The postnatal growth plate undergoes dynamic morphogenetic changes essential for endochondral bone formation. While morphogen signaling in this context is well studied, microRNA-mediated post-transcriptional control is poorly understood. Here, we identify miR-433-3p (miR-433) as a key regulator of chondrocyte proliferation and hypertrophy, acting in part through direct targeting of vital chondrocyte genes. miR-433 is evolutionarily conserved and prominently expressed in precursor chondrocytes embryonically and in the proliferating zone of the growth plate postnatally. To interrogate miR-433 function in vivo, we generated a conditional miR-433 tough decoy (competitive inhibitor) mouse model to decrease endogenous miR-433 activity in a lineage-restricted manner. Male and female mice expressing miR-433 tough decoy in Prrx1-expressing skeletal progenitors and their progeny exhibited shortened and narrower femurs, while significantly decreased trabecular bone volume was only apparent in males. Male miR-433 decoy mice had disorganized growth plates with fewer resting zone cells, abnormal hypertrophic-like cells in the proliferative zone and delayed secondary ossification center development. These defects were accompanied by elevated expression of Sox9, Ihh, PTHrP, Bmpr1a, as well as increased expression of validated miR-433 targets Runx2, Hdac6, and Hif1a. Tempering miR-433 activity increased proliferation in the resting zone at one and three weeks of age, and intensified SOX9 immunofluorescence throughout growth plate, including the hypertrophic zone. The miR-433 target RUNX2 was ectopically expressed within the proliferating zone and showed increased expression in the hypertrophic zone, consistent with premature hypertrophic transition. Luciferase assays confirmed direct targeting of Bmpr1a and Ihh by miR-433. Given that BMP signaling induces Sox9 and IHH promotes Runx2 expression, miR-433 may act as a molecular brake on both BMP and Hedgehog signaling axes, contributing to the spatial restriction of transcriptional programs driving chondrocyte maturation, thereby safeguarding orderly chondrocyte differentiation and bone elongation.

Hutchinson-Gilford Progeria Syndrome (HGPS) is a devastating ultrarare genetic premature aging disease resulting in early atherosclerosis and death during adolescence due to heart failure. Structures of mesenchymal origin, including bone, fat, and muscle, create a progressive skeletal dysplasia, lifelong failure to thrive, and unique bone phenotype. Characterizing the interaction between muscle and bone has emerged as a powerful tool for defining drivers of bone disease in other conditions but has not been previously explored in HGPS. We examined the "muscle-bone unit" using radial pQCT in youth with HGPS aged 2 to 18 years before and after treatment with lonafarnib, a farnesyltransferase inhibitor that extends HGPS lifespan. Untreated radii displayed highly abnormal shapes in 70% of individuals spanning all ages. Compared to controls, HGPS forearm muscle and radial area were lower (p<0.001) and grew more slowly (muscle β=1.4 cm2/year vs. 0.3 cm2/year in HGPS; radius β=5.8 mm2/year vs. 0.5 mm2/year in HGPS). Fat area decreased with age (β=-0.2 cm2/year, p<0.001) and muscle area, normalized for either BMI or radial length, was reduced in HGPS (p=0.02 and p=<0.001, respectively). These normalized outcomes were similar to controls at younger ages but diverged as patients aged. Radial architectural changes were present even before changes in muscle area and represent a pattern distinct from the normal aging process and other muscle-wasting pediatric conditions. Lonafarnib therapy did not normalize the muscle-bone phenotype after 24 months, although some individuals (25%) had partial normalization of radial shape. These results demonstrate that the muscle-bone unit is uncoupled in children with HGPS. Normal muscle mass for body size at younger ages implies that there is an opportunity for early treatment to avoid impending pathology. New strategies are needed to ameliorate this phenotype in HGPS, and this study provides a benchmark for gauging future therapies.

Clinical use of areal bone mineral density (aBMD) to identify fracture risk assumes that aBMD reflects bone mineral content (BMC). Yet, aBMD is calculated using a ratio of BMC and bone area, thus declines in aBMD may reflect a decline in BMC, an increase in bone area, or both. This study identifies groups of individuals defined based upon patterns of change in BMC and bone area across the menopausal transition (MT). The Michigan Bone Health and Metabolism Study is a longitudinal study of women; participants aged 24-50 were recruited in 1992 and followed near annually through 2010. At each visit, a DXA of the femoral neck was assessed. This analysis is based upon data from 97 women with an observed non-surgical final menstrual period (FMP); a dual-energy X-ray absorptiometry (DXA) scan 10 yr before FMP; and at least one post-FMP DXA. Group-based trajectory modeling identified distinct patterns of bone change across the MT. Three trajectory groups were identified for both bone area and BMC. For bone area, 27.8% of women showed initial steep increases in bone area followed by a continued increase around the FMP ("Highest Bone Area" group). For BMC, 26% of women experienced a substantial BMC decline after the FMP ("Fastest BMC Decline" group). Women in the both the "Highest Bone Area" and "Fastest BMC Decline" groups experienced the greatest aBMD decline (mean 12.8% decrease, SD 8.1%) despite higher baseline aBMD. Consideration of BMC and bone area changes across the lifecourse represents a novel approach to understanding overall bone health, and may elucidate an at-risk group not identified on aBMD alone. This information may be highly informative in identifying women at greatest risk for low aBMD and future risk for fracture.

Ossification of the Posterior Longitudinal Ligament (OPLL) and Diffuse Idiopathic Skeletal Hyperostosis (DISH) are debilitating conditions characterized by pain, stiffness, myelopathy, and impaired mobility due to progressive enthesopathies and spinal fractures. These disorders worsen with age and may lead to hemiplegia. The underlying mechanisms of these diseases remain poorly understood, and effective treatments are currently lacking. To elucidate the pathogenesis of OPLL, we conducted a prospective study involving plasma analyte measurement in 50 consecutive OPLL and 25 consecutive cervical osteoarthritic (OA) patients who presented for surgical correction within the same time frame, followed by exome sequencing of 19 genes associated with phosphate wasting and spinal ligament enthesopathy/ossification. Our study identified a significant association between OPLL and ENPP1 deficiency. Specifically, we observed that OPLL patients exhibited decreased plasma levels of inorganic pyrophosphate (PPi) while maintaining unaltered alkaline phosphatase levels. Additionally, 17% of OPLL patients harbored monoallelic pathogenic variants in ENPP1, the mammalian enzyme responsible for extracellular PPi. Using Enpp1-deficient mice (Enpp1asj) to model the condition, we discovered pathologic mineralization of the spine, long bones, and tendons, alongside increased long bone and spinal fracture risk by 17 wk of age. We further assessed the therapeutic potential of two forms of ENPP1 enzyme replacement therapies. Bone-targeted ENPP1 significantly ameliorated the spinal hyperostosis, improved or normalized spinal and long bone fragility, ameliorated tendon enthesopathies, and improved trabecular microarchitecture. Meanwhile, soluble ENPP1 prevented tendon enthesopathies, normalized cortical bone microarchitecture, and improved long bone fragility. Our findings establish a clear link between decreased plasma PPi, ENPP1 deficiency, and OPLL, unveiling additional therapeutic targets to more effectively manage this poorly treated condition.

Despite advancements in fracture prediction tools and osteoporosis management, hip fractures remain a significant consequence of bone fragility, with a 22% one-year mortality. Hip geometric measures (GMs) have been associated with fracture risk; however, their strong correlation hinders the identification of independent influences, leaving their relative predictive value unclear. Statistical shape modelling (SSM) provides a more holistic assessment of hip shape compared to using pre-determined GMs. This study aimed to evaluate whether SSM-derived hip shape from dual-energy X-ray absorptiometry (DXA) scans can predict hip fracture, independently of individual GMs. Previously, we applied SSM to left hip DXA images in UK Biobank, a large prospective cohort with linked hospital records, generating ten orthogonal hip shape modes (HSMs), that explained 86% of shape variance. Additionally, femoral neck width (FNW), femoral head diameter (FHD), and hip axis length (HAL) were derived from these DXAs. In the current analysis, Cox proportional hazard models, adjusted for age, sex, height, weight, bone mineral density (BMD), and GMs (FNW, HAL, FHD), were used to examine the longitudinal associations between each HSM and first incident hospital diagnosed hip fracture. A Bonferroni adjusted p-value threshold (p<0.004) was used to account for the 13 exposures. Among the 38,123 participants (mean age 63.7 years; 52% female; mean follow-up 5 years), 133 (0.35%) experienced subsequent hip fracture. HSM2, characterised by a narrower FNW, a higher neck shaft angle, and reduced acetabular coverage, showed a strong association with hip fracture risk (HR 1.32, 95% CI 1.11-1.58, P 1.47×10-3), which persisted after full adjustment (1.30, 1.09-1.55, 3.27×10-3). There was no evidence for an association with other HSMs. These findings suggest that DXA-derived hip shape is associated with hip fracture risk independently of BMD and GMs. Incorporating global hip shape into fracture risk assessment tools could enhance prediction accuracy and inform targeted interventions.

Hypophosphatasia (HPP) is a heritable multisystem disorder caused by pathogenic variants in the tissue non-specific alkaline phosphatase (ALP)-coding gene ALPL. The genotype-phenotype correlation in heterozygous adults with HPP remains incompletely understood. In this genotype-based study, we aimed to measure the prevalence of pathogenic or likely-pathogenic ALPL variants and test the hypothesis that HPP penetrance is low in adult carriers. A total of 37,147 genomes from unselected individuals visiting a tertiary care, academic medical center were investigated. Variants classified as pathogenic or likely-pathogenic were observed with a prevalence of 0.3% (n=109) or 1/341. Variant c.571G>A was most frequent (67.9%). A subset of 70 individuals had linked electronic health records (EHRs) and were termed ALPL+. All 70 ALPL+ individuals showed mild, mainly neurological, symptoms often reported in adults with HPP. However, low serum ALP, a hallmark of HPP, was found in only 65.7% (38/70) of ALPL+ individuals, and 12.9% (9/70) met the diagnostic criteria for HPP based on consensus guidelines, thus complete penetrance was low. Compared to controls lacking pathogenic or likely-pathogenic variants (ALPL-), the ALPL+ individuals had a higher probability of progression for mobility issues (median age 73 years ALPL+ vs. 82 years ALPL-, p=0.03), as well as a similar probability of progression for fatigue, arthritis or dental problems. Unexpectedly, 3.4% (5/148) of individuals in the ALPL- group met the diagnostic criteria for HPP, possibly due to unidentified variants or non-ALPL genetic factors. Overall, the data support our hypothesis and aids the management of carries of pathogenic ALPL variants.

Treatment decisions are being made for a 74 year-old woman with multiple and recent vertebral fractures. Romosozumab therapy is considered because of superior efficacy compared to other osteoporosis therapies. However, because of her age, well controlled hypertension and mild hyperlipidemia, she is, according to a risk calculator, at high risk for cardiovascular (CV) disease. Romosozumab is contraindicated for patients at very high risk of CV disease, and clinicians are advised to consider the skeletal benefits vs potential CV risks in patients with CV risk factors. The background information leading to that contraindication and recent real-world evidence about the relationship between romosozumab and CV risk is reviewed to aid in the discussion with the patient and her primary care provider.

The Wnt/β-catenin signaling pathway is a classical pathway that regulates bone metabolism. The G protein inhibitory α subunits 1 and 3 (Gαi1/3) can couple with multiple growth factor/cytokine receptors and act as universal adaptor proteins to mediate the activation of key downstream signaling pathways. However, it remains unclear whether and how Gαi1/3 proteins mediate Wnt/β-catenin signal transduction.

The regulation of bone physiology and pathophysiology is intricately controlled by a complex interplay of cellular and molecular mechanisms. In these processes, the precise spatiotemporal coordination of biological activities in bone-resident cells plays a central role. Recently, liquid-liquid phase separation (LLPS), a mechanism underlying membraneless biomolecular condensate formation, has emerged as a transformative area of research. LLPS refers to the phase transition of biomolecules under specific conditions, leading to the formation of biomolecular condensates, which orchestrate diverse cellular functions. In this review, we provide a comprehensive synthesis of how LLPS influences bone turnover, focusing on its role in regulating bone homeostasis and its dysregulation in bone disease pathogenesis. Furthermore, aside from addressing the current challenges and limitations in this nascent field, we explore the implications of LLPS in bone regeneration, preventive strategies, and precision medicine. Despite LLPS research being in its early stages, its rapid advancement underscores its crucial role in bone biology and highlights the urgent need to integrate LLPS insights with translational approaches to advance therapeutic interventions for bone disorders.

G protein α-subunit (Gαs), encoded by GNAS, mediates GPCR signaling through cAMP second messenger pathways, and plays a pivotal role in craniofacial morphogenesis and osteoblast differentiation. Craniosynostosis, one of the most prevalent craniofacial developmental anomalies, is characterized by the premature fusion of cranial sutures. Here, we identify germline heterozygous variants in GNAS as a novel genetic cause of craniosynostosis. Affected individuals presented with multiple-suture synostosis, recognizable dysmorphic features, brachydactyly, short stature, with or without hormone resistance. We identified three de novo missense variants (c.286A>G;p.K96E, c.758A>G;p.Y253C, and c.691C>T;p.R231C) and one maternally inherited splicing variant (c.1039-2A>G). Functional analyses using bioluminescence resonance energy transfer (BRET) assays compared these variants to well-characterized activating variants p.R201H and p.Q227L. All tested variants impaired trimeric G protein assembly to varying degrees and exhibited reduced coupling with PTHR1. While the p.R201H and p.Q227L variants induced excessive cAMP production, the craniosynostosis-associated variants either displayed decreased basal cAMP levels or reduced agonist-induced cAMP production compared to wild-type, suggesting an inactivating nature. In zebrafish models, heterozygous gnas inactivation recapitulated human phenotypes, including multiple-suture synostosis, craniofacial abnormalities, and short stature. Mechanistically, GNAS haploinsufficiency in human mesenchymal stem cells promoted osteogenic differentiation through disrupted cAMP-CREB signaling, which relieved SMAD6-mediated repression of RUNX2 transcription. This study establishes inactivating GNAS variants as a genetic cause of craniosynostosis, uncovers a disease mechanism linking G protein inactivation to craniosynostosis through defective GPCR signal transduction.

Chronic kidney disease (CKD) may be complicated by mineral and bone disorders (CKD-MBD). Data on the association between estimated glomerular filtration rate (eGFR) and bone microarchitecture are limited. We studied the link between eGFR and bone microarchitecture (baseline, changes) assessed by high resolution peripheral quantitative computed tomography (HR-pQCT) in older men followed for 8 years. In 826 men aged ≥60, eGFR was calculated using three equations based on creatinin and cystatin C: CKDEPI-2012, EKFC without race and sex, CKDEPI-2021 without race. Bone microarchitecture was assessed at the distal radius and distal tibia by HR-pQCT at baseline, then after 4 and 8 years. Reaction force and failure load were estimated by microfinite element analysis. Changes in bone measures across the eGFR classes were explored using linear mixed effect models. At baseline, distal radius bone microarchitecture did not differ across the eGFR groups (CKDEPI-2012), whereas distal tibia trabecular measures and failure load were higher in men with decreased eGFR. During the follow-up, lower eGFR was associated with more rapid decrease in total bone mineral density (Tt.BMD), cortical area (Ct.Ar) and BMD (Ct.BMD), trabecular BMD (Tb.BMD), and failure load at the distal radius. Low eGFR was also associated with faster increase in trabecular area (Tb.Ar) and trabecular distribution heterogeneity (Tb.1/N.SD). At the distal tibia, low eGFR was associated with more rapid decrease in Tt.BMD, Ct.Ar, Ct.BMD, Tb.1/N.SD, and failure load as well as with faster increase in Tb.Ar. The patterns were similar for changes expressed as percentages. The patterns were similar for two other equations. Lower eGFR is associated with faster decline in cortical bone microarchitecture and bone strength at the distal radius and tibia in older men. This phenomenon may contribute to the higher fracture risk in older adults with CKD.

More than 770 genetic skeletal disorders have been described, most with disease-causing variants reported in one of over 550 different genes. The ClinGen Skeletal Disorders Gene Curation Expert Panel was established to determine the strength of evidence that supports specific gene-disease relationships. Such information can assist clinical testing laboratories in choosing genes that should be included on diagnostic panels. Nine genes accounting for the most frequently encountered skeletal dysplasias (COL1A1, COL1A2, COL2A1, FGFR3, SLC26A2, TRPV4, COMP, ALPL, and SOX9) associated in the medical literature with 26 different skeletal disorders were reviewed using a semi-quantitative scoring framework. This framework is utilized by ClinGen to assess the clinical validity of gene-disease relationships. All nine genes were "Definitively" associated with at least one skeletal disorder and several were associated with multiple clinically or radiographically distinct skeletal conditions. Among these 26 gene-disease relationships, the ClinGen Skeletal Disorders Gene Curation Expert Panel determined that 22 (84.6%) had Definitive relationships, 2 (7.7%) had Moderate relationships, and 2 (7.7%) had Limited relationships. None of the 26 gene-disease relationships were Disputed or Refuted. For Moderate and Limited gene-disease relationships, clinical and genetic reports from additional probands and their families are needed to upgrade these gene-disease relationships to Definitive. Up-to-date assessments about the strength of the relationship between genes and phenotypes should improve the sensitivity and specificity of genetic testing in individuals with skeletal disease. The expert curations for the nine aforementioned genes are published on the ClinGen website.

High gastrin levels may help explain the association between several conditions and osteoporosis, such as pernicious anaemia, the use of proton pump inhibitors, and atrophic gastritis. This study aimed to determine whether administering a gastrin receptor antagonist (GRA) to older women would lower their bone turnover markers and, therefore, be a suitable preventive measure for osteoporosis. We conducted a randomised, double-blind, placebo-controlled clinical trial to assess the efficacy, safety, and tolerability of an oral GRA (netazepide) 100 mg administered daily for 90 days in postmenopausal women. Our primary endpoint was the change in the bone turnover marker (BTM) plasma CTX (automated immunoassay analyser) at days 0, 7, 28, 56, and 90. We also measured other BTMs, and gastrin and group I pepsinogens (ELISA assays). We studied the effect of the drug on the log-transformed baseline scaled ratio for bone turnover marker and gastric markers using mixed-model ANOVA for the fixed effects of treatment, time, and the treatment-by-time interaction, with the baseline value included as a covariate. We studied 99 women, with a mean age of 60 years and BMD T- scores for the spine and total hip of -0.96 and -0.09, respectively. We found that gastrin increased by 90% in response to GRA as early as 7 days (p-value for treatment 0.0008), and group I pepsinogens decreased by 15% as early as 7 days (p-value 0.0002). There was no significant change in plasma CTX. A high percentage of women (81/99) completed the study, and the GRA was well tolerated. GRA had the expected effects on the gastric markers with an increase in gastrin and a decrease in group I pepsinogens. However, the absence of any change in the bone resorption marker plasma CTX was a bit surprising. Based on this study it appears that short term gastrin receptor antagonism is unlikely to be a successful strategy in the prevention of osteoporosis. However, this a preliminary exploration of a novel hypothesis and larger studies might be needed.

Vitamin C has been long recognized as an important nutrient for skeletal biology, historically attributed to its role in collagen synthesis and connective tissue integrity. Recent studies, however, reveal vitamin C as a critical epigenetic regulator of cellular differentiation. As a required cofactor for α-ketoglutarate-dependent dioxygenases, vitamin C controls the enzymatic activity of a broad array of histone and DNA demethylases, thereby modulating chromatin accessibility and driving cell-specific gene expression. This review provides a novel, integrated perspective that directly links vitamin C's epigenetic functions to osteogenesis and skeletal health, highlighting experimental evidence that redefines its role beyond collagen maturation and antioxidant defense, and elucidating its sex-dimorphic effects. Importantly, inadequate vitamin C status remains widespread across diverse socioeconomic groups even in Western countries, with low vitamin C intake associated to higher risk of osteoporosis and fractures in the elderly. Viewed through the dual lenses of epigenetic-mechanistic function and clinical relevance, vitamin C emerges as a central epigenetic determinant of skeletal health and a safe, low-cost, and scalable adjuvant to complement current bone therapies. Integrating nutrient epidemiology, clinical data and epigenetic-mechanistic insights may enable targeted interventions to enhance skeletal resilience, particularly in vulnerable populations.

For a given bone mineral density, adults with type 2 diabetes (T2D) have greater fracture risk than adults without the disease. To test the hypothesis that T2D lowers the fracture resistance of human cortical bone by negatively altering the bone matrix quality, we acquired cadaveric femurs from 120 female and male donors >50 yr old: 60 without diabetes (Ctrl) & 60 with T2D for ≥10 yr). We scanned a cross-section from each diaphysis using ex vivo micro-computed tomography (μCT), followed by cyclic reference point indentation (cRPI: 0 to 10 N for 20 cycles) and impact micro-indentation on the medial surface. From the medial quadrant, a tensile specimen and a single-edge notched beam (SENB) were mechanically tested to assess differences in fracture resistance. Multiple techniques characterized the organic matrix within the SENB. The cortical bone area and thickness of the diaphysis were higher in T2D than in Ctrl. The average creep indentation distance of periosteal bone tissue was significantly lower with T2D suggesting greater resistance to micro-indentation. Bone material strength index though trended to be lowering in T2D than in Ctrl but only when the comparison was adjusted for age, sex, and body mass index. There were also T2D-related differences in the organic matrix: (i) higher non-enzymatic and mature enzymatic crosslinks, (ii) higher fluorescent advanced glycation end-products, and (iii) higher thermal stability. Despite these tissue- and molecular-level differences, mechanical properties of cortical bone were similar between the 2 groups. Tensile strength was lower (p = .035) while pentosidine was higher (p = .006) in donors with chronic kidney disease than donors without kidney disease, but the difference in strength (p = .055) and pentosidine (p = .151) were not strictly significant when adjusting for covariates. The elevated fracture risk in T2D may not be a problem of poor mechanical properties of cortical bone, despite alterations in the organic matrix.

Current fracture risk assessment does not directly include fall probability, despite most hip fractures resulting from falls. Additionally, the role of trochanteric soft tissue thickness (TST) in hip fracture risk remains unclear. This study aimed to develop a subject-specific fall risk tool and test whether incorporating fall probability and TST improves hip fracture prediction beyond FRAX alone in older adults from the AGES-Reykjavik study. Baseline data from 3242 individuals (58% women) were used to predict repeated falls (≥2 in 12 months) at follow-up (~5 years later) via multivariate logistic regression, considering age, sex, fall history, neuromuscular function, dynamic balance, and medication use. In a case-cohort study (698 hip fractures, 1348 controls; median follow-up 10 years), Cox proportional hazards models assessed hip fracture risk. We compared the predictive value of fall probability and TST combined with FRAX against FRAX alone using time-dependent AUC at 5-, 10-, and 16-year follow-up. At follow-up, 295 individuals had ≥2 falls in the past year. The best model for future falls included a timed up-and-go test, fall history, and grip strength. The probability of falling predicted incident hip fracture and improved hip fracture prediction beyond FRAX, in both men and women. The improved predictive value of fall risk was greater among men than women (e.g. AUC for predicting 10 yrs hip fracture risk, 0.83 (95%CI 0.79-0.87) in men vs 0.75 (95%CI 0.72-0.78) in women). Lower TST was linked to higher hip fracture risk in women but not men. However, adding TST to a model with fall probability and FRAX among women did not enhance time-dependent AUC (p>0.10). In conclusion, fall probability significantly improves hip fracture prediction beyond FRAX, particularly in men. Thus, subject-specific fall risk assessment may enhance clinical evaluation of hip fracture risk in older adults.

Osteoporosis is a major health concern in older individuals. Efficient case-finding is essential for timely risk assessment and treatment for high-risk patients. To prevent fractures and reduce the risk of subsequent disability, approaches offering clinically sufficient sensitivity with acceptable specificity are warranted. Although pharmaceutical osteoporosis treatment is effective, it is often diagnosed at a late stage, for instance following a fracture. The aim of this study was to extend the existing Fracture Risk Evaluation Model (FREM), which identifies individuals at risk of an imminent (one-year) major osteoporotic fracture (MOF) based on administrative health data. This extension (FREMVer2) included data on morbidity and medications and evaluated age-specific risk cut-offs to enhance the risk assessment of MOF and hip fracture (HF) risk, respectively. We included the entire population of Denmark aged ≥45 yr at baseline (2022; N = 2 493 180), not previously diagnosed with osteoporosis or receiving osteoporosis treatment. The cohort was divided into four groups stratified by sex and age (<65 yr, ≥65 yr). Each of the four groups was randomly split into a 60% development, a 20% model validation, and a 20% cut-off validation cohort. All diagnoses from Danish hospitals and filled prescriptions from Danish pharmacies from 2007-2021 were used as possible predictors for MOF. These predictors correspond to information that in Denmark is automatically transferred to general practitioner's electronic health records; hence, prediction would be possible in general practice. Models were constructed by logistic regression with LASSO regularization, determining the preferred regularization hyper parameter by cross-validation and forcing categorical age to be included. Across subgroups models obtained poor to acceptable AUCs of 0.656 to 0.714 for MOF, and acceptableAUCs of 0.728 to 0.764 for hip fractures, and achieved sensitivities of around than 80% or higher in almost all subgroups. This performance, together with the available predictors, makes FREMver2 a feasible decision support system as a step towards an opportunistic screening program in health care settings with access to administrative data.