Lower trabecular bone score in type 2 diabetes mellitus: A role for fat mass and insulin resistance beyond hyperglycaemia

Weight-adjusted waist index is associated with risk of poor bone quality rather than low bone mass in patients with type 2 diabetes

BACKGROUND

Type 2 diabetes (T2D) correlates with an elevated risk of osteoporotic fractures. However, factors influencing bone mineral density (BMD) and trabecular bone score (TBS) in Chinese individuals with T2D remain unclear. This study aimed to investigate the clinical and biochemical determinants of BMD and TBS in patients with T2D, with a focus on elucidating the role of weight-adjusted waist index (WWI) in modulating bone mass and quality in this cohort.

METHODS

Data of 161 women and 153 men with T2D collected between July 2022 and March 2023 in Shenzhen, China, were analyzed in our cross-sectional study. Lumbar spine BMD and TBS of all participants were obtained using dual-energy X-ray absorptiometry. WWI was defined as waist circumference over the square root of weight.

RESULTS

Multivariate regression analysis demonstrated that lumbar spine TBS was inversely correlated with age, menopausal status, and WWI in women (p < 0.05). In men, TBS was negatively associated with age and WWI (p < 0.05). For women, glycated hemoglobin A1c positively influenced BMD (p < 0.05), whereas age, diabetic retinopathy, and N-mid osteocalcin were negatively associated. No significant predictors of BMD were identified in the male cohort. For predicting degraded TBS, the optimal WWI cut-offs were 11.257 cm/√kg (S: 61.1%, E: 80.7%) in males and 11.247 cm/√kg (S: 70.3%, E: 71.1%) in females.

CONCLUSIONS

Our findings highlight WWI as a novel and potentially more precise indicator of body fat, associated with diminished bone quality rather than solely low bone mass in patients with T2D in China. These results suggest that evaluating bone health in individuals with higher WWI may require more than just bone mass assessment. The results also suggest that the optimal WWI cut-off points for predicting degraded TBS are approximately 11.25 cm/√kg, highlighting thresholds for fracture risk.

Bone microstructure and TBS in diabetes: what have we learned? A narrative review

Diabetes is associated with an increased risk of fracture. Areal bone mineral density (aBMD), the most reliable indicator of fracture risk in healthy adults, is low in patients with type 1 diabetes mellitus but normal or high in patients with type 2 diabetes mellitus. Most trabecular and cortical parameters measured by high-resolution peripheral quantitative computed tomography (HR-pQCT) are lower in type 1 diabetes and higher in type 2 diabetes, in parallel with aBMD. In contrast, lumbar spine trabecular bone score (TBS) has been reported to be lower in women with both type 1 and type 2 diabetes. The discordance between improved bone microstructure and degraded TBS reflects the effect of central obesity (currently the subject of a revision to the TBS algorithm). Meanwhile, evidence supports use of TBS in conjunction with aBMD and/or FRAX for improved fracture prediction in patients with type T2D. This position paper, on behalf of the Bone and Diabetes Working Group of the International Osteoporosis Foundation, summarizes alterations in bone microarchitecture measured by HR-pQCT in diabetes. It also addresses the technical and clinical considerations of the trabecular bone score, particularly discussing the significance of this measurement in individuals with diabetes and the influence of abdominal fat.

Bone evaluation and relationship between body composition and bone mass in anorexia nervosa followed up by a multidisciplinary team

PURPOSE

Anorexia nervosa is a psychiatric disorder characterized by self-imposed fasting and significant weight loss, leading to nutrient deficiencies that disrupt bone metabolism. This cross-sectional observational study aimed to characterize the bone health of women with anorexia nervosa using dual-energy X-ray absorptiometry (DXA), trabecular bone score (TBS), and 3D shaper analysis.

METHODS

The study involved 12 women diagnosed with anorexia nervosa monitored by a multidisciplinary team and 11 control subjects. Both groups underwent blood sampling and assessments with DXA, TBS, and 3D shaper analysis.

RESULTS

The results indicated that areal bone mineral density (aBMD) and Z-scores at the total hip and femoral neck were significantly lower in the anorexia group compared to controls (p < 0.05). Additionally, the fat mass index was reduced in women with anorexia (p < 0.05). Appendicular lean mass index (ALMI) was similar between the two groups. 3D shaper analysis revealed that surface BMD (sBMD), volumetric BMD (vBMD), integral vBMD, and trabecular vBMD were generally lower in the anorexia group. Associations were found between proximal femur 3D parameters and total hip and femoral neck aBMD. Moreover, significant correlations were observed between total cortical vBMD, total cortical sBMD, integral vBMD, and TBS. ALMI was associated with total cortical thickness and showed a trend toward association with femoral neck Z-score.

CONCLUSION

In addition to previous studies indicating bone impairment in AN using DXA and TBS, the present study suggests that the 3D Shaper is also capable of detecting bone loss in this disorder. Therefore, the data encourage the further studies to assess the role of the 3D Shaper in prediction of fracture.

Association between current relative fat mass and history of female infertility based on the NHANES survey

Infertility is a significant global issue affecting millions of couples, and increased body fat is considered a major contributing factor. Traditional assessment methods, such as body mass index (BMI) and waist circumference (WC), are limited in accurately reflecting body fat composition. The relative fat mass (RFM) index, a newer tool, provides a more precise assessment of fat content, but its relationship with infertility remains unclear. This study aimed to investigate the correlation between relative fat mass and a history of infertility by analyzing data from the National Health and Nutrition Examination Survey (NHANES). The study included 3915 women aged 18 to 45 years. Infertility status was self-reported, and RFM was calculated using a specific formula. Logistic regression models were employed, adjusting for multiple covariates, to investigate the relationship between RFM and infertility. Women with a history of infertility had a significantly higher RFM when compared to those who were not infertile. Specifically, women in the highest RFM quartile had almost three-fold higher odds of history of infertility than those in the lowest quartile (odds ratio [OR]: 2.87; 95% confidence interval [CI]: 1.85-4.44). Subgroup analyses indicated a stronger association between RFM and a history of infertility; this relationship was predominantly observed in women under 35 years-of-age. Sensitivity analyses confirmed the robustness of these findings. Higher RFM is more likely to be associated with a history of infertility. While RFM provides a more accurate assessment of body fat distribution compared to BMI and WC, making it a valuable tool for evaluating infertility, further research is now needed to determine the impact of interventions based on RFM measurements.

Relative Fat Mass and Physical Indices as Predictors of Gallstone Formation: Insights From Machine Learning and Logistic Regression

Purpose

Gallstones (GS), a prevalent disorder of the biliary tract, markedly impair patients' quality of life. This study aims to construct predictive models employing diverse machine learning algorithms to elucidate risk factors linked to gallstone formation.

Patients and Methods

This study integrated data from the National Health and Nutrition Examination Survey (NHANES) with a cohort of 7868 participants from Wuxi People's Hospital and Wuxi Second People's Hospital, including 830 individuals diagnosed with gallstones. To develop our predictive model, we employed four algorithms-Logistic Regression, Gaussian Naive Bayes (GNB), Multi-Layer Perceptron (MLP), and Support Vector Machine (SVM). The models were validated internally through k-fold cross-validation and externally using independent datasets. Furthermore, we substantiated the link between relative fat mass (RFM) and gallstone formation by employing four logistic regression models, conducting subgroup analyses, and applying restricted cubic spline (RCS) curves.

Results

The logistic regression algorithm demonstrated superior predictive capability for all risk factors associated with gallstone occurrence compared to other machine learning models. SHAP analysis identified RFM, weight-to-waist index (WWI), waist circumference (WC), waist-to-height ratio (WHtR), and body mass index (BMI) as prominent predictors of gallstone occurrence, with RFM emerging as the primary determinant. A fully adjusted multivariate logistic regression analysis revealed a robust positive association between RFM and gallstones. Subgroup analysis further indicated that subgroup factors did not alter the positive relationship between RFM and gallstone prevalence.

Conclusion

Among the four algorithmic models, logistic regression proved most effective in predicting gallstone occurrence. The model developed in this study offers clinicians a valuable tool for identifying critical prognostic factors, facilitating personalized patient monitoring and tailored management.

Age-related trends in trabecular bone scores and bone mineral density in Chinese men with type 2 diabetes mellitus: a cross-sectional study

Patients with Type 2 diabetes mellitus(T2DM) typically have an average or higher bone mineral density (BMD) but are at a significantly higher risk of fracture than patients without diabetes. Trabecular bone score (TBS) is a textural index derived from pixel gray-level variations in lumbar spine DXA image, which has been introduced as an indirect measure of bone quality. This study aimed to discuss the trends and annual rates of change in BMD and TBS with age in Chinese men with T2DM and men without diabetes mellitus. Lumbar spine(LS) TBS was significantly lower in males with T2DM compared to men without diabetes(1.279 ± 0.117 vs. 1.299 ± 0.090, P = 0.005). However, TBS in men with T2DM peaked around age 60, which occurred later and was lower than the peak observed in men without diabetes, who reached their peak TBS around age 50 (1.294 ± 0.126 vs. 1.328 ± 0.088). Femoral neck, total hip, and lumbar spine BMD in men with T2DM were not significantly different from those in men without diabetes. The results showed that both men with or without T2DM exhibited the lowest annual rates of change in TBS at 66-75 years of age, with values of -1.05%(P < 0.001) and - 0.90%(P < 0.001), respectively. Patients with great glycemic control demonstrated higher TBS and BMD. Men with T2DM have later and lower peak TBS and faster bone loss, suggesting that diabetes may negatively impact bone microarchitecture and mineralization.

Characterization of bone disease in cystic fibrosis

With the increased life expectancy of people with cystic fibrosis (CF), clinical attention has focused on prevention and treatment of non-pulmonary comorbidities. CF-related bone disease (CFBD) is a common complication and leads to increased fracture rates. Dual energy X-ray absorptiometry (DXA) is the recommended and gold standard technique to identify and monitor bone health. However, DXA has limitations because of its two-dimensional nature. Complementary tools to DXA are available, such as trabecular bone score (TBS) and vertebral fracture assessment (VFA). Quantitative computed tomography (QCT), magnetic resonance imaging (MRI) and quantitative ultrasound (QUS) may also be useful.

Quantitative ultrasound imaging reveals distinct fracture-associated differences in tibial intracortical pore morphology and viscoelastic properties in aged individuals with and without diabetes mellitus - an exploratory study

Introduction

Diabetes mellitus (DM) is a chronic metabolic disorder that increases fragility fracture risk. Conventional DXA-based areal bone mineral density (aBMD) assessments often underestimate this risk. Cortical Backscatter (CortBS) ultrasound, a radiation-free technique, non-invasively analyzes cortical bone's viscoelastic and microstructural properties. This study aimed to evaluate CortBS's discriminative performance in DM patients compared to DXA and characterize changes in cortical bone microstructure in Type 1 and Type 2 DM (T1DM, T2DM) patients.

Methods

This in-vivo study included 89 DM patients (T1DM = 39, T2DM = 48) and 76 age- and sex-matched controls. DXA measured aBMD, while CortBS measurements were taken at the anteromedial tibia using a medical ultrasound scanner with custom software. Multivariate analysis of variance assessed the impact of DM type on CortBS and DXA measurement results. Partial least squares discriminant analyses with cross-validation were used to compare the discrimination performance for vertebral, non-vertebral, and any fragility fractures, adjusting for gender, age, and anthropometric parameters (weight, height, BMI).

Results

Fractures occurred in 8/23 T1DM, 17/18 T2DM, and 16/55 controls. DXA parameters were reduced in fracture patients, with significant diabetes impact. T2DM was associated with altered CortBS parameters, reduced scatterer density, and larger pores. CortBS outperformed DXA in discriminating fracture risk (0.61 ≤ AUC(DXA) ≤ 0.63, 0.68 ≤ AUC(CortBS) ≤ 0.69).

Conclusions

Both T1DM and T2DM showed altered bone metabolism, with T2DM linked to impaired tissue formation. CortBS provides insights into pathophysiological changes in diabetic bone and provided superior fracture risk assessment in DM patients compared to DXA.

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.

Effect of abdominal tissue thickness on trabecular bone score and fracture risk in adults with diabetes: the Manitoba BMD registry

Individuals with type 2 diabetes have lower trabecular bone score (TBS) and increased fracture risk despite higher bone mineral density. However, measures of trabecular microarchitecture from high-resolution peripheral computed tomography are not lower in type 2 diabetes. We hypothesized that confounding effects of abdominal tissue thickness may explain this discrepancy, since central obesity is a risk factor for diabetes and also artifactually lowers TBS. This hypothesis was tested in individuals aged 40 years and older from a large DXA registry, stratified by sex and diabetes status. When DXA-measured abdominal tissue thickness was not included as a covariate, men without diabetes had lower TBS than women without diabetes (mean difference -0.074, P < .001). TBS was lower in women with versus without diabetes (mean difference -0.037, P < .001), and men with versus without diabetes (mean difference -0.007, P = .042). When adjusted for tissue thickness these findings reversed, TBS became greater in men versus women without diabetes (mean difference +0.053, P < .001), in women with versus without diabetes (mean difference +0.008, P < .001), and in men with versus without diabetes (mean difference +0.014, P < .001). During mean 8.7 years observation, incident major osteoporotic fractures were seen in 7048 (9.6%). Adjusted for multiple covariates except tissue thickness, TBS predicted fracture in all subgroups with no significant diabetes interaction. When further adjusted for tissue thickness, HR per SD lower TBS remained significant and even increased slightly. In conclusion, TBS predicts fractures independent of other clinical risk factors in both women and men, with and without diabetes. Excess abdominal tissue thickness in men and individuals with type 2 diabetes may artifactually lower TBS using the current algorithm, which reverses after accounting for tissue thickness. This supports ongoing efforts to update the TBS algorithm to directly account for the effects of abdominal tissue thickness for improved fracture risk prediction.

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.

Weight-adjusted waist index is a potential early predictor of degraded bone microarchitecture: A cross-sectional study of the national health and nutrition examination survey 2007-2008

PURPOSE

This study aimed to investigate the association between weight-adjusted waist index (WWI) and trabecular bone score (TBS) and to assess the ability of WWI to identify individuals with degraded bone microarchitecture (DBMA).

METHODS

This cross-sectional study included participants aged 20 and older from the National Health and Nutrition Examination Survey. Furthermore, WWI was calculated by waist circumference and body weight. In addition, linear regression models were employed to investigate the association between WWI and TBS, while logistic regression models were employed to determine the association between WWI and the risk of DBMA. Finally, the performance of WWI in identifying individuals with DBMA was using the receiver operating characteristic (ROC) curves with area under the ROC curve.

RESULTS

A total of 4,179 participants with a mean age of 49.90 years were included in the final analysis. WWI was negatively associated with TBS and positively associated with an increased risk of DBMA. Furthermore, the associations between WWI and TBS, as well as DBMA risk, were stable regardless of stratification by age, sex, race, or body mass index (BMI). Moreover, WWI achieved good performances in identifying individuals with DBMA or low TBS. In addition, the combination of WWI and BMI showed better performances in identifying individuals with DBMA or low TBS than WWI or BMI alone.

CONCLUSION

WWI established a negative association with TBS and a positive association with the risk of DBMA. Clinicians should be alert to the potential risk of DBMA among individuals with high WWI. Moreover, WWI, alone or in combination with BMI, has the potential to serve as an early screening strategy in identifying individuals with DBMA.

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.

Lower Adherence to a Mediterranean Diet Is Associated with High Adiposity in Community-Dwelling Older Adults: Results from the Longevity Check-Up (Lookup) 7+ Project

High adiposity impacts health and quality of life in old age, owing to its association with multimorbidity, decreased physical performance, and frailty. Whether a high adherence to a Mediterranean diet (Medi-Diet) is associated with reduced body adiposity in older adults is unclear. The present study was conducted to assess the prevalence of high adiposity in a large sample of community-dwelling older adults. We also explored the relationship between whole-body adiposity estimated through relative fat mass (RFM) and Medi-Diet adherence. Data were obtained from the Longevity Check-up 7+ (Lookup7+) project database. RFM was estimated from anthropometric and personal parameters using a validated equation. RFM was categorized as high if ≥40% in women and ≥30% in men. Information on diet was collected using a food frequency questionnaire, while Medi-Diet adherence was assessed through a modified version of the Medi-Lite scoring system. Analyses were conducted in 2092 participants (mean age 73.1 ± 5.9 years; 53.4% women). Mean RFM was 39.6 ± 5.14% in women and 29.0 ± 3.6% in men. High adiposity was found in 971 (46.4%) participants and was more frequent in those with a low (54.2%) or moderate (46.4%) Medi-Diet adherence compared with the high-adherence group (39.7%, p < 0.001). Logistic regression indicated that older adults with high Medi-Diet adherence were less likely to have a high RFM. Other factors associated with a greater risk of having high adiposity were older age, female sex, and physical inactivity. Our findings support an association between healthy lifestyles, including a greater adherence to a Mediterranean-style diet, and lower body adiposity in older adults.

Reduced High-Density Lipoprotein Cholesterol Is an Independent Determinant of Altered Bone Quality in Women with Type 2 Diabetes

Type 2 diabetes mellitus (T2DM) is associated with an increased fracture risk. Our study aimed to explore differences in bone alterations between T2DM women and controls and to assess clinical predictors of bone impairment in T2DM. For this observational case control study, we recruited 126 T2DM female patients and 117 non-diabetic, age- and BMI-comparable women, who underwent clinical examination, routine biochemistry and dual-energy X-ray absorptiometry (DXA) scans for bone mineral density (BMD) and trabecular bone score (TBS) assessment-derived indexes. These were correlated to metabolic parameters, such as glycemic control and lipid profile, by bivariate analyses, and significant variables were entered in multivariate adjusted models to detect independent determinants of altered bone status in diabetes. The T2DM patients were less represented in the normal bone category compared with controls (5% vs. 12%; p = 0.04); T2DM was associated with low TBS (OR: 2.47, C.I. 95%: 1.19–5.16, p = 0.016) in a regression model adjusted for age, menopausal status and BMI. In women with T2DM, TBS directly correlated with plasma high-density lipoprotein cholesterol (HDL-c) (p = 0.029) and vitamin D (p = 0.017) levels. An inverse association was observed with menopausal status (p < 0.001), metabolic syndrome (p = 0.014), BMI (p = 0.005), and waist circumference (p < 0.001). In the multivariate regression analysis, lower HDL-c represented the main predictor of altered bone quality in T2DM, regardless of age, menopausal status, BMI, waist circumference, statin treatment, physical activity, and vitamin D (p = 0.029; R2 = 0.47), which likely underlies common pathways between metabolic disease and bone health in diabetes.

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.

Insulin resistance and skeletal health

PURPOSE OF REVIEW

Bone fragility is a complication of type 2 diabetes (T2D), and insulin resistance is suspected to contribute to diabetes-related bone deficits. This article provides an overview of emerging clinical research involving insulin resistance and bone health by summarizing recent publications, identifying existing knowledge gaps, and suggesting 'next steps' for this evolving field of research.

RECENT FINDINGS

Clinical studies in children and adults report greater bone density in people with increased insulin resistance, but these associations are often attenuated when adjusting for body size. Advancements in bone imaging methods allow for assessment of nuanced characteristics of bone quality and strength that extend beyond standard bone mineral density assessment methods. For example, several recent studies focusing on lumbar spine trabecular bone score, a relatively new measure of trabecular bone quality from dual-energy X-ray absorptiometry, have reported generally consistent inverse associations with insulin resistance. Longitudinal studies using advanced imaging methods capable of evaluating trabecular bone microstructure and strength, such as high-resolution peripheral quantitative computed tomography, are lacking. Studies in younger individuals are sparse, but emerging data suggest that peak bone mass attainment might be threatened by diabetes progression, and increased visceral fat, suppressed muscle-bone unit, advanced glycation end-products, sedentary lifestyle, and poor diet quality might contribute to diabetes effects on bone. Prospective studies during the transition from adolescence to young adulthood are required.

SUMMARY

Insulin resistance is a main feature of T2D, which is suspected to contribute to subclinical diabetes-related threats to bone health. Future clinical studies should focus on the critical years surrounding peak bone mass and peak bone strength attainment using contemporary imaging techniques.

Imaging techniques to study diabetic bone disease

PURPOSE OF REVIEW

This review article presents the most recent research on bone fragility in individuals with diabetes from a medical imaging perspective.

RECENT FINDINGS

The widespread availability of dual-energy X-ray absorptiometry (DXA) and trabecular bone score (TBS) software has led to recent assessments of bone fragility with this texture parameter in several studies of type 2 diabetes mellitus (T2D), but in few of type 1 diabetes mellitus (T1D). Although most studies show a trend of reduced TBS values in T2D independent of areal bone mineral density (aBMD) of the lumbar spine, some studies also show the limitations of TBS in both T2D and T1D. Given the limitations of DXA to assess bone strength and investigate the etiology of bone fragility in diabetes, more investigators are incorporating three-dimensional (3D) medical imaging techniques in their studies. Recent use of 3D medical imaging to assess bone fragility in the setting of diabetes has been mostly limited to a few cross-sectional studies predominantly incorporating high-resolution peripheral quantitative computed tomography (HR-pQCT). Although HR-pQCT studies indicate higher tibial cortical porosity in subjects with T2D, results are inconsistent in T1D due to differences in study designs, sample sizes, and subject characteristics, among other factors. With respect to central CT, recent studies support a previous finding in the literature indicating femoral neck geometrical impairments in subjects with T2D and provide encouraging results for the incorporation of finite element analysis (FEA) to assess bone strength in studies of T2D. In the recent literature, there are no studies assessing bone fragility in T1D with QCT, and only two studies used pQCT reporting tibial and radial impairments in young women and children with T1D, respectively. Magnetic resonance imaging (MRI) has not been recently used in diabetic studies of bone fragility.

SUMMARY

As bone fragility in diabetes is not explained by DXA-derived aBMD and given the limitations of cross-sectional studies, it is imperative to use 3D imaging techniques for longitudinal assessments of the density, quality, and microenvironment of bone to improve our understanding of the effects of diabetes on bone and reduce the risk of fracture in this large and vulnerable population of subjects with diabetes.

Factors associated with trabecular bone score in postmenopausal women with type 2 diabetes and normal bone mineral density

BACKGROUND

Osteoporosis and type 2 diabetes (T2D) have been recognized as a widespread comorbidity leading to excess mortality and an enormous healthcare burden. In T2D, bone mineral density (BMD) may underestimate the risk of low-energy fractures as bone quality is reduced. It was hypothesized that a decrease in the trabecular bone score (TBS), a parameter assessing bone microarchitecture, may be an early marker of impaired bone health in women with T2D.

AIM

To identify clinical and body composition parameters that affect TBS in postmenopausal women with T2D and normal BMD.

METHODS

A non-interventional cross-sectional comparative study was conducted. Potentially eligible subjects were screened at tertiary referral center. Postmenopausal women with T2D, aged 50-75 years, with no established risk factors for secondary osteoporosis, were included. BMD, TBS and body composition parameters were assessed by dual-energy X-ray absorptiometry. In women with normal BMD, a wide range of anthropometric, general and diabetes-related clinical and laboratory parameters were evaluated as risk factors for TBS decrease using univariate and multivariate regression analysis and analysis of receiver operating characteristic (ROC) curves.

RESULTS

Three hundred twelve women were initially screened, 176 of them met the inclusion criteria and underwent dual X-ray absorptiometry. Those with reduced BMD were subsequently excluded; 96 women with normal BMD were included in final analysis. Among them, 43 women (44.8%) showed decreased TBS values (≤ 1.31). Women with TBS ≤ 1.31 were taller and had a lower body mass index (BMI) when compared to those with normal TBS (Р = 0.008 and P = 0.007 respectively). No significant differences in HbA1c, renal function, calcium, phosphorus, alkaline phosphatase, PTH and 25(ОН)D levels were found. In a model of multivariate linear regression analysis, TBS was positively associated with gynoid fat mass, whereas the height and androgen fat mass were associated negatively (all P < 0.001). In a multiple logistic regression, TBS ≤ 1.31 was associated with lower gynoid fat mass (adjusted odd ratio [OR], 0.9, 95% confidence interval [CI], 0.85-0.94, P < 0.001), higher android fat mass (adjusted OR, 1.13, 95%CI, 1.03-1.24, P = 0.008) and height (adjusted OR, 1.13, 95%CI, 1.05-1.20, P < 0.001). In ROC-curve analysis, height ≥ 162.5 cm (P = 0.04), body mass index ≤ 33.85 kg/m2 (P = 0.002), gynoid fat mass ≤ 5.41 kg (P = 0.03) and android/gynoid fat mass ratio ≥ 1.145 (P < 0.001) were identified as the risk factors for TBS reduction.

CONCLUSION

In postmenopausal women with T2D and normal BMD, greater height and central adiposity are associated with impaired bone microarchitecture.

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.

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.