The global approach to rehabilitation following an osteoporotic fragility fracture: A review of the rehabilitation working group of the International Osteoporosis Foundation (IOF) committee of scientific advisors

PURPOSE

To conduct a review of the current state of the evidence for rehabilitation strategies post-fragility fracture.

METHODS

Narrative review conducted by the Rehabilitation Working Group of the International Osteoporosis Foundation Committee of Scientific Advisors characterizing the range of rehabilitation modalities instrumental for the management of fragility fractures.

RESULTS

Multi-modal exercise post-fragility fracture to the spine and hip is strongly recommended to reduce pain, improve physical function, and improve quality of life. Outpatient physiotherapy post-hip fracture has a stronger evidence base than outpatient physiotherapy post-vertebral fracture. Appropriate nutritional care after fragility fracture provides a large range of improvement in morbidity and mortality. Education increases understanding of osteoporosis which in turn increases utilization of other rehabilitation services. Education may improve other health outcomes such as pain and increase a patient's ability for self-advocacy.

CONCLUSION

Rehabilitation interventions are inter-reliant, and research investigating the interaction of exercise, nutrition, and other multi-modal therapies may increase the relevance of rehabilitation research to clinical care.

Association between bariatric surgery with long-term analgesic prescription and all-cause mortality among patients with osteoarthritis: a general population-based cohort study

OBJECTIVES

There is still a large unmet need for novel osteoarthritis (OA) treatments that could provide clinically important effects on long-term pain relief (≥12 months). We examined the relation of bariatric surgery along with weight loss to analgesic prescription and all-cause mortality among individuals with OA.

METHODS

We conducted a cohort study among individuals with OA using The Health Improvement Network. We compared the rate of no analgesic prescription ≥12 consecutive months and the risk of all-cause mortality using inverse probability weighting Cox-proportional hazard models and the difference in number of analgesic prescriptions (non-steroidal anti-inflammatory drugs, opioids, and paracetamol) in the 50^th, 75^th and 90^th percentiles using quantile regression model between bariatric and non-bariatric cohorts.

RESULTS

Included were 588,494 individuals (694 had bariatric surgery). Compared with non-bariatric group, the rate of no analgesic prescription ≥12 consecutive months was higher (HR = 1.23, 95% CI: 1.08-1.38) in bariatric surgery group, and the number of analgesic prescriptions was lower in the 75^th (44 vs 58) and 90^th (74 vs 106) percentiles during a mean follow-up of 4.3 years. All-cause mortality in bariatric surgery group was lower than comparison group (HR = 0.46, 95% CI: 0.41-0.51).

CONCLUSION

This study presents the first evidence that bariatric surgery was associated with decreased long-term analgesic prescription and decreased all-cause mortality among individuals with OA. However, our findings may be overestimated owing to intractable confounding by indication for bariatric surgery; thus, future studies (e.g., clinical trials) are warranted.

Statistical shape modeling of the hip and the association with hip osteoarthritis: a systematic review

OBJECTIVE

To summarize available evidence on the association between hip shape as quantified by statistical shape modeling (SSM) and the incidence or progression of hip osteoarthritis.

DESIGN

We conducted a systematic search of five electronic databases, based on a registered protocol (available: PROSPERO CRD42020145411). Articles presenting original data on the longitudinal relationship between radiographic hip shape (quantified by SSM) and hip OA were eligible. Quantitative meta-analysis was precluded because of the use of different SSM models across studies. We used the Newcastle-Ottawa Scale (NOS) for risk of bias assessment.

RESULTS

Nine studies (6,483 hips analyzed with SSM) were included in this review. The SSM models used to describe hip shape ranged from 16 points on the femoral head to 85 points on the proximal femur and hemipelvis. Multiple hip shape features and combinations thereof were associated with incident or progressive hip OA. Shape variants that seemed to be consistently associated with hip OA across studies were acetabular dysplasia, cam morphology, and deviations in acetabular version (either excessive anteversion or retroversion).

CONCLUSIONS

Various radiographic, SSM-defined hip shape features are associated with hip OA. Some hip shape features only seem to increase the risk for hip OA when combined together. The heterogeneity of the used SSM models across studies precludes the estimation of pooled effect sizes. Further studies using the same SSM model and definition of hip OA are needed to allow for the comparison of outcomes across studies, and to validate the found associations.

A Phase 2b randomized trial of lorecivivint, a novel intra-articular CLK2/DYRK1A inhibitor and Wnt pathway modulator for knee osteoarthritis

OBJECTIVE

Lorecivivint (LOR; SM04690), an investigational Wnt pathway modulator, previously demonstrated patient-reported and radiographic outcome improvements vs placebo in clinically relevant subjects with moderate to severe knee osteoarthritis (OA). This study's objective was to identify effective LOR doses.

DESIGN

Subjects in this 24-week, Phase 2b, multicenter, randomized, double-blind, placebo (PBO)-controlled trial received an intra-articular injection of 2 mL LOR (0.03, 0.07, 0.15, or 0.23 mg), PBO, or dry-needle sham. The primary efficacy endpoints were changes in Pain NRS [0-10], WOMAC Pain [0-100], WOMAC Function [0-100], and radiographic mJSW outcomes, which were measured using baseline-adjusted analysis of covariance at Week 24. Multiple Comparison Procedure-Modeling (MCP-Mod) was performed for dose modeling.

RESULTS

In total, 695/700 subjects were treated. Pain NRS showed significant improvements vs PBO after treatment with 0.07 mg and 0.23 mg LOR at Weeks 12 (-0.96, 95% CI [-1.54, -0.37], P = 0.001; -0.78 [-1.39, -0.17], P = 0.012) and 24 (-0.70 [-1.34, -0.06], P = 0.031; -0.82 [-1.51, -0.12], P = 0.022). Additionally, 0.07 mg LOR significantly improved WOMAC Pain and Function subscores vs PBO at Week 12 (P = 0.04, P = 0.021), and 0.23 mg LOR significantly improved both WOMAC subscores at Week 24 (P = 0.031, P = 0.017). No significant differences from PBO were observed for other doses. No radiographic progression was observed in any group at Week 24. MCP-Mod identified 0.07 mg LOR as the lowest effective dose.

CONCLUSION

This 24-week Phase 2b trial demonstrated the efficacy of LOR on PROs in knee OA subjects. The optimal dose for future studies was identified as 0.07 mg LOR.

Real-world bone turnover marker use: impact on treatment decisions and fracture

The use of bone turnover marker (BTM) testing for patients with osteoporosis in the USA has not been well characterized. This retrospective US-based real-world data study found BTM testing has some association with treatment decision-making and lower fracture risk in patients with presumed osteoporosis, supporting its use in clinical practice.

INTRODUCTION

The purpose of this study was to characterize bone turnover marker (BTM) testing patterns and estimate their clinical utility in treatment decision-making and fragility fracture risk in patients with osteoporosis using a retrospective claims database.

METHODS

Data from patients aged ≥ 50 years with newly diagnosed osteoporosis enrolled in the Truven MarketScan^® Commercial Claims and Encounters and Medicare Supplemental and Co-ordination of Benefits databases from January 2008 to June 2018 were included. Osteoporosis was ascertained by explicit claims, fragility fracture events associated with osteoporosis, or prescribed anti-resorptive or anabolic therapy. BTM-tested patients were 1:1 propensity score matched to those untested following diagnosis. Generalized estimating equation models were performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for testing versus no testing on both treatment decision-making and fragility fracture.

RESULTS

Of the 457,829 patients with osteoporosis, 6075 were identified with ≥ 1 BTM test following diagnosis; of these patients, 1345 had a unique treatment decision made ≤ 30 days from BTM testing. The percentage of patients receiving BTM tests increased significantly each year (average annual % change: + 8.1%; 95% CI: 5.6-9.0; p = 0.01). Patients tested were significantly more likely to have a treatment decision (OR: 1.14; 95% CI: 1.13-1.15), and testing was associated with lower odds of fracture versus those untested (OR: 0.87; 95% CI: 0.85-0.88).

CONCLUSION

In this large, heterogeneous population of patients with presumed osteoporosis, BTM testing was associated with treatment decision-making, likely leading to fragility fracture reduction following use.

Sleep duration and bone health measures in older men

The associations between objective measures of sleep duration and bone outcomes in older men are unknown. No consistent, significant association was identified between sleep duration and bone mineral density (BMD) in the current analysis. However, future research should determine if vitamin D status modifies this relationship.

INTRODUCTION

Prior studies, predominantly in women, reported that long and short self-reported sleep duration are associated with lower BMD. Associations between actigraphy-determined sleep duration and BMD or bone turnover markers (BTMs) in older men are unknown.

METHODS

Men in The Osteoporotic Fractures in Men (MrOS) Study with wrist actigraphy and concurrent BMD assessment but without comorbidities affecting bone health were included. Sleep duration was considered as a continuous (N = 1926) and dichotomized variable where men were classified as getting the recommended (7-8 h/night; N = 478) or short (< 6 h/night; N = 577) sleep. The cross-sectional association between BMD, BTMs, and sleep duration was examined using a t test or linear regression, where appropriate, in unadjusted and adjusted models.

RESULTS

There were no clinically or statistically significant differences in BMD at the L-spine, total hip, or femoral neck between men getting the recommended vs. short sleep duration, using actigraphy or self-reported sleep duration (all p ≥ 0.07). When sleep duration was considered as a continuous variable, femoral neck BMD was higher in men with longer self-reported sleep duration (β = 0.006 ±0.003, p = 0.02), but this was not significant after further adjustment. In men with low 25OHD (< 20 ng/mL), longer actigraphy-determined sleep duration was associated with higher total hip BMD (β = 0.016 ± 0.008; p = 0.04). Sleep duration and BTMs were not associated.

CONCLUSION

Sleep duration was not associated with hip or L-spine BMD or BTMs in older men. Future research should determine if vitamin D status or other factors modify this relationship.

Subregional statistical shape modelling identifies lesser trochanter size as a possible risk factor for radiographic hip osteoarthritis, a cross-sectional analysis from the Osteoporotic Fractures in Men Study

OBJECTIVE

Statistical shape modelling (SSM) of hip dual-energy X-ray absorptiometry (DXA) scans has identified relationships between hip shape and radiographic hip OA (rHOA). We aimed to further elucidate shape characteristics related to rHOA by focusing on subregions identified from whole-hip shape models.

METHOD

SSM was applied to hip DXAs obtained in the Osteoporotic Fractures in Men Study. Whole-hip shape modes (HSMs) associated with rHOA were combined to form a composite at-risk-shape. Subsequently, subregional HSMs (cam-type and lesser trochanter modes) were built, and associations with rHOA were examined by logistic regression. Subregional HSMs were further characterised, by examining associations with 3D-HSMs derived from concurrent hip CT scans.

RESULTS

4,098 participants were identified with hip DXAs and radiographs. Composite shapes from whole-hip HSMs revealed that lesser trochanter size and cam-type femoral head are related to rHOA. From sub-regional models, lesser trochanter mode (LTM)1 [OR 0.74; 95%CI 0.63.0.87] and cam-type mode (CTM)3 [OR 1.27; 1.13.1.42] were associated with rHOA, associations being similar to those for whole hip HSMs. 515 MrOS participants had hip DXAs and 3D-HSMs derived from hip CT scans. LTM1 was associated with 3D-HSMs that also represented a larger lesser trochanter [3D-HSM7 (beta (β)-0.23;-0.33,-0.14) and 3D-HSM9 (β0.36; 0.27.0.45)], and CTM3 with 3D-HSMs describing cam morphology [3D-HSM3 (β-0.16;-0.25,-0.07) and 3D-HSM6 (β 0.19; 0.10.0.28)].

CONCLUSION

Subregional SSM of hip DXA scans suggested larger lesser trochanter and cam morphology underlie associations between overall hip shape and rHOA. 3D hip modelling suggests our subregional SSMs represent true anatomical variations in hip shape, warranting further investigation.

Low Protein Intake Irrespective of Source is Associated with Higher Mortality Among Older Community-dwelling Men

OBJECTIVES

Our aim was to determine the association between protein intake (overall and by source) and all-cause and cause-specific mortality among older men.

DESIGN

Prospective cohort study.

SETTING

5790 ambulatory community-dwelling older men from multicenter Osteoporotic Fractures in Men (MrOS) study.

MEASUREMENTS

Total energy and protein intake, and protein intake by source (dairy, non-dairy animal, plant) were assessed using a 69-item food frequency questionnaire. We included up to 10-year follow-up with adjudicated cardiovascular, cancer and other mortality outcomes. We used time-to-event analysis with protein exposures, mortality outcome, and adjusted for possible confounders including age, center, education, race, smoking, alcohol use, physical activity, weight, total energy intake (TEI), and comorbidities. Hazard ratios were expressed per each unit=2.9% TEI decrement for all protein intake variables.

RESULTS

The mean (SD) baseline age of 5790 men was 73.6 (5.8) y. There were 1611 deaths and 211 drop-outs prior to 10 years, and 3868 men who were alive at the 10-year follow-up. The mean (SD) total protein intake was 64.7 (25.8) g/d, while the mean (SD) intake expressed as percent of total energy intake (%TEI) was 16.1 (2.9) %TEI. Lower protein intake was associated with an increased risk of death, with unadjusted HR=1.11 (95% CI: 1.06, 1.17) and adjusted HR=1.09 (95% CI: 1.04, 1.14) and the associations for protein intake by source were similar. The adjusted HR for cancer mortality was HR=1.13 (95% CI: 1.03, 1.25) while the association for CVD mortality was HR=1.08 (95% CI: 0.99, 1.18).

CONCLUSIONS

Low protein intake, irrespective of source, was associated with a modest increase in risk of all-cause and cause-specific mortality among older men. Special consideration should be given to level of protein intake among older adults.

Tropomyosin-related kinase A (TrkA) inhibition for the treatment of painful knee osteoarthritis: results from a randomized controlled phase 2a trial

OBJECTIVE

To investigate the TrkA inhibitor, ASP7962, for treatment of painful knee osteoarthritis.

DESIGN

Phase 2a, double-blind, placebo- and naproxen-controlled, double-dummy, parallel-group study. Adults with knee osteoarthritis were randomized (2:2:1) to ASP7962 (100 mg), placebo, or naproxen (500 mg) twice daily (BID) for 4 weeks. Primary endpoint: change from baseline to Week 4 in Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain subscale score. Secondary endpoints: change from baseline to Weeks 1, 2, and End of Treatment (EoT) in WOMAC pain subscale score; change from baseline to Weeks 1, 2, 4, and EoT in WOMAC physical function and stiffness subscales, walking pain and WOMAC total scores; and change from baseline in daily average pain score.

RESULTS

215 participants were randomized (ASP7962 100 mg BID, n = 85; placebo, n = 87; naproxen 500 mg BID, n = 43). No significant difference was observed between ASP7962 and placebo in change from baseline to Week 4 in WOMAC pain subscale score (-0.14; 90% 2-sided CI: -0.62, 0.34; P = 0.316); a significant difference was observed between naproxen and placebo (-0.67; 80% 2-sided CI: -1.12, -0.23; P = 0.027). No differences were observed between ASP7962 and placebo in change from baseline in any WOMAC subscale score; statistically significant changes were observed between naproxen and placebo (P ≤ 0.01, all time points for all WOMAC endpoints). ASP7962 was safe and well-tolerated.

CONCLUSIONS

Four-week treatment with ASP7962 (100 mg BID) did not improve pain or physical function in individuals with painful knee osteoarthritis. ClinicalTrials.gov, NCT02611466; EudraCT Number, 2014-004996-22.

Intra-articular corticosteroids and the risk of knee osteoarthritis progression: results from the Osteoarthritis Initiative

OBJECTIVE

A recent randomized clinical trial reported that repeated intra-articular corticosteroids (IACs) were associated with a greater cartilage loss. This study aimed to examine the relation of IACs to knee radiographic osteoarthritis (ROA) progression in a real-world setting.

DESIGN

A cohort that initiated IACs and a comparison cohort without IACs from participants with mild to moderate knee ROA in the Osteoarthritis Initiative (OAI) were assembled (from 0-month to 48-month). Two measures of knee ROA progression were assessed during the follow-up period: (1) an increase in Kellgren and Lawrence (KL) grade by ≥1 grade or having a knee replacement (i.e., KL grade worsening); and (2) a decrease in joint space width (JSW) by ≥0.7 mm or having a knee replacement (i.e., JSW worsening). The associations of IACs initiation using a propensity-score matched cohort study and continuous IACs using marginal structural models with the risk of knee ROA progression were examined.

RESULTS

Among 684 propensity-score matched participants at baseline (148 IACs initiators, 536 comparators), 65 knees (21.7/100 person-years) in the IACs initiation cohort and 90 knees (7.1/100 person-years) in the comparison cohort experienced KL worsening. The hazard ratios (HRs) of KL worsening from IACs initiation and continuous IACs were 3.02 (95% confidence interval [CI], 2.19-4.16) and 4.67 (95% CI, 2.92-7.47), respectively. The corresponding HRs of JSW worsening were 2.93 (95% CI, 2.13-4.02) and 3.26 (95% CI, 1.78-5.96), respectively. All HRs for continuous use of IACs were further away from the null.

CONCLUSIONS

IACs, especially continuous IACs, may be associated with an increased risk of knee ROA progression.

Inhibition of vascular endothelial growth factor in young adult mice causes low bone blood flow and bone strength with no effect on bone mass in trabecular regions

Objective

To determine the effect of an antibody to vascular endothelial growth factor (VEGF) on bone blood flow, bone strength, and bone mass in the young adult mouse.

Methods

Ten-week-old male BALB/cJ mice were body weight-randomized into either a rodent anti-VEGF monoclonal antibody (anti-VEGF, B20-4.1.1; 5 mg/kg 2×/wk.; n = 12) group or a vehicle (VEH; n = 12) group. After 42 days, mice were evaluated for bone blood flow at the distal femur by ¹⁸F-NaF-PET/CT and then necropsied. Samples from trabecular and cortical bone regions were evaluated for bone strength by mechanical testing, bone mass by peripheral quantitative computed tomography (pQCT), and micoarchitecture (MicroCT). Hydration of the whole femur was studied by proton nuclear magnetic resonance relaxometry (¹H NMR).

Results

Distal femur blood flow was 43% lower in anti-VEGF mice than in VEH mice (p = 0.009). Ultimate load in the lumbar vertebral body was 25% lower in anti-VEGF than in VEH mice (p = 0.013). Bone mineral density (BMD) in the trabecular region of the proximal humeral metaphysis by pQCT, and bone volume fraction and volumetric BMD by MicroCT were the same in the two groups. Volume fraction of bound water (BW) of the whole femur was 14% lower in anti-VEGF than in VEH mice (p = 0.003). Finally, BW, but not cortical tissue mineral density, helped section modulus explain the variance in the ultimate moment experienced by the femur in three-point bending.

Conclusion

Anti-VEGF caused low bone blood flow and bone strength in trabecular bone regions without influencing BMD and microarchitecture. Low bone strength was also associated with low bone hydration. These data suggest that bone blood flow is a novel bone property that affects bone quality.

•

An antibody to vascular endothelial growth factor (anti-VEGF) caused low bone blood flow in a trabecular bone rich region.

•

Anti-VEGF did not affect trabecular bone region and bone hydration of the whole femur were also low, trabecular bone mass was not affected by anti-VEGF.

•

Bone blood flow may be a bone property that affects bone quality through bone hydration.

•

Anti-VEGF caused low trabecular bone strength in the vertebral body and low bone hydration of the whole femur.

Risk factor heterogeneity for medial and lateral compartment knee osteoarthritis: analysis of two prospective cohorts

OBJECTIVE

To evaluate the etiologic heterogeneity between medial and lateral tibiofemoral radiographic osteoarthritis (ROA).

METHODS

Knees without medial or lateral tibiofemoral ROA at baseline were followed for 60-month in Multicenter Osteoarthritis Study (MOST) and for 48-month in Osteoarthritis Initiative (OAI). We examined the relation of previously reported risk factors to incident medial and lateral tibiofemoral ROA separately and determined the etiology heterogeneity with a ratio of rate ratios (RRs) (i.e., the RR for medial tibiofemoral ROA divided by the RR for lateral tibiofemoral ROA) using a duplication method for Cox proportional hazard regression.

RESULTS

Of 2,016 participants in MOST, 436 and 162 knees developed medial or lateral tibiofemoral ROA, respectively. Obesity and varus malalignment were 95% and 466% more strongly associated with incident medial tibiofemoral ROA than with lateral tibiofemoral ROA, respectively (ratios of RRs, 1.95 [95% confidence interval (CI):1.05-3.62] and 5.66 [95% CI:3.20-10.0]). In contrast, the associations of female sex and valgus malalignment with incident medial tibiofemoral ROA were weaker or in an opposite direction compared with lateral tibiofemoral Osteoarthritis (OA) (ratios of RRs, 0.40 [95% CI:0.26-0.63] and 0.20 [95% CI:0.12-0.34], respectively). Older age tended to show a weaker association with incident medial tibiofemoral ROA than with incident lateral tibiofemoral ROA. No heterogeneity was observed for the relation of race, knee injury, or contralateral knee ROA. These findings were closely replicated in OAI.

CONCLUSION

Risk factor profiles for medial and lateral tibiofemoral ROA are different. These results can provide a framework for the development of targeted prevention and potential treatment strategies for specific knee OA subtypes.

Incident fracture is associated with a period of accelerated loss of hip BMD: the Study of Osteoporotic Fractures

Bone loss following a fracture could increase the risk of future fractures. In this study, we found that elderly women who had an upper body fracture or multiple fractures lost more bone at the hip than those who did not fracture. This suggests a possible systemic bone loss response initiated by fracture.

INTRODUCTION

A prior fracture is one of the strongest predictors of subsequent fracture risk, but the etiology of this phenomenon remains unclear. Systemic bone loss post-fracture could contribute to increased risk of subsequent fractures. Therefore, in this study, we investigated whether incident fractures, including those distant to the hip, are associated with accelerated loss of hip bone mineral density (BMD) in elderly women.

METHODS

We analyzed data from 3956 Caucasian women aged ≥ 65 years who were enrolled in the Study of Osteoporotic Fractures and completed hip BMD measurements at study visit 4 (year 6) and visit 6 (year 10). Clinical fractures between visits 4 and 6 were ascertained from triannual questionnaires and centrally adjudicated by review of community radiographic reports. Subjects provided questionnaire information and clinical variables at examinations for known and potential covariates. Generalized linear models were used to calculate average annual percent change in total hip BMD between visits 4 and 6 for each incident fracture type and for upper body and lower body fractures combined. A subset of women (n = 3783) was analyzed for annual total hip BMD change between study visits 4 and 5 and between study visits 5 and 6 to evaluate change in total hip BMD during these 2-year intervals.

RESULTS

Women with incident upper body fracture or incident lower body fracture exhibited reductions in total hip BMD of 0.89 and 0.77% per year, respectively, while women who did not fracture exhibited reductions in total hip BMD of 0.66% per year during the 4-year period. Accelerated loss of hip BMD was isolated to the 2-year time interval that included the fracture. Loss of total hip BMD was not affected by the number of days from fracture to follow up DXA.

CONCLUSIONS

Systemic bone loss following fracture may increase the risk of future fractures at all skeletal sites. There is a need for improved understanding of mechanisms leading to apparent accelerated bone loss following a fracture in order to reduce subsequent fracture risk.

Weight loss in men in late life and bone strength and microarchitecture: a prospective study

Weight loss in men in late life was associated with lower bone strength. In contrast, weight gain was not associated with a commensurate increase in bone strength. Future studies should measure concurrent changes in weight and parameters of bone strength and microarchitecture and evaluate potential causal pathways underlying these associations.

INTRODUCTION

Our aim was to determine associations of weight loss with bone strength and microarchitecture.

METHODS

We used data from 1723 community-dwelling men (mean age 84.5 years) who attended the MrOS study Year (Y) 14 exam and had high-resolution peripheral quantitative computed tomography (HR-pQCT) scans at ≥ 1 skeletal sites (distal tibia, distal radius, or diaphyseal tibia). Weight change from Y7 to Y14 exams (mean 7.3 years between exams) was classified as moderate weight loss (loss ≥ 10%), mild weight loss (loss 5 to < 10%), stable weight (< 5% change), or weight gain (gain ≥ 5%). Mean HR-pQCT parameters (95%CI) were calculated by weight change category using linear regression models adjusted for age, race, site, health status, body mass index, limb length, and physical activity. The primary outcome measure was estimated failure load.

RESULTS

There was a nonlinear association of weight change with failure load at each skeletal site with different associations for weight loss vs. weight gain (p < 0.03). Failure load and total bone mineral density (BMD) at distal sites were lower with greater weight loss with 7.0-7.6% lower failure loads and 4.3-5.8% lower BMDs among men with moderate weight loss compared to those with stable weight (p < 0.01, both comparisons). Cortical, but not trabecular, BMDs at distal sites were lower with greater weight loss. Greater weight loss was associated with lower cortical thickness at all three skeletal sites.

CONCLUSION

Weight loss in men in late life is associated with lower peripheral bone strength and total BMD with global measures reflecting cortical but not trabecular parameters.

Dietary patterns and longitudinal change in hip bone mineral density among older men

Studying dietary patterns is often more informative than individual nutrients or foods. We found that a Prudent dietary pattern (rich in vegetables and fish) was associated with reduced loss of total hip BMD in older men. A Prudent dietary pattern may be a potential lifestyle strategy for minimizing bone loss.

INTRODUCTION

This study aimed to identify baseline dietary patterns using factor analysis in a cohort of older men and to evaluate whether the dietary patterns were associated with bone mineral density change (%ΔBMD) at the total hip and femoral neck over time.

METHODS

Participants (n = 4379; mean age 72.9 ± 5.5 years) were from the Osteoporotic Fractures in Men (MrOS) prospective cohort study and had dietary data collected at baseline (March 2000-April 2002) and BMD measured at baseline and Visit 2 (March 2005-May 2006). Dietary intake was assessed with a brief Block food frequency questionnaire (FFQ); factor analysis was used to derive dietary patterns. BMD was measured by dual-energy x-ray absorptiometry (DXA); %ΔBMD was calculated from baseline to Visit 2. We used generalized linear regression to estimate least square (LS) means of %ΔBMD in quartiles of the dietary pattern scores adjusted for potential confounding factors.

RESULTS

Two major dietary patterns were derived: Prudent (abundant in vegetables, salad, and non-fried fish) and Western (rich in hamburger, fries, processed meats, cheese, and sweets/desserts). There was an inverse association between adherence to the Prudent pattern and total hip %ΔBMD (p-trend = 0.028 after adjusting for age and clinical site; p-trend = 0.033 after further adjustment for smoking, calcium supplement use, diabetes, hypertension, and total energy intake). No other consistent associations between dietary patterns and %ΔBMD were observed.

CONCLUSIONS

Greater adherence to a Prudent dietary pattern may attenuate total hip BMD loss (%ΔBMD) in older men.

A small-molecule inhibitor of the Wnt pathway (SM04690) as a potential disease modifying agent for the treatment of osteoarthritis of the knee

OBJECTIVES

Osteoarthritis (OA) is a degenerative disease characterized by loss of cartilage and increased subchondral bone within synovial joints. Wnt signaling affects the pathogenesis of OA as this pathway modulates both the differentiation of osteoblasts and chondrocytes, and production of catabolic proteases. A novel small-molecule Wnt pathway inhibitor, SM04690, was evaluated in a series of in vitro and in vivo animal studies to determine its effects on chondrogenesis, cartilage protection and synovial-lined joint pathology.

DESIGN

A high-throughput screen was performed using a cell-based reporter assay for Wnt pathway activity to develop a small molecule designated SM04690. Its properties were evaluated in bone-marrow-derived human mesenchymal stem cells (hMSCs) to assess chondrocyte differentiation and effects on cartilage catabolism by immunocytochemistry and gene expression, and glycosaminoglycan breakdown. In vivo effects of SM04690 on Wnt signaling, cartilage regeneration and protection were measured using biochemical and histopathological techniques in a rodent acute cruciate ligament tear and partial medial meniscectomy (ACLT + pMMx) OA model.

RESULTS

SM04690 induced hMSC differentiation into mature, functional chondrocytes and decreased cartilage catabolic marker levels compared to vehicle. A single SM04690 intra-articular (IA) injection was efficacious in a rodent OA model, with increased cartilage thickness, evidence for cartilage regeneration, and protection from cartilage catabolism observed, resulting in significantly improved Osteoarthritis Research Society International (OARSI) histology scores and biomarkers, compared to vehicle.

CONCLUSIONS

SM04690 induced chondrogenesis and appeared to inhibit joint destruction in a rat OA model, and is a candidate for a potential disease modifying therapy for OA.

Targeted spine strengthening exercise and posture training program to reduce hyperkyphosis in older adults: results from the study of hyperkyphosis, exercise, and function (SHEAF) randomized controlled trial

A 6-month randomized controlled trial of spine-strengthening exercise and posture training reduced both radiographic and clinical measures of kyphosis. Participants receiving the intervention improved self-image and satisfaction with their appearance. Results suggest that spine-strengthening exercise and postural training may be an effective treatment option for older adults with hyperkyphosis.

INTRODUCTION

The purpose of the present study is to determine in a randomized controlled trial whether spine-strengthening exercises improve Cobb angle of kyphosis in community-dwelling older adults.

METHODS

We recruited adults ≥60 years with kyphosis ≥40° and enrolled 99 participants (71 women, 28 men), mean age 70.6 ± 0.6 years, range 60-88, with baseline Cobb angle 57.4 ± 12.5°. The intervention included group spine-strengthening exercise and postural training, delivered by a physical therapist, 1-h, three times weekly for 6 months. Controls received four group health education meetings. The primary outcome was change in the gold standard Cobb angle of kyphosis measured from standing lateral spine radiographs. Secondary outcomes included change in kyphometer-measured kyphosis, physical function (modified Physical Performance Test, gait speed, Timed Up and Go, Timed Loaded Standing, 6-Min Walk), and health-related quality of life (HRQoL) (PROMIS global health and physical function indexes, SRS-30 self-image domain). ANCOVA was used to assess treatment effects on change from baseline to 6 months in all outcomes.

RESULTS

There was a -3.0° (95% CI -5.2, -0.8) between-group difference in change in Cobb angle, p = 0.009, favoring the intervention and approximating the magnitude of change from an incident vertebral fracture. Kyphometer-measured kyphosis (p = 0.03) and SRS-30 self-esteem (p < 0.001) showed favorable between-group differences in change, with no group differences in physical function or additional HRQoL outcomes, p > 0.05.

CONCLUSIONS

Spine-strengthening exercise and posture training over 6 months reduced kyphosis compared to control. Our randomized controlled trial results suggest that a targeted kyphosis-specific exercise program may be an effective treatment option for older adults with hyperkyphosis.

TRIAL REGISTRATION NUMBER AND NAME OF TRIAL REGISTER

ClinicalTrials.gov; identifier NCT01751685.

A novel Wnt pathway inhibitor, SM04690, for the treatment of moderate to severe osteoarthritis of the knee: results of a 24-week, randomized, controlled, phase 1 study

OBJECTIVE

To assess the safety, pharmacokinetics, and exploratory efficacy of SM04690, a novel Wnt pathway inhibitor, as a potential disease modifying treatment for knee osteoarthritis (OA).

DESIGN

Subjects with Kellgren-Lawrence grade 2-3 knee OA were randomized in successive dose-escalation cohorts to receive a knee intra-articular (IA) injection with 0.03, 0.07, or 0.23 mg SM04690, or placebo (PBO) (4:1 ratio). Safety, pharmacokinetics, efficacy (WOMAC Total/Function/Pain, Pain VAS, Physician Global Assessment [MDGA], and OMERACT-OARSI Response), OA-related biomarker (P1NP, ß-CTX, and cartilage oligomeric matrix protein [COMP]), and radiographic/imaging data were collected at baseline and during 24-week follow-up.

RESULTS

61 subjects (SM04690 n = 50; PBO n = 11) enrolled. Two dose limiting toxicities (DLTs), increased pain following injection and paroxysmal tachycardia (also the single serious AE), were reported in the 0.07 mg cohort. A total of 72 AEs were reported; Sixteen (occurring in eight subjects) were considered related to study medication. There were three discontinuations; one due to an AE (0.03 mg cohort). Bone marrow edema (BME) remained constant for most subjects. No doses were excluded from further study due to DLT criteria. Plasma levels of SM04690 were below the limit of detection at all time points. At Week 24, improvements from baseline were seen in all cohorts for the exploratory measures WOMAC Total, WOMAC Function, WOMAC Pain, MDGA, Pain VAS, and OMERACT-OARSI response. Joint space width (JSW) improvement was observed in the 0.07 mg cohort (P = 0.02 vs PBO).

CONCLUSION

SM04690 appeared safe and well tolerated, with no evidence of systemic exposure. Exploratory efficacy analyses suggested positive trends for measurements of OA pain, function and disease-modifying osteoarthritis drug (DMOAD) properties. CLINICALTRIALS.

GOV REGISTRATION

NCT02095548.

Cryoneurolysis to treat the pain and symptoms of knee osteoarthritis: a multicenter, randomized, double-blind, sham-controlled trial

OBJECTIVE

Evaluate the efficacy and safety/tolerability of cryoneurolysis for reduction of pain and symptoms associated with knee osteoarthritis (OA).

DESIGN

Randomized, double-blind, sham-controlled, multicenter trial with a 6-month follow-up in patients with mild-to-moderate knee OA. Patients were randomized 2:1 to cryoneurolysis targeting the infrapatellar branch of the saphenous nerve (IPBSN) or sham treatment. The primary endpoint was the change from baseline to Day 30 in the Western Ontario and McMaster Osteoarthritis Index (WOMAC) pain score adjusted by the baseline score and site. Secondary endpoints, including visual analogue scale (VAS) pain score and total WOMAC score, were tested in a pre-defined order.

RESULTS

The intent-to-treat (ITT) population consisted of 180 patients (n = 121 active treatment, n = 59 sham treatment). Compared to the sham group, patients who received active treatment had a statistically significant greater change from baseline in the WOMAC pain subscale score at Day 30 (P = 0.0004), Day 60 (P = 0.0176), and Day 90 (P = 0.0061). Patients deemed WOMAC pain responders at Day 120 continued to experience a statistically significant treatment effect at Day 150. Most expected side effects were mild in severity and resolved within 30 days. The incidence of device- or procedure-related adverse events was similar in the two treatment groups with no occurrence of serious or unanticipated adverse device effects (ADE).

CONCLUSIONS

Cryoneurolysis of the IPBSN resulted in statistically significant decreased knee pain and improved symptoms compared to sham treatment for up to 150 days, and appeared safe and well tolerated.

Osteoarthritis year in review 2016: clinical

Both epidemiologic and clinical research continues to be performed in osteoarthritis (OA). While epidemiologic studies identify risk factors for incident and progressive disease, clinical studies explore the role of both non-pharmacologic and pharmacologic treatments, including oral and intra-articular therapies. We performed a systematic review of the literature using PubMed for the time period between April 1, 2015 to February 22, 2016. Selected publications in the areas of both epidemiology and treatment are reviewed in this article.

Biologic therapies and bone loss in rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a common systemic autoimmune disease of unknown cause, characterized by a chronic, symmetric, and progressive inflammatory polyarthritis. One of the most deleterious effects induced by the chronic inflammation of RA is bone loss. During the last 15 years, the better knowledge of the cytokine network involved in RA allowed the development of potent inhibitors of the inflammatory process classified as biological DMARDs. These new drugs are very effective in the inhibition of inflammation, but there are only few studies regarding their role in bone protection. The principal aim of this review was to show the evidence of the principal biologic therapies and bone loss in RA, focusing on their effects on bone mineral density, bone turnover markers, and fragility fractures.

METHODS

Using the PICOST methodology, two coauthors (PC, LM-S) conducted the search using the following MESH terms: rheumatoid arthritis, osteoporosis, clinical trials, TNF- antagonists, infliximab, adalimumab, etanercept, certolizumab, golimumab, IL-6 antagonists, IL-1 antagonists, abatacept, tocilizumab, rituximab, bone mineral density, bone markers, and fractures. The search was conducted electronically and manually from the following databases: Medline and Science Direct. The search period included articles from 2003 to 2015. The selection included only original adult human research written in English. Titles were retrieved and the same two authors independently selected the relevant studies for a full text. The retrieved selected studies were also reviewed completing the search for relevant articles. The first search included 904 titles from which 253 titles were selected. The agreement on the selection among researchers resulted in a Kappa statistic of 0.95 (p < 0.000). Only 248 abstracts evaluated were included in the acronym PICOST. The final selection included only 28 studies, derived from the systematic search. Additionally, a manual search in the bibliography of the selected articles was made and included into the text and into the section of "small molecules of new agents."

CONCLUSION

Treatment with biologic drugs is associated with the decrease in bone loss. Studies with anti-TNF blocking agents show preservation or increase in spine and hip BMD and also a better profile of bone markers. Most of these studies were performed with infliximab. Only three epidemiological studies analyzed the effect on fractures after anti-TNF blocking agent's treatment. IL-6 blocking agents also showed improvement in localized bone loss not seen with anti-TNF agents. There are a few studies with rituximab and abatacept. Although several studies reported favorable actions of biologic therapies on bone protection, there are still unmet needs for studies regarding their actions on the risk of bone fractures.

Novel statistical methodology reveals that hip shape is associated with incident radiographic hip osteoarthritis among African American women

INTRODUCTION

Hip shape is a risk factor for the development of hip osteoarthritis (OA), and current methods to assess hip shape from radiographs are limited; therefore this study explored current and novel methods to assess hip shape.

METHODS

Data from a prior case-control study nested in the Johnston County OA Project were used, including 382 hips (from 342 individuals). Hips were classified by radiographic hip OA (RHOA) status as RHOA cases (baseline Kellgren Lawrence grade [KLG] 0 or 1, follow-up [mean 6 years] KLG ≥ 2) or controls (KLG = 0 or 1 at both baseline and follow-up). Proximal femur shape was assessed using a 60-point model as previously described. The current analysis explored commonly used principal component analysis (PCA), as well as novel statistical methodologies suited to high dimension low sample size settings (Distance Weighted Discrimination [DWD] and Distance Projection Permutation [DiProPerm] hypothesis testing) to assess differences between cases and controls.

RESULTS

Using these novel methodologies, we were able to better characterize morphologic differences by sex and race. In particular, the proximal femurs of African American women demonstrated significantly different shapes between cases and controls, implying an important role for sex and race in the development of RHOA. Notably, discrimination was improved with the use of DWD and DiProPerm compared to PCA.

CONCLUSIONS

DWD with DiProPerm significance testing provides improved discrimination of variation in hip morphology between groups, and enables subgroup analyses even under small sample sizes.

Do persons with asymmetric hip pain or radiographic hip OA have worse pain and structure outcomes in the knee opposite the more affected hip? Data from the Osteoarthritis Initiative

PURPOSE

To determine if asymmetry between hips in pain or radiographic osteoarthritis (RHOA) is associated with worse pain and joint space narrowing (JSN) at baseline and longitudinally in knees contralateral to more affected hips.

METHODS

We studied 279 participants in the Osteoarthritis Initiative with baseline asymmetry between hips in pain and 483 with asymmetry in RHOA none of whom had a hip replacement for ≥4 years after baseline. RHOA assessed from pelvis radiographs was categorized as none, possible or definite and hip pain on most days of a month in the past year as present/absent. Knee pain (WOMAC scale) and JSN (fixed flexion radiographs) were categorized as none, mild and moderate-severe. We compared knees contralateral and ipsilateral to more affected hips on baseline knee pain and JSN using clustered multinomial regression and on change in knee pain and JSN over 4-5 years using generalized linear and logistic estimating equations.

RESULTS

Knees contralateral to painful hips had less baseline pain ("moderate-severe" vs "none", relative risk ratio [RRR]: 0.39, 95% CI = 0.27-0.57), but greater baseline JSN ("moderate-severe" vs "none", RRR: 1.62, 95% CI = 1.09-2.38) and greater worsening of pain during follow-up (P = 0.001). Knees contralateral to hips with worse RHOA had nonsignificant trends for greater baseline JSN (P = 0.10) and JSN progression (P = 0.17).

CONCLUSION

These findings provide limited support for the hypothesis that early asymmetry in hip pain and RHOA is associated with worse pain and structural outcomes in knees contralateral to the more affected hip.

Thoracic kyphosis and rate of incident vertebral fractures: the Fracture Intervention Trial

SUMMARY

Biomechanical analyses support the theory that thoracic spine hyperkyphosis may increase risk of new vertebral fractures. While greater kyphosis was associated with an increased rate of incident vertebral fractures, our analysis does not show an independent association of kyphosis on incident fracture, after adjustment for prevalent vertebral fracture. Excessive kyphosis may still be a clinical marker for prevalent vertebral fracture.

INTRODUCTION

Biomechanical analyses suggest hyperkyphosis may increase risk of incident vertebral fracture by increasing the load on vertebral bodies during daily activities. We propose to assess the association of kyphosis with incident radiographic vertebral fracture.

METHODS

We used data from the Fracture Intervention Trial among 3038 women 55-81 years of age with low bone mineral density (BMD). Baseline kyphosis angle was measured using a Debrunner kyphometer. Vertebral fractures were assessed at baseline and follow-up from lateral radiographs of the thoracic and lumbar spine. We used Poisson models to estimate the independent association of kyphosis with incident fracture, controlling for age and femoral neck BMD.

RESULTS

Mean baseline kyphosis was 48° (SD = 12) (range 7-83). At baseline, 962 (32%) participants had a prevalent fracture. There were 221 incident fractures over a median of 4 years. At baseline, prevalent fracture was associated with 3.7° greater average kyphosis (95% CI 2.8-4.6, p < 0.0005), adjusting for age and femoral neck BMD. Before adjusting for prevalent fracture, each 10° greater kyphosis was associated with 22% increase (95% CI 8-38%, p = 0.001) in annualized rate of new radiographic vertebral fracture, adjusting for age and femoral neck BMD. After additional adjustment for prevalent fracture, estimated increased annualized rate was attenuated and no longer significant, 8% per 10° kyphosis (95% CI -4 to 22%, p = 0.18).

CONCLUSIONS

While greater kyphosis increased the rate of incident vertebral fractures, our analysis does not show an independent association of kyphosis on incident fracture, after adjustment for prevalent vertebral fracture. Excessive kyphosis may still be a clinical marker for prevalent vertebral fracture.

Sclerostin-antibody treatment of glucocorticoid-induced osteoporosis maintained bone mass and strength

This study was to determine if antibody against sclerostin (Scl-Ab) could prevent glucocorticoid (GC)-induced osteoporosis in mice. We found that Scl-Ab prevented GC-induced reduction in bone mass and bone strength and that the anabolic effects of Scl-Ab might be partially achieved through the preservation of osteoblast activity through autophagy.

INTRODUCTION

Glucocorticoids (GCs) inhibit bone formation by altering osteoblast and osteocyte cell activity and lifespan. A monoclonal antibody against sclerostin, Scl-Ab, increased bone mass in both preclinical animal and clinical studies in subjects with low bone mass. The objectives of this study were to determine if treatment with the Scl-Ab could prevent loss of bone mass and strength in a mouse model of GC excess and to elucidate if Scl-Ab modulated bone cell activity through autophagy.

METHODS

We generated reporter mice that globally expressed dsRed fused to LC3, a protein marker for autophagosomes, and evaluated the dose-dependent effects of GCs (0, 0.8, 2.8, and 4 mg/kg/day) and Scl-Ab on autophagic osteoblasts, bone mass, and bone strength.

RESULTS

GC treatment at 2.8 and 4 mg/kg/day of methylprednisolone significantly lowered trabecular bone volume (Tb-BV/TV) at the lumbar vertebrae and distal femurs, cortical bone mass at the mid-shaft femur (FS), and cortical bone strength compared to placebo (PL). In mice treated with GC and Scl-Ab, Tb-BV/TV increased by 60-125 %, apparent bone strength of the lumbar vertebrae by 30-70 %, FS-BV by 10-18 %, and FS-apparent strength by 13-15 %, as compared to GC vehicle-treated mice. GC treatment at 4 mg/kg/day reduced the number of autophagic osteoblasts by 70 % on the vertebral trabecular bone surface compared to the placebo group (PL, GC 0 mg), and GC + Scl-Ab treatment.

CONCLUSIONS

Treatment with Scl-Ab prevented GC-induced reduction in both trabecular and cortical bone mass and strength and appeared to maintain osteoblast activity through autophagy.

OARSI Clinical Trials Recommendations: Design and conduct of clinical trials for hip osteoarthritis

The ability to assess the efficacy and effectiveness of an intervention for the treatment of hip osteoarthritis (OA) requires strong clinical trial methodology. This consensus paper provides recommendations based on a narrative literature review and best judgment of the members of the committee for clinical trials of hip OA. We provide recommendations on clinical trial design, outcome measures, including structural (radiography), and patient and physician global assessments, performance based measures, molecular markers and experimental endpoints including MRI imaging. This information can be utilized by sponsors of trials for new therapeutic agents for hip OA.

PINP as a biological response marker during teriparatide treatment for osteoporosis

Postmenopausal women with severe osteoporosis may require treatment with the bone anabolic drug teriparatide. While changes in bone mineral density (BMD) are one measure of response, BMD changes often require a minimum of one year to observe measureable changes. Biochemical markers of bone turnover change within 1 to 3 months of initiating osteoporosis therapy. Monitoring with a marker such as procollagen type I N propeptide (PINP), an osteoblast-derived protein, during teriparatide treatment may provide clinically useful information for managing patients with osteoporosis. Clinical trials have shown consistent increases in PINP within 3 months of initiating teriparatide, increases that are significantly greater than placebo and significantly different from baseline. Increases in PINP concentrations during teriparatide treatment correlate well with increases in skeletal activity assessed by radioisotope bone scans and quantitative bone histomorphometry parameters. Individuals treated with teriparatide in clinical trials usually experienced an increase in PINP > 10 mcg/L from baseline, while those given placebo usually did not. In the clinical setting, patients experiencing a significant increase in PINP > 10 mcg/L after initiating teriparatide therapy may receive an earlier confirmation of anabolic effect, while those who do not may be assessed for adherence, proper injection technique, or undetected secondary conditions that might mitigate an anabolic response. PINP monitoring may provide information supplemental to BMD monitoring and be a useful aid in managing patients receiving anabolic osteoporosis treatment in the same way that biochemical markers of bone resorption are useful in monitoring antiresorptive therapy. This review examines PINP as a biological response marker during teriparatide treatment for osteoporosis.

Effects of sequential osteoporosis treatments on trabecular bone in adult rats with low bone mass

We used an osteopenic adult ovariectomized (OVX) rat model to evaluate various sequential treatments for osteoporosis, using FDA-approved agents with complementary tissue-level mechanisms of action. Sequential treatment for 3 months each with alendronate (Aln), followed by PTH, followed by resumption of Aln, created the highest trabecular bone mass, best microarchitecture, and highest bone strength.

INTRODUCTION

Individual agents used to treat human osteoporosis reduce fracture risk by ∼ 50-60%. As agents that act with complementary mechanisms are available, sequential therapies that mix antiresorptive and anabolic agents could improve fracture risk reduction, when compared with monotherapies.

METHODS

We evaluated bone mass, bone microarchitecture, and bone strength in adult OVX, osteopenic rats, during different sequences of vehicle (Veh), parathyroid hormone (PTH), Aln, or raloxifene (Ral) in three 90-day treatment periods, over 9 months. Differences among groups were evaluated. The interrelationships of bone mass and microarchitecture endpoints and their relationship to bone strength were studied.

RESULTS

Estrogen deficiency caused bone loss. OVX rats treated with Aln monotherapy had significantly better bone mass, microarchitecture, and bone strength than untreated OVX rats. Rats treated with an Aln drug holiday had bone mass and microarchitecture similar to the Aln monotherapy group but with significantly lower bone strength. PTH-treated rats had markedly higher bone endpoints, but all were lost after PTH withdrawal without follow-up treatment. Rats treated with PTH followed by Aln had better bone endpoints than those treated with Aln monotherapy, PTH monotherapy, or an Aln holiday. Rats treated initially with Aln or Ral, then switched to PTH, also had better bone endpoints, than monotherapy treatment. Rats treated with Aln, then PTH, and returned to Aln had the highest values for all endpoints.

CONCLUSION

Our data indicate that antiresorptive therapy can be coupled with an anabolic agent, to produce and maintain better bone mass, microarchitecture, and strength than can be achieved with any monotherapy.

The clinical diagnosis of osteoporosis: a position statement from the National Bone Health Alliance Working Group

Osteoporosis causes an elevated fracture risk. We propose the continued use of T-scores as one means for diagnosis but recommend that, alternatively, hip fracture; osteopenia-associated vertebral, proximal humerus, pelvis, or some wrist fractures; or FRAX scores with ≥3% (hip) or 20% (major) 10-year fracture risk also confer an osteoporosis diagnosis.

INTRODUCTION

Osteoporosis is a common disorder of reduced bone strength that predisposes to an increased risk for fractures in older individuals. In the USA, the standard criterion for the diagnosis of osteoporosis in postmenopausal women and older men is a T-score of  ≤ -2.5 at the lumbar spine, femur neck, or total hip by bone mineral density testing.

METHODS

Under the direction of the National Bone Health Alliance, 17 clinicians and clinical scientists were appointed to a working group charged to determine the appropriate expansion of the criteria by which osteoporosis can be diagnosed.

RESULTS

The group recommends that postmenopausal women and men aged 50 years should be diagnosed with osteoporosis if they have a demonstrable elevated risk for future fractures. This includes having a T-score of less than or equal to -2.5 at the spine or hip as one method for diagnosis but also permits a diagnosis for individuals in this population who have experienced a hip fracture with or without bone mineral density (BMD) testing and for those who have osteopenia by BMD who sustain a vertebral, proximal humeral, pelvic, or, in some cases, distal forearm fracture. Finally, the term osteoporosis should be used to diagnose individuals with an elevated fracture risk based on the World Health Organization Fracture Risk Algorithm, FRAX.

CONCLUSIONS

As new ICD-10 codes become available, it is our hope that this new understanding of what osteoporosis represents will allow for an appropriate diagnosis when older individuals are recognized as being at an elevated risk for fracture.

Individual magnetic resonance imaging and radiographic features of knee osteoarthritis in subjects with unilateral knee pain: the health, aging, and body composition study

OBJECTIVE

Strong associations between radiographic features of knee osteoarthritis (OA) and pain have been demonstrated in persons with unilateral knee symptoms. This study was undertaken to compare radiographic and magnetic resonance imaging (MRI) features of knee OA and assess their ability to discriminate between painful and nonpainful knees in persons with unilateral symptoms.

METHODS

The study population included 283 individuals ages 70-79 years with unilateral knee pain who were enrolled in the Health, Aging, and Body Composition Study, a study of weight-related diseases and mobility. Radiographs of both knees were read for Kellgren/Lawrence (K/L) grade and individual radiographic features, and 1.5T MRIs were assessed using the Whole-Organ Magnetic Resonance Imaging Score. The association between structural features and pain was assessed using a within-person case-control design and conditional logistic regression. Receiver operating characteristic (ROC) analysis was then used to test the discriminatory performance of structural features.

RESULTS

In conditional logistic analyses, knee pain was significantly associated with both radiographic features (any joint space narrowing grade ≥ 1) (odds ratio 3.20 [95% confidence interval 1.79-5.71]) and MRI features (any cartilage defect scored ≥ 2) (odds ratio 3.67 [95% confidence interval 1.49-9.04]). However, in most subjects, MRI revealed osteophytes and cartilage and bone marrow lesions in both knees, and using ROC analysis, no individual structural feature discriminated well between painful and nonpainful knees. The best-performing MRI feature (synovitis/effusion) was not significantly more informative than K/L grade ≥ 2 (P = 0.42).

CONCLUSION

In persons with unilateral knee pain, MRI and radiographic features were associated with knee pain, confirming that structural abnormalities in the knee have an important role in the etiology of pain. However, no single MRI or radiographic finding performed well in discriminating between painful and nonpainful knees. Further work is needed to examine how structural and nonstructural factors influence knee pain.

Changes in cortical bone response to high-fat diet from adolescence to adulthood in mice

Diabetic obesity is associated with increased fracture risk in adults and adolescents. We find in both adolescent and adult mice dramatically inferior mechanical properties and structural quality of cortical bone, in agreement with the human fracture data, although some aspects of the response to obesity appear to differ by age.

INTRODUCTION

The association of obesity with bone is complex and varies with age. Diabetic obese adolescents and adult humans have increased fracture risk. Prior studies have shown reduced mechanical properties as a result of high-fat diet (HFD) but do not fully address size-independent mechanical properties or structural quality, which are important to understand material behavior.

METHODS

Cortical bone from femurs and tibiae from two age groups of C57BL/6 mice fed either HFD or low-fat diet (LFD) were evaluated for structural and bone turnover changes (SEM and histomorphometry) and tested for bending strength, bending stiffness, and fracture toughness. Leptin, IGF-I, and non-enzymatic glycation measurements were also collected.

RESULTS

In both young and adult mice fed on HFD, femoral strength, stiffness, and toughness are all dramatically lower than controls. Inferior lamellar and osteocyte alignment also point to reduced structural quality in both age groups. Bone size was largely unaffected by HFD, although there was a shift from increasing bone size in obese adolescents to decreasing in adults. IGF-I levels were lower in young obese mice only.

CONCLUSIONS

While the response to obesity of murine cortical bone mass, bone formation, and hormonal changes appear to differ by age, the bone mechanical properties for young and adult groups are similar. In agreement with human fracture trends, adult mice may be similarly susceptible to bone fracture to the young group, although cortical bone in the two age groups responds to diabetic obesity differently.

Long-term open-label study of tanezumab for moderate to severe osteoarthritic knee pain

OBJECTIVE

This study was designed to evaluate the long-term safety and effectiveness of repeated doses of the humanized anti-nerve growth factor antibody, tanezumab, during open-label treatment of patients with OA knee pain.

DESIGN

The current study (clinicaltrials.gov identifier: NCT00399490) was a multicenter, phase II, open-label, multiple-dose extension of an earlier randomized clinical trial. All patients (N=281) received infusions of tanezumab 50μg/kg on Days 1 and 56 with subsequent doses administered at 8-week intervals (up to a total of eight infusions). The primary endpoint of this study was safety. Effectiveness evaluations included overall knee pain, Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index subscales, and subject global assessment (SGA) of response to therapy on 0-100 point visual analog scales.

RESULTS

Repeated administration of tanezumab resulted in a low incidence of treatment-related adverse events (AEs; 7.5%). The rate of serious AEs was also low (2.8%) with none considered treatment-related. Few AEs of abnormal peripheral sensation were reported; hypoesthesia was reported by nine patients (3.2%), paresthesia by seven patients (2.5%), and hyperesthesia, peripheral neuropathy, and sensory disturbance were each reported by one patient (0.4% for each). Most AEs of abnormal peripheral sensation were rated as mild (95%) and the majority (65%) resolved before study completion. At Week 8, overall knee pain and SGA improved from baseline by a mean (± standard error) of -12.8 (±1.78) and 8.0 (±1.66), respectively. Similar improvements occurred for WOMAC subscales.

CONCLUSIONS

Repeated injections of tanezumab in patients with moderate to severe knee OA provide continued pain relief and improved function with a low incidence of side effects. Additional studies to define the efficacy and duration of pain reduction and to provide a more complete assessment of long-term safety are warranted.

Insights into the genetic architecture of osteoarthritis from stage 1 of the arcOGEN study

Objectives

The genetic aetiology of osteoarthritis has not yet been elucidated. To enable a well-powered genome-wide association study (GWAS) for osteoarthritis, the authors have formed the arcOGEN Consortium, a UK-wide collaborative effort aiming to scan genome-wide over 7500 osteoarthritis cases in a two-stage genome-wide association scan. Here the authors report the findings of the stage 1 interim analysis.

Methods

The authors have performed a genome-wide association scan for knee and hip osteoarthritis in 3177 cases and 4894 population-based controls from the UK. Replication of promising signals was carried out in silico in five further scans (44 449 individuals), and de novo in 14 534 independent samples, all of European descent.

Results

None of the association signals the authors identified reach genome-wide levels of statistical significance, therefore stressing the need for corroboration in sample sets of a larger size. Application of analytical approaches to examine the allelic architecture of disease to the stage 1 genome-wide association scan data suggests that osteoarthritis is a highly polygenic disease with multiple risk variants conferring small effects.

Conclusions

Identifying loci conferring susceptibility to osteoarthritis will require large-scale sample sizes and well-defined phenotypes to minimise heterogeneity.

Bone mineral density and prevalent osteoarthritis of the hip in older men for the Osteoporotic Fractures in Men (MrOS) Study Group

SUMMARY

We evaluated the association of bone mineral density (BMD) and osteoarthritis (OA) of the hip in elderly men. We found that elderly men with moderate to severe radiographic hip OA (RHOA) had significantly higher areal BMD (aBMD) and volumetric BMD (vBMD) at both the lumbar spine and hip compared to age similar controls without OA.

INTRODUCTION

We evaluated the association of BMD measured by dual energy X-ray absorptiometry (DXA) and quantitative computerized tomography (integral, cortical, and trabecular vBMD) and RHOA in a cohort of elderly men.

METHODS

A cross-sectional analysis was conducted within the Study of Osteoporotic Fractures in Men, a prospective cohort study of 5,995 US men age > or = 65 years. Standing pelvic x-rays were done in 4,024 subjects and scored for prevalent RHOA severity. DXA was done in 3,886 subjects, and aBMD and vBMD associations were compared with RHOA score using linear regression, adjusting for covariates.

RESULTS

Both moderate and severe RHOA groups had significantly higher aBMD at all BMD sites (range, 3.7-10.0% difference; p value 0.0012 and p value < 0.005) compared to the control group with no RHOA. The difference remained strong after adjusting for covariates. While the total hip and lumbar spine cortical vBMD measurements of subjects with moderate or severe RHOA was increased compared to controls, trabecular vBMD was not.

CONCLUSION

Older men, with both moderate and severe RHOA, had significantly higher aBMD and integral vBMD at the hip and lumbar spine compared to controls without RHOA.

Association of 25-hydroxyvitamin D with prevalent osteoarthritis of the hip in elderly men: the osteoporotic fractures in men study

OBJECTIVE

To examine the cross-sectional association of serum levels of 25-hydroxyvitamin D, or 25(OH)D, with prevalent radiographic hip osteoarthritis (OA) in elderly men.

METHODS

In a cohort of 1,104 elderly men from the Osteoporotic Fractures in Men Study, 25(OH)D serum levels were determined by mass spectrometry, followed by pelvic radiographs approximately 4.6 years later. Categories of vitamin D levels were defined as follows: deficiency as < or =15 ng/ml, insufficiency as 15.1-30 ng/ml, and sufficiency as >30 ng/ml. Radiographs were assessed for severity of hip OA using a summary grade of 0-4 for individual features of hip OA. Logistic regression was used to assess associations of serum 25(OH)D levels with prevalent radiographic hip OA; covariates included age, clinic site, season at the time of blood withdrawal, self-reported hip pain for >30 days, timed 6-meter walk, presence of at least 1 coexisting condition, and self-rated health status.

RESULTS

Men with radiographic hip OA had a slower 6-meter walking time (P < 0.0001), reported more hip pain (P = 0.0001), had a lower vitamin D level (P = 0.0002), and had a higher prevalence of vitamin D insufficiency (P = 0.002) and vitamin D deficiency (P = 0.012) compared with controls. Higher 25(OH)D levels were associated with a lower prevalence of radiographic hip OA (odds ratio [OR] 1.39 per 1 SD decrease in 25[OH]D, 95% confidence interval [95% CI] 1.11-1.74) after adjusting for age, season, and clinic site. Men with vitamin D insufficiency had an increased likelihood of prevalent radiographic hip OA (OR 2.19, 95% CI 1.21-3.97) compared with men with sufficient levels of 25(OH)D, and in men with vitamin D deficiency, there was a tendency toward an increased likelihood of radiographic hip OA (OR 1.99, 95% CI 0.83-4.74).

CONCLUSION

Men with vitamin D deficiencies are twice as likely to have prevalent radiographic hip OA, and therefore vitamin D therapy to augment skeletal health in the elderly is warranted.

Pre-radiographic MRI findings are associated with onset of knee symptoms: the most study

OBJECTIVE

Magnetic resonance imaging (MRI) has greater sensitivity to detect osteoarthritis (OA) damage than radiographs but it is uncertain which MRI findings in early OA are clinically important. We examined MRI abnormalities detected in knees without radiographic OA and their association with incident knee symptoms.

METHOD

Participants from the Multicenter Osteoarthritis Study (MOST) without frequent knee symptoms (FKS) at baseline were eligible if they also lacked radiographic features of OA at baseline. At 15 months, knees that developed FKS were defined as cases while control knees were drawn from those that remained without FKS. Baseline MRIs were scored at each subregion for cartilage lesions (CARTs); osteophytes (OST); bone marrow lesions (BML) and cysts. We compared cases and controls using marginal logistic regression models, adjusting for age, gender, race, body mass index (BMI), previous injury and clinic site.

RESULTS

36 case knees and 128 control knees were analyzed. MRI damage was common in both cases and controls. The presence of a severe CART (P=0.03), BML (P=0.02) or OST (P=0.02) in the whole knee joint was more common in cases while subchondral cysts did not differ significantly between cases and controls (P>0.1). Case status at 15 months was predicted by baseline damage at only two locations; a BML in the lateral patella (P=0.047) and at the tibial subspinous subregions (P=0.01).

CONCLUSION

In knees without significant symptoms or radiographic features of OA, MRI lesions of OA in only a few specific locations preceded onset of clinical symptoms and suggest that changes in bone play a role in the early development of knee pain. Confirmation of these findings in other prospective studies of knee OA is warranted.

A variant near the interleukin-6 gene is associated with fat mass in Caucasian men

Context

Regulation of fat mass appears to be associated with immune functions. Studies of knockout mice show that endogenous interleukin (IL)-6 can suppress mature-onset obesity.

Objective

To systematically investigate associations of single nucleotide polymorphisms (SNPs) near the IL-6 (IL6) and IL-6 receptor (IL6R) genes with body fat mass, in support for our hypothesis that variants of these genes can be associated with obesity.

Design and Study Subjects

The Gothenburg Osteoporosis and Obesity Determinants (GOOD) study is a population-based cross-sectional study of 18-20 years old men (n=1 049), from the Gothenburg area (Sweden). Major findings were confirmed in two additional cohorts consisting of elderly men from the Osteoporotic Fractures in Men (MrOS) Sweden (n=2 851) and MrOS US (n=5 611) multicenter population-based studies.

Main Outcome

The genotype distributions and their association with fat mass in different compartments, measured with dual-energy X-ray absorptiometry (DXA).

Results

Out of 18 evaluated tag single nucleotide polymorphisms (SNPs) near the IL6 and IL6R genes, a recently identified SNP rs10242595 G/A [minor allele frequency (MAF) = 29%] 3′ of the IL6 gene was negatively associated with the primary outcome total body fat mass (effect size -0.11 standard deviation (SD) units/A allele, P=0.02). This negative association with fat mass was also confirmed in the combined MrOS Sweden and MrOS US cohorts (effect size -0.05 SD units/A allele; P=0.002). When all three cohorts were combined (n= 8 927, Caucasian subjects), rs10242595*A showed a negative association with total body fat mass (effect size -0.05 SD units/A allele, P<0.0002). Furthermore, the rs10242595*A was associated with low body mass index [(BMI, effect size -0.03, P<0.001)] and smaller regional fat masses. None of the other SNPs investigated in the GOOD study were reproducibly associated with body fat.

Conclusions

The IL6 gene polymorphism rs10242595*A is associated with decreased fat mass in three combined cohorts of 8 927 Caucasian men.

The association of proximal femoral shape and incident radiographic hip OA in elderly women

PURPOSE

Variations in femoral head shape are reported to predict incident hip osteoarthritis (OA). This study evaluated if proximal femur shape at baseline was a risk factor for incident radiographic hip OA (RHOA) after 8.3 years of follow-up in a cohort of elderly Caucasian women.

METHODS

Supine pelvic radiographs were obtained as part of the Study of Osteoporotic Fractures (SOF) at baseline and Visit 5 (8.3 years later), and were scored for RHOA. A nested case-control study was performed: hips were eligible for inclusion if they had no prevalent RHOA in either hip at baseline. Cases of incident RHOA were defined as no RHOA at baseline and RHOA in their right hip present at Visit 5 [or right total hip replacement (THR) for OA between baseline for follow-up] and a random selection of one half of all incident RHOA cases plus right THR cases (n=102) were chosen. A random selection (n=249) of control subjects who had no RHOA in their right hip at both baseline and follow-up visit were included for comparison. The shape of the right proximal femur was outlined on a digitized baseline radiograph and a statistical image analysis technique, Active Shape Modeling (ASM), was used to generate 10 unique and independent "modes" or variations in shape, which explained 95% of the variance in the shape of the proximal femurs studied. Any hip shape was therefore described as the average shape plus a linear combination of these 10 independent modes of variation. The values for each of these 10 modes for each hip analyzed were entered into a logistic regression model as independent predictors of incident RHOA adjusting for covariates.

RESULTS

The incident RHOA cases were slightly taller, heavier and had higher total hip bone mineral density (BMD) than control subjects (P<0.05), but were otherwise similar demographically. Results of ASM showed that Modes 1, 2 and 3 together explained 81% of the variance in proximal femur shape among all subjects analyzed. Modes 3, 5, 9 which accounted for 8.9%, 3.3% and 0.8% of the variance respectively, were significant predictors of incident RHOA with adjusted odds-ratios ranging from 1.61 to 1.99 (P<0.001) for every 1 standard deviation (SD) increase in the mode score.

CONCLUSION

These results suggest that variations in the relative sizes of the femoral head and neck at baseline are modest determinants of incident RHOA in elderly Caucasian women.

Changes in proximal femoral mineral geometry precede the onset of radiographic hip osteoarthritis: The study of osteoporotic fractures

OBJECTIVE

Radiographic hip osteoarthritis (RHOA) is associated with increased hip areal bone mineral density (aBMD). This study was undertaken to examine whether femoral geometry is associated with RHOA independent of aBMD.

METHODS

Participants in the Study of Osteoporotic Fractures in whom pelvic radiographs had been obtained at visits 1 and 5 (mean 8.3 years apart) and hip dual x-ray absorptiometry (DXA) had been performed (2 years after baseline) were included. Prevalent and incident RHOA phenotypes were defined as composite (osteophytes and joint space narrowing [JSN]), atrophic (JSN without osteophytes), or osteophytic (femoral osteophytes without JSN). Analogous definitions of progression were based on minimum joint space and total osteophyte score. Hip DXA scans were assessed using the Hip Structural Analysis program to derive geometric measures, including femoral neck length, width, and centroid position. Relative risks and 95% confidence intervals for prevalent, incident, and progressive RHOA per SD increase in geometric measure were estimated in a hip-based analysis using multinomial logistic regression with adjustment for age, body mass index, knee height, and total hip aBMD.

RESULTS

In 5,245 women (mean age 72.6 years), a wider femoral neck with a more medial centroid position was associated with prevalent and incident osteophytic and composite RHOA phenotypes (P < 0.05). Increased neck width and centroid position were associated with osteophyte progression (both P < 0.05). No significant geometric associations with atrophic RHOA were found.

CONCLUSION

Differences in proximal femoral bone geometry and spatial distribution of bone mass occur early in hip OA and predict prevalent, incident, and progressive osteophytic and composite phenotypes, but not the atrophic phenotype. These bone differences may reflect responses to loading occurring early in the natural history of RHOA.

Measurement of the toughness of bone: a tutorial with special reference to small animal studies

Quantitative assessment of the strength and toughness of bone has become an integral part of many biological and bioengineering studies on the structural properties of bone and their degradation due to aging, disease and therapeutic treatment. Whereas the biomechanical techniques for characterizing bone strength are well documented, few studies have focused on the theory, methodology, and various experimental procedures for evaluating the fracture toughness of bone, i.e., its resistance to fracture, with particular reference to whole bone testing in small animal studies. In this tutorial, we consider the many techniques for evaluating toughness and assess their specific relevance and application to the mechanical testing of small animal bones. Parallel experimental studies on wild-type rat and mouse femurs are used to evaluate the utility of these techniques and specifically to determine the coefficient of variation of the measured toughness values.

Precision of 3.0 Tesla quantitative magnetic resonance imaging of cartilage morphology in a multicentre clinical trial

OBJECTIVE

Quantitative MRI (qMRI) of cartilage morphology is a promising tool for disease-modifying osteoarthritis drug (DMOAD) development. Recent studies at single sites have indicated that measurements at 3.0 Tesla (T) are more reproducible (precise) than those at 1.5 T. Precision errors and stability in multicentre studies with imaging equipment from various vendors have, however, not yet been evaluated.

METHODS

A total of 158 female participants (97 Kellgren and Lawrence grade (KLG) 0, 31 KLG 2 and 30 KLG 3) were imaged at 7 clinical centres using Siemens Magnetom Trio and GE Signa Excite magnets. Double oblique coronal acquisitions were obtained at baseline and at 3 months, using water excitation spoiled gradient echo sequences (1.0x0.31x0.31 mm3 resolution). Segmentation of femorotibial cartilage morphology was performed using proprietary software (Chondrometrics GmbH, Ainring, Germany).

RESULTS

The precision error (root mean square coefficient of variation (RMS CV)%) for cartilage thickness/volume measurements ranged from 2.1%/2.4% (medial tibia) to 2.9%/3.3% (lateral weight-bearing femoral condyle) across all participants. No significant differences in precision errors were observed between KLGs, imaging sites, or scanner manufacturers/types. Mean differences between baseline and 3 months ranged from <0.1% (non-significant) in the medial to 0.94% (p<0.01) in the lateral femorotibial compartment, and were 0.33% (p<0.02) for the total femorotibial subchondral bone area.

CONCLUSIONS

qMRI performed at 3.0 T provides highly reproducible measurements of cartilage morphology in multicentre clinical trials with equipment from different vendors. The technology thus appears sufficiently robust to be recommended for large-scale multicentre trials.

Estrogen receptor alpha genotype is associated with a reduced prevalence of radiographic hip osteoarthritis in elderly Caucasian women

PURPOSE

This study evaluated the association between polymorphisms in the estrogen receptor (ER) alpha gene (ESR1) and prevalent and incident radiographic hip osteoarthritis (RHOA) in a large, well-defined prospective cohort of elderly Caucasian women.

METHODS

Prevalent and incident RHOA was evaluated from all available pelvis X-rays obtained from the Study of Osteoporotic Fractures at baseline and after a mean of 8.3 years. Evaluable DNA samples were available from 4746 of these subjects. RHOA cases were defined by published methods. The ESR1 polymorphisms at intron I (Pvu II for a T/C substitution and Xba I for an A/G substitution) were genotyped in the context of a multiplex polymerase chain reaction (PCR) amplification followed by allele-specific single nucleotide polymorphism (SNP) detection with immobilized oligonucleotide probes in linear arrays. Multiple logistic regression was performed to estimate odds ratios (ORs) and 95% confidence intervals (95% CI) associated with the T/C and A/G polymorphisms.

RESULTS

RHOA was present in 12.1% of subjects, of whom 325 had joint space narrowing (JSN) score > or =3 and 130 had an osteophyte score > or =2 and JSN score > or =2. There was a significant reduction in the odds of prevalent RHOA for individuals with the C/C compared to T/T genotype at the Pvu II site with an OR of 0.71 (95% CI: 0.55-0.92) (P=0.01). Adjustments for age, weight, height, hip Bone mineral density (BMD) and estrogen use did not alter the relationship between the C/C genotype and reduced risk of RHOA, with an OR of 0.71 (95% CI: 0.54-0.94) (P=0.01). The risk of incident RHOA was reduced for the Pvu II C/C compared to the T/T genotype (P=0.11). Also, the reduced risk of incident RHOA in C/C subjects varied by estrogen use. There was no association between the Xba I G/G or G/A genotypes and RHOA with OR of 0.82 (95% CI: 0.61-1.10) (P=0.19) compared to women with A/A genotype.

CONCLUSIONS

We conclude that the C/C genotype of the ER alpha Pvu II polymorphism was associated with a modestly reduced risk of prevalent and incident RHOA in elderly Caucasian women. Additional work is required to understand how the intron I ESR1 polymorphism may alter joint degeneration.

Estrogen Deficiency Induces Bone Loss in Mice Lacking ITAM Adapter Proteins, DAP12 and FcRg (89.31)

DAP12 and or FcRγ ITAM signals are required during normal osteoclast (OC) development in vivo and in vitro. To determine whether ITAM deficient mice are resistant to bone loss induced by estrogen deficiency, we performed ovariectomy (OVX) or SHAM surgery on 10–12 week female DAP12−/−, FcRγ−/−, DAP12−/−FcRγ−/− and control C57BL/6 (B6) mice. MicroCT of the distal femur showed statistically significant losses of trabecular bone in DAP12−/−FcRγ−/−, DAP12−/−, FcRγ−/− and B6 OVX groups compared to SHAM groups, BV/TV dropping from 56% to 35% (p&lt;0.01), 21% to 12% (p&lt;0.01), 12% to 7% (p&lt;0.01), and 6% to 3% (p&lt;0.05) respectively. Bone turnover measured by serum osteocalcin and urinary DPD increased at 4 weeks post-OVX in all four strains. In vitro OC bone resorption assays revealed a 2.7 or 3.6 fold increase in OC resorption from B6 and FcRγ−/− OVX mice that were not seen in DAP12−/− and DAP12−/−FcRγ−/− OVX OC. FSH, reported to stimulate postmenopausal osteoporosis, combined with RANKL could not rescue the in vitro OC defect in DAP12−/− and DAP12−/−FcRγ−/− cultures. TGB-β followed by TNF-α stimulation induced OC differentiation in B6 cells in vitro without RANKL; however, DAP12−/− and DAP12−/−FcRγ−/− OC cultures were not rescued. We conclude that OC differentiation during estrogen deficiency induced osteoporosis bypasses the requirement of ITAM signaling and the unidentified novel effect is microenvironment dependent.

Classification of osteoarthritis biomarkers: a proposed approach

OBJECTIVE

Osteoarthritis (OA) biomarkers are needed by researchers and clinicians to assist in disease diagnosis and assessment of disease severity, risk of onset, and progression. As effective agents for OA are developed and tested in clinical studies, biomarkers that reliably mirror or predict the progression or amelioration of OA will also be needed.

METHODS

The NIH-funded OA Biomarkers Network is a multidisciplinary group interested in the development and validation of OA biomarkers. This review summarizes our efforts to characterize and classify OA biomarkers.

RESULTS

We propose the "BIPED" biomarker classification (which stands for Burden of Disease, Investigative, Prognostic, Efficacy of Intervention and Diagnostic), and offer suggestions on optimal study design and analytic methods for use in OA investigations.

CONCLUSION

The BIPED classification provides specific biomarker definitions with the goal of improving our ability to develop and analyze OA biomarkers, and to communicate these advances within a common framework.