Compromised cortical bone compartment in type 2 diabetes mellitus patients with microvascular disease

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.

Correlation between bone mineral density and type 2 diabetes mellitus in elderly men and postmenopausal women

The relationship between bone mineral density and type 2 diabetes is still controversial. The aim of this study is to investigate the relationship between type 2 diabetes mellitus (T2DM) and bone mineral density (BMD) in elderly men and postmenopausal women. The participants in this study included 692 postmenopausal women and older men aged ≥ 50 years, who were divided into the T2DM group and non-T2DM control group according to whether or not they had T2DM. The data of participants in the two groups were collected from the inpatient medical record system and physical examination center systems, respectively, of the Tertiary Class A Hospital. All data analysis is performed in SPSS Software. Compared with all T2DM group, the BMD and T scores of lumbar spines 1-4 (L1-L4), left femoral neck (LFN) and all left hip joints (LHJ) in the non-T2DM group were significantly lower than those in the T2DM group (P < 0.05), and the probability of major osteoporotic fracture in the next 10 years (PMOF) was significantly higher than that in T2DM group (P < 0.001). However, with the prolongation of the course of T2DM, the BMD significantly decreased, while fracture risk and the prevalence of osteoporosis significantly increased (P < 0.05). We also found that the BMD of L1-4, LFN and LHJ were negatively correlated with homeostatic model assessment-insulin resistance (HOMA-IR) (P = 0.028, P = 0.01 and P = 0.047, respectively). The results also showed that the BMD of LHJ was positively correlated with indirect bilirubin (IBIL) (P = 0.018). Although the BMD was lower in the non-T2DM group than in the T2DM group, the prolongation of the course of T2DM associated with the lower BMD. And the higher prevalence of osteoporosis and fracture risk significantly associated with the prolongation of the course of T2DM. In addition, BMD was significantly associated with insulin resistance (IR) and bilirubin levels in T2DM patients.Registration number: China Clinical Trials Registry: MR-51-23-051741; https://www.medicalresearch.org.cn/search/research/researchView?id=c0e5f868-eca9-4c68-af58-d73460c34028 .

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.

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.

LOX-1 regulation of H-type vascular endothelial cell regeneration in hyperglycemia

AIMS

Diabetic osteoporosis (DOP) is the most common secondary form of osteoporosis. Diabetes mellitus affects bone metabolism; however, the underlying pathophysiological mechanisms remain unclear. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) expression is upregulated in conditions characterized by vascular injury, such as atherosclerosis, hypertension, and diabetes. Additionally, Notch, HIF-1α, and VEGF are involved in angiogenesis and bone formation. Therefore, we aimed to investigate the expression of Notch, HIF-1α, and VEGF in the LOX-1 silencing state.

METHODS

Rat bone H-type vascular endothelial cells (THVECs) were isolated and cultured in vitro. Cell identification was performed using immunofluorescent co-expression of CD31 and Emcn. Lentiviral silencing vector (LV-LOX-1) targeting LOX-1 was constructed using genetic recombination technology and transfected into the cells. The experimental groups included the following: NC group, HG group, LV-LOX-1 group, LV-CON group, HG + LV-LOX-1 group, HG + LV-CON group, HG + LV-LOX-1 + FLI-06 group, HG + LV-CON + FLI-06 group, HG + LV-LOX-1 + LW6 group, and HG + LV-CON + LW6 group. The levels of LOX-1, Notch, Hif-1α, and VEGF were detected using PCR and WB techniques to investigate whether the expression of LOX-1 under high glucose conditions has a regulatory effect on downstream molecules at the gene and protein levels, as well as the specific molecular mechanisms involved.

RESULTS

High glucose (HG) conditions led to a significant increase in LOX-1 expression, leading to inhibition of angiogenesis, whereas silencing LOX-1 can reverse this phenomenon. Further analysis reveals that changes in LOX-1 will promote changes in Notch/HIF-1α and VEGF. Moreover, Notch mediates the activation of HIF-1α and VEGF.

CONCLUSIONS

The activation of LOX-1 and the inhibition of Notch/HIF-1α/VEGF in THVECs are the main causes of DOP. These findings contribute to our understanding of the pathogenesis of DOP and offer a novel approach for preventing and treating osteoporosis.

Predicting Osteoporotic Fracture in Patients With Early-Stage Diabetic Kidney Disease Using a Radiomic Model: A Longitudinal Cohort Study

OBJECTIVE

There is an urgent need for effective predictive strategies to accurately evaluate the risk of fragility fractures in elderly patients in the early stages of diabetic kidney disease (DKD).

METHODS

This longitudinal cohort study included 715 older patients in the early stages of DKD diagnosed between January 2015 and August 2019. Patients were randomly allocated to a training cohort (n = 499) and a validation cohort (n = 216). The least absolute shrinkage and selection operator method was used to select key features for dual-energy x-ray absorptiometry-based radiomic analysis. A radiomic model was constructed using Cox proportional hazards regression. The performance of the radiomic model was compared with that of traditional fracture assessment tools through a receiver operating characteristic curve, calibration curve, and decision curve analysis.

RESULTS

Over a mean follow-up period of 4.72 ± 1.60 years, 65 participants (9.09%) experienced incident fragility fractures. Seventeen features were ultimately selected to create the radiomic model. The calibration plots of this model demonstrated satisfactory agreement between the observed and predicted outcomes. Moreover, the radiomic model outperformed traditional fracture assessment tools in both the training and validation cohorts according to the area under the receiver operating characteristic curve and decision curve analysis.

CONCLUSIONS

The novel radiomic model has demonstrated a more effective prediction of fragility fracture in elderly patients in the early stages of DKDcompared to traditional fracture assessment tools.

Microvascular disease not type 2 diabetes is associated with increased cortical porosity: A study of cortical bone microstructure and intracortical vessel characteristics

Introduction

Fracture risk is elevated in type 2 diabetes (T2D) despite normal or even high bone mineral density (BMD). Microvascular disease (MVD) is a diabetic complication, but also associated with other diseases, for example chronic kidney disease. We hypothesize that increased fracture risk in T2D could be due to increased cortical porosity (Ct.Po) driven by expansion of the vascular network in MVD. The purpose of this study was to investigate associations of T2D and MVD with cortical microstructure and intracortical vessel parameters.

Methods

The study group consisted of 75 participants (38 with T2D and 37 without T2D). High-resolution peripheral quantitative CT (HR-pQCT) and dynamic contrast-enhanced MRI (DCE-MRI) of the ultra-distal tibia were performed to assess cortical bone and intracortical vessels (outcomes). MVD was defined as ≥1 manifestation including neuropathy, nephropathy, or retinopathy based on clinical exams in all participants. Adjusted means of outcomes were compared between groups with/without T2D or between participants with/without MVD in both groups using linear regression models adjusting for age, sex, BMI, and T2D as applicable.

Results

MVD was found in 21 (55 %) participants with T2D and in 9 (24 %) participants without T2D. In T2D, cortical pore diameter (Ct.Po.Dm) and diameter distribution (Ct.Po.Dm.SD) were significantly higher by 14.6 μm (3.6 %, 95 % confidence interval [CI]: 2.70, 26.5 μm, p = 0.017) and by 8.73 μm (4.8 %, CI: 0.79, 16.7 μm, p = 0.032), respectively. In MVD, but not in T2D, cortical porosity was significantly higher by 2.25 % (relative increase = 12.9 %, CI: 0.53, 3.97 %, p = 0.011) and cortical BMD (Ct.BMD) was significantly lower by -43.6 mg/cm3 (2.6 %, CI: -77.4, -9.81 mg/cm3, p = 0.012). In T2D, vessel volume and vessel diameter were significantly higher by 0.02 mm3 (13.3 %, CI: 0.004, 0.04 mm3, p = 0.017) and 15.4 μm (2.9 %, CI: 0.42, 30.4 μm, p = 0.044), respectively. In MVD, vessel density was significantly higher by 0.11 mm-3 (17.8 %, CI: 0.01, 0.21 mm-3, p = 0.033) and vessel volume and diameter were significantly lower by -0.02 mm3 (13.7 %, CI: -0.04, -0.004 mm3, p = 0.015) and - 14.6 μm (2.8 %, CI: -29.1, -0.11 μm, p = 0.048), respectively.

Conclusions

The presence of MVD, rather than T2D, was associated with increased cortical porosity. Increased porosity in MVD was coupled with a larger number of smaller vessels, which could indicate upregulation of neovascularization triggered by ischemia. It is unclear why higher variability and average diameters of pores in T2D were accompanied by larger vessels.

Reduction of the trans-cortical vessel was associated with bone loss, another underlying mechanism of osteoporosis

RATIONALE

Numerous studies have established a robust association between bone morrow microvascular diseases and osteoporosis. This study sought to investigate the relationship between alterations in trans-cortical vessel (TCVs) and the onset of osteoporosis in various mouse models.

METHODS

Aged mice, ovariectomized mice, and db/db mice, were utilized as osteoporosis models. TCVs in the tibia were detected using tissue clearing and light sheet fluorescence microscopy imaging. Femurs bone mass were analyzed using micro-CT scanning. Correlations between the number of TCVs and bone mass were analyzed using Pearson correlation analysis.

RESULTS

All osteoporosis mouse models showed a significant reduction in the number of TCVs compared to the control group. Correlation analysis revealed a positive association between the number of TCVs and bone mass. TCVs were also expressed high levels of CD31 and EMCN proteins as type H vessels.

CONCLUSIONS

This study underscores a consistent correlation between the number of TCVs and bone mass. Moreover, TCVs may serve as a potential biomarker for bone mass evaluation.

Use of noninvasive imaging to identify causes of skeletal fragility in adults with diabetes: a review

Diabetes, a disease marked by consistent high blood glucose levels, is associated with various complications such as neuropathy, nephropathy, retinopathy, and cardiovascular disease. Notably, skeletal fragility has emerged as a significant complication in both type 1 (T1D) and type 2 (T2D) diabetic patients. This review examines noninvasive imaging studies that evaluate skeletal outcomes in adults with T1D and T2D, emphasizing distinct skeletal phenotypes linked with each condition and pinpointing gaps in understanding bone health in diabetes. Although traditional DXA-BMD does not fully capture the increased fracture risk in diabetes, recent techniques such as quantitative computed tomography, peripheral quantitative computed tomography, high-resolution quantitative computed tomography, and MRI provide insights into 3D bone density, microstructure, and strength. Notably, existing studies present heterogeneous results possibly due to variations in design, outcome measures, and potential misclassification between T1D and T2D. Thus, the true nature of diabetic skeletal fragility is yet to be fully understood. As T1D and T2D are diverse conditions with heterogeneous subtypes, future research should delve deeper into skeletal fragility by diabetic phenotypes and focus on longitudinal studies in larger, diverse cohorts to elucidate the complex influence of T1D and T2D on bone health and fracture outcomes.

Diabetes and the Microvasculature of the Bone and Marrow

PURPOSE OF REVIEW

The purpose of this review is to highlight the evidence of microvascular dysfunction in bone and marrow and its relation to poor skeletal outcomes in diabetes mellitus.

RECENT FINDINGS

Diabetes mellitus is characterized by chronic hyperglycemia, which may lead to microangiopathy and macroangiopathy. Micro- and macroangiopathy have been diagnosed in Type 1 and Type 2 diabetes, coinciding with osteopenia, osteoporosis, enhanced fracture risk and delayed fracture healing. Microangiopathy has been reported in the skeleton, correlating with reduced blood flow and perfusion, vasomotor dysfunction, microvascular rarefaction, reduced angiogenic capabilities, and augmented vascular permeability. Microangiopathy within the skeleton may be detrimental to bone and manifest as, among other clinical abnormalities, reduced mass, enhanced fracture risk, and delayed fracture healing. More investigations are required to elucidate the various mechanisms by which diabetic microvascular dysfunction impacts the skeleton.

Medications and medical expenditures for diabetic patients with osteoporosis in Beijing, China: A retrospective study

AIMS

This study aimed to clarify the changes in treatment regimens and medical expenditures in diabetic patients with osteoporosis.

METHODS

We recruited 2,853,036 diabetic patients from the Beijing medical insurance database between 2016 and 2018. Among them, 406,221 patients also had osteoporosis. Clinical characteristics, treatment regimens, and medical costs were investigated in diabetic patients with and without osteoporosis.

RESULTS

Diabetes and osteoporosis were most prevalent in participants aged 45---84 years. Compared with diabetic patients without osteoporosis, those with osteoporosis were prone to developing comorbidities and diabetic complications. They often required multiple glucose-lowering drugs and had a higher rate of insulin use. Similarly, osteoporosis leads to an increased number of medications for non-hypoglycemia as well as higher healthcare costs. These medications and costs increased with the number of complications and comorbidities. Interestingly, from 2016 to 2018, although diabetic patients with osteoporosis took more drugs, medical costs were lower year by year.

CONCLUSIONS

Osteoporosis might contribute to a worse condition in diabetic patients, and this population often requires more medications with higher medical costs.

When Cortical Bone Matrix Properties Are Indiscernible between Elderly Men with and without Type 2 Diabetes, Fracture Resistance Follows Suit

Type 2 diabetes mellitus (T2DM) is a metabolic disease affecting bone tissue and leading to increased fracture risk in men and women, independent of bone mineral density (BMD). Thus, bone material quality (i.e., properties that contribute to bone toughness but are not attributed to bone mass or quantity) is suggested to contribute to higher fracture risk in diabetic patients and has been shown to be altered. Fracture toughness properties are assumed to decline with aging and age-related disease, while toughness of human T2DM bone is mostly determined from compression testing of trabecular bone. In this case-control study, we determined fracture resistance in T2DM cortical bone tissue from male individuals in combination with a multiscale approach to assess bone material quality indices. All cortical bone samples stem from male nonosteoporotic individuals and show no significant differences in microstructure in both groups, control and T2DM. Bone material quality analyses reveal that both control and T2DM groups exhibit no significant differences in bone matrix composition assessed with Raman spectroscopy, in BMD distribution determined with quantitative back-scattered electron imaging, and in nanoscale local biomechanical properties assessed via nanoindentation. Finally, notched three-point bending tests revealed that the fracture resistance (measured from the total, elastic, and plastic J-integral) does not significantly differ in T2DM and control group, when both groups exhibit no significant differences in bone microstructure and material quality. This supports recent studies suggesting that not all T2DM patients are affected by a higher fracture risk but that individual risk profiles contribute to fracture susceptibility, which should spur further research on improving bone material quality assessment in vivo and identifying risk factors that increase bone fragility in T2DM. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Application of machine learning algorithms to predict osteoporosis in postmenopausal women with type 2 diabetes mellitus

PURPOSE

The screening and diagnosis of osteoporosis in patients with type 2 diabetes mellitus (T2DM) based on bone mineral density remains challenging because of the limited availability and accessibility of dual-energy X-ray absorptiometry. We aimed to develop and validate models to predict the risk of osteoporosis in postmenopausal women with T2DM based on machine learning (ML) algorithms.

METHODS

This retrospective study included 303 postmenopausal women with T2DM. To develop prediction models for osteoporosis, we applied nine ML algorithms combined with demographic, clinical, and laboratory data. The least absolute shrinkage and selection operator were used to perform feature selection. We used the bootstrap resampling technique for model training and validation. To test the performance of the models, we calculated indices including the area under the receiver operating characteristic curve (AUROC), accuracy, sensitivity, specificity, positive predictive value, negative predictive value, F1 score, calibration curve, and decision curve analysis. Furthermore, we conducted fivefold cross-validation for parameter optimization and model validation. Feature importance was assessed using the SHapley additive explanation (SHAP).

RESULTS

We identified 10 independent predictors as the most valuable features. An AUROC of 0.616-1.000 was observed for nine ML algorithms. The extreme gradient boosting (XGBoost) model exhibited the best performance, outperforming conventional risk assessment tools and registering 0.993 in the training set, 0.798 in the validation set, and 0.786 in the test set for fivefold cross-validation. Using SHAP, we found that the explanatory variables contributed to the model and their relationship with osteoporosis occurrence. Furthermore, we developed a user-friendly tool for calculating the risk of osteoporosis.

CONCLUSIONS

With the integration of demographic and clinical risk factors, ML algorithms can accurately predict osteoporosis. The XGBoost model showed ideal performance. With the incorporation of these models in the clinic, patients may benefit from early osteoporosis diagnosis and treatment.

A simple fragility fracture risk score for type 2 diabetes patients: a derivation, validation, comparison, and risk stratification study

OBJECTIVES

The aims of this study were to develop and validate 2 simple scores for stratification of the risks of (1) any fragility (AF) and (2) major osteoporotic fracture (MOF) in type 2 diabetes (T2D) patients; we also compared the performance of these scores with that of the Fracture Risk Assessment Tool (FRAX) and its adjustments.

DESIGN AND METHODS

In this longitudinal cohort study, 1855 patients with T2D were enrolled from January 2015 to August 2019. Cox proportional hazard regression was used to model the 5-year risk of AF and MOF. These scores were internally validated using a bootstrap resampling method of 1000.

RESULTS

During a median follow-up of 5 years, 119 (6.42%) cases of AF and 92 (4.96%) cases of MOFs were identified. Both the concordance index (C-index) and calibration plots indicated improved identification performance using the newly established scores. Furthermore, these scores also showed improved outcomes regarding the decision curve analysis (DCA) and area under the curve (AUC) compared to the widely used FRAX and its derivatives. More importantly, these scores successfully separated T2D patients into risk groups according to significant differences in fracture incidence.

CONCLUSIONS

These novel scores enable simple and reliable fracture risk stratification in T2D patients. Future work is needed to validate these findings in external cohort(s).

Antiresorptive Versus Anabolic Therapy in Managing Osteoporosis in People with Type 1 and Type 2 Diabetes

Diabetes is characterized by hyperglycemia, but the two main types, type 1 diabetes (T1D) and type 2 diabetes (T2D), have distinct pathophysiology and epidemiological profiles. Individuals with T1D and T2D have an increased risk of fractures, particularly of the hip, upper arm, ankle, and nonvertebral sites. The risk of fractures is higher in T1D compared to T2D. The diagnosis of osteoporosis in individuals with T1D and T2D follows similar criteria as in the general population, but treatment thresholds may differ. Antiresorptive therapies, the first-line treatment for osteoporosis, are effective in individuals with T2D. Observational studies and post hoc analyses of previous trials have indicated that antiresorptive drugs, such as bisphosphonates and selective estrogen receptor modulators, are equally effective in reducing fracture risk and increasing bone mineral density (BMD) in individuals with and without T2D. Denosumab has shown similar effects on vertebral fracture risk but increases the risk of nonvertebral fractures. Considering the low bone turnover observed in T1D and T2D, anabolic therapies, which promote bone formation and resorption, have emerged as a potential treatment option for bone fragility in this population. Data from observational studies and post hoc analyses of previous trials also showed similar results in increasing BMD and reducing the risk of fractures in people with or without T2D. However, no evidence suggests that anabolic therapy has greater efficacy than antiresorptive drugs. In conclusion, there is an increased risk of fractures in T1D and T2D. Reductions in BMD cannot solely explain the relationship between T1D and T2D and fractures. Bone microarchitecture and other factors play a role. Antiresorptive and anabolic therapies have shown efficacy in reducing fracture risk in individuals with T2D, but the evidence is more robust for antiresorptive drugs. Evidence in T1D is scant. Further research is needed to fully understand the underlying mechanisms and optimize management strategies for bone fragility in T1D and T2D. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Microvascular Disease Associates with Larger Osteocyte Lacunae in Cortical Bone in Type 2 Diabetes Mellitus

Clinical studies indicate that microvascular disease (MVD) affects bone microstructure and decreases bone strength in type 2 diabetes mellitus (T2D). Osteocytes are housed in small voids within the bone matrix and lacunae and act as sensors of mechanical forces in bone. These cells regulate osteoclastic bone resorption and osteoblastic bone formation as well as osteocytic perilacunar remodeling. We hypothesized that MVD changes morphometric osteocyte lacunar parameters in individuals with T2D. We collected iliac crest bone biopsies from 35 individuals (10 female, 25 male) with T2D with MVD (15%) or without MVD (21%) with a median age of 67 years (interquartile range [IQR] 62-72 years). The participants were included based on c-peptide levels >700 pmol L-1, absence of anti-GAD65 antibodies, and glycated hemoglobin (HbA1c) levels between 40 and 82 mmol mol-1 or 5.8% and 9.7%, respectively. We assessed osteocyte lacunar morphometric parameters in trabecular and cortical bone regions using micro-computed tomography (micro-CT) at a nominal resolution of 1.2 μm voxel size. The cortical osteocyte lacunar volume (Lc.V) was 7.7% larger (p = 0.05) and more spherical (Lc.Sr, p < 0.01) in the T2D + MVD group. Using linear regression, we found that lacunar density (Lc.N/BV) in trabecular but not cortical bone was associated with HbA1c (p < 0.05, R 2 = 0.067) independently of MVD. Furthermore, Lc.V was larger and Lc.Sr higher in the center than in the periphery of the trabecular and cortical bone regions (p < 0.05). In conclusion, these data imply that MVD may impair skeletal integrity, possibly contributing to increased skeletal fragility in T2D complicated by MVD. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

High-resolution peripheral quantitative computed tomography: research or clinical practice?

High-resolution peripheral quantitative CT (HR-pQCT) is a low-dose three-dimensional imaging technique, originally developed for in vivo assessment of bone microarchitecture at the distal radius and tibia in osteoporosis. HR-pQCT has the ability to discriminate trabecular and cortical bone compartments, providing densitometric and structural parameters. At present, HR-pQCT is mostly used in research settings, despite evidence showing that it may be a valuable tool in osteoporosis and other diseases. This review summarizes the main applications of HR-pQCT and addresses the limitations that currently prevent its integration into routine clinical practice. In particular, the focus is on the use of HR-pQCT in primary and secondary osteoporosis, chronic kidney disease (CKD), endocrine disorders affecting bone, and rare diseases. A section on novel potential applications of HR-pQCT is also present, including assessment of rheumatic diseases, knee osteoarthritis, distal radius/scaphoid fractures, vascular calcifications, effect of medications, and skeletal muscle. The reviewed literature seems to suggest that a more widespread implementation of HR-pQCT in clinical practice would offer notable opportunities. For instance, HR-pQCT can improve the prediction of incident fractures beyond areal bone mineral density provided by dual-energy X-ray absorptiometry. In addition, HR-pQCT may be used for the monitoring of anti-osteoporotic therapy or for the assessment of mineral and bone disorder associated with CKD. Nevertheless, several obstacles currently prevent a broader use of HR-pQCT and would need to be targeted, such as the small number of installed machines worldwide, the uncertain cost-effectiveness, the need for improved reproducibility, and the limited availability of reference normative data sets.

Development of Machine Learning Models for Predicting Osteoporosis in Patients with Type 2 Diabetes Mellitus-A Preliminary Study

Purpose

Diagnosing osteoporosis in T2DM based on bone mineral density (BMD) remains challenging. We sought to develop prediction models employing machine learning algorithms for use as screening instruments for osteoporosis in T2DM patients.

Patients and Methods

Data were collected from 433 participants and analyzed using nine categorical machine learning algorithms to select features based on demographic and clinical variables. Multiple classification models were compared using the area under the receiver operating characteristic curve (ROC-AUC), accuracy, sensitivity, specificity, the average precision (AP), precision, F1 score, precision-recall curves, calibration plots, and decision curve analysis (DCA) to determine the best model. In addition, 5-fold cross-validation was utilized to optimize the model, followed by an evaluation of feature significance using Shapley Additive exPlanations (SHAP). Using latent class analysis (LCA), distinct subpopulations were identified by constructing several discrete clusters.

Results

In this study, nine feature variables were identified to construct predictive models for osteoporosis in individuals with T2DM. The machine learning algorithms achieved an AP range of 0.444-1.000. The XGBoost model was selected as the final prediction model with an AUROC of 0.940 in the training set, 0.772 in the validation set for 5-fold cross-validation, and 0.872 in the test set. Using SHAP methodology, 25(OH)D was identified as the most important risk factor. Additionally, a 3-Class model was constructed using LCA, which categorized individuals into high, medium, and low-risk groups.

Conclusion

Our study developed a predictive model with high accuracy and clinical validity for predicting osteoporosis in type 2 diabetes patients. We also identified three subpopulations with varying osteoporosis risk using clustering. However, limited sample size warrants cautious interpretation of results, and validation in larger cohorts is needed.

The effect of type 2 diabetes mellitus on the prognosis of osteoporotic vertebral compression fracture with osteoporotic fracture classification after vertebroplasty

BACKGROUND

To analyze the clinical and radiological effects of type 2 diabetes mellitus on the prognosis of osteoporotic vertebral compression fracture after percutaneous vertebroplasty, and explore the prognostic value of osteoporotic fracture classification.

METHODS

Osteoporotic vertebral compression fracture patients who received vertebroplasty from January 1, 2016 to June 30, 2021 were divided into type 2 diabetes mellitus group and control group in this retrospective cohort study. Visual analogue scale, Oswestry Disability Index, bone cement leakage, new compression fracture, anterior, middle, and posterior portion heights of vertebral body and local Cobb angle on X-ray before surgery, 2 days after surgery, 6 months, and 12 months after surgery were recorded, and the osteoporotic fracture classification was performed. P < 0.05 was set as statistical significance.

RESULTS

A total of 261 vertebral bodies were included, containing 68 in the type 2 diabetes mellitus group and 193 in the control group. There were no differences in baseline characteristics between the two groups. At 6 months after vertebroplasty, the local Cobb angle of the type 2 diabetes mellitus group was 8.29 ± 4.90° greater than that of the control group 6.05 ± 5.18° (P = 0.002). At 12 months, compared with pre-operation, the anterior portion height recovered 8.13 ± 12.90%, which was less than 12.51 ± 14.92% of the control group (P = 0.032), and 19.07 ± 16.47% of the middle portion height recovery was less than the control group's 24.63 ± 17.67% (P = 0.024). Compared with the control group, osteoporotic fracture 2 vertebral bodies of the type 2 diabetes mellitus group at 12 months postoperatively in middle portion height (14.82 ± 14.71% vs 24.78 ± 18.16%, P = 0.023) and local Cobb angle (5.65 ± 4.06° vs 3.26 ± 4.86°, P = 0.043) restored significantly worse. Besides, osteoporotic fracture 3 with type 2 diabetes mellitus restored worse in anterior portion height (5.40 ± 11.02% vs 13.57 ± 12.79%, P = 0.008), middle portion height (11.22 ± 15.53% vs 17.84 ± 12.36%, P = 0.041) and local Cobb angle (10.85 ± 3.79 vs 7.97 ± 3.83°, P = 0.002) at 12 months postoperatively. There was no difference in radiological outcomes of osteoporotic fracture 4 between the two groups.

CONCLUSIONS

The degree of fractured vertebral compression, the recovery of the height and angle obtained immediately after surgery and the clinical symptoms in type 2 diabetes mellitus patients were not different from those in the control. However, vertebral body morphology of type 2 diabetes mellitus patients was worse since the sixth month after surgery. Osteoporotic fracture classification has a good prognostic reference value for both the control and the type 2 diabetes mellitus population.

Biochemical Markers of Bone Fragility in Patients with Diabetes. A Narrative Review by the IOF and the ECTS

CONTEXT

The risk of fragility fractures is increased in both type 1 and type 2 diabetes. Numerous biochemical markers reflecting bone and/or glucose metabolism have been evaluated in this context. This review summarizes current data on biochemical markers in relation to bone fragility and fracture risk in diabetes.

METHODS

Literature review by a group of experts from the International Osteoporosis Foundation (IOF) and European Calcified Tissue Society (ECTS) focusing on biochemical markers, diabetes, diabetes treatments and bone in adults.

RESULTS

Although bone resorption and bone formation markers are low and poorly predictive of fracture risk in diabetes, osteoporosis drugs seem to change bone turnover markers in diabetics similarly to non-diabetics, with similar reductions in fracture risk. Several other biochemical markers related to bone and glucose metabolism have been correlated with BMD and/or fracture risk in diabetes, including osteocyte-related markers such as sclerostin, HbA1c and advanced glycation end products (AGEs), inflammatory markers and adipokines, as well as IGF-1 and calciotropic hormones.

CONCLUSION

Several biochemical markers and hormonal levels related to bone and/or glucose metabolism have been associated with skeletal parameters in diabetes. Currently, only HbA1c levels seem to provide a reliable estimate of fracture risk, while bone turnover markers could be used to monitor the effects of anti-osteoporosis therapy.

Role of Advanced Glycation End-Products and Oxidative Stress in Type-2-Diabetes-Induced Bone Fragility and Implications on Fracture Risk Stratification

Type 2 diabetes (T2D) and osteoporosis (OP) are major causes of morbidity and mortality that have arelevant health and economic burden. Recent epidemiological evidence suggests that both of these disorders are often associated with each other and that T2D patients have an increased risk of fracture, making bone an additional target of diabetes. As occurs for other diabetic complications, the increased accumulation of advanced glycation end-products (AGEs) and oxidative stress represent the major mechanisms explaining bone fragility in T2D. Both of these conditions directly and indirectly (through the promotion of microvascular complications) impair the structural ductility of bone and negatively affect bone turnover, leading to impaired bone quality, rather than decreased bone density. This makes diabetes-induced bone fragility remarkably different from other forms of OP and represents a major challenge for fracture risk stratification, since either the measurement of BMD or the use of common diagnostic algorithms for OP have a poor predictive value. We review and discuss the role of AGEs and oxidative stress on the pathophysiology of bone fragility in T2D, providing some indications on how to improve fracture risk prediction in T2D patients.

N-acetyl-L-cysteine attenuates oxidative stress-induced bone marrow endothelial cells apoptosis by inhibiting BAX/caspase 3 pathway

Bone marrow endothelial cells (BMECs) play a crucial role in the maintenance of bone homeostasis. The decline in BMECs is associated with abnormal bone development and loss. At present, the mechanism of age-related oxidative stress enhancement in BMEC dysfunction remains unclear. Our experiment explored injury caused by oxidative stress enhancement in BMECs both in vivo and in vitro. The BMECs, indicators of oxidative stress, bone mass, and apoptosis-related proteins were analyzed in different age groups. We also evaluated the ability of N-Acetyl-L-cysteine (NAC) attenuate oxidative stress injury in BMECs. NAC treatment attenuated reactive oxygen species (ROS) overgeneration and apoptosis in BMECs in vitro and alleviated the loss of BMECs and bone mass in vivo. In conclusion, this study could improve our understanding of the mechanism of oxidative stress-induced BMECs injury and whether NAC has therapeutic potential in senile osteoporosis.

Bone quality in endocrine diseases: determinants and clinical relevance

PURPOSE

Bone is one of the main targets of hormones and endocrine diseases are frequent causes of secondary osteoporosis and fractures in real-world clinical practice. However, diagnosis of skeletal fragility and prediction of fractures in this setting could be a challenge, since the skeletal alterations induced by endocrine disorders are not generally captured by dual-energy X-ray absorptiometry (DXA) measurement of bone mineral density (BMD), that is the gold standard for diagnosis of osteoporosis in the general population. The aim of this paper is to review the existing evidence related to bone quality features in endocrine diseases, proposing assessment with new techniques in the future.

METHODS

A comprehensive search within electronic databases was performed to collect reports of bone quality in primary hyperparathyroidism, hypoparathyroidism, hyperthyroidism, hypercortisolism, growth hormone deficiency, acromegaly, male hypogonadism and diabetes mellitus.

RESULTS

Using invasive and non-invasive techniques, such as high-resolution peripheral quantitative computed tomography or DXA measurement of trabecular bone score (TBS), several studies consistently reported altered bone quality as predominant determinant of fragility fractures in subjects affected by chronic endocrine disorders.

CONCLUSIONS

Assessment of skeletal fragility in endocrine diseases might take advantage from the use of techniques to detect perturbation in bone architecture with the aim of best identifying patients at high risk of fractures.

Contributors to impaired bone health in type 2 diabetes

Type 2 diabetes (T2D) is associated with numerous complications, including increased risk of fragility fractures, despite seemingly protective factors [e.g., normal bone mineral density and increased body mass index(BMI)]. However, fracture risk in T2D is underestimated by current fracture risk calculators. Importantly, post-fracture mortality is worse in T2D following any fracture, highlighting the importance of identifying high-risk patients that may benefit from targeted management. Several diabetes-related factors are associated with increased fracture risk, including exogenous insulin therapy, vascular complications, and poor glycaemic control, although detailed comprehensive studies to identify the independent contributions of these factors are lacking. The underlying pathophysiological mechanisms are complex and multifactorial, with different factors contributing during the course of T2D disease. These include obesity, hyperinsulinaemia, hyperglycaemia, accumulation of advanced glycation end products, and vascular supply affecting bone-cell function and survival and bone-matrix composition. This review summarises the current understanding of the contributors to impaired bone health in T2D, and proposes an updated approach to managing these patients.

Association of Bone Turnover Markers with Type 2 Diabetes Mellitus and Microvascular Complications: A Matched Case-Control Study

Purpose

The aim of this study was to evaluate the association of bone turnover markers (BTMs) with type 2 diabetes mellitus (T2DM) and microvascular complications.

Methods

A total of 166 T2DM patients and 166 non-diabetic controls matched by gender and age were enrolled. T2DM patients were sub-classified into groups based on whether they had diabetic peripheral neuropathy (DPN), diabetic retinopathy (DR), and diabetic kidney disease (DKD). Clinical data including demographic characteristics and blood test results [serum levels of osteocalcin (OC), N-terminal propeptide of type 1 procollagen (P1NP), and β-crosslaps (β-CTX)] were collected. Logistic regression and restrictive cubic spline curves were performed to examine the association of BTMs with the risk of T2DM and microvascular complications.

Results

After adjusting for family history of diabetes, sex and age, an inverse association was observed between elevated serum OC levels [O, p < 0.001] and increased serum P1NP levels , p < 0.001] with the risk of T2DM. Moreover, there was an inverse linear association of serum OC and P1NP levels with the risk of T2DM. However, β-CTX was not associated with T2DM. Further analysis showed a nonlinear association between OC and the risk of DR, while P1NP and β-CTX were not correlated with DR. Serum concentrations of BTMs were not associated with the risks of DPN and DKD.

Conclusion

Serum OC and P1NP levels were negatively correlated with T2DM risk. Particularly, serum OC levels were associated with DR risk. Given that BTMs are widely used as markers of bone remodeling, the present finding provides a new perspective for estimating the risk of diabetic microvascular complications.

Meta-analysis of Diabetes Mellitus-Associated Differences in Bone Structure Assessed by High-Resolution Peripheral Quantitative Computed Tomography

PURPOSE OF REVIEW

Diabetes mellitus is defined by elevated blood glucose levels caused by changes in glucose metabolism and, according to its pathogenesis, is classified into type 1 (T1DM) and type 2 (T2DM) diabetes mellitus. Diabetes mellitus is associated with multiple degenerative processes, including structural alterations of the bone and increased fracture risk. High-resolution peripheral computed tomography (HR-pQCT) is a clinically applicable, volumetric imaging technique that unveils bone microarchitecture in vivo. Numerous studies have used HR-pQCT to assess volumetric bone mineral density and microarchitecture in patients with diabetes, including characteristics of trabecular (e.g. number, thickness and separation) and cortical bone (e.g. thickness and porosity). However, study results are heterogeneous given different imaging regions and diverse patient cohorts.

RECENT FINDINGS

This meta-analysis assessed T1DM- and T2DM-associated characteristics of bone microarchitecture measured in human populations in vivo reported in PubMed- and Embase-listed publications from inception (2005) to November 2021. The final dataset contained twelve studies with 516 participants with T2DM and 3067 controls and four studies with 227 participants with T1DM and 405 controls. While T1DM was associated with adverse trabecular characteristics, T2DM was primarily associated with adverse cortical characteristics. These adverse effects were more severe at the radius than the load-bearing tibia, indicating increased mechanical loading may compensate for deleterious bone microarchitecture changes and supporting mechanoregulation of bone fragility in diabetes mellitus. Our meta-analysis revealed distinct predilection sites of bone structure aberrations in T1DM and T2DM, which provide a foundation for the development of animal models of skeletal fragility in diabetes and may explain the uncertainty of predicting bone fragility in diabetic patients using current clinical algorithms.

Glycemic Control and Bone in Diabetes

PURPOSE OF REVIEW

This review summarizes recent developments on the effects of glycemic control and diabetes on bone health. We discuss the foundational cellular mechanisms through which diabetes and impaired glucose control impact bone biology, and how these processes contribute to bone fragility in diabetes.

RECENT FINDINGS

Glucose is important for osteoblast differentiation and energy consumption of mature osteoblasts. The role of insulin is less clear, but insulin receptor deletion in mouse osteoblasts reduces bone formation. Epidemiologically, type 1 (T1D) and type 2 diabetes (T2D) associate with increased fracture risk, which is greater among people with T1D. Accumulation of cortical bone micro-pores, micro-vascular complications, and AGEs likely contribute to diabetes-related bone fragility. The effects of youth-onset T2D on peak bone mass attainment and subsequent skeletal fragility are of particular concern. Further research is needed to understand the effects of hyperglycemia on skeletal health through the lifecycle, including the related factors of inflammation and microvascular damage.

Ginsenoside Rg1 interferes with the progression of diabetic osteoporosis by promoting type H angiogenesis modulating vasculogenic and osteogenic coupling

Ginsenoside Rg1 (Rg1) has been demonstrated to have antidiabetic and antiosteoporotic activities. The aim of this study was to investigate the protective effect of Rg1 against diabetic osteoporosis and the underlying mechanism. In vitro, we found that Rg1 increased the number of osteoprogenitors and alleviated high glucose (HG) induced apoptosis of osteoprogenitors by MTT assays and flow cytometry. qRT‒PCR and western blot analysis suggested that Rg1 can also promote the secretion of vascular endothelial growth factor (VEGF) by osteoprogenitors and promote the coupling of osteogenesis and angiogenesis. Rg1 can also promote the proliferation of human umbilical vein endothelial cells (HUVECs) cultured in high glucose, enhance the angiogenic ability of endothelial cells, and activate the Notch pathway to promote endothelial cells to secrete the osteogenesis-related factor Noggin to regulate osteogenesis, providing further feedback coupling of angiogenesis and osteogenesis. Therefore, we speculated that Rg1 may have similar effects on type H vessels. We used the Goto-Kakizaki (GK) rat model to perform immunofluorescence staining analysis on two markers of type H vessels, Endomucin (Emcn) and CD31, and the osteoblast-specific transcription factor Osterix, and found that Rg1 stimulates type H angiogenesis and bone formation. In vivo experiments also demonstrated that Rg1 promotes VEGF secretion, activates the Noggin/Notch pathway, increases the level of coupling between type H vessels and osteogenesis, and improves the bone structure of GK rats. All of these data reveal that Rg1 is a promising candidate drug for treating diabetic osteoporosis as a potentially bioactive molecule that promotes angiogenesis and osteointegration coupling.

Type 2 diabetes and bone fragility in children and adults

Type 2 diabetes (T2D) is a global epidemic disease. The prevalence of T2D in adolescents and young adults is increasing alarmingly. The mechanisms leading to T2D in young people are similar to those in older patients. However, the severity of onset, reduced insulin sensitivity and defective insulin secretion can be different in subjects who develop the disease at a younger age. T2D is associated with different complications, including bone fragility with consequent susceptibility to fractures. The purpose of this systematic review was to describe T2D bone fragility together with all the possible involved pathways. Numerous studies have reported that patients with T2D show preserved, or even increased, bone mineral density compared with controls. This apparent paradox can be explained by the altered bone quality with increased cortical bone porosity and compr-omised mechanical properties. Furthermore, reduced bone turnover has been described in T2D with reduced markers of bone formation and resorption. These findings prompted different researchers to highlight the mechanisms leading to bone fragility, and numerous critical altered pathways have been identified and studied. In detail, we focused our attention on the role of microvascular disease, advanced glycation end products, the senescence pathway, the Wnt/β-catenin pathway, the osteoprotegerin/receptor-activator of nuclear factor kappa B ligand, osteonectin and fibroblast growth factor 23. The understanding of type 2 myeloid bone fragility is an important issue as it could suggest possible interventions for the prevention of poor bone quality in T2D and/or how to target these pathways when bone disease is clearly evident.

Increased Cortical Porosity, Reduced Cortical Thickness, and Reduced Trabecular and Cortical Microhardness of the Superolateral Femoral Neck Confer the Increased Hip Fracture Risk in Individuals with Type 2 Diabetes

Individuals with diabetes mellitus type 2 (T2DM) have approximately 30% increased risk of hip fracture; however, the main cause of the elevated fracture risk in those subjects remains unclear. Moreover, micromechanical and microarchitectural properties of the superolateral femoral neck-the common fracture-initiating site-are still unknown. We collected proximal femora of 16 men (eight with T2DM and eight controls; age: 61 ± 10 years) at autopsy. After performing post-mortem bone densitometry (DXA), the superolateral neck was excised and scanned with microcomputed tomography (microCT). We also conducted Vickers microindentation testing. T2DM and control subjects did not differ in age (p = 0.605), body mass index (p = 0.114), and femoral neck bone mineral density (BMD) (p = 0.841). Cortical porosity (Ct.Po) was higher and cortical thickness (Ct.Th) was lower in T2DM (p = 0.044, p = 0.007, respectively). Of trabecular microarchitectural parameters, only structure model index (p = 0.022) was significantly different between T2DM subjects and controls. Control group showed higher cortical (p = 0.002) and trabecular bone microhardness (p = 0.005). Increased Ct.Po and decreased Ct.Th in T2DM subjects increase the propensity to femoral neck fracture. Apart from the deteriorated cortical microarchitecture, decreased cortical and trabecular microhardness suggests altered bone composition of the superolateral femoral neck cortex and trabeculae in T2DM. Significantly deteriorated cortical microarchitecture of the superolateral femoral neck is not recognized by standard DXA measurement of the femoral neck.

Influence of type 2 diabetes microangiopathy on bone mineral density and bone metabolism: A meta-analysis

Background

Diabetic microangiopathy is a type of vascular dysfunction. The effect of type 2 diabetes microangiopathy (DMA) on bone mineral density (BMD) and bone metabolism is still unclear.

Objective

A meta-analysis was performed to investigate the effects of microangiopathy on BMD and bone metabolism in type 2 diabetic patients.

Methods

We searched the PubMed, Embase, Cochrane Library and CNKI databases to identify observational studies investigating the effects of type 2 diabetes microangiopathy on BMD or bone metabolism. The time limit for the literature retrieval was from the establishment of the database to September 25, 2021. The Newcastle–Ottawa scale (NOS) and the Agency for Healthcare Research and Quality (AHRQ) scale were used to evaluate the quality of the studies. RevMan 5.3 software was used for the data analysis. Stata 14.0 was used to quantitatively evaluate the publication bias of the outcome indicators.

Results

In total, 12 observational studies were included, including 7 cohort studies, 4 case–control studies and 1 cross-sectional study. In total, 2,500 patients with type 2 diabetes were included. Among them, 1,249 patients had microangiopathy (DMA group), and 1,251 patients did not have microangiopathy (control group). The results of the meta-analysis showed that the BMDs of the femoral neck (SMD = −1.34, 95% CI = −2.22 to −0.45, P = 0.003), lumbar spine (SMD = −0.69, 95% CI = −1.31 to −0.08, P = 0.03) and Ward's triangle (SMD = −2.84, 95% CI = −4.84 to −0.83, P = 0.006) in the DMA group were lower than those in the control group. In the comparison of the bone metabolism indexes, the contents of N-terminal propeptide of type I procollagen (P1NP) (SMD = 0.18, 95% CI = 0.03 to 0.32, P = 0.02), osteocalcin (SMD = 6.97, 95% CI = 3.46 to 10.48, P < 0. 0001), parathyroid hormone (PTH) (SMD = 0.38, 95% CI = 0.03 to 0.73, P = 0.03) and C-telopeptide of type 1 collagen (CTX) (SMD = 0.39, 95% CI = 0.03 to 0.75, P = 0.03) in serum from the DMA group were higher than those in serum from the control group. The serum content of 25-hydroxyvitamin D₃ (25(OH)D₃) (SMD = −0.63, 95% CI = −1.19 to −0.07, P = 0.03) in the DMA group was lower than that in the control group. There was no significant difference in serum alkaline phosphatase (ALP), calcium or phosphorus between the two groups (P > 0.05).

Conclusions

Type 2 diabetes microangiopathy can reduce the lumbar spine, femoral neck and Ward's triangle BMD and has a higher risk of osteoporosis or osteoporosis fractures. The levels of P1NP, PTH, CTX and OC in the serum of patients with type 2 diabetes microangiopathy are higher, and the lower 25(OH)D₃ content may be a mechanism by which DMA destroys bone metabolism balance.

•

The effect of type 2 diabetes microangiopathy on bone mineral density and bone metabolism is still unclear.

•

Type 2 diabetes microangiopathy can reduce the lumbar spine, femoral neck and Ward's triangle BMD.

•

Type 2 diabetes microangiopathy has a higher risk of osteoporosis or osteoporosis fractures.

Risk Factors for Chronic Non-Communicable Diseases and Osteoporotic Fractures in a Middle and Elderly-Aged Population

Aim. To study the associations of risk factors for chronic non-communicable diseases (CNCDs) and osteoporotic fractures (OFs) in a population sampling over 50 years. Materials and Methods. The data of a cross-sectional population-based study obtained in the Russian part of the international project HAPIEE (Novosibirsk) are analyzed. The present analysis comprised 7363 men and women aged 50–69 years old. We have assessed the frequency of OFs for the last 12 months and risk factors of CNCDs. Cross-sectional associations between OF history and potential determinants were analyzed using multivariable-adjusted logistic regression. Results. The frequency of OFs in the last 12 months was 3.6% (3.2% in men and 4.0% in women, p = 0.074). In men, the probability of OFs increased with an elevation of blood pressure (BP), high-density lipoprotein cholesterol (HDL-C), ethanol consumption, and reduced with increased body mass index (BMI). In women, the probability of a fracture increased with current smoking and an increased duration of post-menopause and reduced with an increase in triglycerides (TG) levels, independently of other factors. Conclusions. A syndemia of risk factors, both generally recognized for OFs (BMI, tobacco smoking, alcohol consumption, postmenopausal duration) and new factors associated with CNCDs (BP, HDL, TG), have been defined.

Obesity and Bone Health: A Complex Relationship

Recent scientific evidence has shown an increased risk of fractures in patients with obesity, especially in those with a higher visceral adipose tissue content. This contradicts the old paradigm that obese patients were more protected than those with normal weight. Specifically, in older subjects in whom there is a redistribution of fat from subcutaneous adipose tissue to visceral adipose tissue and an infiltration of other tissues such as muscle with the consequent sarcopenia, obesity can accentuate the changes characteristic of this age group that predisposes to a greater risk of falls and fractures. Other factors that determine a greater risk in older subjects with obesity are chronic proinflammatory status, altered adipokine secretion, vitamin D deficiency, insulin resistance and reduced mobility. On the other hand, diagnostic tests may be influenced by obesity and its comorbidities as well as by body composition, and risk scales may underestimate the risk of fractures in these patients. Weight loss with physical activity programs and cessation of high-fat diets may reduce the risk. Finally, more research is needed on the efficacy of anti-osteoporotic treatments in obese patients.

Bone mass and microarchitecture in T2DM patients and corticosteroids therapy: the Bushehr Elderly Health program

Purpose

Our study examined whether T2DM and glucocorticoids treatment affect bone quality and quantity that are measured by Bone Mineral Density (BMD) and Trabecular Bone Score (TBS).

Materials & methods

Participants in this study were 2294 women and men aged over 60 years who participated in stage II of the Bushehr Elderly Health (BEH) program. Patients with T2DM and those who received glucocorticoids were included. BMD was detected using the DXA method and the TBS of L1-L4 was evaluated by TBS iNsight® software. To evaluate the correlation between TBS and BMD levels with diabetes and taking corticosteroids sex-specific multivariable linear regression models were appplied.

Results

TBS and BMD were not significantly different in those who had received glucocorticoids versus those who did not.T2DM revealed a significant association with both BMD and TBS in men (beta = 0.12, p < 0.001 and beta = 0.063, p = 0.03, respectively). BMD values were significantly higher in diabetic women (beta = 0.073, p < 0.01). BMI had a significant association with both TBS and BMD but in an opposite direction, in women and men (BMD: beta = -0.22, -0.24, and regarding TBS: beta = 0.37, 0.25, all p-values < 0.001).

Conclusion

Our findings showed that T2DM had major effects on BMD in both men and women. However, T2DM only affects TBS in men. Furthermore, neither BMD nor TBS were affected by GC intake in men or women.Based on the variable importance of covariates, BMI was the most influential factor on both BMD and TBS, although in opposite directions, in both sexes.

Bone Microarchitecture and Strength in Long-Standing Type 1 Diabetes

Type 1 diabetes (T1DM) is associated with an increased fracture risk, specifically at nonvertebral sites. The influence of glycemic control and microvascular disease on skeletal health in long-standing T1DM remains largely unknown. We aimed to assess areal (aBMD) and volumetric bone mineral density (vBMD), bone microarchitecture, bone turnover, and estimated bone strength in patients with long-standing T1DM, defined as disease duration ≥25 years. We recruited 59 patients with T1DM (disease duration 37.7 ± 9.0 years; age 59.9 ± 9.9 years.; body mass index [BMI] 25.5 ± 3.7 kg/m² ; 5-year median glycated hemoglobin [HbA1c] 7.1% [IQR 6.82-7.40]) and 77 nondiabetic controls. Dual-energy X-ray absorptiometry (DXA), high-resolution peripheral quantitative computed tomography (HRpQCT) at the ultradistal radius and tibia, and biochemical markers of bone turnover were assessed. Group comparisons were performed after adjustment for age, gender, and BMI. Patients with T1DM had lower aBMD at the hip (p < 0.001), distal radius (p = 0.01), lumbar spine (p = 0.04), and femoral neck (p = 0.05) as compared to controls. Cross-linked C-telopeptide (CTX), a marker of bone resorption, was significantly lower in T1DM (p = 0.005). At the distal radius there were no significant differences in vBMD and bone microarchitecture between both groups. In contrast, patients with T1DM had lower cortical thickness (estimate [95% confidence interval]: -0.14 [-0.24, -0.05], p < 0.01) and lower cortical vBMD (-28.66 [-54.38, -2.93], p = 0.03) at the ultradistal tibia. Bone strength and bone stiffness at the tibia, determined by homogenized finite element modeling, were significantly reduced in T1DM compared to controls. Both the altered cortical microarchitecture and decreased bone strength and stiffness were dependent on the presence of diabetic peripheral neuropathy. In addition to a reduced aBMD and decreased bone resorption, long-standing, well-controlled T1DM is associated with a cortical bone deficit at the ultradistal tibia with reduced bone strength and stiffness. Diabetic neuropathy was found to be a determinant of cortical bone structure and bone strength at the tibia, potentially contributing to the increased nonvertebral fracture risk. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

FSH may mediate the association between HbA1c and bone turnover markers in postmenopausal women with type 2 diabetes

INTRODUCTION

Recent studies in postmenopausal women have found associations of follicle-stimulating hormone (FSH) levels with both glucose metabolism and bone turnover. The objective of the study was to investigate whether FSH may contribute to suppressed bone turnover markers (BTMs) in postmenopausal women with type 2 diabetes (T2D).

MATERIALS AND METHODS

888 postmenopausal women with T2D, 352 nondiabetes (prediabetes plus normoglycemia) were included from the METAL study. HbA1c, sex hormones, 25-hydroxy vitamin D (25(OH)D), serum procollagen type I N-terminal propeptide (P1NP), and β-C-terminal telopeptide (β-CTX) were measured.

RESULTS

P1NP and β-CTX decreased in postmenopausal T2D women compared with nondiabetes controls (both p < 0.001). The major factors responsible for the changes in P1NP were HbA1c (β = - 0.050, p < 0.001), 25(OH)D (β = - 0.003, p = 0.006), FSH (β = 0.001, p = 0.044) and metformin (β = - 0.109, p < 0.001), for β-CTX were HbA1c (β = - 0.049, p < 0.001), body mass index (BMI) (β = - 0.011, p = 0.005), 25(OH)D (β = - 0.003, p = 0.003), FSH (β = 0.002, p = 0.022) and metformin (β = - 0.091, p = 0.001) in postmenopausal T2D women based on multivariate regression analysis. With the increase in HbA1c, FSH decreased significantly (p for trend < 0.001). Mediation analysis demonstrated that FSH partly mediated the suppression of LnP1NP and Lnβ-CTX by HbA1c (β = - 0.009 and - 0.010, respectively), and Lnβ-CTX by BMI (β = - 0.015) when multiple confounders were considered (all p < 0.05).

CONCLUSION

HbA1c was the crucial determinant contributing to the suppression of BTMs. FSH might play a novel mediation role in BTM suppression due to HbA1c or BMI.

Assessment and treatment of osteoporosis and fractures in type 2 diabetes

There is substantial, and growing, evidence that type 2 diabetes (T2D) is associated with skeletal fragility, despite often preserved bone mineral density. As post-fracture outcomes, including mortality, are worse in people with T2D, bone management should be carefully considered in this highly vulnerable group. However, current fracture risk calculators inadequately predict fracture risk in T2D, and dedicated randomised controlled trials identifying optimal management in patients with T2D are lacking, raising questions about the ideal assessment and treatment of bone health in these people. We synthesise the current literature on evaluating bone measurements in T2D and summarise the evidence for safety and efficacy of both T2D and anti-osteoporosis medications in relation to bone health in these patients.

Evaluation of Quality and Bone Microstructure Alterations in Patients with Type 2 Diabetes: A Narrative Review

Bone fragility is a common complication in subjects with type 2 diabetes mellitus (T2DM). However, traditional techniques for the evaluation of bone fragility, such as dual-energy X-ray absorptiometry (DXA), do not perform well in this population. Moreover, the Fracture Risk Assessment Tool (FRAX) usually underestimates fracture risk in T2DM. Importantly, novel technologies for the assessment of one microarchitecture in patients with T2DM, such as the trabecular bone score (TBS), high-resolution peripheral quantitative computed tomography (HR-pQCT), and microindentation, are emerging. Furthermore, different serum and urine bone biomarkers may also be useful for the evaluation of bone quality in T2DM. Hence, in this article, we summarize the limitations of conventional tools for the evaluation of bone fragility and review the current evidence on novel approaches for the assessment of quality and bone microstructure alterations in patients with T2DM.

Bone fragility in diabetes: novel concepts and clinical implications

Increased fracture risk represents an emerging and severe complication of diabetes. The resulting prolonged immobility and hospitalisations can lead to substantial morbidity and mortality. In type 1 diabetes, bone mass and bone strength are reduced, resulting in up to a five-times greater risk of fractures throughout life. In type 2 diabetes, fracture risk is increased despite a normal bone mass. Conventional dual-energy x-ray absorptiometry might underestimate fracture risk, but can be improved by applying specific adjustments. Bone fragility in diabetes can result from cellular abnormalities, matrix interactions, immune and vascular changes, and musculoskeletal maladaptation to chronic hyperglycaemia. This Review summarises how the bone microenvironment responds to type 1 and type 2 diabetes, and the mechanisms underlying fragility fractures. We describe the value of novel imaging technologies and the clinical utility of biomarkers, and discuss current and future therapeutic approaches that protect bone health in people with diabetes.

Contribution of peripheral neuropathy to poor bone health in the feet of people with type 2 diabetes mellitus

AIMS

To evaluate the impact of peripheral neuropathy on bone health in people with type 2 diabetes mellitus (T2DM).

METHODS

Participants with T2DM were grouped according to the presence of peripheral neuropathy as assessed by vibration perception threshold (VPT). Recruitment ensured groups were balanced for age, sex and body mass index (BMI). Bone health was measured by calcaneal quantitative ultrasound (QUS) and compared between groups. Calcaneal QUS parameters were correlated across the cohort with VPT and other prespecified variables.

RESULTS

Thirty-four participants (17 per group) were included with mean age 68 ± 12 years, 47% male, with median BMI 29.9 (IQR 26.9-32.7) kg/m². The peripheral neuropathy group had significantly lower mean Stiffness Index (87 ± 12 versus 101 ± 16, p = 0.01), Speed of Sound (1542 ± 28 versus 1574 ± 34 m/s, p < 0.01), and a trend towards lower Broadband Ultrasound Attenuation (113 ± 10 versus 120 ± 12 dB/MHz, p = 0.07). Pedal bone health asymmetry was not a significant feature in those with peripheral neuropathy. All calcaneal QUS parameters correlated negatively with VPT, although significance of the relationship with Broadband Ultrasound Attenuation was nullified if controlled for diabetes duration or time on insulin. Broadband Ultrasound Attenuation showed independent negative correlation with diabetes duration.

CONCLUSIONS

People with T2DM and peripheral neuropathy have poorer bone health as measured by calcaneal QUS than those without peripheral neuropathy, independent of age, sex and BMI.

Bone Density and Structure in Overweight Men With and Without Diabetes

OBJECTIVE

Metabolic syndrome (MetS), type 1 diabetes (T1D), and type 2 diabetes, are associated with an increased risk of fractures; however, the impact of obesity on bone deficits in diabetes is unknown. We aimed to compare markers of bone structure, bone density, and bone turnover in non-diabetic overweight men with MetS and overweight men with T1D or T2D.

METHODS AND RESEARCH DESIGN

In this cross-sectional study we included participants from two previously described study cohorts consisting of participants with diabetes and participants with MetS. Participants underwent dual-energy X-ray absorptiometry measuring areal bone mineral density (aBMD) at the hip and lumbar spine, High Resolution peripheral Quantitative (HRpQCT) scan of the tibia and radius and measurement of circulating bone turnover markers. We compared groups with unpaired t test and performed multiple linear regression with adjustment for age, body mass index, and smoking.

RESULTS

We included 33 participants with T1D, 25 participants with T2D, and 34 participants with MetS. Bone turnover markers levels were comparable between T1D and MetS. aBMD at the hip was lower in T1D compared to MetS, also after adjustment. P1NP and Osteocalcin levels were lower among individuals with T2D compared to MetS, whereas aBMD were similar between the groups after multiple adjustments. We observed no difference in volumetric BMD at the tibia or radius between MetS and T1D and T2D, respectively. Participants with T2D had a higher trabecular number and lower trabecular separation compared to individuals with MetS at the tibia, which remained signficant after multiple adjustments.

CONCLUSION

In conclusion, we observed no clinically important differences in bone density or structure between men with T2D, T1D, or MetS. However, men with T2D displayed lower bone turnover compared to MetS highlighting that T2D per se and not obesity, is associated with low bone turnover.

Vascular Complications in Individuals with Type 2 Diabetes Mellitus Additionally Increase the Risk of Femoral Neck Fractures Due to Deteriorated Trabecular Microarchitecture

Individuals with diabetes mellitus type 2 (T2DM) have an increased risk of hip fracture, especially if vascular complications are present. However, microstructural origins of increased bone fragility in T2DM are still controversial. DXA measurement of the contralateral hip and three-dimensional microCT analyses of femoral neck trabecular microarchitecture were performed in 32 individuals (26 women and 6 men, 78 ± 7 years). The specimens were divided to two groups: T2DM individuals with hip fracture (DMFx, n = 18) and healthy controls (CTL, n = 14). DMFx group consisted of individuals with vascular complications (DMFx_VD, n = 8) and those without vascular complications (DMFx_NVD, n = 10). T-score was significantly lower in DMFx_VD and DMFx_NVD than in controls (p < 0.001). BV/TV, Tb.N, Tb.Sp, SMI, and FD varied among DMFx_NVD, DMFx_VD, and CTL groups (p = 0.023, p = 0.004, p = 0.008, p = 0.001, p = 0.007, respectively). Specifically, BV/TV of DMFx_VD was significantly lower than that of DMFx_NVD group (p = 0.020); DMFx_NVD group had higher Tb.N and lower Tb.Sp compared with DMFx_VD (p = 0.006, p = 0.012, respectively) and CTL (p = 0.026, p = 0.035, respectively). DMFx group and healthy controls showed similar BV/TV, Tb.Th, Tb.N, Tb.Sp, Conn.D, DA, and FD (p = 0.771, p = 0.503, p = 0.285, p = 0.266, p = 0.208, p = 0.235, p = 0.688, respectively), while SMI was significantly higher in controls (p = 0.005). Two distinct phenotypes of bone fragility were identified in T2DM patients: patients with vascular complications showed impaired trabecular microarchitecture, whereas bone fragility in the group without vascular complications was independent on trabecular microarchitecture pattern. Such heterogeneity among T2DM patients may explain contradicting literature data and may set a basis for further studies to evaluate fracture risk related to T2DM.

Differential risk of fracture attributable to type 2 diabetes mellitus according to skeletal site

BACKGROUND

Impaired bone quality, especially related to accumulation of advanced glycation end-products (AGEs) and higher incidence of falls contribute substantially to a higher risk of fracture associated with type 2 diabetes mellitus (T2DM). These factors may predispose to fractures more at skeletal sites where impaired bone toughness and falls play a larger pathogenic role (such as hip fractures) compared to skeletal sites where they are less important (such as vertebral fractures).

OBJECTIVE

To determine if the associations of T2DM with prevalent and incident vertebral fractures are as strong as they are for hip and other non-vertebral fractures.

METHODS

Amongst 80,238 individuals in the Manitoba Bone Density Program database (mean [SD] age 64.4 [11.1] years, 89.8% female, 8676 with diagnosed T2DM) with a baseline BMD test (1996-2016), we estimated hazard ratios (HRs) for incident clinical fracture at different skeletal sites in those with compared to those without T2DM using Cox proportional hazards models over a mean (SD) 9.0 (5.0) year follow-up period. We also estimated odds ratios for prevalent vertebral fracture on VFA images amongst 9594 individuals (mean [SD] 76 [6.8] years, 1185 with T2DM diagnosis at time of DXA-VFA) and for prior clinical fractures at different skeletal sites using logistic regression models.

RESULTS

After multivariable adjustment, T2DM was associated with incident hip (HR 1.63, 95% CI 1.44 to 1.85) and proximal humerus fractures (HR 1.59, 95% CI 1.39 to 1.83), but was not associated with incident forearm fracture (HR 1.00, 95% CI 0.86 to 1.17) and only weakly with incident clinical vertebral fracture (HR 1.16, 95% CI 1.01 to 1.33). Similarly, T2DM was associated with prior hip (OR 1.78, 95% CI 1.21 to 2.61) and prior proximal humerus fracture (OR 1.31, 95% CI 1.02 to 1.68) but not with prior forearm (OR 0.89, 95% CI 0.74 to 1.06) or prevalent vertebral fracture on VFA images (OR 0.91, 95% CI 0.77 to 1.08).

CONCLUSION

T2DM is a stronger risk factor for hip and proximal humerus fractures than for vertebral and wrist fractures. Further research is warranted to determine if the known differences in falls and/or bone quality between T2DM and age-related osteoporosis account for these differential associations.

Prevalence and Risk Factors of Osteoporosis in Patients with Type 2 Diabetes Mellitus in Nanchang (China): A Retrospective Cohort Study

OBJECTIVE

To retrospectively review the clinical data of type 2 diabetes mellitus (T2DM) patients hospitalized in Nanchang, China, summarized the prevalence of osteoporosis (OP) in T2DM patients in this area, and analyzed related influencing factors.

METHODS

The clinical data of hospitalized patients with T2DM were collected retrospectively. According to the results of bone mineral density test, the subjects were divided into the normal bone mass group, the osteopenia group, and the OP group. Age, gender, educational background, body mass index (BMI), waist-to-hip ratio (WHR), duration of T2DM, glycosylated hemoglobin, serum lipids, and complications of T2DM in the three groups were analyzed and compared.

RESULTS

The prevalence of OP in patients with T2DM was 35.77%. There were statistically significant differences in age, gender, BMI, WHR, duration of T2DM, educational background, the level of high-density lipoprotein cholesterol (HDL-C), the prevalence of diabetic retinopathy (DR), and diabetic peripheral neuropathy among the three groups (P < 0.05). Logistic regression analysis showed that increasing age, prolonged duration of T2DM, low BMI, high levels of HDL-C, and complicated DR were risk factors for osteopenia and OP.

CONCLUSION

The prevalence of OP in T2DM was high. Risk factors for abnormal bone mass in T2DM might be females, advanced age, long duration of T2DM, low BMI, high levels of HDL-C, and diabetic microangiopathy.

Do patients with type 2 diabetes have impaired hip bone microstructure? A study using 3D modeling of hip dual-energy X-ray absorptiometry

AIM

Patients with type 2 diabetes (T2DM) have more risk of bone fractures. However, areal bone mineral density (aBMD) by conventional dual-energy x-ray absorptiometry (DXA) is not useful for identifying this risk. This study aims to evaluate 3D-DXA parameters determining the cortical and trabecular compartments in patients with T2DM compared to non-diabetic subjects and to identify their determinants.

MATERIALS AND METHODS

Case-control study in 111 T2DM patients (65.4 ± 7.6 years old) and 134 non-diabetic controls (64.7 ± 8.6-year-old). DXA, 3D-DXA modelling via 3D-Shaper software and trabecular bone score (TBS) were used to obtain aBMD, cortical and trabecular parameters, and lumbar spine microarchitecture, respectively. In addition, biochemical markers as 25-hydroxyvitamin d, type I procollagen N-terminal propeptide (P1NP), C-terminal telopeptide of type I collagen (CTX), and glycated haemoglobin (HbA1c) were analysed.

RESULTS

Mean-adjusted values showed higher aBMD (5.4%-7.7%, ES: 0.33-0.53) and 3D-DXA parameters (4.1%-10.3%, ES: 0.42-0.68) in the T2DM group compared with the control group. However, TBS was lower in the T2DM group compared to the control group (-14.7%, ES: 1.18). In addition, sex (β = 0.272 to 0.316) and body mass index (BMI) (β = 0.236 to 0.455) were the most consistent and positive predictors of aBMD (p ≤ 0.01). BMI and P1NP were negative predictors of TBS (β = -0.530 and -0.254, respectively, p ≤ 0.01), while CTX was a positive one (β = 0.226, p=0.02). Finally, BMI was consistently the strongest positive predictor of 3D-DXA parameters (β = 0.240 to 0.442, p<0.05).

CONCLUSION

Patients with T2DM present higher bone mass measured both by conventional DXA and 3D-DXA, suggesting that 3D-DXA technology is not capable of identifying alterations in bone structure in this population. Moreover, BMI was the most consistent determinant in all bone outcomes.

Fracture risk assessment in diabetes mellitus

Growing evidence suggests that diabetes mellitus is associated with an increased risk of fracture. Bone intrinsic factors (such as accumulation of glycation end products, low bone turnover, and bone microstructural changes) and extrinsic factors (such as hypoglycemia caused by treatment, diabetes peripheral neuropathy, muscle weakness, visual impairment, and some hypoglycemic agents affecting bone metabolism) probably contribute to damage of bone strength and the increased risk of fragility fracture. Traditionally, bone mineral density (BMD) measured by dual x-ray absorptiometry (DXA) is considered to be the gold standard for assessing osteoporosis. However, it cannot fully capture the changes in bone strength and often underestimates the risk of fracture in diabetes. The fracture risk assessment tool is easy to operate, giving it a certain edge in assessing fracture risk in diabetes. However, some parameters need to be regulated or replaced to improve the sensitivity of the tool. Trabecular bone score, a noninvasive tool, indirectly evaluates bone microstructure by analyzing the texture sparsity of trabecular bone, which is based on the pixel gray level of DXA. Trabecular bone score combined with BMD can effectively improve the prediction ability of fracture risk. Quantitative computed tomography is another noninvasive examination of bone microstructure. High-resolution peripheral quantitative computed tomography can measure volume bone mineral density. Quantitative computed tomography combined with microstructure finite element analysis can evaluate the mechanical properties of bones. Considering the invasive nature, the use of microindentation and histomorphometry is limited in clinical settings. Some studies found that the changes in bone turnover markers in diabetes might be associated with fracture risk, but further studies are needed to confirm this. This review focused on summarizing the current development of these assessment tools in diabetes so as to provide references for clinical practice. Moreover, these tools can reduce the occurrence of fragility fractures in diabetes through early detection and intervention.

Non‐Obese MKR Mouse Model of Type 2 Diabetes Reveals Skeletal Alterations in Mineralization and Material Properties

Obesity is a common comorbidity of type 2 diabetes (T2D). Therefore, increased risk of fragility fractures in T2D is often confounded by the effects of obesity. This study was conducted to elucidate the mechanistic basis by which T2D alone leads to skeletal fragility. We hypothesized that obesity independent T2D would deteriorate bone's material quality by accumulating defects in the mineral matrix and undesired modifications in its organic matrix associated with increased oxidative stress and hyperglycemia. To test this hypothesis, we used 15‐week‐old male non‐obese mice with engineered muscle creatine kinase promoter/human dominant negative insulin growth factor 1 (IGF‐I) receptor (MKR) and FVB/N wild‐type (WT) controls (n = 12/group). MKR mice exhibit reduced insulin production and loss of glycemic control leading to diabetic hyperglycemia, verified by fasting blood glucose measurements (>250 mg/dL), without an increase in body weight. MKR mice showed a significant decrease in femoral radial geometry (cortical area, moment of inertia, cortical thickness, endosteal diameter, and periosteal diameter). Bone mineral density (BMD), as assessed by micro–computed tomography (μCT), remained unchanged; however, the quality of bone mineral was altered. In contrast to controls, MKR mice had significantly increased hydroxyapatite crystal thickness, measured by small‐angle X‐ray scattering, and elongated c‐axis length of the crystals evaluated by confocal Raman spectroscopy. There was an increase in changes in the organic matrix of MKR mice, associated with enhanced glycoxidation (carboxymethyl‐lysine [CML] and pentosidine) and overall glycation (fluorescent advanced glycation end products), both of which were associated with various measures of bone fragility. Moreover, increased CML formation positively correlated with elongated mineral crystal length, supporting the role of this negatively charged side chain to attract calcium ions, promote growth of hydroxyapatite, and build a physical link between mineral and collagen. Collectively, our results show, for the first time, changes in bone matrix in a non‐obese T2D model in which skeletal fragility is attributable to alterations in the mineral quality and undesired organic matrix modifications. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Fracture Patterns in Type 1 and Type 2 Diabetes Mellitus: A Narrative Review of Recent Literature

PURPOSE OF REVIEW

In this narrative review, we have summarized the literature on fracture risk in T1DM and T2DM with a special focus on fracture site, time patterns, glucose-lowering drugs, and micro- and macrovascular complications.

RECENT FINDINGS

T1DM and T2DM were associated with an overall increased fracture risk, with preferent locations at the hip, vertebrae, humerus, and ankle in T1DM and at the hip, vertebrae, and likely humerus, distal forearm, and foot in T2DM. Fracture risk was higher with longer diabetes duration and the presence of micro- and macrovascular complications. In T2DM, fracture risk was higher with use of insulin, sulfonylurea, and thiazolidinediones and lower with metformin use. The increased fracture risk in T1DM and T2DM concerns specific fracture sites, and is higher in subjects with longer diabetes duration, vascular complications, and in T2DM with the use of specific glucose-lowering medication.

Continuous subcutaneous insulin infusion ameliorates bone structures and mechanical properties in type 2 diabetic rats by regulating bone remodeling

Continuous subcutaneous insulin infusion (CSII) is an intensive insulin therapy for patients with type 2 diabetes mellitus (T2DM) who have poor glycemic control, but its effect on T2DM-related bone disorder is unclear. This study described the possible mechanisms by which CSII affects bone remodeling, structures, and mechanical properties in T2DM rats. Herein, male rats (6-week-old) were assigned randomly to 4-week and 8-week administration groups, each of which included healthy control, T2DM, CSII, and Placebo groups. Then, metabolic markers, bone formation and resorption markers in serum and protein expressions of osteoclastogenesis regulators in tibias were detected. Meanwhile, microstructures, nanostructures, macro-mechanical properties, nano-mechanical properties, and mineral compositions in femurs were evaluated. 4-week later, CSII treatment restored circulatory metabolites, bone formation and resorption markers, and osteoclastogenesis regulators, improved certain bone microstructures, decreased matrix mineralization, and increased fracture toughness in T2DM rats. For 8-week group, CSII treatment restored bone formation and resorption markers, osteoclastogenesis regulators, and bone microstructures, besides improved bone mineral compositions and nanostructures, enhanced bone mechanical properties such as fracture toughness, maximum load, elastic modulus, indentation modulus and hardness. Collectively, 8-week CSII treatment is more conducive to ameliorating bone structures and mechanical properties in T2DM rats by regulating bone remodeling compared with 4-week CSII treatment, thus improving whole bone quality and providing valuable information for clinical prevention and treatment of T2DM-related bone disorders.

Update on the pathogenesis and treatment of skeletal fragility in type 2 diabetes mellitus

Fracture risk is increased in patients with type 2 diabetes mellitus (T2DM). In addition, these patients sustain fractures despite having higher levels of areal bone mineral density, as measured by dual-energy X-ray absorptiometry, than individuals without T2DM. Thus, additional factors such as alterations in bone quality could have important roles in mediating skeletal fragility in patients with T2DM. Although the pathogenesis of increased fracture risk in T2DM is multifactorial, impairments in bone material properties and increases in cortical porosity have emerged as two key skeletal abnormalities that contribute to skeletal fragility in patients with T2DM. In addition, indices of bone formation are uniformly reduced in patients with T2DM, with evidence from mouse studies published over the past few years linking this abnormality to accelerated skeletal ageing, specifically cellular senescence. In this Review, we highlight the latest advances in our understanding of the mechanisms of skeletal fragility in patients with T2DM and suggest potential novel therapeutic approaches to address this problem.