Journal of Bone and Mineral Research

Purpose: The Fracture Risk Assessment Tool (FRAX) excludes objective skeletal muscle health and genetic variables. We evaluated the prognostic associations of handgrip-defined probable/possible sarcopenia and genome-wide polygenic scores (GPS) with 10-year fracture risk, and their incremental predictive value beyond FRAX across racial/ethnic groups and GPS strata. Methods: We analyzed 2,051 postmenopausal women from the Women's Health Initiative. Race-specific analyses focused on Black, Hispanic, and White participants (n=2,009), excluding American Indian/Alaska Native and Asian/Pacific Islander individuals due to sparse fracture events. Sarcopenia status was operationalized by low handgrip strength alone via EWGSOP2 (<16.0 kg) and AWGS 2025 (<18.0-20.0 kg) criteria. Fine-Gray models estimated subdistribution hazard ratios (sHR), treating death as a competing risk. Predictive performance at 10 years was assessed using time-dependent AUC, Brier scores, and decision curve analysis (DCA). Results: Handgrip-defined probable or possible sarcopenia prevalence was 4.4% (EWGSOP2) and 6.4% (AWGS 2025). Black women demonstrated lower risk for major osteoporotic fractures (MOF) (adjusted sHR=0.19, 95% CI: 0.08-0.48) and hip fractures (adjusted sHR=0.07, 95% CI: 0.01-0.52) compared to White women. Neither sarcopenia status nor high GPS showed statistically significant independent associations with fractures after FRAX adjustment. Adding sarcopenia status to baseline FRAX (AUC: 0.71 for MOF; 0.69 for hip) yielded near-identical AUCs, Brier scores, and within-sample net benefit. Conclusion: Handgrip-defined probable/possible sarcopenia and current GPS do not provide independent or incremental predictive value beyond the clinical FRAX framework within this genomic sub-sample of older women.

Pseudoxanthoma elasticum (PXE) is a rare inherited disorder characterized by progressive ectopic calcification of soft connective tissues, including skin, arteries, and eyes, leading to significant morbidity. PXE results from loss of functional ABCC6, a liver specific ATP efflux conduit. Reduced ATP release into the circulation limits its conversion into AMP and the mineralization inhibitor pyrophosphate (PPi). Consequently, low plasma PPi levels drive ectopic calcification in PXE. Although oral PPi supplementation can inhibit ectopic calcification in Abcc6-/- mice, impractically high doses are needed, due to its rapid hydrolysis in the gastrointestinal tract. Here, we evaluated phosphocitrate, an exceedingly more potent mineralization inhibitor, in vitro and in Abcc6-/- mice. In ATDC5 cells, 1 {micro}M phosphocitrate significantly inhibited mineralization following induction, comparable to approximately tenfold higher concentrations of PPi. In vivo, daily intraperitoneal administration of phosphocitrate (4.7 {micro}mol/kg bw) markedly reduced calcification in muzzle skin and kidneys, whereas an at least fivefold higher dose of PPi was needed to achieve a similar effect. Oral administration required substantially higher doses of both compounds ([~]2.4 mmol/kg bw), but PC remained more effective than PPi at inhibiting soft tissue calcification in Abcc6-/- mice. Importantly, unlike PPi, oral phosphocitrate did not adversely affect skeletal strength or stiffness, even at supraphysiological doses. In summary, phosphocitrate is a more potent inhibitor of ectopic calcification than PPi in Abcc6-/- mice. While optimization of oral delivery remains necessary, its increased potency supports the potential of alternative administration routes, including subcutaneous delivery, as a practical therapeutic strategy for PXE.

Vitamin D receptor (VDR) signaling is essential for osteoblast maturation and skeletal mineralization, yet the intracellular mechanisms linking VDR activity to matrix production remain poorly defined. Here, we show that vdr-/- calvarial osteoblasts initiate differentiation but fail to complete the transition to a mature, mineralizing state, exhibiting suppressed late-stage markers such as Dmp1, Phex, and Col1a1 and defective nodule formation both in vivo and in vitro. Transcriptomic profiling revealed a SMAD network imbalance, with elevated inhibitory SMADs and attenuated phosphorylation of both SMAD1/5/9 and SMAD2/3. Whereas SMAD1/5/9 activation was preserved in vivo and restored by exogenous BMP2 in vitro, consistent with in vivo paracrine BMP availability, reduced SMAD2/3 phosphorylation persisted in both contexts, indicating a cell-autonomous defect. Mechanistically, vdr-/- osteoblasts displayed impaired intracellular Ca{superscript 2} dynamics and diminished CaMKII activation, with VDR/RXR occupancy detected near the Camk2g locus. Pharmacological CaMKII inhibition (KN-93) recapitulated the phenotype, reducing SMAD2/3 phosphorylation and mineralization and establishing CaMKII as an upstream regulator of SMAD2/3. A milk-based diet rescued skeletal defects in vdr-/- mice in a calcium-independent manner and selectively restored CaMKII-SMAD2/3 signaling. Metabolomic profiling identified the omega-6 fatty acid {gamma}-linolenic acid (GLA) as an elevated circulating mediator; exogenous GLA restored Ca{superscript 2} flux, CaMKII activation, SMAD2/3 phosphorylation, matrix production, and mineralization, without reactivating Runx2, Sp7, or BMP-SMAD1/5/9 signaling, and dependent on CaMKII activity. These findings reveal a VDR-independent, GLA-inducible CaMKII-SMAD2/3 mineralization program, positioning metabolic modulation of calcium signaling as a strategy to restore osteoblast function under impaired vitamin D signaling.

Objective: To examine associations between volume and intensity of leisure time physical activity (LTPA) and fracture risk during midlife and determine whether adherence to World Health Organisation (WHO) physical activity recommendations was associated with fracture risk. Methods: Cross-sectional analysis of UK Biobank participants aged 40 to 65 years using self-reported physical activity and fracture data. LTPA volume (LTPAV) was derived from walking, moderate and vigorous activity. Participants were categorised into LTPAV quintiles and by adherence to WHO physical activity recommendations. Multivariable logistic regression examined associations with self-reported fracture within the previous five years, with sex stratified analyses. Results: Among 322,749 participants, 53% were female with a mean age of 47 years. Fracture risk increased with higher LTPAV, although the association was non-linear and varied by age and sex. The strongest associations were in the highest quintile among men and women aged 40 to 49 years (OR 1.81, 95% CI 1.64 to 1.99 and OR 1.42, 95% CI 1.28 to 1.58 respectively). In mutually adjusted models, vigorous activity demonstrated the strongest independent association with fracture risk. Meeting WHO physical activity recommendations, without exceeding them, was not associated with increased fracture risk. Conclusions: Higher fracture risk was observed in individuals undertaking higher volumes of leisure-time physical activity, with the association largely driven by vigorous-intensity activity. The association was strongest in adults aged 40 to 49 years and in men. Physical activity consistent with current WHO recommendations was not associated with increased fracture risk, supporting continued promotion of physical activity during midlife.

Geroprotectors extend lifespan and improve several aspects of healthspan, yet their effects on skeletal ageing remain poorly understood. They hold potential advantages over current bone-targeted osteoporosis therapies, as they may simultaneously improve bone, neuromuscular function, and vision, thereby reducing the risk of falls, the major cause of fractures. Here we examined, for the first time, the long-term effects of rapamycin, acarbose, and 17-estradiol, administered at lifespan-extending doses on trabecular and cortical bone architecture in male and female UM-HET3 mice measured with micro-computed tomography at 12 and 22 months of age. Bayesian modelling analysis reveals that all interventions produced responses in trabecular bone in females at 22 months. These effects were driven mainly by increases in trabecular number, with little evidence for changes in trabecular thickness. In contrast, treatment effects in males were generally negligible. Cortical responses were modest. Moderate increases in cortical area fraction were observed in females treated with rapamycin or 17-estradiol at 22 months, whereas cortical thickness remained largely unchanged, suggesting a geometrical rather than anabolic effect. Interestingly, geroprotectors strongest skeletal responses in females contrasts with the predominantly male-biased lifespan extension reported for acarbose and 17-estradiol, suggesting differential mechanisms mediating lifespan extension and bone structure preservation.

PurposeEstrogen deficiency drives bone loss through interacting endocrine, oxidative, inflammatory and bone-remodeling disturbances. Ergothioneine (EGT) is a diet-derived thiol/thione antioxidant whose effects on the estrogen-deficient skeleton are unknown. We evaluated whether EGT, alone or combined with vitamin K2, vitamin D3 and magnesium L-threonate, attenuates the skeletal and systemic consequences of ovariectomy (OVX) in mice. MethodsForty-eight female C57BL/6J mice underwent sham surgery or OVX and received daily oral gavage for 12 weeks of vehicle, alendronate (1.53 mg/kg), EGT (30 mg/kg/day), EGT with vitamin K2 (40 {micro}g/kg/day) and vitamin D3 (500 IU/kg/day), or EGT with vitamin K2, magnesium L-threonate (350 mg/kg/day) and vitamin D3 (n = 5-6 analysed per group). Outcomes included the uterine index, tibial micro-computed tomography, distal-femoral histology, and serum bone turnover markers (CTX-I, PINP, osteocalcin), sex hormones, TNF-, IL-6, SOD and MDA. OVX lowered the uterine index and induced tibial trabecular deterioration, with increased CTX-I, decreased PINP and osteocalcin, elevated TNF- and IL-6, reduced SOD and increased MDA (all P < 0.01 vs sham). Alendronate restored tibial micro-CT bone-volume fraction (BV/TV) and trabecular number (P < 0.01 vs OVX). The EGT-based regimens did not significantly restore tibial micro-CT BV/TV, trabecular thickness or trabecular number (all P > 0.05 vs OVX), but significantly increased trabecular area on distal-femoral histology (OVX 7.6% vs 14.2-15.0% across regimens; P < 0.05 vs OVX) and lowered CTX-I, TNF-, IL-6 and MDA while raising SOD and partially restoring PINP and osteocalcin (P < 0.05-0.01 vs OVX). Because the histological and micro-CT endpoints were assessed at different skeletal sites, structural interpretation is cautious. Apparent increases in serum estradiol were assay-dependent and are regarded as exploratory. Ergothioneine-based nutritional regimens improved the systemic oxidative, inflammatory and bone-turnover environment of estrogen-deficient bone loss and preserved distal-femoral trabecular area on histology, although tibial three-dimensional microarchitecture by micro-CT was not restored. Because the histological and micro-CT endpoints were assessed at different skeletal sites, the structural interpretation is necessarily cautious. These findings support further evaluation of EGT as a dietary adjunct, with mechanistic and dose-optimization studies warranted.

Bone remodeling is a tightly regulated physiological process that maintains bone health through coordinated action of bone-resorbing osteoclasts and bone-forming osteoblasts. Disruption of this balance, such as the one induced by estrogen decline after menopause, results in bone loss and osteoporosis. Genetic factors play an important role in determining bone mineral density (BMD) loss over time. However, translating genetic associations into individualized risk prediction remains challenging due to small effect size of individuals variants and non-linear interactions within the bone remodeling unit. Here, we present a bone cell population dynamics model that includes major regulatory pathways, such as the RANK/RANKL/OPG axis, Wnt signaling, and hormonal regulation by estrogen, parathyroid hormone, and TGF-{beta}. We calibrate the model on clinical data from healthy postmenopausal women, and women with reduced BMD undergoing anti-osteoporotic therapy. The calibrated model captures healthy BMD decline in postmenopausal women and therapeutic response to anti-osteoporotic medications. We mechanistically incorporate the effect of 22 variants across 8 genes involved in bone remodeling and simulate BMD trajectories in 1,000 virtual subjects differing by ancestry and genetic makeup. The median predicted 5-year BMD loss was 3.57% (95% prediction interval: 1.31-5.24), consistent with the values reported in the literature. The virtual individuals with African ancestry were predicted to experience the highest average 5-year BMD loss. The strongest genetic risk factors for bone loss were predicted to be CYP19A1 rs727479 and OPG rs3102735, while LRP5 rs11228240 emerged as a protective factor that could partially counteract the detrimental effects of other variants. Several epistatic effects were observed in the genetic interaction analysis. Mechanistically, our model suggested that estrogen exerts its effect on bone remodeling primarily by modulating osteoclast apoptosis. Overall, this framework demonstrates a proof-of-concept for integration of genetic risk factors into mechanistic models of disease and can be extended to other conditions with polygenic inheritance.

Purpose: Psychosocial factors are underexplored in relation to osteoporosis. This study examined whether depressive symptoms are associated with incident osteoporosis in middle aged and older adults, and whether this association is modified by age or sex. Methods: Prospective cohort study of 8,577 adults aged [&ge;]50 years from the English Longitudinal Study of Ageing. The sample were free of osteoporosis at baseline (2002-2003) and were followed up for incident osteoporosis until wave 11 (2023-2024). Depressive symptoms were measured at baseline (2002-03) using the 8-item Center for Epidemiologic Studies-Depression Scale (CES-D). Cox proportional hazards regressions were used to estimate associations, adjusting for age, sex and wealth. Results: Over 20 years of follow-up, 948 (11.1%) participants reported incident osteoporosis. Each one-point increase in baseline CES-D was associated with a higher hazard of incident osteoporosis adjusted for age, sex, and wealth (hazard ratio (HR) 1.07, 95% CI 1.04-1.11, p<0.001). The association was modified by age (interaction p=0.008) and concentrated in participants aged 50-64 years at baseline (HR 1.10, 95% CI 1.06-1.14), with no significant association in older age strata. Osteoporosis incidence was higher in women, but this was not modified by depressive symptoms. Findings were robust to sequential adjustment (informed by a directed acyclic graph) for education, wealth, inflammatory conditions and health behaviours (HR 1.04, 95% CI 1.01-1.08) Conclusion: Depressive symptoms are associated with incident osteoporosis over two decades of follow-up, particularly among adults aged 50-64. Mid-life may represent a target for psychosocial intervention to support bone health.

Osteoporosis is a prevalent skeletal disorder characterized by deterioration of bone microarchitecture and loss of bone mineral density, leading to increased fracture risk and substantial health and economic burdens, particularly among older adults. Bone remodeling is orchestrated by a complex interplay of systemic and local regulators, among which vitamin D plays a central role in maintaining skeletal homeostasis. Although numerous studies have examined the effects of vitamin D on bone metabolism, outcomes have been inconsistent across populations, dosing regimens, and experimental models. To clarify the net skeletal impact of vitamin D, we investigated its effects in postmenopausal osteoporosis (PMO). Vitamin D (1,25-dihydroxyvitamin D3- active form of vitamin D) supplementation effectively prevented bone loss in ovariectomized mice, at both lower and higher concentrations. Mechanistically, vitamin D promoted osteoclast differentiation in vitro, consistent with its RANKL-dependent pro-osteoclastogenic activity, yet paradoxically conferred bone protection in vivo. This discrepancy was explained by vitamin Ds profound immunomodulatory effects, which reshaped both innate and adaptive immune responses to suppress osteoclast formation and function. Concurrently, vitamin D improved intestinal barrier integrity and restored gut microbial composition, thereby stabilizing the gut-immune-bone axis and reducing pro-resorptive inflammatory signaling. Together, these findings demonstrate that vitamin D prevents bone loss through the coordinated regulation of immune and gut homeostasis, reconciling its apparent pro-resorptive effects in vitro with its overall anti-resorptive outcomes in vivo. This integrated mechanism highlights immune-gut microbial modulation as a key mediator of vitamin D-induced bone preservation and supports the development of vitamin D as an immunotherapeutic adjunct for the prevention and management of PMO. Altogether, our findings for the first time dissect the paradox surrounding the osteoprotective property of vitamin D supplementation.

Implant-associated bone infection involves a complex interplay between pathogenic stimuli and host cell responses, yet analysis in preclinical models has typically relied on qualitative or semi-quantitative measures. We aimed to establish a quantified evaluation framework to define host-pathogen relationships in a preclinical implant infection model. Staphylococcus aureus-coated stainless-steel implants were inserted trans-cortically in mouse tibiae and bone changes recorded longitudinally by in vivo micro-CT. An automated segmentation task list was developed to independently isolate and quantify cortical, periosteal-reactive, and trabecular bone compartments. RGB trichrome histomorphometry was used to quantify bone matrix integrity, osteocyte lacunar geometry, and osteoclastic activity. Droplet digital PCR was used to determine absolute bacterial and host genome copy number. Infected implants produced marked reductions in trabecular bone volume fraction, number, and bone mineral density (BMD), together with decreased cortical bone volume fraction and increased cortical porosity, accompanied by significant elevations in periosteal bone volume fraction. Histologically, infected bone exhibited increased eroded surface indicative of osteoclastic resorption, extensive degraded bone matrix and pathological remodelling of osteocyte lacunae towards circularity, consistent with an osteocytic osteolysis response. Infection-induced changes to cortical bone structure correlated mostly with host cell rather than bacterial load; however, cortical BMD negatively correlated with the bacterial:host genome ratio. This multifaceted, quantified framework reveals distinct pathobiological effects of implant-associated infection on trabecular, cortical, and periosteal bone compartments, bone matrix and osteocyte and osteoclast populations, consistent with reports in human patients, suggesting that major pathological changes are driven by the host bone cell response to infection.

Teriparatide (PTH 1-34) is an anabolic agent used to treat osteoporosis, yet clinical response varies widely among patients. To investigate genetic and sex-specific determinants of skeletal response, we administered intermittent PTH to male and female mice from eight genetically diverse inbred strains. Mice were treated for four weeks, and bone phenotypes were assessed via DXA, microCT, and mechanical testing. Response to PTH was highly strain- and sex-dependent, with some strains responding at the femur but not the spine, and vice versa. Heritability estimates for PTH-induced changes in bone mineral density (BMD), cortical area, breaking strength, and trabecular bone volume fraction (BV/TV) ranged from moderate to high, with BV/TV showing the strongest genetic influence. Cortical bone response mechanisms differed by sex: males exhibited periosteal expansion, while females showed endosteal remodeling. These findings mirror clinical observations where hip non-response is more prevalent than spine non-response and suggest that genetic background and sex significantly influence therapeutic outcomes. Our data support the use of genetically diverse mouse models to elucidate the genetic architecture of PTH response and highlight the potential for personalized approaches in osteoporosis treatment. Future genome-wide association studies in outbred mice may identify specific loci mediating skeletal responsiveness to PTH, advancing precision medicine strategies for bone anabolic therapies. LAY SUMMARYTeriparatide, a drug used to treat osteoporosis, consists of the active portion of parathyroid hormone (PTH). Information from clinical studies suggests that not all patients will respond to this medication. We used eight strains of inbred mice to study the impact of genetic background and sex on the response to PTH. We learned that response to PTH is driven by both genetics and sex. Some strains responded at the femur, but not the spine and vice versa. These results may explain why a failure to respond at the hip in humans is more common than at the spine.

1.Cancer-induced bone pain (CIBP) occurs in a majority of patients when primary or metastatic cancer develops within the bone. This pain has a significant impact on quality of life, yet there are limited effective treatment options available. Nerve sprouting is a complex mechanism that has been implicated in CIBP. Netrin-1 is a neuronal guidance molecule that is produced by numerous cell types, including cancer cells. In this study we aimed to determine whether netrin-1 inhibition (with NP137 - a humanized IGg1 monoclonal antibody) could ameliorate nerve sprouting, and nociception by extension, in three models of CIBP - osteosarcoma, metastatic breast cancer, and metastatic prostate cancer. Sustained administration of NP137 failed to produce an anti-nociceptive effect in these models, but a delayed onset was observed in the osteosarcoma model. NP137 did not produce a disease-modifying effect, as micro-computed tomography did not reveal reduced bone destruction in the NP137-treated groups. Additionally, there was no nerve fibre density reduction in any of the groups at the late-stage of the disease, suggesting that nerve sprouting occurs in early- to mid-stage CIBP development. Investigation of NP137 exposure indicated that serum levels of NP137 were comparable between the sham and cancer groups. Our study indicates that netrin-1 may play a role in early-stage CIBP development, but inhibition of this mechanism does not produce robust anti-nociception.

Abstract Calcific deposits in the arterial media have been associated with a number of metabolic and genetic disorders including diabetes, chronic kidney disease and generalized arterial calcification of infancy. While medial calcification and physiologic hard tissue mineralization in the skeleton are both regulated by several common determinants, emerging data suggest that there might be fundamental differences in the mechanisms underlying these two processes. Objective: We previously demonstrated that elastin haploinsufficiency delays medial calcification in MGP-deficient mice. Here, using mice in which a human ELN transgene rescues mouse elastin deficiency, we investigated whether the origin and abundance of arterial elastin differentially affect the initiation and progression of medial calcification. Approach and Results: We pursued a transgenic approach to alter the arterial elastin scaffold in MGP-deficient mice. Our analyses of a humanized MGP-deficient model with 40% reduction of medial elastin content showed a complete absence of the early-stage vascular calcification. Additionally, we showed that mouse and human elastin orthologues affect vascular calcification in a comparable manner. Conclusion: Arterial elastin abundance, rather than orthologue origin, modulates the initiation and progression of medial calcification in MGP-deficient mice. A further reduction in arterial elastin beyond that achieved by elastin haploinsufficiency profoundly delays mineral deposition and maturation, whereas restoration of elastin abundance through transgenic human ELN expression restores arterial calcification.

Background: Viable pediatric human growth plate (GP) tissue is rarely available for translational research, limiting direct investigation of human longitudinal bone growth and pediatric growth disorders. In this proof-of-concept study, we aimed to determine whether it is feasible to establish a clinically integrated ex vivo human GP model using tissue obtained during routine percutaneous epiphysiodesis (PE) procedures in adolescents treated for extreme tall stature or leg length difference due to trauma. Methods: GP tissue and cells were collected during PE and processed using protocols adapted from established methods of human osteoarthritic cartilage processing within the RAAK study. Feasibility was assessed by evaluating tissue collection, cell isolation, contamination rate, monolayer expansion, and generation of three-dimensional cartilage pellets. Proliferation of GP-derived chondrocytes was compared with osteoarthritis-derived articular chondrocytes, and histological assessment was performed to evaluate cartilage-like matrix formation. Results: Across consecutive surgical procedures, viable GP tissue could be obtained reproducibly, with only few samples failing to yield cells and no relevant contamination issues. Isolated GP chondrocytes expanded successfully in two-dimensional culture and showed a strong early proliferative response compared with RAAK-derived chondrocytes. In addition, GP-derived cells formed three-dimensional organoids and histology confirmed cartilage-like matrix deposition supporting their capacity to generate neo-cartilage tissue in vitro. Conclusion: This study demonstrates feasibility to obtain, culture, and functionally assess viable human GP tissue from routine PE surgery. As such, the Leiden ex vivo human GP model provides a unique platform to study local mechanisms of endochondral bone growth, link genetic determinants of height to functional GP biology, and support future therapeutic research in pediatric growth disorders.

We here determined therapeutic efficacy and mode-of-action of human induced pluripotent-derived therapeutic stem cells (hiMSCs) across in vivo mouse and ex vivo human osteoarthritis models. hiMSC treatment in DMM-mice significantly reduced OARSI damage scores, which was affirmed by a decrease in the catabolic marker Mmp13 and an increase in the anabolic marker Col2. These treatment effects appeared, irrespective of modifying factors such as xeno-free media or thermosensitive hydrogel carrier. Subsequently treatment of hiMSC+gel in human osteoarthritic cartilage explants showed a transcriptome-wide significant activation of the cholesterol and sterol synthesis pathways marked by genes such as MVD, DHCR7, MSMO1, FABP3. Additionally, we showed that these changes alleviated OA-associated imbalances of the cellular Zinc-ion homeostasis pathways, represented by genes such as MT1F, MT1G, MT1H and SLC30A1. Spatial transcriptomics then sensitively captured that hiMSC+gel treatment evoked, specifically at the superficial cartilage layer, a consistent upregulation of healthy chondrocyte markers such as CHAD, ACAN, FRZB, and SOX9, alongside a suppression of catabolic and inflammatory mediators such as SERPINE1, SPP1, MMP13, ADAMTS5. Our findings link therapeutic outcomes of hiMSC treatment to precise spatially resolved molecular changes in human tissue, that would otherwise be obscured by heterogeneous cell populations. Collectively our study highlighted that hiPSC-derived stem cell therapy (hiMSCs) could provide a scalable off-the-shelf solution to treat osteoarthritis, with strong prospects for clinical applications in the near future.

The clinical utility of monitoring longitudinal changes in musculoskeletal trajectories, including bone mineral density (BMD), muscle strength, height, and weight for fracture prediction, remains underutilized, as current gold-standard tools such as the Fracture Risk Assessment Tool (FRAX) rely solely on cross-sectional baseline data. This study aimed to determine whether a deep learning model integrating individualized musculoskeletal trajectories improves fracture prediction accuracy compared to established static benchmarks. We developed the Hybrid Trajectory-Based model (HyTrax), a Transformer-based deep learning model that encodes sequential measurements of hip and spine BMD, grip strength, height, and weight as temporal tokens, incorporating subject-specific slopes derived from linear mixed-effects models. The model was trained and internally validated in 27,512 postmenopausal women from the Women's Health Initiative (WHI) and externally evaluated in 1,193 participants from the Framingham Heart Study (FHS). In the WHI validation set, the HyTrax + FRAX (BMD) ensemble model achieved a time-dependent Area Under the Curve (AUC) of 0.85 for Major Osteoporotic Fracture, outperforming both the longitudinal Transformer alone (AUC = 0.80) and the standard FRAX-BMD model (AUC = 0.82). The HyTrax + FRAX (BMD) ensemble model demonstrated favorable discrimination and improved risk stratification (Net Reclassification Improvement +26.5%) in WHI. Evaluation in the FHS cohort demonstrated the transportability of the longitudinal embeddings, with the HyTrax + Baseline 2 ensemble model (integrating longitudinal embeddings with clinical risk factors, BMD, and grip strength) achieving an AUC of 0.74. Explainability analyses identified early longitudinal weight fluctuations and overall height loss trajectories as important predictors of future fracture risk, alongside static factors such as age and genetic predisposition. By leveraging individualized trajectories through deep sequential modeling with baseline FRAX probability, the HyTrax + FRAX (BMD) ensemble model improved fracture discrimination over static assessments, offering a framework for incorporating repeated clinical measures into fracture prediction.

Abstract Purpose: Haemochromatosis due to HFE-C282Y homozygosity can lead to excess iron absorption and is typically associated with liver malignancy, plus widespread arthritis. Recent evidence suggests that limb fractures are more common, but little is known about vertebral effects. This study investigated the association of vertebral compression fractures, assessed with intelligent dual-energy X-ray absorptiometry (iDXA), and HFE genotype in a large community cohort. Methods: UK Biobank data from 227 European genetic ancestry C282Y homozygotes (mean 64.6 years) and 234 age, sex, and BMI-matched controls without common HFE haemochromatosis variants were included. Lateral vertebral assessment scans (iDXA, GE-Lunar) were acquired at imaging reassessment (2014-2020) and reviewed, blind to genotype, for radiological evidence of vertebral fracture. Matched logistic regression models assessed associations between C282Y homozygosity and vertebral fractures. Results: 78 vertebral fractures (16.9%) were identified within 461 participants. Male C282Y homozygotes had increased odds of vertebral fracture (n=22/89, 24.7%) compared to participants without HFE alleles (n=9/90, 10.0%); Odds Ratio [OR]: 2.95, 95%CI: 1.28-6.85, p=0.01. The association persisted after excluding individuals with a diagnosis of haemochromatosis (OR: 3.37, 95% CI: 1.41-8.10, p=0.007). No excess fracture risk was observed in female C282Y homozygotes (n=23/138, 16.7%) vs those without HFE alleles (n=24/144, 16.7%); OR: 0.99, 95%CI: 0.53-1.87, p=1.00. Conclusion: In this community-based imaging study, male HFE C282Y homozygotes had a markedly higher likelihood of vertebral fractures than those without HFE variants. These findings support further evaluation of vertebral fracture assessment in C282Y homozygous men to ensure prompt treatment to prevent future fracture if appropriate.

Question Are adverse childhood experiences (ACEs) associated with altered growth trajectories in childhood? Findings In this cohort study of 412,549 children and adolescents, ACEs were associated with lower height throughout childhood, earlier pubertal timing, and shorter final stature. Height differences emerged approximately 2 years before ACE documentation and were greatest among those with earlier documentation. Meaning These findings suggest that early adversity affects physical growth in children and may serve as a measurable indicator of the biological consequences of early-life stress, especially in those with documentation of ACEs prior to the onset of typical pubertal growth. Importance Adverse childhood experiences (ACEs) are among the strongest risk factors for long-term mental and physical health complications, yet their impact on physical growth in childhood remains incompletely understood. Objective To determine the association of ACEs on childhood growth trajectories and growth dynamics. Design, Setting and Participants Retrospective cohort study using longitudinal electronic health record data. Data was collected from participants between February 1999 and August 2025. A large academic medical center biobank linked to deidentified electronic health records in the southeastern United States. A total of 412,549 individuals with at least 2 recorded height measurements between the ages of 2 and 20 were included in the primary analysis. Growth curve analyses were performed in a subset of 199,844 individuals with at least 3 height measurements spanning at least 2 years. Genetic analyses were performed in a subset of 10,114 individuals of primarily European ancestry. Exposure(s) Documented exposure to adverse childhood experiences before age 18 years identified through a natural language processing algorithm. Main Outcome(s) and Measure(s) Height-for-age z-scores across childhood, final attained height, and growth curve parameters estimated using SuperImposition by Translation and Rotation (SITAR) modeling. Results Among 412,549 participants, 18,502 (4.5%) had clinically documented ACEs during childhood. ACE documentation was associated with lower height-for-age z-scores throughout childhood and adolescence. Final attained height was significantly lower among ACE-documented individuals, with mean differences of -3.0 cm among males (174.0 cm vs 177.0 cm, p < 0.001) and -1.3 cm among females (161.8 cm vs 163.1 cm, p < 0.001). Height differences emerged approximately 2 years before clinical ACE documentation. Earlier age at first ACE documentation was associated with progressively shorter final attained height, with each year decrease in age at ACE documentation associated with a decrease in final height of -0.20 cm in females and -0.35 cm in males. Those with first ACE documented prior to pubertal age also showed the most pronounced growth dynamic differences, with males demonstrating a mean reduction in size of 5.25 cm (95% CI, -6.79 cm to -3.70 cm) and 1.26-year earlier pubertal timing (95% CI, -1.50 to -1.03 years), and females demonstrating a reduction in growth curve size of 3.62 cm (95% CI, -4.83 to -2.41 cm) and 1.14-year earlier pubertal timing (95% CI, -1.29 to -0.99 years). Conclusions and Relevance In this large clinical cohort, clinically documented ACEs were associated with time-dependent reductions in stature, earlier pubertal timing, and short final attained height. These findings suggest that early childhood adversity may have lasting effects on physical development and highlight growth trajectories as a potential marker of the biological consequences of early-life stress.

Fracture nonunion remains a major cause of morbidity, yet patient-specific factors associated with impaired healing remain incompletely characterized. Anemia has been associated with adverse orthopaedic outcomes, but its relationship with fracture nonunion is poorly understood. We examined whether pre-fracture anemia, anemia burden, and clinically relevant anemia subtypes were associated with nonunion following tibial or femoral fractures. Using commercial and Medicare fee-for-service claims from 2016 through 2023, we identified adults aged 19 years or older with a tibial or femoral fracture, continuous enrollment during the preceding year and for at least six months after fracture, and no baseline cancer. Pre-fracture anemia was evaluated as any anemia, the number of distinct anemia diagnoses, and nutritional, hemolytic, aplastic, and other anemia subgroups. Nonunion occurring six to eighteen months after fracture was assessed using incidence rates and multivariable-adjusted hazard models. Among 326,673 adults, 149,704 had pre-fracture anemia and 176,969 did not. The crude incidence of nonunion was 42% higher among individuals with anemia than among those without anemia (incidence rate ratio, 1.42; 95% confidence interval, 1.32 to 1.53) and increased with greater anemia burden. After adjustment for demographic and clinical characteristics, including prior fractures at other anatomical sites, pre-fracture anemia remained associated with nonunion following tibial and femoral fractures, with hazard ratios of 1.83 (95% confidence interval, 1.54 to 2.18) and 1.38 (95% confidence interval, 1.26 to 1.50), respectively. Associations were also observed for nutritional and other anemias, whereas estimates for hemolytic and aplastic anemias were limited by few nonunion events. Within the femur, the association was strongest for distal fractures. These findings demonstrate that pre-fracture anemia is independently associated with nonunion. The increase in risk with greater anemia burden and findings across evaluable subgroups suggest that pre-fracture anemia may help identify patients at increased risk of impaired fracture healing.

Abstract Fractures in older adults cause high morbidity and mortality. This study aims to identify fracture incidence and risk factors, and to develop the Fracture Risk Model-Abu Dhabi (FRM-AD). Method This retrospective cohort study of 1757 males and females aged 40+ from Abu Dhabi, United Arab Emirates, who participated in a screening program from 2016 to 2020, followed until 2024 for 4.7 years, SD =1.8. It utilized Electronic Medical Records (EMRs) data and telephone interviews. The outcome assessed was the occurrence of fractures. Results There were 58 out of the 1149 females (5.0%) and 26 out of the 608 males (4.3%) who had at least one incident fracture. Hip and vertebral fractures accounted for 12.1% and 11.5%, respectively. There was an annual incidence of 10.5 fractures per 1,000 person-years, 10.7 cases among females and 9.9 among males, rising after age 80 to 39.1 among females and 25.3 among males. Fracture Predictors identified using Poisson regression analysis were older age, smoking, history of previous fracture(s), interaction of history of fracture in a parent with a family history of osteoporosis, positive history of hip fracture in a parent after the age of 40, lack of dyslipidemia diagnosis and the interaction of diabetes mellitus diagnosis and family history of osteoporosis. A higher Body Mass Index (BMI) increased the risk of fractures in this cohort, especially in obese males. Logistic regression of variables at the end of follow-up showed that lower latest vitamin D levels were associated with increased fracture risk. FRM-AD, derived using Poisson regression, performed well in predicting fractures, with Receiver Operating Characteristic (ROC) curves of 0.736 (0.677-0.794) and 0.742 (0.684-0.800) without and with BMD, respectively. The FRAX AUC to predict MOF and hip fracture ranged between 0.624 and 0.683. Conclusion In this Emirati cohort, the locally derived FRM-AD showed moderate discrimination for incident fracture and outperformed FRAX-AD, suggesting that a locally derived model may improve fracture risk stratification. Several risk factors and predictors were identified that can be targeted for prevention.