were stratified by location and organisation, with 30 facilities randomised to provide residents with additional milk, yoghurt, and cheese that contained 562 (166) mg/day calcium and 12 (6) g/day protein achieving a total intake of 1142 (353) mg calcium/day and 69 (15) g/day protein (1.1 g/kg body weight). The 30 control facilities maintained their usual menus, with residents consuming 700 (247) mg/day calcium and 58 (14) g/day protein (0.9 g/kg body weight).

MAIN OUTCOME MEASURES

Group differences in incidence of fractures, falls, and all cause mortality.

RESULTS

Data from 27 intervention facilities and 29 control facilities were analysed. A total of 324 fractures (135 hip fractures), 4302 falls, and 1974 deaths were observed. The intervention was associated with risk reductions of 33% for all fractures (121 v 203; hazard ratio 0.67, 95% confidence interval 0.48 to 0.93; P=0.02), 46% for hip fractures (42 v 93; 0.54, 0.35 to 0.83; P=0.005), and 11% for falls (1879 v 2423; 0.89, 0.78 to 0.98; P=0.04). The risk reduction for hip fractures and falls achieved significance at five months (P=0.02) and three months (P=0.004), respectively. Mortality was unchanged (900 v 1074; hazard ratio 1.01, 0.43 to 3.08).

CONCLUSIONS

Improving calcium and protein intakes by using dairy foods is a readily accessible intervention that reduces the risk of falls and fractures commonly occurring in aged care residents.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12613000228785.

Systemic mastocytosis identified in two women developing fragility fractures during lactation

Two women presenting with fragility fractures during lactation had bone mineral density (BMD) reduced more greatly than usually associated with lactation. The first woman was 29 years old with a BMD T-score of - 3.2 SD at the spine and- 2.0 SD at the femoral neck. The second woman was 35 years old with a BMD T-score of - 4.5 SD at the spine and - 2.8 SD at the femoral neck. Both women had increased cortical porosity and reduced trabecular density. Investigation identified an elevated serum tryptase, and marrow biopsy confirmed the diagnosis of mastocytosis. Lactation causes bone loss, but the occurrence of fractures in the setting of severe deficits in BMD and microstructural deterioration signals the need to consider additional causes of bone loss.

The effects of muscle contraction and recombinant osteocalcin on insulin sensitivity ex vivo

We tested whether GPRC6A, the putative receptor of undercarboxylated osteocalcin (ucOC), is present in mouse muscle and whether ucOC increases insulin sensitivity following ex vivo muscle contraction. GPPRC6A is expressed in mouse muscle and in the mouse myotubes from a cell line. ucOC potentiated the effect of ex vivo contraction on insulin sensitivity.

INTRODUCTION

Acute exercise increases skeletal muscle insulin sensitivity. In humans, exercise increases circulating ucOC, a hormone that increases insulin sensitivity in rodents. We tested whether GPRC6A, the putative receptor of ucOC, is present in mouse muscle and whether recombinant ucOC increases insulin sensitivity in both C2C12 myotubes and whole mouse muscle following ex vivo muscle contraction.

METHODS

Glucose uptake was examined in C2C12 myotubes that express GPRC6A following treatment with insulin alone or with insulin and increasing ucOC concentrations (0.3, 3, 10 and 30 ng/ml). In addition, glucose uptake, phosphorylated (p-)AKT and p-AS160 were examined ex vivo in extensor digitorum longus (EDL) dissected from C57BL/6J wild-type mice, at rest, following insulin alone, after muscle contraction followed by insulin and after muscle contraction followed by recombinant ucOC then insulin exposure.

RESULTS

We observed protein expression of the likely receptor for ucOC, GPRC6A, in whole muscle sections and differentiated mouse myotubes. We observed reduced GPRC6A expression following siRNA transfection. ucOC significantly increased insulin-stimulated glucose uptake dose-dependently up to 10 ng/ml, in differentiated mouse C2C12 myotubes. Insulin increased EDL glucose uptake (∼30 %, p < 0.05) and p-AKT and p-AKT/AKT compared with rest (all p < 0.05). Contraction prior to insulin increased muscle glucose uptake (∼25 %, p < 0.05), p-AKT, p-AKT/AKT, p-AS160 and p-AS160/AS160 compared with contraction alone (all p < 0.05). ucOC after contraction increased insulin-stimulated muscle glucose uptake (∼12 % p < 0.05) and p-AS160 (<0.05) more than contraction plus insulin alone but without effect on p-AKT. In the absence of insulin and/or of contraction, ucOC had no significant effect on muscle glucose uptake.

CONCLUSIONS

GPRC6A, the likely receptor of osteocalcin (OC), is expressed in mouse muscle. ucOC treatment augments insulin-stimulated skeletal muscle glucose uptake in C2C12 myotubes and following ex vivo muscle contraction. ucOC may partly account for the insulin sensitizing effect of exercise.

Recurrence of bilateral atypical femoral fractures associated with the sequential use of teriparatide and denosumab: a case report

We report that a postmenopausal woman with osteoporosis developed bilateral incomplete atypical femoral fractures (AFFs) after seven years of bisphosphonate therapy. Cessation of the bisphosphonate and treatment with teriparatide was associated with near complete radiological resolution of the AFFs. After 12 months without treatment, denosumab was commenced to prevent structural deterioration. Six months later she developed recurrent bilateral AFFs. This case highlights the management dilemma in patients with ongoing bone loss but prone to stress fractures associated with antiresorptive therapy. Stopping the antiresorptive is recommended but structural decay will recur predisposing to fragility fractures. If the antiresorptive is continued, bone material composition will be further compromised predisposing to atypical fractures. Teriparatide may assist healing of stress fractures and improvement in bone matrix composition. Later antiresosrptive therapy to preserve bone microstructure may compromise material composition.

Bone's Material Constituents and their Contribution to Bone Strength in Health, Disease, and Treatment

Type 1 collagen matrix volume, its degree of completeness of its mineralization, the extent of collagen crosslinking and water content, and the non-collagenous proteins like osteopontin and osteocalcin comprise the main constituents of bone's material composition. Each influences material strength and change in different ways during advancing age, health, disease, and drug therapy. These traits are not quantifiable using bone densitometry and their plurality is better captured by the term bone 'qualities' than 'quality'. These qualities are the subject of this manuscript.

Measurement of cortical porosity of the proximal femur improves identification of women with nonvertebral fragility fractures

We tested whether cortical porosity of the proximal femur measured using StrAx1.0 software provides additional information to areal bone mineral density (aBMD) or Fracture Risk Assessment Tool (FRAX) in differentiating women with and without fracture. Porosity was associated with fracture independent of aBMD and FRAX and identified additional women with fractures than by osteoporosis or FRAX thresholds.

INTRODUCTION

Neither aBMD nor the FRAX captures cortical porosity, a major determinant of bone strength. We therefore tested whether combining porosity with aBMD or FRAX improves identification of women with fractures.

METHODS

We quantified femoral neck (FN) aBMD using dual-energy X-ray absorptiometry, FRAX score, and femoral subtrochanteric cortical porosity using StrAx1.0 software in 211 postmenopausal women aged 54-94 years with nonvertebral fractures and 232 controls in Tromsø, Norway. Odds ratios (ORs) were calculated using logistic regression analysis.

RESULTS

Women with fractures had lower FN aBMD, higher FRAX score, and higher cortical porosity than controls (all p < 0.001). Each standard deviation higher porosity was associated with fracture independent of FN aBMD (OR 1.39; 95% confidence interval 1.11-1.74) and FRAX score (OR 1.58; 1.27-1.97) in all women combined. Porosity was also associated with fracture independent of FRAX score in subgroups with normal FN aBMD (OR 1.88; 1.21-2.94), osteopenia (OR 1.40; 1.06-1.85), but not significantly in those with osteoporosis (OR 1.48; 0.68-3.23). Of the 211 fracture cases, only 18 women (9%) were identified using FN aBMD T-score < -2.5, 45 women (21%) using FRAX threshold >20%, whereas porosity >80th percentile identified 61 women (29%). Porosity identified 26% additional women with fractures than identified by the osteoporosis threshold and 21% additional women with fractures than by this FRAX threshold.

CONCLUSIONS

Cortical porosity is a risk factor for fracture independent of aBMD and FRAX and improves identification of women with fracture.

Changes in quality of life associated with fragility fractures: Australian arm of the International Cost and Utility Related to Osteoporotic Fractures Study (AusICUROS)

We investigated change in health-related quality of life due to fracture in Australian adults aged over 50 years. Fractures reduce quality of life with the loss sustained at least over 12 months. At a population level, the loss was equivalent to 65 days in full health per fracture.

PURPOSE

We aimed to quantify the change in health-related quality of life (HRQoL) that occurred as a consequence of a fracture using the EQ-5D-3 L questionnaire.

METHODS

Adults aged ≥50 years with a low to moderate energy fracture were recruited from eight study centres across Australia. This prospective study included an 18-month follow-up of participants recruited within 2 weeks of a fracture (hip, wrist, humerus, vertebral and ankle). Information collected at baseline and 4, 12 and 18 months included characteristics of participants such as income level, education and prior fracture status. At 12 months post-fracture, the cumulative loss of quality of life was estimated using multivariate regression analysis to identify the predictors of HRQoL loss.

RESULTS

Mean HRQoL for all participants before fracture was 0.86, with wrist fracture having the highest pre-fracture HRQoL (0.90), while vertebral fracture had the lowest (0.80). HRQoL declined to 0.42 in the immediate post-fracture period. Only participants with a wrist, humerus or ankle fracture returned to their pre-fracture HRQoL after 18 months. An increased loss of HRQoL over 12 months was associated with HRQoL prior to the fracture, hospitalisation, education and fracture site. The multiple regression explained 30 % of the variation in the cumulative HRQoL loss at 12 months post-fracture for all fractures.

CONCLUSION

Low to moderate energy fractures reduce HRQoL, and this loss is sustained for at least 12 months or, in the case of hip and spine fractures, at least 18 months. At a population level, this represents an average loss of 65 days in full health per fragility fracture. This significant burden reinforces the need for cost-effective fracture prevention strategies.

Testosterone levels increase in association with recovery from acute fracture in men

In this longitudinal case-control study, acute fracture was associated with low serum testosterone, which was transient in 43% of men. While assessment of gonadal status is part of the assessment of bone fragility, measurement of testosterone in the early period after fracture may overestimate the prevalence of androgen deficiency.

INTRODUCTION

Measurement of circulating testosterone is recommended in the evaluation of bone fragility in men. Since acute illness can transiently decrease circulating testosterone, we quantified the association of acute fracture and serum testosterone levels.

METHODS

A case-control study was conducted involving 240 men with a radiologically confirmed minimal trauma fracture presenting to a tertiary referral hospital and 89 age-matched men without a history of minimal trauma fracture serving as controls. Follow-up testosterone levels 6 months after baseline were available for 98 cases and 27 controls. Results were expressed as the median and interquartile (IQR) range.

RESULTS

Compared to controls, cases had lower total testosterone [TT, 7.2 (3.5, 10.8) vs 13.6 (10.9, 17.1) nmol/L, p < 0.001]. The 143 cases treated as inpatients had lower testosterone levels than the 97 cases treated as outpatients [TT 4.7 (2.3, 8.1) vs 10.3 (7.5, 12.7) nmol/L, p < 0.001]. Group differences in calculated free testosterone (cFT) were comparable to the group differences in TT. At follow-up, in 98 cases, median TT increased from 6.5 nmol/L (3.2, 8.5) to 9.6 nmol/L (6.9, 12.0) p < 0.0001, and SHBG remained unchanged. Of cases with low testosterone, 43% with TT <10 nmol/L and/or cFT <230 pmol/L at presentation were reclassified as androgen sufficient at follow-up. TT was unchanged in the controls.

CONCLUSIONS

Low testosterone levels in men presenting with an acute fracture may, at least in part, be due to an acute, fracture-associated, stress response. To avoid over diagnosis, evaluation for testosterone deficiency should be deferred until recovery from the acute event.

Exercise-induced inhibition of remodelling is focally offset with fatigue fracture in racehorses

Bone remodelling is inhibited by high repetitive loading. However, in subchondral bone of racehorses in training, eroded surface doubled in association with fatigue fracture and there was greater surrounding trabecular bone volume suggesting trabecular modelling unloads the bone focally, allowing damage repair by remodelling.

INTRODUCTION

Remodelling replaces damaged bone with new bone but is suppressed during high magnitude repetitive loading when damage is most likely. However, in cortical bone of racehorses, at sites of fatigue fracture, focal porosity, consistent with remodelling, is observed in proportion to the extent of surrounding callus. Focal areas of porosity are also observed at sites of fatigue damage in subchondral bone. We hypothesised that fatigued subchondral bone, like damaged cortical bone, is remodelled focally in proportion to the modelling of surrounding trabecular bone.

METHODS

Eroded and mineralizing surfaces and bone area were measured using backscattered scanning electron microscopy of post-mortem specimens of the distal third metacarpal bone in 11 racehorses with condylar fractures (cases) and eight racehorses in training without fractures (controls).

RESULTS

Cases had a two-fold greater eroded surface per unit area at the fracture site than controls (0.81 ± 0.10 vs. 0.40 ± 0.12 mm(-1), P = 0.021) but not at an adjacent site (0.22 ± 0.09 vs. 0.30 ± 0.11 mm(-1), P = 0.59). Area fraction of surrounding trabecular bone was higher in cases than controls (81 ± 2 vs. 72 ± 2 %, P = 0.0020) and the eroded surface at the fracture site correlated with the surrounding trabecular area (adjusted R (2) = 0.63, P = 0.0010).

CONCLUSION

In conclusion, exercise-induced inhibition of remodelling is offset at sites of fatigue fracture. Modelling of trabecular bone may contribute to unloading these regions, allowing repair by remodelling.

A new method of segmentation of compact-appearing, transitional and trabecular compartments and quantification of cortical porosity from high resolution peripheral quantitative computed tomographic images

A transitional or cortico-trabecular junctional zone exists at any location composed of both cortical and trabecular bones such as the metaphyses of tubular bones and short bones like the femoral neck. The transitional zone comprises the inner cortex adjacent to the medullary canal and trabeculae abutting against the cortex contiguous with the endocortical surface. This is a site of vigorous remodeling. Intracortical remodeling cavitates the inner cortex expanding this transitional zone at the price of compact-appearing cortex so that it contains porosity, cortical fragments that resemble trabeculae, and trabeculae abutting the eroding cortex. The porosity of the transitional zone is an important source of bone loss. It reduces bone strength exponentially and is a quantifiable `fingerprint' of structural deterioration. A new automated method of segmentation of bone from background and bone into its compact-appearing cortex, transitional zone, and trabecular compartment is described, with a new approach to quantification of cortical porosity. Segmentation is achieved by automatically selecting attenuation profile curves perpendicular to the periosteal surface. Local bone edges are identified as the beginning and the end of the rising and falling S-shaped portions of the curve enabling the delineation of the compartments. Analyzing ~3600 consecutive overlapping profiles around the perimeter of each cross-sectional slice segments the compartments. Porosity is quantified as the average void volume fraction of all voxels within each compartment. To assess accuracy at the distal radius and tibia, μCT images of cadaveric specimens imaged at 19 μm voxel size served as the gold standard. To assess accuracy at the proximal femur, scanning electron microscopy (SEM) images of specimens collected at 2.5 μm resolution served as the gold standard. Agreement between HRpQCT and the gold standards for segmentation and quantification of porosity at the distal radius and tibia ranged from R(2)=0.87 to 0.99, and for the proximal femur ranged from 0.93 to 0.99. The precision error in vivo for segmentation and quantification of porosity in HRpQCT images at the distal radius, given by the root mean square error of the coefficient of variation, ranged from 0.54% for porosity of the transitional zone to 3.98% for area of the compact-appearing cortex. Segmentation of the transitional zone minimizes errors in apportioning cortical fragments and cortical porosity to the medullary compartment and so is likely to allow accurate assessment of fracture risk and the morphological effects of growth, aging, diseases and therapies.

Treatment failure in osteoporosis

Guidelines concerning the definition of failure of therapies used to reduce the risk of fracture are provided.

INTRODUCTION

This study aims to provide guidelines concerning the definition of failure of therapies used to reduce the risk of fracture.

METHODS

A working group of the Committee of Scientific Advisors of the International Osteoporosis Foundation was convened to define outcome variables that may assist clinicians in decision making.

RESULTS

In the face of limited evidence, failure of treatment may be inferred when two or more incident fractures have occurred during treatment, when serial measurements of bone remodelling markers are not suppressed by anti-resorptive therapy and where bone mineral density continues to decrease.

CONCLUSION

The provision of pragmatic criteria to define failure to respond to treatment provides an unmet clinical need and may stimulate research into an important issue.

Skeletal and hormonal responses to vitamin D supplementation during sunlight deprivation in Antarctic expeditioners

Sunlight deprivation results in vitamin D deficiency but serum vitamin D levels can be maintained above 50 nmol/L when supplemented with 50,000 IU at least every alternate month.

INTRODUCTION

Antarctic expeditioners are exposed to prolonged sunlight deprivation resulting in vitamin D deficiency. We hypothesised that monthly dosing of 50,000 IU vitamin D (~1,600 IU daily) will increase serum 25-hydroxyvitamin D (25(OH)D), suppress parathyroid hormone (PTH) and improve bone mineral density (BMD), 50,000 IU alternate months (~800 IU daily) will maintain these measures, while a single 50,000 IU dose pre-departure (~1,00 IU daily) will not be protective.

METHODS

This was a randomised double-blind study involving 110 healthy adults: 91 males, mean age 41 years (range 24-65 years) working in Antarctica for up to 12 months, who we administered 50,000 IU vitamin D3 monthly, alternate months or a single dose pre-departure. Serum 25(OH)D, PTH, osteocalcin, CTx and calcium were assessed at baseline, mid- and end of expedition. Proximal femur and lumbar spine BMD were assessed pre- and post-expedition.

RESULTS

Baseline 25(OH)D was 59 ± 14 nmol/L. By mid-expedition, 25(OH)D increased by 7 nmol/L in those supplemented monthly (p < 0.05) and remained unchanged in those supplemented in alternate months. In those given a single dose pre-departure, 25(OH)D decreased by 8 nmol/L (p < 0.05) and PTH increased by 27% (p < 0.09). Serum osteocalcin increased by ~22% in all groups but BMD remained unchanged. If serum 25(OH)D was >50 nmol/L at baseline, 25(OH)D was maintained above this level with all regimens. If 25(OH)D was <50 nmol/L at baseline, monthly or alternate month regimens were needed to achieve levels >50 nmol/L, the single pre-departure dose was ineffective.

CONCLUSION

During sunlight deprivation of up to 12 months, serum 25(OH)D levels can be maintained above 50 nmol/L when expeditioners are provided with 50,000 I U at least every alternate month.

Epidemiology and structural basis of racial differences in fragility fractures in Chinese and Caucasians

Chinese have similar vertebral fracture prevalence but lower incidence of hip and distal forearm fractures than in Caucasians. The underlying structural and biomechanical basis of racial differences in bone fragility is still largely undefined but Chinese assemble their smaller appendicular skeleton with thicker cortices and trabeculae compared with Caucasians. Vertebral fracture prevalence is similar by race, but the incidence of hip and distal forearm fractures is lower in Chinese than in Caucasians. This racial dimorphism cannot be explained by differences in areal bone mineral density (aBMD) as aBMD is lower in Chinese mainly due to their smaller size. The underlying structural and biomechanical basis of racial differences in bone fragility is still largely undefined but Chinese assemble their smaller appendicular skeleton with more mineralised bone matrix within it; the cortices are thicker and perhaps less porous while trabeculae are fewer but thicker and more connected. This configuration produces a bone with a lower surface/volume ratio, which in turn reduces the surface available for remodelling to occur upon so that the lower surface/volume ratio may make the bone less exposed to remodelling and the thicker cortices and trabeculae less vulnerable to remodelling when it does occur during advancing age. However, prospective studies are needed to define racial differences at the age of onset, rate of bone loss from the intracortical, endocortical and trabecular components of the endosteal envelope and bone formation upon the periosteal envelope; notions of bone 'loss' are derived mainly from cross-sectional studies. Studies of the site- and surface-specific changes in bone modelling and remodelling are needed to better define racial differences in bone fragility in old age.

Predictors of new and severe vertebral fractures: results from the HORIZON Pivotal Fracture Trial

We examined prevalent and recent vertebral fractures in 1 year as predictors of new vertebral fractures over subsequent 2 years using data from RCT placebo patients. We found that prevalent and recent vertebral fractures strongly and independently predicted subsequent vertebral fractures including those which were severe.

INTRODUCTION

While several studies have shown that prevalent vertebral fractures (pVFx) increase the risk of new vertebral fractures (VFx), the impact of recent vertebral fractures on future fractures is less studied.

METHODS

Data from the placebo arm of the HORIZON Pivotal Fracture Trial, an international trial of zoledronic acid in postmenopausal, osteoporotic women between 65 and 85 years, were used. We included the subset of 2677 women with annual spinal radiographs to study the impact of vertebral fractures in year 1 (Y1 VF) on those occurring in years 2 and 3 using morphometric and semiquantitative (SQ) criteria. In addition, a subset of severe VFx was defined using SQ criteria. Logistic regression examined the impact of pVFx and Y1 VF on all incident VFx and on severe incident VFx.

RESULTS

Two hundred fourty-five (9.1%) women sustained a new VFx in years 2-3. VFx risk in years 2-3 was 3.9% in those without pVFx or VFy1 and 29.8% in those with both risk factors. Both pVF and VFy1 remained independent predictors for future VF when they were both entered into a logistic regression model (odds ratio (OR) = 3.3; 95% confidence interval (CI), 2.3-4.7; OR = 3.7, 95% CI, 2.3, 5.8, respectively). ORs were similar after adjustment. Of the total number of women, 4.1% had severe VFx. PVFx and Y1 VF were also significant predictors of severe VFx; however, Y1 VF appeared more strongly predictive of severe VFx.

CONCLUSIONS

Prevalent and incident vertebral fractures are highly predictive of subsequent new and severe vertebral fractures. Women with both of these risk factors are likely to benefit from anti-osteoporosis treatment.

Towards a diagnostic and therapeutic consensus in male osteoporosis

The consensus views on osteoporosis in men are reported.

INTRODUCTION

A workshop was convened within a meeting on osteoporosis in men to identify areas of consensus amongst the panel (the authors) and the participants of the meeting.

METHODS

A public debate with an expert panel on preselected topics was conducted.

RESULTS AND CONCLUSIONS

Consensus views were reached on diagnostic criteria and several aspects on the pathophysiology and treatment of osteoporosis in men.

The effect of acute exercise on undercarboxylated osteocalcin in obese men

SUMMARY

The purpose of this study was to examine if the reduction in glucose post-exercise is mediated by undercarboxylated osteocalcin (unOC). Obese men were randomly assigned to do aerobic or power exercises. The change in unOC levels was correlated with the change in glucose levels post-exercise. The reduction in glucose post-acute exercise may be partly related to increased unOC.

INTRODUCTION

Osteocalcin (OC) in its undercarboxylated (unOC) form may contribute to the regulation of glucose homeostasis. As exercise reduces serum glucose and improves insulin sensitivity in obese individuals and individuals with type 2 diabetes (T2DM), we hypothesised that this benefit was partly mediated by unOC.

METHODS

Twenty-eight middle-aged (52.4 ± 1.2 years, mean ± SEM), obese (BMI = 32.1 ± 0.9 kg m(-2)) men were randomly assigned to do either 45 min of aerobic (cycling at 75% of VO(2peak)) or power (leg press at 75% of one repetition maximum plus jumping sequence) exercises. Blood samples were taken at baseline and up to 2 h post-exercise.

RESULTS

At baseline, unOC was negatively correlated with glucose levels (r = -0.53, p = 0.003) and glycosylated haemoglobin (HbA1c) (r = -0.37, p = 0.035). Both aerobic and power exercises reduced serum glucose (from 7.4 ± 1.2 to 5.1 ± 0.5 mmol L(-1), p = 0.01 and 8.5 ± 1.2 to 6.0 ± 0.6 mmol L(-1), p = 0.01, respectively). Aerobic exercise significantly increased OC, unOC and high-molecular-weight adiponectin, while power exercise had a limited effect on OC and unOC. Overall, those with higher baseline glucose and HbA1c had greater reductions in glucose levels after exercise (r = -0.46, p = 0.013 and r = -0.43, p = 0.019, respectively). In a sub-group of obese people with T2DM, the percentage change in unOC levels was correlated with the percentage change in glucose levels post-exercise (r = -0.51, p = 0.038).

CONCLUSIONS

This study reports that the reduction in serum glucose post-acute exercise (especially aerobic exercise) may be partly related to increased unOC.

Structural decay of bone microarchitecture in men with prostate cancer treated with androgen deprivation therapy

CONTEXT

Androgen deprivation therapy (ADT) used in the treatment of prostate cancer reduces bone mineral density (BMD) and predisposes to fractures. The structural basis of the BMD deficit and bone fragility is uncertain.

OBJECTIVE AND PATIENTS

We investigated changes in bone microarchitecture in 26 men (70.6±6.8 yr) with nonmetastatic prostate cancer during the first year of ADT using the new technique of high-resolution peripheral quantitative computed tomography.

DESIGN AND SETTING

We conducted a 12-month prospective observational study in the setting of a tertiary referral center.

RESULTS

After 12 months of ADT, total volumetric density decreased by 5.2±5.4% at the distal radius and 4.2±2.7% at the distal tibia (both P<0.001). This was due to a decrease in cortical volumetric BMD (by 11.3±8.6% for radius and 6.0±4.2% for tibia, all P<0.001) and trabecular density (by 3.5±6.0% for radius and 1.5±2.3% for tibia, all P<0.01), after correcting for trabecularization of cortical bone. Trabecular density decreased due to a decrease in trabecular number at both sites (P<0.05). Total testosterone, but not estradiol, levels were independently associated with total and corrected cortical volumetric BMD at the tibia.

CONCLUSIONS

Sex steroid deficiency induced by ADT for prostate cancer results in microarchitectural decay. Bone fragility in these men may be more closely linked to testosterone than estradiol deficiency.

Skeletal and hormonal responses to sunlight deprivation in Antarctic expeditioners

Serum 25(OH)D levels decline without sunlight exposure. We studied 120 expeditioners to Antarctica to determine the skeletal and hormonal responses to sunlight deprivation. With emerging vitamin D insufficiency, serum calcium decreased, PTH increased, and bone loss at the proximal femur was observed. Baseline serum 25(OH)D levels >100 nmol/L prevented vitamin D insufficiency.

INTRODUCTION

Vitamin D stores deplete without adequate sunlight exposure unless supplementation is provided. We studied 120 healthy adults who spent a year in Antarctica as a model for sunlight deprivation to define the timing and magnitude of the skeletal and hormonal responses to emerging vitamin D insufficiency.

METHODS

Fasting blood samples were assessed at baseline, 6 and 12 months for serum 25-hydroxyvitamin D (25(OH)D), osteocalcin (OC), bone formation (P1NP) and resorption (CTx), PTH and calcium. Lumbar spine and proximal femur BMD was measured using DXA. Differences over time were determined using repeated measures ANOVA. Percent changes were expressed as (Delta value/(value A + value B)/2) x 100. Relationships between outcome measures were determined using Spearman's correlations.

RESULTS

Vitamin D insufficiency (<50 nmol/L) was observed in 85% of expeditioners by 6 months when serum calcium decreased and PTH increased (p < 0.01). By 12 months, OC increased by 7.4 +/- 3.0% (p < 0.05), and BMD decreased by 1.0 +/- 2.0% at the total proximal femur (p < 0.05). For those with vitamin D sufficiency at baseline (>50 nmol/L), sunlight deprivation produced vitamin D insufficiency within 4 months unless baseline values were >100 nmol/L.

CONCLUSION

Supplementation may be necessary for expeditioners with limited access to UV light.

Thinking inside and outside the envelopes of bone: dedicated to PDD

INTRODUCTION

Bone modeling and remodeling is the final common pathway expressing all genetic and environmental factors that influence the attainment and maintenance of bone's material and structural strength. Modeling and remodeling require a surface, and during growth this cellular machinery fashions bone's external size, shape, and internal architecture by depositing bone on, and removing bone from, both its periosteal (external) and endosteal (internal) envelopes. Bone is distributed and redistributed to achieve strength commensurate with its loading requirements.

METHODS

Advancing age is associated with: (1) a reduction in the volume of bone resorbed by each basic multicellular unit (BMU); (2) an even greater reduction in the volume of bone formed by each BMU so that each remodeling event, whether adaptive or reparative, removes bone from the bone; (3) increased remodeling (number of BMUs) on the three (endocortical, intracortical, and trabecular) components of its endosteal envelope in midlife in women and late in life in both sexes; and (4) reduced bone formation on the periosteal envelope. The net effect is cortical thinning, increased intracortical porosity, trabecular thinning, and loss of connectivity.

RESULTS

While remodeling intensity on an envelope determines structure (e.g., trabecular perforations), the surface area of the envelope determines remodeling intensity, and, so, structure. High remodeling on trabecular surfaces decreases as trabeculae (with their surface) are lost. Conversely, remodeling on the endocortical and intracortical envelopes increases their surface area, so remodeling intensity increases and bone loss becomes predominantly cortical.

CONCLUSIONS

Understanding bone structural strength and its decay and the effects of genetic factors, exercise, nutrition, and drug therapy on bone requires thinking outside and inside these envelopes; their absolute and relative movements during growth and aging determine bone structure and its strength.

Women and men with hip fractures have a longer femoral neck moment arm and greater impact load in a sideways fall

INTRODUCTION

In a case control study, we report that women and men with hip fractures have a longer moment arm of the force applied on the proximal femur during a sideways fall, a structural feature that may contribute to fracture risk. The impact load and its direction during a sideways fall onto the greater trochanter are partly determined by the geometry of the proximal femur. We hypothesized that the hip geometry in elderly with hip fractures produces a greater impact on the hip during a sideways fall.

METHODS

We studied 41 female (77.2 +/- 9.9 years) and 22 male (76.2 +/- 12.1 years) patients with hip fractures and 40 female (85.7 +/- 6.0 years) and 17 male (84.3 +/- 10.1 years) controls. Hip geometry was analyzed on the nonfracture hip in patients and left hip in controls using dual-energy X-ray absorptiometry.

RESULTS

There was no difference in areal bone mineral density (aBMD), hip axis length, femoral neck axis length, or neck-shaft angle between cases and controls. However, the moment arm of the force on the hip during a sideways fall was 7.3% and 9.5% longer resulting in 5.6% and 9.1% greater moment in such a fall in female and male cases relative to their respective controls independent of height and weight (all p < 0.056). In multivariate logistic regression analysis, only the moment arm length in a sideways fall was associated with increased risk of hip fracture in females (odds ratio = 1.91, 95%CI: 1.14-3.20 for each SD increase in moment arm length of sideways fall, p = 0.02) and males (odds ratio = 2.69, 95% CI, 1.19-6.09, p = 0.01).

CONCLUSIONS

A longer moment arm in the sideways fall increases the resultant force applied to the hip predisposing to hip fracture.

Structural basis of growth-related gain and age-related loss of bone strength

If bone strength was the only requirement of skeleton, it could be achieved with bulk, but bone must also be light. During growth, bone modelling and remodelling optimize strength, by depositing bone where it is needed, and minimize mass, by removing it from where it is not. The population variance in bone traits is established before puberty and the position of an individual's bone size and mass tracks in the percentile of origin. Larger cross-sections have a comparably larger marrow cavity, which results in a lower volumetric BMD (vBMD), thereby avoiding bulk. Excavation of a marrow cavity thus minimizes mass and shifts the cortex radially, increasing rigidity. Smaller cross-sections are assembled by excavating a smaller marrow cavity leaving a relatively thicker cortex producing a higher vBMD, avoiding the fragility of slenderness. Variation in cellular activity around the periosteal and endocortical envelopes fashions the diverse shapes of adjacent cross-sections. Advancing age is associated with a decline in periosteal bone formation, a decline in the volume of bone formed by each basic multicellular unit (BMU), continued resorption by each BMU, and high remodelling after menopause. Bone loss in young adulthood has modest structural and biomechanical consequences because the negative BMU balance is driven by reduced bone formation, remodelling is slow and periosteal apposition continues shifting the thinned cortex radially. But after the menopause, increased remodelling, worsening negative BMU balance and a decline in periosteal apposition accelerate cortical thinning and porosity, trabecular thinning and loss of connectivity. Interstitial bone, unexposed to surface remodelling becomes more densely mineralized, has few osteocytes and greater collagen cross-linking, and accumulates microdamage. These changes produce the material and structural abnormalities responsible for bone fragility.

Fractures during growth: potential role of a milk-free diet

Dietary calcium deficiency may increase fracture risk. In girls, 29.4% of fracture cases and 11.8% of controls without fracture had a history of milk-free diet. The odds ratio (OR) for fracture with a milk-free diet in girls was 4.6, p < 0.01. In boys, 23% of cases and 19% of controls had a history of a milk-free diet; OR = 1.3, NS). A milk-free diet due to cow's milk allergy is associated with increased fracture risk in girls.

INTRODUCTION

An intake of calcium below the reference daily intake (RDI) of 800-1200 mg/day during growth is thought to increase fracture risk even though convincing evidence for this view is scarce. The paucity of evidence may be partly due to many trial participants being calcium replete. Children and adolescents with cow's milk allergy (CMA) avoid milk and have a calcium intake below the RDI. The aim of this study was to examine the association between consumption of a milk-free diet and fracture risk.

METHODS

In this case-control study conducted in Poland, 57 boys and 34 girls aged 2.5-20 years with fractures (cases) were randomly matched by age and sex with 171 boys and 102 girls without fractures (controls). Weight and height were examined using standard methods. Bone mineral density (BMD) and body composition were measured using dual-energy X-ray absorptiometry. Conditional logistic regression and Bayesian analyses were used to determine the proportion of the fracture risk attributable to a milk-free diet.

RESULTS

In girls, 29.4% of cases and 11.8% of controls had a history of milk-free diet producing an odds ratio (OR) for fracture associated with a milk-free diet of 4.6 (95% confidence interval [CI]: 1.4-15.5, p < 0.01). In boys, 23% of cases and 19% of controls had a history of a milk-free diet; OR = 1.3 (95% CI: 0.6-2.7, NS). If the prevalence of CMA in the population is 5%, only 6.7% of the fractures occurring are attributable to CMA and the associated nutritional deficit.

CONCLUSIONS

Cow's milk allergy is associated with increased fracture risk in girls. Whether this association is due to the illness, calcium deficit or a deficit in other milk nutrients is uncertain. These data suggest that the contribution of milk-free diet to fracture liability among children and adolescents is modest.

Is a change in bone mineral density a sensitive and specific surrogate of anti-fracture efficacy?

Anti-resorptive agents perturb steady state remodeling; they suppress, but do not abolish, the birth rate of new basic multicellular units (BMUs). In doing so, remodeling goes to completion with bone formation in the many BMUs created before treatment but now with fewer resorption cavities appearing concurrently. As a result, cortical porosity and trabecular stress concentrators decrease reducing bone fragility. From this improved bone strength, steady state is re-established at a slower remodeling rate that again produces bone fragility but more slowly as fewer new BMUs, each with a less negative BMU balance, produce cortical thinning and porosity, trabecular thinning and loss of connectivity while bone fragility progresses rapidly in controls. Thus, the fracture risk reduction--the incidence of fractures in patients treated with an anti-resorptive agent relative to the incidence in controls--is the net effect of the slowing or partial reversal of fragility and then reduced progression of structural abnormalities in treated patients and continued structural decay in controls. Although some morphological features in treated patients and controls may be captured in the bone mineral density (BMD) measurement, many are not. The early increase in BMD is largely determined by the pre-treatment remodeling rate whereas the later and more modest BMD increase is a function of the degree of suppression of remodeling and secondary mineralization. When pre-treatment remodeling rate is low, the increase in BMD is small but the fracture risk reduction (relative to controls with comparable baseline characteristics) is no different to that in patients with high baseline remodeling (relative to their controls) and a greater BMD increase. Therefore, a small increase in BMD does not mean treatment has failed and a large increase in BMD is not indicative of a greater fracture risk reduction.

Non-compliance: the Achilles' heel of anti-fracture efficacy

About 50% of patients fail to comply or persist with anti-osteoporosis treatment regimens within 1 year. Poor compliance is associated with higher fracture rates. Causes of poor compliance are unknown. As it is not possible to predict poor compliance, close monitoring of compliance is needed. Despite evidence supporting the anti-fracture efficacy of several pharmacological agents, approximately 50% of patients do not follow their prescribed treatment regimen and/or discontinue treatment within 1 year. Poor compliance is associated with higher fracture rates and increased morbidity, mortality and cost. However, as poor compliance, even to placebo, is associated with adverse outcomes, the higher morbidity appears to be only partly the result of lack of treatment: as yet, undefined characteristics place poor compliers at higher risk of morbidity and mortality. Only a small proportion (e.g., 6%) of the variability in compliance is explained by putative causal factors such as older age, co-morbidity or greater number of medications. Regimens with longer dosing intervals, such as weekly dosing, improve compliance, persistence and outcomes, but only modestly. As it is not possible to predict poor compliance, close monitoring of compliance should be an obligatory duty in clinical care. How this is best achieved has yet to be established, but poor persistence occurs as early as 3 months of starting treatment, indicating the need for early monitoring.

Insights into material and structural basis of bone fragility from diseases associated with fractures: how determinants of the biomechanical properties of bone are compromised by disease

Minimal trauma fractures in bone diseases are the result of bone fragility. Rather than considering bone fragility as being the result of a reduced amount of bone, we recognize that bone fragility is the result of changes in the material and structural properties of bone. A better understanding of the contribution of each component of the material composition and structure and how these interact to maintain whole bone strength is obtained by the study of metabolic bone diseases. Disorders of collagen (osteogenesis imperfecta and Paget's disease of bone), mineral content, composition and distribution (fluorosis and osteomalacia); diseases of high remodeling (postmenopausal osteoporosis, hyperparathyroidism, and hyperthyroidism) and low remodeling (osteopetrosis, pycnodysostosis); and other diseases (idiopathic male osteoporosis, corticosteroid-induced osteoporosis) produce abnormalities in the material composition and structure that lead to bone fragility. Observations in patients and in animal models provide insights on the biomechanical consequences of these illnesses and the nature of the qualities of bone that determine its strength.

Middle East and North Africa consensus on osteoporosis

With the increasing life expectancy, osteoporosis is becoming a major worldwide health problem. The magnitude of the disease may become larger in developing countries, more particularly in the Middle East region where the prevalence of low bone mass is higher than in western countries. Although several local organizations and countries have developed guidelines for osteoporosis, no previous regional guidelines have been developed encompassing all Middle-Eastern and North African countries. The present document reviews all the regional published data on bone mineral density, risk factors, fracture prevalence and vitamin D status. It also gives simple recommendations applicable to all these countries. This document was endorsed by leading members of all the different regional countries including, Iran, Egypt, Tunisia, Jordan, Palestine, Syria, Iraq, Libya, Oman, Kuwait, Saudi Arabia and Bahrain.

The spinal curvature irregularity index independently identifies vertebral fractures

INTRODUCTION AND HYPOTHESIS

The spinal curvature irregularity index (SCII) is a quantitative measure of the irregularity of the spinal curvature. We evaluated the predictive ability of SCII to identify subjects with vertebral fractures (VF).

METHODS

Vertebral heights were measured by quantitative vertebral morphometry in 461 Lebanese women 20-89 years of age and VFs were ascertained by the grade 1 Eastell method. SCII scores were log-transformed and expressed as Z-SCII, the number of standard deviations above or below the mean ln(SCII) of young patients without VF. Univariate and multivariate binary logistic regression models were used to identify clinical predictors of VF.

RESULTS

Women with a higher SCII were more likely to have prevalent VF. A higher SCII was associated with a greater prevalence of VF within each category of femoral neck BMD (normal, osteopenia, osteoporosis). In univariate analysis, predictors of VF included Z-SCII (odds ratio, OR: 2.21, 95% CI: 1.80-2.71) and femoral neck T-score (OR: 1.35, 95% CI: 1.12-1.63). In multivariate analysis, predictors of VF were: Z-SCII (OR: 1.54, 95% CI: 1.02-2.32), femoral neck T-score (OR: 1.41, 95% CI: 1.11-1.78) and age(3) (OR: 1.40, 95% CI 1.10-1.82). At a cutoff SCII of 9.5%, the sensitivity and specificity of SCII for VF were 71 and 64% respectively, and higher SCII cutoffs identified VFs with greater specificity.

CONCLUSION

The SCII is a robust, simple and independent indicator of the presence of VFs.

Skeletal benefits from calcium supplementation are limited in children with calcium intakes near 800 mg daily

INTRODUCTION AND HYPOTHESIS

Calcium supplementation enhances bone mass accrual during administration, with a sustained benefit observed using milk-based calcium but not calcium salts. We tested the hypothesis that calcium from milk minerals but not calcium carbonate will be sustained after supplementation was discontinued.

METHODS

Ninety-nine pre-pubertal boys and girls aged 5-11 years were followed for 12 months after being randomized to receive 800 mg/day of calcium from milk minerals (MM) or calcium carbonate (CC), or a placebo (Pla) in a 10-month double blind study. Total body and regional BMC, and femoral shaft bone dimensions were measured using dual energy x-ray absorptiometry. Group differences were determined using ANCOVA.

RESULTS

In the intention to treat analysis of the entire sample, no group differences were observed in increments in BMC or bone dimensions during or after supplementation. In those children who remained pre-pubertal, greater gains in pelvis BMC in the milk mineral group than controls were sustained (37.9 versus 29.3% respectively, p<0.02).

CONCLUSION

In healthy children consuming about 800 mg calcium daily, calcium supplementation with milk minerals or calcium carbonate does not appear to be produce biologically meaningful benefits to skeletal health. A benefit of calcium supplementation in pre-pubertal was evident, but inconclusive, with the biological significance of the effect of calcium supplementation at the pelvis, and the longevity of this effect to be determined.

Calcitriol does not prevent bone loss in patients with asthma receiving corticosteroid therapy: a double-blind placebo-controlled trial

INTRODUCTION

Oral glucocorticoid therapy reduces bone mineral density (BMD) and increases fracture risk. It is uncertain whether inhaled glucocorticoids, the most commonly used long-term therapy for asthma, have a similar effect. If bone loss does occur, it is unclear whether this is preventable by calcitriol. Patients with asthma receiving inhalational plus intermittent oral glucocorticoids lose bone, and treatment with 0.5 microg/day of calcitriol will prevent bone loss.

METHODS

A 2-year randomized double-blind placebo-controlled trial. One hundred eight patients with asthma were stratified by gender, age, and inhaled glucocorticoid dose and treated with calcitriol (n=55) or placebo (n=53). There were 41 men (mean age 53.2+/-1.7 years) and 67 women (mean age 49.1+/-1 years) with moderate to severe asthma (requiring >/=800 microg/day of beclomethasone dipropionate or equivalent maintenance therapy). BMD values at the lumbar spine (LS) and femoral neck (FN) were measured at baseline and at 6, 12, and 24 months using dual x-ray absorptiometry.

RESULTS

Changes in LS and FN BMD. Bone loss occurred in both groups at the FN (both p<0.03) and at the LS in the calcitriol (p<0.001), but not the control, group. Bone loss was not less in the calcitriol group at either site.

CONCLUSION

Patients with asthma receiving inhalational plus intermittent short courses of oral glucocorticoids lose bone. Calcitriol is unlikely to be appropriate therapy against this bone loss.

The population burden of fractures originates in women with osteopenia, not osteoporosis

INTRODUCTION

Osteoporosis is associated with increased risk for fracture. However, most postmenopausal women have bone mineral density (BMD) within the normal or osteopenic range. The aim of this study was to determine the proportion of the population burden of fragility fractures arising from women at modest risk for fracture.

METHODS

We measured baseline BMD in a population-based random sample of 616 postmenopausal women aged 60-94 years and followed these individuals for a median of 5.6 years (IQR 3.9-6.5) to determine the incidence of fractures according to age, BMD and the presence of a prior fracture.

RESULTS

Based on WHO criteria, 37.6% of the women had normal total hip BMD, 48.0% had osteopenia and 14.5% had osteoporosis. The incidence of fracture during follow-up was highest in women with osteoporosis, but only 26.9% of all fractures arose from this group; 73.1% occurred in women without osteoporosis (56.5% in women with osteopenia, 16.6% in women with normal BMD). Decreasing BMD, increasing age and prior fracture contributed independently to increased fracture risk; in a multivariate model, the relative risk for fracture increased 65% for each SD decrease in BMD (RR=1.65, 95%CI 1.32-2.05), increased 3% for every year of age (RR=1.03, 95%CI 1.01-1.06) and doubled with prevalent fracture (RR=2.01, 95% CI 1.40-2.88). A prevalent fracture increased the risk for fractures such that women with osteopenia and prevalent fracture had the same, if not greater, risk as women with osteoporosis alone.

CONCLUSIONS

Reducing the population burden of fractures requires attention to women with osteopenia, as well as osteoporosis, because over half of the fragility fractures in the population arise in these individuals, and women with osteopenia plus a prevalent fracture have the same fracture risk as women with osteoporosis.

Bone fragility in men--where are we?

INTRODUCTION

This is a summary of several aspects of the epidemiology, pathogenesis and treatment arising directly and indirectly from the proceedings of the Third International Osteoporosis in Men meeting held in Genoa in May 2005. Advances in the study of bone fragility in men have taken place, but many challenges remain.

OBSERVATIONS

Although the epidemiology of hip fractures is well documented, the epidemiology of other non-vertebral fractures is less well defined even though these fractures contribute substantially to the global burden of fractures in men. The epidemiology of vertebral fragility fractures is derived mostly from cross sectional data. The comparable prevalence of vertebral fractures in men and women is likely to be misleading because of traumatic vertebral fractures that arise in young men. Prospective studies are needed to define the proportion of these fractures that are traumatic. After the age of 50 years, the incidence of vertebral fractures in men is about one third to one half of that in women. As in women, most vertebral and non-vertebral fragility fractures occur in persons without osteoporosis. Identifying these individuals is an unmet challenge. The absolute risk for fractures appears no different by sex in men and women of the same age and bone mineral density (BMD) so that the diagnostic threshold for osteoporosis in women can be used in men. Fracture risk varies around the world and is unlikely to be explained solely by variations in BMD, though there are few data comparing men and women of different races. Both the notion that men lose less bone than women from the endosteal envelope and that they gain more on the periosteal envelope during advancing age needs reassessment as recent evidence challenges these observations. Sex differences in the net gain and loss from these surfaces are likely to be site specific, and research is needed to specify this heterogeneity and the reasons for it. The independent and co-dependent effects of sex hormones and the growth hormone/insulin like growth factor 1 axis on periosteal and endosteal modeling and remodeling during growth as well as ageing are poorly defined. The anti-fracture efficacy and safety of androgens and other agents remain incompletely investigated in men.

CONCLUSION

A great deal of research is needed to advance our understanding of bone fragility in men.

Strontium ranelate reduces the risk of nonvertebral fractures in postmenopausal women with osteoporosis: Treatment of Peripheral Osteoporosis (TROPOS) study

BACKGROUND

Strontium ranelate, a new oral drug shown to reduce vertebral fracture risk in postmenopausal women with osteoporosis, was studied in the Treatment of Peripheral Osteoporosis (TROPOS) study to assess its efficacy and safety in preventing nonvertebral fractures also.

METHODS

Strontium ranelate (2 g/d) or placebo were randomly allocated to 5091 postmenopausal women with osteoporosis in a double-blind placebo-controlled 5-yr study with a main statistical analysis over 3 yr of treatment.

FINDINGS

In the entire sample, relative risk (RR) was reduced by 16% for all nonvertebral fractures (P = 0.04), and by 19% for major fragility fractures (hip, wrist, pelvis and sacrum, ribs and sternum, clavicle, humerus) (P = 0.031) in strontium ranelate-treated patients in comparison with the placebo group. Among women at high risk of hip fracture (age > or = 74 yr and femoral neck bone mineral density T score < or = -3, corresponding to -2.4 according to NHANES reference) (n = 1977), the RR reduction for hip fracture was 36% (P = 0.046). RR of vertebral fractures was reduced by 39% (P < 0.001) in the 3640 patients with spinal x-rays and by 45% in the subgroup without prevalent vertebral fracture. Strontium ranelate increased bone mineral density throughout the study, reaching at 3 yr (P < 0.001): +8.2% (femoral neck) and +9.8% (total hip). Incidence of adverse events (AEs) was similar in both groups.

CONCLUSION

This study shows that strontium ranelate significantly reduces the risk of all nonvertebral and in a high-risk subgroup, hip fractures over a 3-yr period, and is well tolerated. It confirms that strontium ranelate reduces vertebral fractures. Strontium ranelate offers a safe and effective means of reducing the risk of fracture associated with osteoporosis.

Fracture incidence and association with bone mineral density in elderly men and women: the Rotterdam Study

The incidence of all non-vertebral fractures, as well as the relation to bone mineral density (BMD), was quantified in 7806 men and women from the Rotterdam Study, a prospective, population-based cohort study of men and women aged 55 years and older. In addition, the sensitivity of using a T-score at or below -2.5 for identifying subjects at risk for fractures was assessed. At baseline, between 1990 and 1993, femoral neck BMD was measured by dual energy X-ray absorptiometry (DXA). Subsequently, gender-specific T-scores were calculated using the NHANES reference population. During a mean follow-up of 6.8 years, information on incident non-vertebral fractures was gathered. In general, hip, wrist and upper humerus fractures are the most frequent fractures in both men and women. Femoral neck BMD appears to be an equally important risk factor in both genders, and is especially related to hip fractures. For all non-vertebral fractures, the age-adjusted hazard ratio (95% confidence interval) per standard deviation decrease in femoral neck BMD was 1.5 (1.4-1.6) for women and 1.4 (1.2-1.6) for men. For hip fractures, the hazard ratios were 2.1 (1.7-2.5) for women and 2.3 (1.6-3.3) for men. Only 44% of all non-vertebral fractures occurred in women with a T-score below -2.5; in men, this percentage was even lower (21%). Thus, there is a clear need for the development of more sensitive risk assessment tools, using not only BMD, but also other clinical predictors of fractures.

The effect of mechanical loading on the size and shape of bone in pre-, peri-, and postpubertal girls: a study in tennis players

Exercise during growth results in biologically important increases in bone mineral content (BMC). The aim of this study was to determine whether the effects of loading were site specific and depended on the maturational stage of the region. BMC and humeral dimensions were determined using DXA and magnetic resonance imaging (MRI) of the loaded and nonloaded arms in 47 competitive female tennis players aged 8-17 years. Periosteal (external) cross-sectional area (CSA), cortical area, medullary area, and the polar second moments of area (I(P), mm4) were calculated at the mid and distal sites in the loaded and nonloaded arms. BMC and I(P) of the humerus were 11-14% greater in the loaded arm than in the nonloaded arm in prepubertal players and did not increase further in peri- or postpubertal players despite longer duration of loading (both, p < 0.01). The higher BMC was the result of a 7-11% greater cortical area in the prepubertal players due to greater periosteal than medullary expansion at the midhumerus and a greater periosteal expansion alone at the distal humerus. Loading late in puberty resulted in medullary contraction. Growth and the effects of loading are region and surface specific, with periosteal apposition before puberty accounting for the increase in the bone's resistance to torsion and endocortical contraction contributing late in puberty conferring little increase in resistance to torsion. Increasing the bone's resistance to torsion is achieved by modifying bone shape and mass, not necessarily bone density.

Fracture thresholds revisited. Geelong Osteoporosis Study

Osteoporosis, in the absence of fracture, is defined as a deficit in bone mineral density (BMD) of 2.5 SD or more below the young adult reference mean in postmenopausal Caucasian populations. BMD is a measure of fracture risk but not the sole predictor. We have assessed a combination of easily accessible measures of age, height, weight, and BMD to improve fracture risk assessment. Women with low trauma fractures and a control group were recruited from south-eastern Australia. Discriminant analysis derived multivariate equations that assessed fracture risk. Age was not in the best models at the spine and forearm sites. Weight and height contributed to the relationship for the forearm sites only. At the proximal femur, the BMD level that separates fracture cases from nonfracture cases, increases with age. These separation levels of BMD were higher than the WHO's level of osteoporosis (T-score < -2.5 SD) at ages older than 62 years. This increasing BMD threshold with age suggests that other age-related risk factors assume increasing importance among the elderly.