Discrepancies in bone mineral density and fracture risk in patients with type 1 and type 2 diabetes--a meta-analysis

Single-cell RNA sequencing reveals a distinct profile of bone immune microenvironment and decreased osteoclast differentiation in type 2 diabetic mice

The pathogenic effects of type 2 diabetes on bone tissue are gaining attention, but the cellular and molecular mechanisms underlying osteoimmunology are still unclear in diabetes-related bone diseases. We delineated the single-cell transcriptome of bone marrow cells from both wide type and type 2 diabetes mice, which provided the first detailed global profile of bone marrow cells and revealed a distinct bone immune microenvironment at the genetic level under type 2 diabetic condition. It was observed that osteoclast activity was inhibited due to a dysregulated cytokine network, which ultimately led to decreased osteoclast formation and differentiation. In type 2 diabetes mice, a specific C d 36 + cluster (cluster 18, monocytes/macrophages 2) was identified as the precursor of osteoclasts with diminished differentiation potential. AP-1 was demonstrated to be the key transcription factor in the underlying mechanism.

Mineral and cross-linking in collagen fibrils: The mechanical behavior of bone tissue at the nano-scale

The mineralized collagen fibril is the main building block of hard tissues and it directly affects the macroscopic mechanics of biological tissues such as bone. The mechanical behavior of the fibril itself is determined by its structure: the content of collagen molecules, minerals, and cross-links, and the mechanical interactions and properties of these components. Advanced glycation end products (AGEs) form cross-links between tropocollagen molecules within the collagen fibril and are one important factor that is believed to have a major influence on the tissue. For instance, it has been shown that brittleness in bone correlates with increased AGEs densities. However, the underlying nano-scale mechanisms within the mineralized collagen fibril remain unknown. Here, we study the effect of mineral and AGEs cross-linking on fibril deformation and fracture behavior by performing destructive tensile tests using coarse-grained molecular dynamics simulations. Our results demonstrate that after exceeding a critical content of mineral, it induces stiffening of the collagen fibril at high strain levels. We show that mineral morphology and location affect collagen fibril mechanics: The mineral content at which this stiffening occurs depends on the mineral's location and morphology. Further, both, increasing AGEs density and mineral content lead to stiffening and increased peak stresses. At low mineral contents, the mechanical response of the fibril is dominated by the AGEs, while at high mineral contents, the mineral itself determines fibril mechanics.

Fracture risk revisited: Bone mineral density T-score and fracture risk in type 2 diabetes

AIM

To study the association between femoral neck (FN) bone mineral density (BMD) T-score and fracture risk in individuals with and without type 2 diabetes (T2D).

MATERIALS AND METHODS

We performed a single-centre retrospective cohort study using the Danish National Health Service. BMD of the FN was measured by dual-energy X-ray absorptiometry. Cox proportional hazards regression models were used to study the association between FN BMD T-score and fractures in individuals with and without T2D separately, adjusted for age, comorbidities and comedication. The results from this analysis were used to estimate the 10-year absolute fracture risk.

RESULTS

In total, there were 35,129 women (2362 with T2D) and 7069 men (758 with T2D). The FN BMD T-score was significantly associated with risk of any, hip and major osteoporotic fracture in men and women with [adjusted hazard risk ratios (aHR) women, hip: 1.57; 95% confidence interval (CI) 1.24-2.00, incidence rate (IR) 8.7; aHR men, hip: 1.55; 95% CI 1.01-2.36, IR 4.6] and without T2D (aHR women, hip: 1.75; 95% CI 1.64-1.87, IR 7.0; aHR men, hip: 1.97, 95% CI 1.73-2.25, IR 6.3), and its ability to predict fracture risk was similar. Fracture IRs were not significantly different for individuals with or without T2D, nor was the estimated cumulative 10-year fracture risk.

CONCLUSIONS

The FN BMD T-score was significantly associated with hip, non-spine and major osteoporotic fracture risk in men and women with and without T2D. Fracture risk for a given T-score and age was equal in individuals with and without T2D, as was the ability of the FN BMD T-score to predict fracture risk.

The association of type 2 diabetes-related characteristics with fracture risk at different sites

AIM

To determine the association of diabetes-related characteristics with fractures at different sites in individuals with type 2 diabetes (T2D).

MATERIALS AND METHODS

We conducted a cohort study using the Clinical Practice Research Datalink (CPRD) GOLD. Patients aged over 30 years with T2D were identified within the CPRD. Patients were followed from the start of diabetes treatment until the end of data collection, death, or the occurrence of a fracture. Cox proportional hazards models were used to estimate the hazard ratios for the association of the individual characteristics (diabetes duration, glycated haemoglobin [HbA1c] level, and microvascular complications) with fracture risk, adjusted for demographics, comorbidities and comedication.

RESULTS

A diabetes duration of >10 years was associated with an increased risk of any fracture and major osteoporotic fractures (MOFs), while a diabetes duration of >8 years was associated with an increased hip fracture risk, compared to a duration <2 years. An HbA1c level <6% was associated with an increased fracture risk compared to HbA1c values of 6% to <7%. The presence of one or two microvascular complications was associated with an increased risk of any fracture and MOFs and the presence of two microvascular complications was associated with an increased hip fracture risk, compared to no microvascular complications.

CONCLUSION

In conclusion, our study shows that a diabetes duration of 10 years or more, strict glycaemic control resulting in HbA1c levels below 6%, and/or the presence of at least one microvascular complication increased the risk of any fracture, hip fractures, MOFs, and humerus fractures, but not ankle, scapula or skull fractures.

A Randomized Controlled Trial on the Effect of Luseogliflozin on Bone Microarchitecture Evaluated Using HR-pQCT in Elderly Type 2 Diabetes

INTRODUCTION

Bone fragility is a critical issue in the treatment of elderly people with type 2 diabetes (T2D). In the Canagliflozin Cardiovascular Assessment Study, the subjects with T2D who were treated with canagliflozin showed a significant increase in fracture events compared to a placebo group as early as 12 weeks post-initiation. In addition, it has been unclear whether sodium-glucose co-transporter 2 (SGLT2) inhibitors promote bone fragility. We used high-resolution peripheral quantitative computed tomography (HR-pQCT) to prospectively evaluate the short-term effect of the SGLT2 inhibitor luseogliflozin on bone strength and microarchitecture in elderly people with T2D.

METHODS

This was a single-center, randomized, open-label, active-controlled pilot trial for ≥ 60-year-old Japanese individuals with T2D without osteoporosis. A total of 22 subjects (seven women and 15 men) were randomly assigned to a Lusefi group (added luseogliflozin 2.5 mg) or a control group (added metformin 500 mg) and treated for 48 weeks. We used the second-generation HR-pQCT (Xtreme CT II®, Scanco Medical, Brüttisellen, Switzerland) before and 48 weeks after the treatment to evaluate the subjects' bone microarchitecture and estimate their bone strength.

RESULTS

Twenty subjects (Lusefi group, n = 9; control group, n = 11) completed the study, with no fracture events. As the primary outcome, the 48-week changes in the bone strength (stiffness and failure load) estimated by micro-finite element analysis were not significantly different between the groups. As the secondary outcome, the changes in all of the cortical/trabecular microarchitectural parameters at the radius and tibia from baseline to 48 weeks were not significantly different between the groups.

CONCLUSIONS

In the pilot trial, we observed no negative effect of 48-week luseogliflozin treatment on bone microarchitecture or bone strength in elderly people with T2D.

TRIAL REGISTRATION

UMIN-CTR no. 000036202 and jRCT 071180061.

Prevalence of vertebral fractures and associated factors in thai diabetic postmenopausal women

T2DM (Type 2 Diabetes Mellitus) patients with vertebral fractures have a higher mortality rate than non-DM (nondiabetic patients). However, the prevalence of vertebral fractures in the Asian diabetic population is not well established. Moreover, despite an apparent increase in fracture risk in patients with diabetes, Asian countries have provided contradictory data demonstrating that bone mineral density (BMD) varies significantly in T2DM patients. The aim of this study was to examine and compare the prevalence of vertebral fractures and osteoporosis, as well as BMD and the FRAX score, between individuals with and without T2DM and assess the association of these factors with vertebral fractures. Postmenopausal Thai women attending diabetic and health check-up clinics were recruited. BMD at the lumbar spine, total hip, and femoral neck was measured via dual-energy X-ray absorptiometry. A morphometric vertebral fracture (VF) was defined by a lateral thoracolumbar (T-L) X-ray radiograph. The Fracture Risk Assessment Tool (FRAX) was used to calculate the 10-year probabilities of hip and major osteoporotic fracture (MOF), which were calculated on the basis of the Thai FRAX model. A total of 435 participants were recruited, including 145 postmenopausal women with T2DM and 290 non-DM individuals. T2DM patients had a significantly greater BMI (p = 0.006) and BMD at the femoral neck (p = 0.024) and total hip (p = 0.017), but there was no significant difference in the FRAX score, including the 10-year probability of hip fracture or MOF, either with or without BMD, between individuals with and without T2DM. The prevalence of osteoporosis in non-DM women was significantly higher at the femoral neck (OR = 0.56, 95% CI: 0.34 to 0.93, p = 0.029) but comparable at the lumbar spine. Individuals with T2DM had a significantly higher rate of vertebral fractures, particularly those involving two or more levels, than those without T2DM. Diabetes was significantly associated with [Formula: see text]2 VF (OR = 3.83, 95% CI: 1.77 to 8.28, p = 0.001), and the association remained unchanged after controlling for other clinical factors (adjusted OR = 3.72, 95% CI 1.70-8.15; p = 0.001). Our study demonstrated a greater prevalence of multiple ([Formula: see text] two levels) VFs in women with T2DM than in non-DM controls.

Microvascular disease and early diabetes onset are associated with deficits in femoral neck bone density and structure among older adults with longstanding type 1 diabetes

Adults with type 1 diabetes (T1D) have increased hip fracture risk, yet no studies have assessed volumetric bone density or structure at the hip in older adults with T1D. Here, we used previously collected 3D CT scans of the proximal femur from older adults with longstanding T1D and non-diabetic controls to identify bone deficits that may contribute to hip fracture in T1D. In this retrospective cohort study, we identified 101 adults with T1D and 181 age-, sex-, and race-matched non-diabetic controls (CON) who received abdominal or pelvis CT exams from 2010 to 2020. Among adults with T1D, 33 (33%) had mild-to-moderate nephropathy, 61 (60%) had neuropathy, and 71 (70%) had retinopathy. Within the whole cohort, adults with T1D tended to have lower FN density, though differences did not reach statistical significance. The subset of the T1D group who were diagnosed before age 15 had lower total BMC (-14%, TtBMC), cortical BMC (-19.5%, CtBMC), and smaller Ct cross-sectional area (-12.6, CtCSA) than their matched controls (p<.05 for all). Individuals with T1D who were diagnosed at a later age did not differ from controls in any bone outcome (p>.21). Furthermore, adults with T1D and nephropathy had lower FN aBMD (-10.6%), TtBMC (-17%), CtBMC (-24%), and smaller CtCSA (-15.4%) compared to matched controls (p<.05 for all). Adults with T1D and neuropathy had cortical bone deficits (8.4%-12%, p<.04). In summary, among older adults with T1D, those who were diagnosed before the age of 15 yr, as well as those with nephropathy and neuropathy had unfavorable bone outcomes at the FN, which may contribute to the high risk of hip fractures among patients with T1D. These novel observations highlight the longstanding detrimental impact of T1D when present during bone accrual and skeletal fragility as an additional complication of microvascular disease in individuals with T1D.

[Etiopathogenetic features of bone metabolism in patients with diabetes mellitus and Charcot foot]

Diabetic neuropathy is one of the most common diabetes mellitus complications associated with mediocalcinosis of the lower extremities, a significant decrease in feet bone mineral density, and a high incidence of cardiovascular disease. In most cases, calcium-phosphorus metabolism changes occur in patients with diabetic neuroarthropathy, or Charcot foot, when we can observe feet local osteoporosis, which in 90% of cases associated with a vessel's calcification of the lower extremities in the majority of diabetes population. A large number of studies presented literature have demonstrated that patients with Charcot foot can have accelerated bone metabolism and increased bone resorption. Patients with Charcot foot often have crucial abnormalities in the calcium-phosphorus parameters, bone metabolism, and levels of vitamin D and its metabolites. In addition, the duration of diabetes mellitus, the degree of its compensation widely affects the development of its micro- and macrovascular complications, which could also accelerate the development of mineral and bone disorders in these types of patients. Multifactorial pathogenesis of these disorders complicates the management of patients with a long and complicated course of diabetes mellitus. This review discusses the peculiarities of vitamin D metabolism, the importance of timely diagnosis in phosphorus-calcium disorders, and the specifics of therapy in these patients. Special attention is paid to the timely diagnosis of the Charcot's foots acute stage based on the bone marrow edema by MRI evaluation and the possibility of reducing the immobilization period.

Insulin resistance, bone health, and fracture risk

Insulin resistance, defined as an impaired biological response to insulin stimulation in target tissues, arises most frequently in the presence of central obesity. Although obesity is generally associated with increased bone mass, recent data challenge this view and, if complicated by T2DM, obese patients are at high risk for fragility fractures. IR may play a key role in this increased fracture risk through effects on bone quality rather than bone quantity. Further understanding of the mechanisms and approaches to prevent osteoporotic fractures in IR-related diseases is needed.

CLINICAL RELEVANCE

The dramatic increase in obesity and metabolic syndrome (MetS) over the last half-century has led to a worldwide epidemic of type 2 diabetes mellitus (T2DM) as well as in the incidence of insulin resistance (IR). IR is defined as an impaired biological response to insulin stimulation in target tissues and is primarily related to the liver, muscle, and adipose tissue. The most frequent underlying cause is central obesity, and it is known that excess abdominal adipose tissue secretes increased amounts of free fatty acids, which directly affects insulin signalling, reduces glucose uptake in muscle, and triggers excessive triglyceride synthesis and gluconeogenesis in the liver. When pancreatic β cells are unable to secrete the higher levels of insulin needed, T2DM, the main complication of IR, occurs.

OBSERVATIONS

Although obesity is generally associated with increased bone mass, recent data challenge this view and highlight the multifaceted nature of the obesity-bone relationship. Patients with T2DM are at significant risk for well-known complications of diabetes, including retinopathy, nephropathy, macrovascular disease, and neuropathy, but it is clear that they are also at high risk for fragility fractures. Moreover, recent data provide strong evidence that IR may key role in the increased fracture risk observed in both obesity and T2DM.

CONCLUSIONS

In this concise review article, the role of IR in increased risk of osteoporotic fractures in MetS, obesity, and T2DM is discussed and summarised, including consideration of the need for fracture risk assessment as a 'preventive measure', especially in patients with T2DM and chronic MetS with abdominal obesity. Personalised and targeted diagnostic and therapeutic approaches to prevent osteoporotic fractures in IR-related diseases are needed and could make significant contributions to health outcomes.

Diabetes Risk Factors and Bone Microarchitecture as Assessed by High-Resolution Peripheral Quantitative Computed Tomography in Adults With Long-standing Type 1 Diabetes

OBJECTIVE

To determine whether type 1 diabetes and its complications are associated with bone geometry and microarchitecture.

RESEARCH DESIGN AND METHODS

This cross-sectional study was embedded in a long-term observational study. High-resolution peripheral quantitative computed tomography (HR-pQCT) scans of the distal radius and distal and diaphyseal tibia were performed in a subset of 183 participants with type 1 diabetes from the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study and 94 control participants without diabetes. HbA1c, skin advanced glycation end products (AGEs), and diabetes-related complications were assessed in EDIC participants with >30 years of follow-up.

RESULTS

Compared with control participants (aged 60 ± 8 years, 65% female), EDIC participants (aged 60 ± 7 years, diabetes duration 38 ± 5 years, 51% female) had lower total bone mineral density (BMD) at the distal radius (-7.9% [95% CI -15.2%, -0.6%]; P = 0.030) and distal tibia (-11.3% [95% CI -18.5%, -4.2%]; P = 0.001); larger total area at all sites (distal radius 4.7% [95% CI 0.5%, 8.8%; P = 0.030]; distal tibia 5.9% [95% CI 2.1%, 9.8%; P = 0.003]; diaphyseal tibia 3.4% [95% CI 0.8%, 6.1%; P = 0.011]); and poorer radius trabecular and cortical microarchitecture. Estimated failure load was similar between the two groups. Among EDIC participants, higher HbA1c, AGE levels, and macroalbuminuria were associated with lower total BMD. Macroalbuminuria was associated with larger total area and lower cortical thickness at the distal radius. Higher HbA1c and AGE levels and lower glomerular filtration rate, peripheral neuropathy, and retinopathy were associated with deficits in trabecular microarchitecture.

CONCLUSIONS

Type 1 diabetes is associated with lower BMD, larger bone area, and poorer trabecular microarchitecture. Among participants with type 1 diabetes, suboptimal glycemic control, AGE accumulation, and microvascular complications are associated with deficits in bone microarchitecture and lower BMD.

Bone Fragility in Diabetes and its Management: A Narrative Review

Bone fragility is a serious yet under-recognised complication of diabetes mellitus (DM) that is associated with significant morbidity and mortality. Multiple complex pathophysiological mechanisms mediating bone fragility amongst DM patients have been proposed and identified. Fracture risk in both type 1 diabetes (T1D) and type 2 diabetes (T2D) continues to be understated and underestimated by conventional risk assessment tools, posing an additional challenge to the identification of at-risk patients who may benefit from earlier intervention or preventive strategies. Over the years, an increasing body of evidence has demonstrated the efficacy of osteo-pharmacological agents in managing skeletal fragility in DM. This review seeks to elaborate on the risk of bone fragility in DM, the underlying pathogenesis and skeletal alterations, the approach to fracture risk assessment in DM, management strategies and therapeutic options.

Fractures in women with type 2 diabetes are associated with marked deficits in cortical parameters and trabecular plates

The basis for increased fracture risk in type 2 diabetes (T2DM) is not well understood. In this multi-ethnic, population-based study (n = 565), we investigated bone microstructure, trabecular plate/rod morphology, and mineralization in women with T2DM (n = 175) with and without fracture using a second-generation HRpQCT and individual trabecula segmentation and mineralization (ITS; ITM). Covariate-adjusted aBMD was 3.0%-6.5% higher at all sites (all p<.005) in T2DM vs controls. By HRpQCT, T2DM had higher covariate-adjusted trabecular vBMD (5.3%-6.4%) and number (3.8%-5.1%) and greater cortical area at the radius and tibia. Covariate-adjusted cortical porosity was 10.0% higher at the tibia only in T2DM vs controls, but failure load did not differ. Among women with T2DM, those with adult atraumatic fracture (n = 59) had 5.2%-8.5% lower adjusted aBMD at all sites by DXA compared with those without fracture (n = 103). By HRpQCT, those with fracture had lower adjusted total vBMD and smaller cortical area (10.2%-16.1%), lower cortical thickness (10.5-15.8%) and lower cortical vBMD associated with 18.1 and 17.2% lower failure load at the radius and tibia, respectively (all p<.05); plate volume and thickness were 5.7% and 4.7% lower, respectively, (p<.05) while rod volume fraction was 12.8% higher in the fracture group at the tibia only. Sodium glucose cotransporter 2 inhibitor users (SGLT2i; n = 19), tended to have lower radial rod tissue mineral density by ITS (p=.06). GLP1 agonist users (n = 19) had trabecular deficits at both sites and higher cortical porosity and larger pores at the distal tibia. In summary, T2DM is associated with increased cortical porosity while those with T2DM and fracture have more marked cortical deficits and fewer trabecular plates associated with lower failure load.

The Value of Mandibular Indices on Cone Beam Computed Tomography in Secondary Causes of Low Bone Mass

Background: As implant treatment cases increase, many cases of failure/side effects also occur. Generally, dental clinics determine the density of the jawbone using cone beam CT (CBCT). Considering the known potential role of this tool for bone assessment in primary osteoporosis, this study evaluated patients with secondary endocrine causes of low bone mass. Methods: The study included 83 patients with endocrine causes of osteoporosis who were evaluated by dual-energy X-ray absorptiometry (DXA), trabecular bone score (TBS), and mental foramen (MF) region CBCT. The following CBCT indices were measured: anterior (A)-thickness of inferior mandibular cortex 10 mm anterior from MF; molar (M)-thickness of inferior mandibular cortex 10 mm posterior from MF; posterior (P)-thickness of inferior mandibular cortex 25 mm posterior from MF; symphysis (S)-thickness of inferior mandibular cortex equidistant from the centers of right and left MF. Results: The highest correlation coefficient in the secondary causes group was between the A index and the lumbar BMD (r = 0.375, p = 0.001) and the P index and the femoral neck BMD (r = 0.38, p = 0.001). Hypercortisolism seems to be the most predictable cause of secondary osteoporosis using the A, M, and P indices. The A, M, and P indices showed predictive values of the bone micro-architecture that was evaluated using TBS score, and were statistically significant. The symphysis index does not significantly predict osteoporosis or impaired bone micro-architecture. Conclusions: These findings support the potential usefulness of A, M, and P CBCT-derived radiomorphometric mandibular indices in secondary osteoporosis, underlining the well-known effects of these pathologies on bone micro-architecture rather than bone quantity.

Genetic and Modifiable Risk Factors for Postoperative Complications of Total Joint Arthroplasty: A Genome-Wide Association and Mendelian Randomization Study

Background: Total joint arthroplasty (TJA) is an orthopedic procedure commonly used to treat damaged joints. Despite the efficacy of TJA, postoperative complications, including aseptic prosthesis loosening and infections, are common. Moreover, the effects of individual genetic susceptibility and modifiable risk factors on these complications are unclear. This study analyzed these effects to enhance patient prognosis and postoperative management. Methods: We conducted an extensive genome-wide association study (GWAS) and Mendelian randomization (MR) study using UK Biobank data. The cohort included 2964 patients with mechanical complications post-TJA, 957 with periprosthetic joint infection (PJI), and a control group of 398,708 individuals. Genetic loci associated with postoperative complications were identified by a GWAS analysis, and the causal relationships of 11 modifiable risk factors with complications were assessed using MR. Results: The GWAS analysis identified nine loci associated with post-TJA complications. Two loci near the PPP1R3B and RBM26 genes were significantly linked to mechanical complications and PJI, respectively. The MR analysis demonstrated that body mass index was positively associated with the risk of mechanical complications (odds ratio [OR]: 1.42; p < 0.001). Higher educational attainment was associated with a decreased risk of mechanical complications (OR: 0.55; p < 0.001) and PJI (OR: 0.43; p = 0.001). Type 2 diabetes was suggestively associated with mechanical complications (OR, 1.18, p = 0.02), and hypertension was suggestively associated with PJI (OR, 1.41, p = 0.008). Other lifestyle factors, including smoking and alcohol consumption, were not causally related to postoperative complications. Conclusions: The genetic loci near PPP1R3B and RBM26 influenced the risk of post-TJA mechanical complications and infections, respectively. The effects of genetic and modifiable risk factors, including body mass index and educational attainment, underscore the need to perform personalized preoperative assessments and the postoperative management of surgical patients. These results indicate that integrating genetic screening and lifestyle interventions into patient care can improve the outcomes of TJA and patient quality of life.

Assessment of causal association between the socio-economic status and osteoporosis and fractures: a bidirectional Mendelian randomization study in European population

The correlation between socio-economic status (SES) and bone-related diseases garners increasing attention, prompting a bidirectional Mendelian randomization (MR) analysis in this study. Genetic data on SES indicators (average total household income before tax, years of schooling completed, and Townsend Deprivation Index at recruitment), femoral neck bone mineral density (FN-BMD), heel bone mineral density (eBMD), osteoporosis, and five different sites of fractures (spine, femur, lower leg-ankle, foot, and wrist-hand fractures) were derived from genome-wide association summary statistics of European ancestry. The inverse variance weighted method was employed to obtain the causal estimates, complemented by alternative MR techniques, including MR-Egger, weighted median, and MR-pleiotropy residual sum and outlier (MR-PRESSO). Furthermore, sensitivity analyses and multivariable MR were performed to enhance the robustness of our findings. Higher educational attainment exhibited associations with increased eBMD (β: .06, 95% confidence interval [CI]: 0.01-0.10, P = 7.24 × 10-3), and reduced risks of osteoporosis (OR: 0.78, 95% CI: 0.65-0.94, P = 8.49 × 10-3), spine fracture (OR: 0.76, 95% CI: 0.66-0.88, P = 2.94 × 10-4), femur fracture (OR: 0.78, 95% CI: 0.67-0.91, P = 1.33 × 10-3), lower leg-ankle fracture (OR: 0.79, 95% CI: 0.70-0.88, P = 2.05 × 10-5), foot fracture (OR: 0.78, 95% CI: 0.66-0.93, P = 5.92 × 10-3), and wrist-hand fracture (OR: 0.83, 95% CI: 0.73-0.95, P = 7.15 × 10-3). Material deprivation appeared to increase the risk of spine fracture (OR: 2.63, 95% CI: 1.43-4.85, P = 1.91 × 10-3). A higher FN-BMD level positively affected increased household income (β: .03, 95% CI: 0.01-0.04, P = 6.78 × 10-3). All these estimates were adjusted for body mass index, type 2 diabetes, smoking initiation, and frequency of alcohol intake. The MR analyses show that higher educational levels is associated with higher eBMD, reduced risk of osteoporosis and fractures, while material deprivation is positively related to spine fracture. Enhanced FN-BMD correlates with increased household income. These findings provide valuable insights for health guideline formulation and policy development.

Thioredoxin Interacting Protein Expressed in Osteoblasts Mediates the Anti-Proliferative Effects of High Glucose and Modulates the Expression of Osteocalcin

BACKGROUND

Hyperglycemia is associated with impaired bone health in patients with diabetes mellitus. Although a direct detrimental effect of hyperglycemia on the bone has been previously reported, the specific molecular mediator(s) responsible for the inhibitory effect of high glucose levels on the bone remains unclear. We hypothesized that thioredoxin-interacting protein (Txnip), an essential mediator of oxidative stress, is such a mediator.

METHODS

We cultured MG-63 cells (immortalized human osteoblasts) with normal or high glucose concentrations and transfected them with scrambled or Txnip-specific small interfering RNA (siRNA).

RESULTS

High glucose levels increased Txnip expression and reduced MG-63 cell proliferation. The high-glucose level mediated reduction in cell proliferation was prevented in Txnip siRNA-transfected cells. In addition, we demonstrated that silencing Txnip mRNA expression in osteoblasts reduced the expression of the osteocalcin gene. Our results suggest that high glucose levels or silencing of Txnip mRNA expression may induce apoptosis in osteoblasts.

CONCLUSIONS

Our findings indicate that Txnip is an intracellular mediator of the anti-proliferative effects of extracellular high glucose levels on osteoblasts.

Bone metabolism in diabetes: a clinician's guide to understanding the bone-glucose interplay

Skeletal fragility is an increasingly recognised, but poorly understood, complication of both type 1 and type 2 diabetes. Fracture risk varies according to skeletal site and diabetes-related characteristics. Post-fracture outcomes, including mortality risk, are worse in those with diabetes, placing these people at significant risk. Each fracture therefore represents a sentinel event that warrants targeted management. However, diabetes is a very heterogeneous condition with complex interactions between multiple co-existing, and highly correlated, factors that preclude a clear assessment of the independent clinical markers and pathophysiological drivers for diabetic osteopathy. Additionally, fracture risk calculators and routinely used clinical bone measurements generally underestimate fracture risk in people with diabetes. In the absence of dedicated prospective studies including detailed bone and metabolic characteristics, optimal management centres around selecting treatments that minimise skeletal and metabolic harm. This review summarises the clinical landscape of diabetic osteopathy and outlines the interplay between metabolic and skeletal health. The underlying pathophysiology of skeletal fragility in diabetes and a rationale for considering a diabetes-based paradigm in assessing and managing diabetic bone disease will be discussed.

Antidiabetic Agents and Bone Quality: A Focus on Glycation End Products and Incretin Pathway Modulations

Diabetes mellitus is associated with inadequate bone health and quality and heightened susceptibility to fractures, even in patients with normal or elevated bone mineral density. Elevated advanced glycation end-products (AGEs) and a suppressed incretin pathway are among the mechanisms through which diabetes affects the bone. Accordingly, the present review aimed to investigate the effects of antidiabetic medications on bone quality, primarily through AGEs and the incretin pathway. Google Scholar, Cochrane Library, and PubMed were used to examine related studies until February 2024. Antidiabetic medications influence AGEs and the incretin pathway directly or indirectly. Certain antidiabetic drugs including metformin, glucagon-like peptide-1 receptor agonists (GLP-1RA), dipeptidyl-peptidase-4 (DDP-4) inhibitors, α-glucosidase inhibitors (AGIs), sodium-glucose co-transporter-2 inhibitors, and thiazolidinediones (TZDs), directly affect AGEs through multiple mechanisms. These mechanisms include decreasing the formation of AGEs and the expression of AGEs receptor (RAGE) in tissue and increasing serum soluble RAGE levels, resulting in the reduced action of AGEs. Similarly, metformin, GLP-1RA, DDP-4 inhibitors, AGIs, and TZDs may enhance incretin hormones directly by increasing their production or suppressing their metabolism. Additionally, these medications could influence AGEs and the incretin pathway indirectly by enhancing glycemic control. In contrast, sulfonylureas have not demonstrated any obvious effects on AGEs or the incretin pathway. Considering their favorable effects on AGEs and the incretin pathway, a suitable selection of antidiabetic drugs may facilitate more protective effects on the bone in diabetic patients.

Epidemiology of fractures in adults of African ancestry with diabetes mellitus: A systematic review and meta-analysis

Diabetes mellitus (DM) is associated with increased fracture risk in White adults. However, the impact of DM on fractures in Black adults is unknown. This systematic review and meta-analysis investigated the association between DM and fractures in adults of African ancestry. MEDLINE, Scopus, CINAHL and Embase databases were searched from their inception up to November 2023 for all studies in the English language investigating the epidemiology of fractures (prevalence, incidence, or risk) in Black men and women (age ≥ 18 years) with type 1 or type 2 DM. Effect sizes for prevalence of previous fractures (%) and incident fracture risk (hazard ratio [HR]) were calculated using a random-effects model on Stata (version 18.0). There were 13 eligible studies, of which 12 were conducted in Black adults from the United States, while one was conducted in adults of West African ancestry from Trinidad and Tobago. We found no fracture data in Black adults with DM living in Africa. Five studies were included in a meta-analysis of incident fracture risk, reporting data from 2926 Black and 6531 White adults with DM. There was increased risk of fractures in Black adults with DM compared to non-DM (HR = 1.65; 95 % confidence interval [CI]: 1.14, 2.39). The risk of fractures was also higher in White adults with DM compared to non-DM (HR = 1.31; 95 % CI: 1.06, 1.61) among these studies. Five studies were included in a meta-analysis of fracture prevalence, of which three also reported fracture prevalence in White adults. There were 175 previous fractures among 993 Black adults with DM and 384 previous fractures among 1467 White adults with DM, with a pooled prevalence of 17.5 % (95 % CI: 15.4, 19.6) and 25.8 % (95 % CI: 4.8, 46.8), respectively. Our results indicate a high burden of fractures in Black adults with DM.

Excess Risk of Injury in Individuals With Type 1 or Type 2 Diabetes Compared With the General Population

OBJECTIVE

To estimate the relative risk (RR) and excess hospitalization rate for injury in individuals with diabetes compared with the general population.

RESEARCH DESIGN AND METHODS

Data were obtained from the Australian National Diabetes Services Scheme, hospitalization data sets, the Australian Pharmaceutical Benefits Scheme, the National Death Index, and the census spanning from 2011 to 2017. Hospitalizations for injury were coded as head and neck, lower-extremity, upper-extremity, or abdominal and thoracic injury; burns; or other injury. Poisson regression was used to estimate the age- and sex-adjusted RR of hospitalization for injury.

RESULTS

The total number of hospitalizations for any injury was 117,705 in people with diabetes and 3,463,173 in the general population. Compared with that in the general population, an elevated adjusted risk of admission was observed for any injury (RR 1.22; 95% CI 1.21, 1.22), head and neck (1.28; 1.26, 1.30), lower extremity (1.24; 1.23, 1.26), abdominal and thoracic (1.29; 1.27, 1.30), upper extremity (1.03; 1.02, 1.05), burns (1.52; 1.44, 1.61), and other injury (1.37; 1.33, 1.40). The adjusted RR of any injury was 1.62 (1.58, 1.66) in individuals with type 1 diabetes, 1.65 (1.63, 1.66) in those with type 2 diabetes who were taking insulin, and 1.07 (1.06, 1.08) in individuals with type 2 diabetes not using insulin. Falls were the primary cause of injury in individuals with diabetes.

CONCLUSIONS

Individuals with diabetes, especially those using insulin, had a higher risk of hospitalization for injury compared with the general population.

Increased AGE Cross-Linking Reduces the Mechanical Properties of Osteons

The osteon is the primary structural component of bone, contributing significantly to its unique toughness and strength. Despite extensive research on osteonal structure, the properties of osteons have not been fully investigated, particularly within the context of bone fragility diseases like type 2 diabetes mellitus (T2DM). This study aims to isolate osteons from bovine bone, simulate the effects of increased advanced glycation end-products (AGEs) in T2DM through ribosylation, and evaluate the mechanical properties of isolated osteons. Osteons extracted from the posterior section of bovine femur mid-diaphysis were processed to achieve a sub-millimeter scale for microscale imaging. Subsequently, synchrotron radiation micro-computed tomography was employed to precisely localize and isolate the osteon internally. While comparable elastic properties were observed between control and ribosylated osteons, the presence of AGEs led to decreased strain to failure. Young's modulus was quantified (9.9 ± 4.9 GPa and 8.7 ± 3 GPa, respectively), aligning closely with existing literature. This study presents a novel method for the extraction and isolation of osteons from bone and shows the detrimental effect of AGEs at the osteonal level.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11837-024-06716-x.

Recent Progress in the Research on RNA-Binding Proteins in Bone Development and Diseases

RNA-binding proteins (RBPs), which regulate gene expression through post-transcriptional modifications of RNAs, play a role in diverse biological processes that include bone cell development and bone tissue formation. RBP dysregulation may result in aberrant bone homeostasis and contribute to various bone diseases. The function of RBPs in bone physiology and pathophysiology and the underlying molecular mechanisms have been extensively studied in recent years. This article provides a review of such studies, highlighting the potential of RBPs as pivotal targets for therapeutic intervention.

Association between bone turnover markers, bone mineral density, and serum osteoglycine in middle-aged men with Type 2 Diabetes mellitus

BACKGROUND

Patients with Type 2 diabetes mellitus (T2DM) have decreased bone health. We aimed to investigate serum levels of bone turnover markers (BTMs) (markers of bone formation and bone resorption) and bone mineral density (BMD) at three sites (lumber, neck femur, and total femur) in middle-aged men with type 2 diabetes and to analyze the relationship between them. Also to evaluate serum osteoglycin as a novel marker and its relation to BTMs, BMD, and diabetic status.

METHODS

We recruited seventy-eight patients with T2DM and thirteen non-diabetic, male volunteers as a control group. BMD was measured using a DEXA scan. BTMs (carboxy-terminal crosslinking telopeptide of type 1 collagen [CTX] and procollagen type 1 N propeptide [P1NP]), osteoglycin, PTH, and vitamin D were estimated. Data was compared among subjects and statistical analysis was performed.

RESULTS

Most of the patients were having normal BMD with no significant difference between patients and the controls. BTMs and osteoglycin were significantly higher and vitamin D was significantly lower in the diabetic patients. Serum osteoglycin was positively correlated with DEXA Neck Femur (r = 0.233; p-value < 0.05).

CONCLUSION

Body mass index and Serum osteoglycin have a significant positive effect on BMD. Both markers of bone formation and bone resorption were increased indicating a state of increased bone turnover in T2DM.

Association of depressive symptoms with incident fractures: the Japan Public Health Center-based Prospective Study for the Next Generation (JPHC-NEXT)

This 5-year longitudinal study investigated the relationship between depressive symptoms and fracture risk in a large Japanese cohort. Depressive symptoms were a significant risk factor for hip fractures in women.

PURPOSE

A relationship between depressive symptoms and fractures has not been clearly demonstrated. We aimed to investigate the relationship between depressive symptoms and 5-year fracture risk in the Japan Public Health Center-based Prospective Study for the Next Generation.

METHODS

From 2011 to 2016, 114,092 participants were enrolled, and a follow-up survey was conducted 5 years later. We analyzed 30,552 men and 38,063 women aged 40-74 years who had no past fractures at baseline. Presence of depressive symptoms was defined as a modified 11-item Center for Epidemiological Studies Depression Scale score of 8 or higher, a history of depression, or use of antidepressants. Subjects were asked to report vertebral, upper limb, and/or hip fractures, except for traffic or work accidents, that occurred during the follow-up period. The adjusted odds ratios (AORs) and 95% confidence intervals (CIs) for fracture were analyzed via logistic regression analysis to evaluate the relationship between depressive symptoms and fracture.

RESULTS

Women with depressive symptoms demonstrated a high AOR for hip fractures (AOR: 2.78, 95% CI: 1.30 - 5.92); this result was consistent in post menopause women. In men, this association was not found for any age group or any type of fracture.

CONCLUSIONS

Depressive symptoms in women may increase the risk of hip fractures. Further studies are required to explore this relationship in more detail.

Unveiling novel metabolic alterations in postmenopausal osteoporosis and type 2 diabetes mellitus through NMR-based metabolomics: A pioneering approach for identifying early diagnostic markers

BACKGROUND AND AIMS

Postmenopausal osteoporosis (PMO) and type 2 diabetes mellitus (T2DM) frequently coexist in postmenopausal women. The study aimed to explore metabolic variations linked to these circumstances and their simultaneous presence through proton nuclear magnetic resonance metabolomics (1H NMR).

MATERIALS AND METHODS

Serum samples from 80 postmenopausal women, including 20 PMO individuals, 20 T2DM, 20 T2DM + PMO, and 20 healthy postmenopausal women, were analyzed using 1H NMR spectroscopy.

RESULTS

Our study revealed significant metabolic profile differences among the four groups. Notably, the T2DM + PMO group showed elevated levels of alanine, pyruvate, glutamate, lactate, and aspartate, indicating their involvement in lipid metabolism, energy, and amino acids. Importantly, our multivariate statistical analysis identified a metabolite set that accurately distinguished the groups, suggesting its potential as an early diagnostic marker.

CONCLUSION

The 1H NMR metabolomics approach uncovered metabolic biomarkers intricately linked to postmenopausal osteoporosis (PMO), type 2 diabetes mellitus (T2DM), and their concurrent presence. Among these biomarkers, alanine emerged as a pivotal player, showing its significant role in the metabolic landscape associated with PMO and T2DM. These findings shed light on the pathophysiological mechanisms underlying these conditions and underscore alanine's potential as a diagnostic biomarker.

Usefulness of DXA-based bone strain index in postmenopausal women with type 2 diabetes mellitus

Bone Strain Index (BSI) is a new dual-energy x-ray absorptiometry (DXA)-based index. We retrospectively evaluated data from 153 postmenopausal women with a history of type 2 diabetes mellitus (T2DM). Lumbar spine and femoral Bone Strain Index (BSI) were sensitive to skeletal impairment in postmenopausal women suffering from T2DM.

PURPOSE

Bone Strain Index (BSI) is a new dual-energy X-ray absorptiometry (DXA)-based measurement. We evaluated the performance of BSI in predicting the presence of fragility fractures in type 2 diabetes mellitus (T2DM) postmenopausal women.

METHODS

We retrospectively evaluated data from a case-control study of 153 postmenopausal women with a history of at least 5 years of T2DM (age from 40 to 90 years). For each subject, we assessed the personal or familiar history of previous fragility fractures and menopause age, and we collected data about bone mineral density (BMD), BSI, and Trabecular Bone Score (TBS) measurements. Statistical analysis was performed having as outcome the history of fragility fractures.

RESULTS

Out of a total of 153 subjects, n = 22 (14.4%) presented at least one major fragility fracture. A negative correlation was found between lumbar BSI and lumbar BMD (r =  - 0.49, p < 0.001) and between total femur BSI and total femur BMD (r =  - 0.49, p < 0.001). A negative correlation was found between femoral neck BSI and femoral neck BMD (r =  - 0.22, p < 0.001). Most DXA-based variables were individually able to discriminate between fractured and non-fractured subjects (p < 0.05), and lumbar BSI was the index with the most relative difference between the two populations, followed by femoral BSI.

CONCLUSION

Lumbar spine and femoral BSI are sensitive to skeletal impairment in postmenopausal women suffering from T2DM. The use of BSI in conjunction with BMD and TBS can improve fracture risk assessment.

The Biomechanics of Musculoskeletal Tissues during Activities of Daily Living: Dynamic Assessment Using Quantitative Transmission-Mode Ultrasound Techniques

The measurement of musculoskeletal tissue properties and loading patterns during physical activity is important for understanding the adaptation mechanisms of tissues such as bone, tendon, and muscle tissues, particularly with injury and repair. Although the properties and loading of these connective tissues have been quantified using direct measurement techniques, these methods are highly invasive and often prevent or interfere with normal activity patterns. Indirect biomechanical methods, such as estimates based on electromyography, ultrasound, and inverse dynamics, are used more widely but are known to yield different parameter values than direct measurements. Through a series of literature searches of electronic databases, including Pubmed, Embase, Web of Science, and IEEE Explore, this paper reviews current methods used for the in vivo measurement of human musculoskeletal tissue and describes the operating principals, application, and emerging research findings gained from the use of quantitative transmission-mode ultrasound measurement techniques to non-invasively characterize human bone, tendon, and muscle properties at rest and during activities of daily living. In contrast to standard ultrasound imaging approaches, these techniques assess the interaction between ultrasound compression waves and connective tissues to provide quantifiable parameters associated with the structure, instantaneous elastic modulus, and density of tissues. By taking advantage of the physical relationship between the axial velocity of ultrasound compression waves and the instantaneous modulus of the propagation material, these techniques can also be used to estimate the in vivo loading environment of relatively superficial soft connective tissues during sports and activities of daily living. This paper highlights key findings from clinical studies in which quantitative transmission-mode ultrasound has been used to measure the properties and loading of bone, tendon, and muscle tissue during common physical activities in healthy and pathological populations.

Effects of Exogenous GIP and GLP-2 on Bone Turnover in Individuals With Type 2 Diabetes

CONTEXT

Individuals with type 2 diabetes (T2D) have an increased risk of bone fractures despite normal or increased bone mineral density. The underlying causes are not well understood but may include disturbances in the gut-bone axis, in which both glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-2 (GLP-2) are regulators of bone turnover. Thus, in healthy fasting participants, both exogenous GIP and GLP-2 acutely reduce bone resorption.

OBJECTIVE

The objective of this study was to investigate the acute effects of subcutaneously administered GIP and GLP-2 on bone turnover in individuals with T2D.

METHODS

We included 10 men with T2D. Participants met fasting in the morning on 3 separate test days and were injected subcutaneously with GIP, GLP-2, or placebo in a randomized crossover design. Blood samples were drawn at baseline and regularly after injections. Bone turnover was estimated by circulating levels of collagen type 1 C-terminal telopeptide (CTX), procollagen type 1 N-terminal propeptide (P1NP), sclerostin, and PTH.

RESULTS

GIP and GLP-2 significantly reduced CTX to (mean ± SEM) 66 ± 7.8% and 74 ± 5.9% of baseline, respectively, compared with after placebo (P = .001). In addition, P1NP and sclerostin increased acutely after GIP whereas a decrease in P1NP was seen after GLP-2. PTH levels decreased to 67 ± 2.5% of baseline after GLP-2 and to only 86 ± 3.4% after GIP.

CONCLUSION

Subcutaneous GIP and GLP-2 affect CTX and P1NP in individuals with T2D to the same extent as previously demonstrated in healthy individuals.

Evaluating compliance with the care standard of proactively assessing bone health in patients with diabetes: a pilot audit of practice across Asia by the Asia Pacific Consortium on Osteoporosis (APCO)

This pilot audit explored how bone health is assessed patients with diabetes in diverse centres across Asia. Only 343 of 1092 (31%) audited patients had a bone health assessment, 27% of whom were diagnosed with osteoporosis. Quality improvement strategies are needed to address gaps in patient care in this area.

PURPOSE

The Asia Pacific Consortium on Osteoporosis (APCO) Framework outlines clinical standards for assessing and managing osteoporosis. A pilot audit evaluated adherence to clinical standard 4, which states that bone health should be assessed in patients with conditions associated with bone loss and/or increased fracture risk; this report summarises the audit findings in patients with diabetes. A secondary aim was to assess the practicality and real-world use of the APCO bone health audit tool kit.

METHODS

Eight centres across Asia participated in the pilot audit, selecting diabetes as the target group. Participants reviewed their practice records for at least 20 consecutively treated patients with the target condition. Questions covered routine investigations, bone health assessment, osteoporosis diagnosis, and patient referral pathways. Data were summarised descriptively.

RESULTS

The participants represented public hospitals, university medical centres, and private clinics from India, Malaysia, Pakistan, Singapore, Taiwan, and Vietnam that see an estimated total of 95,000 patients with diabetes per year. Overall, only 343 of 1092 audited patients (31%) had a bone health assessment. Osteoporosis was subsequently diagnosed in 92 of 343 (27%) patients.

CONCLUSION

Bone health was not assessed in most patients with diabetes. The results provide insight into current practices across diverse Asian centres and demonstrate the practical value of the audit tool kit. Participant feedback has been used to improve the tool kit. Results of this pilot audit are being used in the respective centres to inform quality improvement projects needed to overcome the gap in patient care.

Impact of High-Fat Diet and Exercise on Bone and Bile Acid Metabolism in Rats

Bile acids help facilitate intestinal lipid absorption and have endocrine activity in glucose, lipid and bone metabolism. Obesity and exercise influence bile acid metabolism and have opposite effects in bone. This study investigates if regular exercise helps mitigate the adverse effects of obesity on bone, potentially by reversing alterations in bile acid metabolism. Four-month-old female Sprague Dawley rats either received a high-fat diet (HFD) or a chow-based standard diet (lean controls). During the 10-month study period, half of the animals performed 30 min of running at moderate speed on five consecutive days followed by two days of rest. The other half was kept inactive (inactive controls). At the study's end, bone quality was assessed by microcomputed tomography and biomechanical testing. Bile acids were measured in serum and stool. HFD feeding was related to reduced trabecular (-33%, p = 1.14 × 10-7) and cortical (-21%, p = 2.9 × 10-8) bone mass and lowered femoral stiffness (12-41%, p = 0.005). Furthermore, the HFD decreased total bile acids in serum (-37%, p = 1.0 × 10-6) but increased bile acids in stool (+2-fold, p = 7.3 × 10-9). These quantitative effects were accompanied by changes in the relative abundance of individual bile acids. The concentration of serum bile acids correlated positively with all cortical bone parameters (r = 0.593-0.708), whilst stool levels showed inverse correlations at the cortical (r = -0.651--0.805) and trabecular level (r = -0.656--0.750). Exercise improved some trabecular and cortical bone quality parameters (+11-31%, p = 0.043 to 0.001) in lean controls but failed to revert the bone loss related to the HFD. Similarly, changes in bile acid metabolism were not mitigated by exercise. Prolonged HFD consumption induced quantitative and qualitative alterations in bile acid metabolism, accompanied by bone loss. Tight correlations between bile acids and structural indices of bone quality support further functional analyses on the potential role of bile acids in bone metabolism. Regular moderate exercise improved trabecular and cortical bone quality in lean controls but failed in mitigating the effects related to the HFD in bone and bile acid metabolism.

Romosozumab rescues impaired bone mass and strength in a murine model of diabetic kidney disease

As international incidence of diabetes and diabetes-driven comorbidities such as chronic kidney disease (CKD) continue to climb, interventions are needed that address the high-risk skeletal fragility of what is a complex disease state. Romosozumab (Romo) is an FDA-approved sclerostin inhibitor that has been shown to increase bone mineral density and decrease fracture rates in osteoporotic patients with mild to severe CKD, but its effect on diabetes-weakened bone is unknown. We aimed to test Romo's performance in a model of combined diabetes and CKD. 6-week old male C57BL/6 mice were randomly divided into control (CON) and disease model (STZ-Ad) groups, using a previously established streptozotocin- and adenine-diet-induced model. After 16 weeks of disease induction, both CON and STZ-Ad groups were subdivided into two treatment groups and given weekly subcutaneous injections of 100 μL vehicle (phosphorus buffered saline, PBS) or 10 mg/kg Romo. Mice were euthanized after 4 weeks of treatment via cardiac exsanguination and cervical dislocation. Hindlimb bones and L4 vertebrae were cleaned of soft tissue, wrapped in PBS-soaked gauze and stored at -20C. Right tibiae, femora, and L4s were scanned via microcomputed tomography; tibiae were then tested to failure in 4-pt bending while L4s were compression tested. Romo treatment significantly increased cortical and trabecular bone mass in both STZ-Ad and CON animals. These morphological improvements created corresponding increases in cortical bending strength and trabecular compression strength, with STZ-Ad treated mice surpassing vehicle CON mice in all trabecular mechanics measures. These results suggest that Romo retains its efficacy at increasing bone mass and strength in diabetic kidney disease.

Skeletal Fragility in Adult People Living With Type 1 Diabetes

Advances in the management of people with type 1 diabetes (T1D) led to longer life expectancy, but with it an aging population with age-associated conditions. While macrovascular and microvascular complications are widely recognized, bone fragility has received considerably less attention, although fractures lead to high morbidity and mortality. Hip fracture risk is up to sixfold higher in T1D than in nondiabetic controls and significantly higher than in type 2 diabetes. Hip fractures occur at a younger age, and the consequences are worse. The risk of nonvertebral fractures is also significantly increased. Altered bone quality is a major underlying mechanism. Areal BMD measured by DXA underestimates fracture risk. BMD testing is recommended in T1D patients with poor glycemic control and/or microvascular complications. Trabecular bone score is mildly reduced, and its ability to predict fractures in T1D is unknown. Bone turnover markers, particularly procollagen type 1 N-terminal propeptide, are suppressed and do not predict fracture risk in T1D. T1D-related risk factors for fractures include disease onset at age <20 years, longer disease duration, HbA1c ≥8%, hypoglycemic episodes and microvascular complications. Data regarding the efficacy of therapeutic interventions to prevent or treat skeletal fragility in T1D is scant. Adequate calcium and vitamin D intake and fall prevention are recommended. Antiosteoporosis therapies are recommended in T1D patients with previous hip or vertebral fragility fracture, more than 1 other fragility fracture, BMD T-score < -2.5 at the femoral neck or spine, and increased FRAX score. Fracture risk assessment needs to be part of the management of people with T1D.

Smoking habits and osteoporosis in community-dwelling men subjected to dual-X-ray absorptiometry: a cross-sectional study

BACKGROUND

Active and Environmental Tobacco Smoke (ETS) are a global cause of death. Osteoporosis (Op) is the most common metabolic bone disorder worldwide, impacting on mortality and disability, with high health and welfare costs. Active smoking is a known risk factor for Op, but there is few information regarding Op and ETS in men.

PURPOSE

The study aim is to evaluate the association between smoking habits and Op in community-dwelling men that have been subjected to Dual-X-ray Absorptiometry and completed a questionnaire about their own and cohabiter's smoking habits.

METHODS

We performed a cross-sectional study based on administrative data. This study is part of the SIMON protocol. The binary logistic regression analysis was used to estimate the role of ETS on the risk of Op, adjusting for age, body mass index (BMI), type 2 diabetes mellitus (T2DM) and eGFR.

RESULTS

Four hundred sixteen men were selected and, based on questionnaire replies, 167 were classified as current smokers (CS), 93 as passive smokers (PS) and 156 as never smokers (NS). NS showed a lower prevalence of past fragility fracture, radiological features of osteoporosis and hypovitaminosis D compared to PS and CS (p < 0.05). NS showed a lower prevalence of Op compared to PS and CS, also after correction for age, BMI, T2DM and eGFR (p < 0.05).

CONCLUSION

The study results demonstrate that PS and CS have a higher risk of Op, fragility fractures and vitamin D deficiency compared to NS.

Eight Weeks of Intermittent Exercise in Hypoxia, with or without a Low-Carbohydrate Diet, Improves Bone Mass and Functional and Physiological Capacity in Older Adults with Type 2 Diabetes

In an increasingly aging and overweight population, osteoporosis and type 2 diabetes (T2DM) are major public health concerns. T2DM patients experience prejudicial effects on their bone health, affecting their physical capacity. Exercise in hypoxia (EH) and a low-carbohydrate diet (LCD) have been suggested for therapeutic benefits in T2DM, improving bone mineral content (BMC) and glycemic control. This study investigated the effects of EH combined with an LCD on body composition and functional and physiologic capacity in T2DM patients. Older T2DM patients (n = 42) were randomly assigned to the following groups: (1) control group: control diet + exercise in normoxia; (2) EH group: control diet + EH; (3) intervention group: LCD + EH. Cardiopulmonary tests (BRUCE protocol), body composition (DEXA), and functional capacity (6MWT, handgrip strength) were evaluated. Body mass index (kg/m2) and body fat (%) decreased in all groups (p < 0.001). BMC (kg) increased in all groups (p < 0.001) and was significantly higher in the EH and EH + LCD groups (p < 0.001). VO2peak improved in all groups (p < 0.001), but more so in the hypoxia groups (p = 0.019). Functional capacity was increased in all groups (p < 0.001), but more so in the EH group in 6MWT (p = 0.030). EH with and without an LCD is a therapeutic strategy for improving bone mass in T2DM, which is associated with cardiorespiratory and functional improvements.

Bone Health in Patients With Type 2 Diabetes

The association between type 2 diabetes mellitus (T2DM) and skeletal fragility is complex, with effects on bone at the cellular, molecular, and biomechanical levels. As a result, people with T2DM, compared to those without, are at increased risk of fracture, despite often having preserved bone mineral density (BMD) on dual-energy x-ray absorptiometry (DXA). Maladaptive skeletal loading and changes in bone architecture (particularly cortical porosity and low cortical volumes, the hallmark of diabetic osteopathy) are not apparent on routine DXA. Alternative imaging modalities, including quantitative computed tomography and trabecular bone score, allow for noninvasive visualization of cortical and trabecular compartments and may be useful in identifying those at risk for fractures. Current fracture risk calculators underestimate fracture risk in T2DM, partly due to their reliance on BMD. As a result, individuals with T2DM, who are at high risk of fracture, may be overlooked for commencement of osteoporosis therapy. Rather, management of skeletal health in T2DM should include consideration of treatment initiation at lower BMD thresholds, the use of adjusted fracture risk calculators, and consideration of metabolic and nonskeletal risk factors. Antidiabetic medications have differing effects on the skeleton and treatment choice should consider the bone impacts in those at risk for fracture. T2DM poses a unique challenge when it comes to assessing bone health and fracture risk. This article discusses the clinical burden and presentation of skeletal disease in T2DM. Two clinical cases are presented to illustrate a clinical approach in assessing and managing fracture risk in these patients.

A Causal Relationship Between Type 1 Diabetes and Risk of Osteoporosis: A Univariable and Multivariable Mendelian Randomization Study

Objective: This Mendelian randomization (MR) analysis aims to investigate the causal relationship between type 1 diabetes (T1D) and osteoporosis (OP). Methods: Single nucleotide polymorphisms (SNPs) associated with T1D were selected from the summary statistics of the genome-wide association study (GWAS) in European ancestry as instrumental variables (IVs) for univariable MR (UVMR) to explore the causal relationship between T1D and OP. Inverse variance weighting (IVW) was the primary method used to assess possible causality between T1D and OP. MR-PRESSO and MR-Egger intercepts were used to assess the horizontal pleiotropy of the IVs, and Q tests and the "leave-one-out" method were used to test for heterogeneity of MR results. Multivariable MR (MVMR) analysis was used to account for potential confounders such as smoking, obesity, drinking, and serum 25-hydroxyvitamin D (25OHD) concentrations. Result: Inverse variance weighted estimates suggest T1D may increase risk of OP (UVMR: OR = 1.06, 95% CI: 1.02-1.10, p = 0.002) (MVMR: OR = 1.50, 95% CI: 1.07-1.90, p < 0.001). Conclusion: Our findings suggest that T1D can increase the risk of OP.

MiR-144-5p and miR-21-5p do not drive bone disease in a mouse model of type 1 diabetes mellitus

The increased risk of fractures in patients with type 1 diabetes mellitus (T1DM) is nowadays well recognized. However, the exact mechanism of action of diabetic bone disease has not been fully elucidated. MicroRNAs (miRNAs) are gene regulators that operate post-transcriptionally and have been implicated in the development of various metabolic disorders including T1DM. Previous studies have implicated a role for miR-144-5p and miR-21-5p, which are involved in controlling oxidative stress by targeting Nrf2, in T1DM. To date, it is unclear whether miR-144-5p and miR-21-5p affect bone health in T1DM. Thus, this study aimed to investigate the influence of miR-144-5p and miR-21-5p knockdown in the development of bone disease in T1DM male mice. Therefore, T1DM was induced in 10-wk-old male mice using streptozotocin (STZ). One week later, after development of hyperglycemia, antagomir-144-5p and antagomir-21-5p or their non-targeting control were administered at 10 mg/kg BW once a week until the end of the experiment. At 14 wk of age, glucose levels, bone, and fat mass were analyzed. The results revealed that treating T1DM male mice with antagomir-144-5p and antagomir-21-5p did not protect against diabetes development or bone loss, despite the successful downregulation of the miRNAs and the normalization of Nrf2 mRNA levels in bone tissue. Histological and serological parameters of bone formation or resorption were not altered by the antagomir treatment. Finally, we measured the expression of miRNA-144-5p or miRNA-21-5p in the serum of 30 individuals with T1DM and compared them to non-diabetic controls, but did not find an altered expression of either miRNA. In conclusion, the knockdown of miR-144-5p and miR-21-5p does not affect STZ-induced diabetes development or loss of bone mass in male mice. However, it does normalize expression of the anti-oxidant factor Nrf2 in diabetic bone tissue.

Age and sex are excellent predictors of bone complications in patients with type 2 diabetes with no history of osteoporotic fracture or treatment for osteoporosis

OBJECTIVE

To identify patients with type 2 diabetes mellitus (T2DM) with no history of fracture or osteoporosis treatment who are at risk of bone complications through the assessment of bone quality and quantity.

METHODS

Of the outpatients attending our clinic during 2021 to 2022, we retrospectively enrolled 137 (men/women: 85/52, median age: 65 years) consecutive patients aged ≥40 years who had T2DM but no history of fracture or osteoporosis treatment. The lumbar spine and femoral neck bone mineral density and the trabecular bone score were determined using dual-energy X-ray absorptiometry. Independent factors associated with bone disease were identified using logistic regression analysis, and odds ratios (ORs) were calculated.

RESULTS

Age and female sex were significantly associated with high ORs for development of bone disease. The integrated risk of bone complications was nearly 40-fold higher in older (≥65 years) women than in younger (<65 years) men. This difference remained after adjustment for the duration of T2DM, body mass index, and HbA1c level.

CONCLUSIONS

Older women have the highest risk of osteopenia and osteoporosis among patients with T2DM who have no history of fracture or osteoporosis treatment. These patients should undergo intensive monitoring for bone fragility from an early stage of their disease.

Ten tips on how to assess bone health in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) experience a several-fold increased risk of fracture. Despite the high incidence and the associated excess morbidity and premature mortality, bone fragility in CKD, or CKD-associated osteoporosis, remains a blind spot in nephrology with an immense treatment gap. Defining the bone phenotype is a prerequisite for the appropriate therapy of CKD-associated osteoporosis at the patient level. In the present review, we suggest 10 practical 'tips and tricks' for the assessment of bone health in patients with CKD. We describe the clinical, biochemical, and radiological evaluation of bone health, alongside the benefits and limitations of the available diagnostics. A bone biopsy, the gold standard for diagnosing renal bone disease, is invasive and not widely available; although useful in complex cases, we do not consider it an essential component of bone assessment in patients with CKD-associated osteoporosis. Furthermore, we advocate for the deployment of multidisciplinary expert teams at local, national, and potentially international level. Finally, we address the knowledge gaps in the diagnosis, particularly early detection, appropriate "real-time" monitoring of bone health in this highly vulnerable population, and emerging diagnostic tools, currently primarily used in research, that may be on the horizon of clinical practice.

Exploration of shared gene signatures and molecular mechanisms between type 2 diabetes and osteoporosis

Type 2 diabetes mellitus (T2D) and osteoporosis (OP) are systemic metabolic diseases and often coexist. The mechanism underlying this interrelationship remains unclear. We downloaded microarray data for T2D and OP from the Gene Expression Omnibus (GEO) database. Using weighted gene co-expression network analysis (WGCNA), we identified co-expression modules linked to both T2D and OP. To further investigate the functional implications of these associated genes, we evaluated enrichment using ClueGO software. Additionally, we performed a biological process analysis of the genes unique in T2D and OP. We constructed a comprehensive miRNA-mRNA network by incorporating target genes and overlapping genes from the shared pool. Through the implementation of WGCNA, we successfully identified four modules that propose a plausible model that elucidates the disease pathway based on the associated and distinct gene profiles of T2D and OP. The miRNA-mRNA network analysis revealed co-expression of PDIA6 and SLC16A1; their expression was upregulated in patients with T2D and islet β-cell lines. Remarkably, PDIA6 and SLC16A1 were observed to inhibit the proliferation of pancreatic β cells and promote apoptosis in vitro, while downregulation of PDIA6 and SLC16A1 expression led to enhanced insulin secretion. This is the first study to reveal the significant roles of PDIA6 and SLC16A1 in the pathogenesis of T2D and OP, thereby identifying additional genes that hold potential as indicators or targets for therapy.

Links among Obesity, Type 2 Diabetes Mellitus, and Osteoporosis: Bone as a Target

Obesity, type 2 diabetes mellitus (T2DM) and osteoporosis are serious diseases with an ever-increasing incidence that quite often coexist, especially in the elderly. Individuals with obesity and T2DM have impaired bone quality and an elevated risk of fragility fractures, despite higher and/or unchanged bone mineral density (BMD). The effect of obesity on fracture risk is site-specific, with reduced risk for several fractures (e.g., hip, pelvis, and wrist) and increased risk for others (e.g., humerus, ankle, upper leg, elbow, vertebrae, and rib). Patients with T2DM have a greater risk of hip, upper leg, foot, humerus, and total fractures. A chronic pro-inflammatory state, increased risk of falls, secondary complications, and pharmacotherapy can contribute to the pathophysiology of aforementioned fractures. Bisphosphonates and denosumab significantly reduced the risk of vertebral fractures in patients with both obesity and T2DM. Teriparatide significantly lowered non-vertebral fracture risk in T2DM subjects. It is important to recognize elevated fracture risk and osteoporosis in obese and T2DM patients, as they are currently considered low risk and tend to be underdiagnosed and undertreated. The implementation of better diagnostic tools, including trabecular bone score, lumbar spine BMD/body mass index (BMI) ratio, and microRNAs to predict bone fragility, could improve fracture prevention in this patient group.

Dietary inflammatory pattern and risk of hip fracture in the Nurses' Health Study

Our immune system activity is impacted by what we eat and can influence fracture risk under certain conditions. In this article, we show that postmenopausal women with a pro-inflammatory dietary pattern have an increased risk of hip fracture.

PURPOSE

The immune system influences bone homeostasis and can increase the risk of fracture under certain pro-inflammatory conditions. Immune system activity is impacted by dietary patterns. Using the empirical dietary inflammatory pattern (EDIP), we investigated whether postmenopausal women with a pro-inflammatory dietary pattern had an increased risk of hip fracture.

METHODS

The study population consisted of postmenopausal women participating in the Nurses' Health Study from 1980 to 2014, who reported information on lifestyle and health, including hip fractures, on biennial questionnaires, while semiquantitative food frequency questionnaires (FFQs) were completed every fourth year. Hazard ratios (HR) for hip fracture were computed using Cox proportional hazards models, adjusting for potential confounders.

RESULTS

EDIP was calculated using intake information from the FFQ for 87,955 postmenopausal participants, of whom 2348 sustained a non-traumatic hip fracture during follow-up. After adjustment for confounders, there was a 7% increase in the risk of hip fracture per 1 SD increase in EDIP (HR 1.07, 95% CI 1.02-1.12), and the uppermost quintile had a 22% greater risk compared to the lowest (HR 1.22, 95% CI 1.06-1.40). For the separate components of the EDIP, we found that higher intakes of low-energy beverages (diet sodas) were independently associated with an increased risk of hip fracture, while higher intakes of green leafy vegetables were associated with a reduced risk.

CONCLUSION

A pro-inflammatory dietary pattern was associated with an increased risk of hip fracture among postmenopausal women.

Diabetes and osteoporosis: a two-sample mendelian randomization study

BACKGROUND

The effects on bone mineral density (BMD)/fracture between type 1 (T1D) and type 2 (T2D) diabetes are unknown. Therefore, we aimed to investigate the causal relationship between the two types of diabetes and BMD/fracture using a Mendelian randomization (MR) design.

METHODS

A two-sample MR study was conducted to examine the causal relationship between diabetes and BMD/fracture, with three phenotypes (T1D, T2D, and glycosylated hemoglobin [HbA1c]) of diabetes as exposures and five phenotypes (femoral neck BMD [FN-BMD], lumbar spine BMD [LS-BMD], heel-BMD, total body BMD [TB-BMD], and fracture) as outcomes, combining MR-Egger, weighted median, simple mode, and inverse variance weighted (IVW) sensitivity assessments. Additionally, horizontal pleiotropy was evaluated and corrected using the residual sum and outlier approaches.

RESULTS

The IVW method showed that genetically predicted T1D was negatively associated with TB-BMD (β = -0.018, 95% CI: -0.030, -0.006), while T2D was positively associated with FN-BMD (β = 0.033, 95% CI: 0.003, 0.062), heel-BMD (β = 0.018, 95% CI: 0.006, 0.031), and TB-BMD (β = 0.050, 95% CI: 0.022, 0.079). Further, HbA1c was not associated with the five outcomes (β ranged from - 0.012 to 0.075).

CONCLUSIONS

Our results showed that T1D and T2D have different effects on BMD at the genetic level. BMD decreased in patients with T1D and increased in those with T2D. These findings highlight the complex interplay between diabetes and bone health, suggesting potential age-specific effects and genetic influences. To better understand the mechanisms of bone metabolism in patients with diabetes, further longitudinal studies are required to explain BMD changes in different types of diabetes.

Sex- and Age-Specific Prevalence of Osteopenia and Osteoporosis: Sampling Survey

BACKGROUND

Osteopenia and osteoporosis are posing a long-term influence on the aging population's health contributing to a higher risk of mortality, loss of autonomy, hospitalization, and huge health system costs and social burden. Therefore, more pertinent data are needed to demonstrate the current state of osteoporosis.

OBJECTIVE

This sampling survey seeks to assess the trends in the prevalence of osteopenia and osteoporosis in a Chinese Han population.

METHODS

A community-based cross-sectional study involving 16,377 participants used a multistage sampling method. Bone mineral density was measured using the quantitative ultrasonic densitometry. Student t test and Mann-Whitney U test were used to test the difference between normally and nonnormally distributed quantitative variables between male and female participants. A chi-square (χ2) test was used to compare categorized variables. Stratified analysis was conducted to describe the prevalence rates of osteoporosis (T score ≤-2.5) and osteopenia (T score -2.5 to -1.0) across age, sex, calcium intake, and menopause. A direct standardization method was used to calculate the age-standardized prevalence rates of osteoporosis and osteopenia. T-score was further categorized into quartiles (T1-T4) by age- and sex-specified groups.

RESULTS

The prevalence rates of osteopenia and osteoporosis were 40.5% (6633/16,377) and 7.93% (1299/16,377), respectively, and the age-standardized prevalence rates were 27.32% (287,877,129.4/1,053,861,940) and 3.51% (36,974,582.3/1,053,861,940), respectively. There was an increase in osteopenia and osteoporosis prevalence from 21.47% (120/559) to 56.23% (754/1341) and 0.89% (5/559) to 17.23% (231/1341), respectively, as age increased from 18 years to 75 years old. The prevalence rates of osteopenia and osteoporosis were significantly higher in female participants (4238/9645, 43.94% and 1130/9645, 11.72%) than in male participants (2395/6732, 35.58% and 169/6732, 2.51%; P<.001), and in postmenopausal female participants (3638/7493, 48.55% and 1053/7493, 14.05%) than in premenopausal female participants (538/2026, 26.55% and 53/2026, 2.62%; P<.001). In addition, female participants with a history of calcium intake had a lower osteoporosis prevalence rate than female participants without any history of calcium intake in all age groups (P=.004). From low quartile to high quartile of T-score, the prevalence of diabetes mellitus (752/4037, 18.63%; 779/4029, 19.33%; 769/3894, 19.75%; and 869/3879, 22.4%) and dyslipidemia (2228/4036, 55.2%; 2304/4027, 57.21%; 2306/3891, 59.26%; and 2379/3878, 61.35%) were linearly increased (P<.001), while the prevalence of cancer (112/4037, 2.77%; 110/4029, 2.73%; 103/3894, 2.65%; and 77/3879, 1.99%) was decreased (P=.03).

CONCLUSIONS

Our data imply that as people age, osteopenia and osteoporosis are more common in females than in males, particularly in postmenopausal females than in premenopausal females, and bone mineral density significantly affects the prevalence of chronic diseases. These findings offer information that can be applied to intervention programs meant to prevent or lessen the burden of osteoporosis in China.

Diagnosing Osteoporosis in Diabetes-A Systematic Review on BMD and Fractures

PURPOSE OF REVIEW

Recently, the American Diabetes Association updated the 2024 guidelines for Standards of Care in Diabetes and recommend that a T-score of - 2.0 in patients with diabetes should be interpreted as equivalent to - 2.5 in people without diabetes. We aimed to evaluate the most recent findings concerning the bone mineral density (BMD)-derived T-score and risk of fractures related to osteoporosis in subjects with diabetes.

RECENT FINDINGS

The dual-energy X-ray absorptiometry (DXA) scan is the golden standard for evaluating BMD. The BMD-derived T-score is central to fracture prediction and signifies both diagnosis and treatment for osteoporosis. However, the increased fracture risk in diabetes is not sufficiently explained by the T-score, complicating the identification and management of fracture risk in these patients. Recent findings agree that subjects with type 2 diabetes (T2D) have a higher T-score and higher fracture risk compared with subjects without diabetes. However, the actual number of studies evaluating the direct association of higher fracture risk at higher T-score levels is scant. Some studies support the adjustment based on the 0.5 BMD T-score difference between subjects with T2D and subjects without diabetes. However, further data from longitudinal studies is warranted to validate if the T-score treatment threshold necessitates modification to prevent fractures in subjects with diabetes.

Effect of Calcium and Vitamin D Supplementation (Dairy vs. Pharmacological) on Bone Health of Underprivileged Indian Children and Youth with Type-1 Diabetes: A Randomized Controlled Trial

BACKGROUND

Bone health is affected by chronic childhood disorders including type-1 diabetes mellitus (T1DM). We conducted this randomized controlled trial with the objective of investigating the effect of 1-year supplementation of vitamin-D with milk or with pharmacological calcium on bone mass accrual in underprivileged Indian children and youth with T1DM.

METHODS

5 to 23year old (n = 203) underprivileged children and youth with T1DM were allocated to one of three groups: Milk (group A-received 200 ml milk + 1000 international unit (IU) vitamin-D3/day), Calcium supplement (group B-received 500 mg of calcium carbonate + 1000 IU of vitamin-D3/day) or standard of care/control (group C). Anthropometry, clinical details, biochemistry, diet (3-day 24-h recall), physical activity (questionnaires adapted for Indian children) and bone health parameters (using dual-energy X-ray absorptiometry and peripheral quantitative computed tomography- DXA and pQCT respectively) were evaluated at enrolment and end of 12 month intervention.

RESULTS

Total body less head(TBLH) bone mineral content (BMC(g)) and bone mineral density (BMD(gm/cm2)) were significantly higher at end of study in girls in both supplemented groups (TBLHBMC-A-1011.8 ± 307.8, B-983.2 ± 352.9, C-792.8 ± 346.8. TBLHBMD-A-± 0.2, B-0.8 ± 0.2, C-0.6 ± 0.2, p < 0.05). Z score of lumbar spine bone mineral apparent density of supplemented participants of both sexes was significantly higher than controls (Boys- A-0.7 ± 1.1, B-0.6 ± 1.4, C- -0.7 ± 1.1; Girls- A-1.1 ± 1.1, B-0.9 ± 3.4, C- -1.7 ± 1.3, p < 0.05). A significantly higher percentage increase was found in cortical thickness in girls in both supplemented groups (A-17.9 ± 28.6, B-15.3 ± 16.5, C-7.6 ± 26.2); the differences remained after adjusting for confounders.

CONCLUSION

Supplementation with milk or pharmacological calcium (+vitaminD3) improved bone outcomes-particularly geometry in children with T1DM with more pronounced effect in girls. Pharmacological calcium may be more cost effective in optimising bone health in T1DM in resource limited settings.

Health Perceptions, Multimorbidity, and New Fractures and Mortality Among Patients With a Fracture

Importance

A high proportion of patients who sustain a fracture have multimorbidity. However, the association of multimorbidity with postfracture adverse outcomes, such as subsequent fractures and premature mortality, has not been widely explored.

Objective

To examine the association of multimorbidity and self-rated health with subsequent fractures and mortality after fracture.

Design, Setting, and Participants

This prospective cohort study included participants from New South Wales, Australia, in the Sax Institute's 45 and Up Study (n = 267 357). Participants were recruited from July 2005 to December 2009 and followed up from the date of the incident fracture until subsequent fracture, death, or the end of the study (April 2017), whichever occurred first, with questionnaire data linked to hospital admission and medication records. Data analysis was reported between March and September 2023.

Exposures

Charlson Comorbidity Index (CCI) score and self-rated health (SRH).

Main Outcomes and Measures

The main outcomes were subsequent fracture or mortality after an incident fracture. Associations between SRH measures and subsequent fracture and mortality were also assessed. All analyses were stratified by sex given the different fracture and mortality risk profiles of females and males.

Results

Of 25 280 adults who sustained incident fractures, 16 191 (64%) were female (mean [SD] age, 74 [12] years) and 9089 (36%) were male (mean [SD] age, 74 [13] years). During a median follow-up time of 2.8 years (IQR, 1.1-5.2 years), 2540 females (16%) and 1135 males (12%) sustained a subsequent fracture and 2281 females (14%) and 2140 males (24%) died without a subsequent fracture. Compared with a CCI score of less than 2, those with a CCI score of 2 to 3 had an increased risk of subsequent fracture (females: hazard ratio [HR], 1.16 [95% CI, 1.05-1.27]; males: HR, 1.25 [95% CI, 1.09-1.43]) and mortality (females: HR, 2.19 [95% CI, 1.99-2.40]; males: HR, 1.89 [95% CI, 1.71-2.09]). Those with a CCI score of 4 or greater had greater risks of subsequent fracture (females: HR, 1.33 [95% CI, 1.12-1.58]; males: HR, 1.48 [95% CI, 1.21-1.81]) and mortality (females: HR, 4.48 [95% CI, 3.97-5.06]; males: HR, 3.82 [95% CI 3.41-4.29]). Self-rated health was also significantly associated with subsequent fracture and mortality. Those reporting the poorest health and quality of life had the highest subsequent fracture risks, and their mortality risks were even higher.

Conclusions and Relevance

In this cohort study, both CCI and SRH measures were associated with increased risk of subsequent fractures and mortality after fracture, underscoring the importance of managing the care of patients with comorbidities who sustain a fracture.

The multi-faceted nature of age-associated osteoporosis

Age-associated osteoporosis (AAOP) poses a significant health burden, characterized by increased fracture risk due to declining bone mass and strength. Effective prevention and early treatment strategies are crucial to mitigate the disease burden and the associated healthcare costs. Current therapeutic approaches effectively target the individual contributing factors to AAOP. Nonetheless, the management of AAOP is complicated by the multitude of variables that affect its development. Main intrinsic and extrinsic factors contributing to AAOP risk are reviewed here, including mechanical unloading, nutrient deficiency, hormonal disbalance, disrupted metabolism, cognitive decline, inflammation and circadian disruption. Furthermore, it is discussed how these can be targeted for prevention and treatment. Although valuable as individual targets for intervention, the interconnectedness of these risk factors result in a unique etiology for every patient. Acknowledgement of the multifaceted nature of AAOP will enable the development of more effective and sustainable management strategies, based on a holistic, patient-centered approach.

Synergistic effect of metformin and vitamin D3 on osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells under high d-glucose conditions

Introduction

Vitamin D3 plays a vital role in bone health, with low levels of vitamin D3 being related to skeletal fragility, fractures, and metabolic disorders such as diabetes. Metformin is known as an antihyperglycemic agent for regulating blood sugar. A correlation between diabetes mellitus and osteoporosis is attracting considerable interest, and research to find the prevention and treatment is gradually being studied. In this study, we investigated the effect of metformin and vitamin D3 on osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells (AT-MSCs) under high d-glucose concentrations and optimized by combining vitamin D3 and metformin in the process.

Methods

ROS production of AT-MSCs under high d-glucose conditions was measured by DCFH-DA assay. The differentiated AT-MSCs were analyzed by Alizarin Red S staining and optical density measurement. The investigation involved the examination of osteogenic master genes' expressions using quantitative reverse transcription polymerase chain reaction (qRT-PCR) techniques.

Results

Interestingly, the results have shown that human AT-MSCs will exhibit high ROS accumulation and low osteogenic differentiation capabilities, indicated by low calcium deposition, as well as low expression of indicative genes such as ALP, Runx-2 under high d-glucose conditions. The combination of vitamin D3 and metformin remarkedly accelerated the osteogenic differentiation of AT-MSCs under high d-glucose concentrations more effectively than the administration of either agent.

Conclusions

This study partially explains an aspect of an in vitro model for pre-clinical drug screening for osteoporosis-related diabetic pathological mechanisms, which can be applied for further research on the prevention or treatment of osteoporosis in diabetic patients.