Bone mineral density is not sensitive enough to assess the risk of vertebral fractures in type 2 diabetic women

The trajectory of osteoblast progenitor cells in patients with type 2 diabetes and the predictive model for their osteogenic differentiation ability

The fate of osteoprogenitor cells along with the progression of type 2 diabetes (T2DM) and factors determining the fate of those cells remains to be elucidated. This cross-sectional study included 18 normoglycemic, 27 prediabetic, and 73 T2DM to determine osteogenic differentiation across the continuum of dysglycemia and to construct a model to predict the fate of osteoprogenitor cells. This study demonstrated a preserved osteogenic differentiation ability of peripheral blood-derived mononuclear cells (PBMC) isolated from normoglycemic and prediabetic but a progressive decline in their osteogenic differentiation during the progression of T2DM. The rate of osteogenic differentiation rapidly declined by 4-7% annually during the first 10 years of diabetes and then slowed down. A predictive model composed of three independent risk factors, including age, duration of diabetes, and glomerular filtration rate, demonstrated an AuROC of 0.834. With a proposed cut-off of 21.25, this model had 72.0% sensitivity, 87.5% specificity, and 78.9% accuracy in predicting the fate of osteoprogenitor cells. In conclusion, this study provided a perspective on the osteogenic differentiation ability of the osteoprogenitor cells across a continuum of dysglycemia and a predictive model with good diagnostic performance for the prediction of the fate of osteoprogenitor cells in patients with T2DM.

Receptors of Advanced Glycation End Product (RAGE) Suppression Associated With a Preserved Osteogenic Differentiation in Patients With Prediabetes

Type 2 diabetes is widely documented for osteogenic differentiation defect and impaired bone quality, which is related to the skeletal accumulation of advanced glycation end products (AGEs). Prediabetes is a condition in which hyperglycemia is lower than the threshold for the diagnosis of diabetes. Prediabetic animal models consistently demonstrate impaired osteogenic differentiation and deteriorated bone microarchitecture. However, no evidence shows defects in osteoblast development and skeletal effects of AGEs in prediabetic individuals. Therefore, it remains to be elucidated whether impaired osteogenic differentiation ability and altered cellular response to AGEs occur in patients with prediabetes. This cross-sectional study included 28 patients with prediabetes as defined by impaired fasting glucose criteria, fasting plasma glucose (FPG) between 100-125 mg/dl and 17 age-matched normoglycemic controls to elucidate osteogenic differentiation and AGER expression in the PBMC derived from those individuals. The PBMC-isolated from both groups showed similar rates of expression of osteoblast-specific genes, namely, ALPL, BGLAP, COL1A1, and RUNX2/PPAR (89.3% and 88.2%, p = 1.000), and showed comparable levels of expression of those genes. By using age- and pentosidine-matched normoglycemic individuals as references, the PBMC-isolated from prediabetic patients demonstrated lower expression of both AGER and BAX/BCL2. The expression of AGER and BAX/BCL2 significantly correlated to each other (r = 0.986, p <0.0001). The multivariate analysis demonstrated that serum pentosidine is an independent risk factor for AGER expression. With logistic regression analysis, the area under the ROC curve (AUC) for serum pentosidine at the cut-off level of 2.1 ng/ml and FPG at 100 mg/dl, which is a cut-off point for prediabetes, was significantly higher for predicting AGER expression than that of serum pentosidine alone (0.803 vs 0.688, p = 0.048), indicating that serum pentosidine was a good predictor of AGER expression in prediabetic individuals. In conclusion, this study demonstrated a preserved osteogenic differentiation in the PBMC derived from prediabetic individuals. In addition, those PBMC with preserved osteogenic differentiation potential showed the suppression of both cellular RAGE and apoptotic-related signals. Serum pentosidine was an independent risk factor for cellular RAGE expression and is conceivably a good predictor for AGER suppression in prediabetic individuals.

Systematic Review: Are the Elderly With Diabetes Mellitus Type 2 Prone to Fragility Fractures?

Diabetes mellitus type 2 (T2DM) is an emerging public health issue with high prevalence rates among older adults while fragility fractures constitute a significant public health burden with a great impact. Osteoporosis is the most important metabolic bone disease in patients with diabetes mellitus. Based on current evidence, individuals with T2DM are more vulnerable to fragility fractures than their non-diabetic counterparts, although until now, there aren’t any systematic reviews or meta-analyses concerning the impact of T2DM on the risk of fragility fractures in elderly patients. The aim of this study is to fill this gap in the current literature concerning this specific patient group.

Literature in PubMed and Google Scholar was searched for relevant articles published up to January 2021. The keywords used were: elderly, diabetes mellitus type 2, and fragility fractures. Among the 180 articles retrieved, only four full-text articles were eligible and, finally, two studies (one population-based cohort study and one cross-sectional study) met the inclusion criteria for the review. Although we identified 15 records through the manual research, finally 17 records were included in the current review. The records retrieved from the manual research were 11 prospective cohort studies, two population-based studies, one prospective observational study, and one retrospective cohort study. The author's name, year of publication, country, type of study, and number of patients were reported.

According to this systematic review, there is almost consensus about the increased prevalence of all kinds of fragility fractures and especially low-energy hip fractures among elderly patients with T2DM compared with their counterparts without T2DM while there is relative controversy concerning non-vertebral fractures. Vertebral fractures in the elderly with T2DM require further evaluation because the results from cohort studies are more conflicting. Finally, insulin usage can increase the possibility of fragility fractures and can even double this risk. Bone fragility should be recognized as a new complication of T2DM, especially in elderly patients, due to several additional aggravating factors such as senile osteoporosis, severe vitamin D deficiency, presence of many comorbidities, increased possibility of insulin usage, and the presence of diabetes-related complications (mainly neuropathy and retinopathy). Clinicians who treat these patients should be aware of the special diagnostic and therapeutic approaches concerning these patients.

Age-Influenced Receptors of Advanced Glycation End Product Overexpression Associated With Osteogenic Differentiation Impairment in Patients With Type 2 Diabetes

Preclinical studies have found impaired osteogenic differentiation to be associated with type 2 diabetes (T2DM), which is related to skeletal accumulation of advanced glycation end products (AGEs). Our previous study also showed impaired osteogenic differentiation in peripheral blood-derived mononuclear cells (PBMC) isolated from patients with long-standing T2DM, which is conceivably due to the overexpression of receptor of advance glycation end products (RAGE) and the enhancement of cellular apoptosis. However, the existence of RAGE overexpression in earlier stages of diabetes remains unclear, as do the factors influencing that RAGE overexpression. This cross-sectional study enrolled 40 patients with T2DM treated with metformin monotherapy and 30 age-matched non-diabetic controls (NDM) to investigate the overexpression of RAGE in PBMC derived from patients with earlier stage diabetes, as well as to explore its determining factors. Almost all (90%) PBMC-isolated from NDM (NDM-pD) expressed osteoblast-specific genes including ALPL, BGLAP, COL1A1, and RUNX2/PPAR while only 40% of PBMC-derived from diabetic patients (DM-pD) expressed those genes. By using age- and pentosidine-matched NDM-pD as a reference, AGER and BAX/BCL2 expression in PBMC isolated from diabetic patients showing impaired osteoblast-specific gene expression (DM-iD) were 6.6 and 5 folds higher than the reference while AGER and BAX/BCL2 expression in DM-pD were comparable to the reference. AGER expression showed a significant positive correlation with age (r=0.470, p=0.003). The multivariate analysis demonstrated that both age and AGER expression correlated with the potential for osteogenic differentiation in the PBMC isolated from patients with diabetes. In conclusion, this study showed osteogenic differentiation impairment in approximately half of PBMC derived from type 2 diabetic patients receiving metformin monotherapy. Both AGER and BAX/BCL2 overexpression were demonstrated only in PBMC-isolated from diabetic patients with poor osteogenic differentiation. Therefore, this study not only illustrated the existence of RAGE overexpression in PBMC derived from patients with early stages of T2DM but also strengthened the linkage between that RAGE overexpression and the retardation of osteogenic differentiation. Age was also shown to be a positive influencing factor for RAGE overexpression. Furthermore, both age and RAGE overexpression were demonstrated as independent risk factors for determining osteogenic differentiation potential of the PBMC-isolated from T2DM.

Association of type 2 diabetes with anthropometrics, bone mineral density, and body composition in a large-scale screening study of Korean adults

OBJECTIVES

Type 2 diabetes mellitus (T2DM) is a common, chronic disease that is closely associated with anthropometric indices related to obesity. However, no study published to date has simultaneously examined the associations of T2DM with anthropometrics, bone mineral density (BMD), and body composition variables. The present study aimed to evaluate the associations of T2DM with anthropometrics, BMD and body composition variables and to identify the best indicator of T2DM in Korean adults.

METHODS

The data used in this study were obtained from the Korea National Health and Nutrition Examination Survey conducted from 2008 to 2011. A total of 7,835 participants aged from 40 to 90 years were included in this study. A binary logistic regression analysis was performed to examine the significance of differences between the groups with and without T2DM, and the areas under the receiver operating characteristic (AUCs) curves were calculated to compare the predictive power of all variables.

RESULTS

In men, waist-to-height ratio (WHtR) displayed the strongest association with T2DM (adjusted odds ratio (OR) = 1.838 [1.513-2.233], adjusted p<0.001), and waist circumference (WC) and WHtR were the best indicators (WC: AUC = 0.662 [0.639-0.685], WHtR: AUC = 0.680 [0.658-0.703]) of T2DM among all the variables. In women, left leg (LL) and right leg (RL) fat displayed strong negative associations with T2DM (LL fat: adjusted OR = 0.367 [0.321-0.419], adjusted p<0.001, RL fat: adjusted OR = 0.375 [0.329-0.428], adjusted p<0.001), and WC and WHtR were excellent indicators (WC: AUC = 0.730 [0.709-0.750], WHtR: AUC = 0.747 [0.728-0.766]) of T2DM among all the variables. In particular, the WHtR in men and LL and RL fat in women exhibited the strongest associations with T2DM, and the predictive power of the WC and WHtR was stronger than BMD, fat, and muscle mass variables in both men and women. Additionally, the predictive power of the WC and WHtR was stronger in women than in men.

DISCUSSION

Of the anthropometric indices, BMD, and body fat and muscle variables, the best indicators of T2DM were WC and WHtR in both Korean men and women. The results of the present investigation will provide basic information for clinical studies of patients with T2DM and evidence for the prevention and management of T2DM.

Contribution of Diabetes to the Incidence and Prevalence of Comorbid Conditions (Cancer, Periodontal Disease, Fracture, Impaired Cognitive Function, and Depression): A Systematic Review of Epidemiological Studies in Japanese Populations

BACKGROUND

Several epidemiological studies have determined the relationship between diabetes and the incidence and/or prevalence of recently identified comorbid conditions (cancer, periodontal disease, fracture, cognitive impairment, and depression). These relationships may vary by country or race/ethnicity. We aimed to systematically review studies in this field conducted with the Japanese population because such a review in the Japanese population has never been undertaken.

METHODS

We conducted systematic literature searches in PubMed and Ichushi-Web databases for studies published until December 2016. Studies comparing the incidence and/or prevalence of the comorbidities among the Japanese population were included. The studies were classified as integrated analyses, cohort studies, case-control studies, or cross-sectional studies.

RESULTS

We identified 33 studies (cancer: 17, periodontal disease: 5, fracture: 5, cognitive impairment: 4, and depression: 2). Although several cohort studies and meta-analyses had assessed the development of cancer in diabetes, there was scant epidemiological evidence for the other conditions. Indeed, only one cohort study each had been conducted for periodontal disease, fracture, and cognitive impairment, whereas other evidence was cross-sectional, some of which was induced from baseline characteristic tables of studies designed for other purposes.

CONCLUSION

In Japan, there is insufficient evidence about the relationship between diabetes and the incidence/prevalence of periodontal disease, fracture, cognitive impairment, and depression. By contrast, several cohort studies and integrated analyses have been conducted for the relationship with cancer. Further studies should be undertaken to estimate the contribution of diabetes on the incidence/prevalence of comorbidities that may be specific to the Japanese population.

Vertebral Fracture Risk in Diabetic Elderly Men: The MrOS Study

Type 2 diabetes (T2DM) is associated with a significant increase in risk of nonvertebral fractures, but information on risk of vertebral fractures (VFs) in subjects with T2DM, particularly among men, is lacking. Furthermore, it is not known whether spine bone mineral density (BMD) can predict the risk of VF in T2DM. We sought to examine the effect of diabetes status on prevalent and incident vertebral fracture, and to estimate the effect of lumbar spine BMD (areal and volumetric) as a risk factor for prevalent and incident morphometric vertebral fracture in T2DM (n = 875) and nondiabetic men (n = 4679). We used data from the Osteoporotic Fractures in Men (MrOS) Study, which enrolled men aged ≥65 years. Lumbar spine areal BMD (aBMD) was measured with dual-energy X-ray absorptiometry (DXA), and volumetric BMD (vBMD) by quantitative computed tomography (QCT). Prevalence (7.0% versus 7.7%) and incidence (4.4% versus 4.5%) of VFs were not higher in T2DM versus nondiabetic men. The risk of prevalent (OR, 1.05; 95% CI, 0.78 to 1.40) or incident vertebral-fracture (OR, 1.28; 95% CI, 0.81 to 2.00) was not higher in T2DM versus nondiabetic men in models adjusted for age, clinic site, race, BMI, and aBMD. Higher spine aBMD was associated with lower risk of prevalent VF in T2DM (OR, 0.55; 95% CI, 0.48 to 0.63) and nondiabetic men (OR, 0.66; 95% CI, 0.5 to 0.88) (p for interaction = 0.24) and of incident VF in T2DM (OR, 0.50; 95% CI, 0.41 to 0.60) and nondiabetic men (OR, 0.54; 95% CI, 0.33 to 0.88) (p for interaction = 0.77). Results were similar for vBMD. In conclusion, T2DM was not associated with higher prevalent or incident VF in older men, even after adjustment for BMI and BMD. Higher spine aBMD and vBMD are associated with lower prevalence and incidence of VF in T2DM as well as nondiabetic men. © 2017 American Society for Bone and Mineral Research.

Impaired osteogenic differentiation and enhanced cellular receptor of advanced glycation end products sensitivity in patients with type 2 diabetes

Preclinical studies have demonstrated impaired osteoblast differentiation in type 2 diabetes (T2DM), which is related to skeletal accumulation of advanced glycation end products (AGEs). However, the role of AGE in osteoblast differentiation in patients with T2DM is unclear. This cross-sectional study was performed to investigate osteoblast differentiation and its association with serum pentosidine and soluble receptor of AGEs (sRAGE). Twenty-seven patients with T2DM and 15 age-matched controls were included to measure sRAGE and osteogenic differentiation in mononuclear cells derived from peripheral blood. The mononuclear cells isolated from patients with T2DM showed a significantly lower rate of osteogenic differentiation (7.4% vs 86.7%, p < 0.0001) with a lower level of ALPL, COL1A1, and BGLAP expression than those of controls by 11-, 44-, and 15-fold respectively, together with nonvisualized mineralization by alizarin red S staining. The levels of pentosidine and sRAGE were comparable in both groups. AGER expression was significantly higher in the T2DM group. BAX expression was also significantly higher in the T2DM group, and showed a strong correlation with AGER expression (r = 0.86, p < 0.0001). Fasting plasma glucose (FPG) level, AGER expression, and BAX expression showed a strong correlation with osteogenic differentiation defects on univariate analysis. However, only FPG showed a correlation with this defect in a multivariate analysis. In conclusion, patients with T2DM showed impairment of osteoblast differentiation, and FPG was an independent risk factor for this impairment. Moreover, T2DM showed a higher cellular sensitivity for activation of receptor of AGEs and higher cellular apoptosis, which may contribute to the defect in osteoblast differentiation.

Low-trauma fractures without osteoporosis

In clinical practice, areal bone mineral density (aBMD) is usually measured using dual-energy X-ray absorptiometry (DXA) to assess bone status in patients with or without osteoporotic fracture. As BMD has a Gaussian distribution, it is difficult to define a cutoff for osteoporosis diagnosis. Based on epidemiological considerations, WHO defined a DXA-based osteoporosis diagnosis with a T-score <-2.5. However, the majority of individuals who have low-trauma fractures do not have osteoporosis with DXA (i.e., T-score <-2.5), and some of them have no decreased BMD at all. Some medical conditions (spondyloarthropathies, chronic kidney disease and mineral bone disorder, diabetes, obesity) or drugs (glucocorticoids, aromatase inhibitors) are more prone to cause fractures with subnormal BMD. In the situation of fragility fractures with subnormal or normal BMD, clinicians face a difficulty as almost all the pharmacologic treatments have proved their efficacy in patients with low BMD. However, some data are available in post hoc analyses in patients with T score >-2. Overall, in patients with a previous fragility fracture (especially vertebra or hip), treatments appear to be effective. Thus, the authors recommend treating some patients with a major fragility fracture even if areal BMD T score is above -2.5.

Efficacy and Safety of Risedronate in Osteoporosis Subjects with Comorbid Diabetes, Hypertension, and/or Dyslipidemia: A Post Hoc Analysis of Phase III Trials Conducted in Japan

Many osteoporotics have comorbid diabetes mellitus (DM), hypertension (HT), and dyslipidemia (DL). However, whether such comorbidities alter response to anti-osteoporotic treatment is unknown. We did post hoc analyses of combined data from three risedronate Japanese phase III trials to determine whether the presence of DM, HT, or DL affects its efficacy and safety. Data from 885 subjects who received 48-week treatment with risedronate were collected and combined from the three phase III trials. They were divided into two groups by the presence or absence of comorbidities: DM (n = 53) versus non-DM (n = 832); HT (n = 278) versus non-HT (n = 607); and DL (n = 292) versus non-DL (n = 593). Bone mineral density (BMD), urinary type 1 collagen N-telopeptide (uNTX), and serum bone-specific alkaline phosphatase (BAP) were measured at baseline and sequentially until 48 weeks. BMD or bone markers were not different between any of the two groups. Overall, BMD was increased by 5.52%, and uNTX and BAP were decreased by 35.4 and 33.8%, respectively. Some bone markers were slightly lower in DM and DL subjects, but the responses to risedronate were not significantly different. Statin users had lower uNTX and BAP, but showed no difference in the treatment response. All the other medications had no apparent effect. Adverse event incidence was marginally higher in DL compared with non-DL (Relative risk 1.06; 95% confidence interval 1.01-1.11), but was not related to increase in any specific events. Risedronate shows consistent safety and efficacy in suppressing bone turnover and increasing BMD in osteoporosis patients with comorbid DM, HT, and/or DL.

The utility of lumbar spine trabecular bone score and femoral neck bone mineral density for identifying asymptomatic vertebral fractures in well-compensated type 2 diabetic patients

The objective of the study was to evaluate the usefulness of trabecular bone score (TBS) and bone mineral density (BMD) for identifying vertebral fractures (VFx) in well-compensated type 2 diabetic (T2D) patients. TBS and femoral neck BMD below certain cutoffs may be useful for identifying VFx in well-compensated T2D patients.

INTRODUCTION

In T2D, the prevalence of VFx is increased, especially in poorly compensated and complicated diabetic patients. The possibility of predicting the fracture risk in T2D patients by measuring BMD and TBS, an indirect parameter of bone quality, is under debate. Therefore, the objective was to evaluate the usefulness of TBS and BMD for identifying VFx in well-compensated T2D patients.

METHODS

Ninety-nine T2D postmenopausal women in good metabolic control (glycosylated haemoglobin 6.8 ± 0.7 %) and 107 control subjects without T2D were evaluated. In all subjects, we evaluated the following: the BMD at the lumbar spine (LS) and the femoral neck (FN); the TBS by dual X-ray absorptiometry; and VFx by radiography. In T2D subjects, the presence of diabetic retinopathy, neuropathy, and nephropathy was evaluated.

RESULTS

T2D subjects had increased VFx prevalence (34.3 %) as compared to controls (18.7 %) (p = 0.01). T2D subjects presented higher BMD (LS -0.8 ± 1.44, FN -1.06 ± 1.08), as compared to controls (LS -1.39 ± 1.28, p = 0.002; FN -1.45 ± 0.91, p = 0.006, respectively). TBS was not different between diabetics and controls. In fractured T2D patients, LS-BMD, FN-BMD, and TBS were reduced (-1.2 ± 1.44; -1.44 ± 1.04; 1.072 ± 0.15) and the prevalence of retinopathy (15.4 %) was increased than in nonfractured T2D subjects (-0.59 ± 1.4, p = 0.035; -0.87 ± 1.05, p = 0.005; 1.159 ± 0.15, p = 0.006; 1.8 %, p = 0.04, respectively). The combination of TBS ≤1.130 and FN-BMD less than -1.0 had the best diagnostic accuracy for detecting T2D fractured patients (SP 73.8 %, SN 63.6 %, NPV 78.9 %, PPV 56.8 %).

CONCLUSIONS

TBS and FN-BMD below certain cutoffs may be useful for identifying VFx in well-compensated T2D patients.

Insights into bone fragility in diabetes: the crucial role of bone quality on skeletal strength

Meta-analyses have revealed that the relative risk of hip fractures in patients with type 1 and type 2 diabetes mellitus is higher than that in non-diabetic subjects. The risk of fracture in patients with diabetes mellitus increases along with a decrease in bone mineral density (BMD) similarly to those in non-diabetic patients. However, the observed risk of fracture is higher than expected one by BMD in both type 1 and type 2 diabetic patients, indicating that precise estimation of bone fragility by BMD values in patients with diabetes is difficult. Bone strength consists of BMD and bone quality, for this reason, poor bone quality is a most suitable and explicable cause for elevated fracture risk in this population. This bone fragility observed in patients with diabetes mellitus is caused by unique pathogenesis in diabetes, suggesting that osteoporosis in diabetic patients may be one of the diabetic complications and that specific diagnostic criteria for this osteoporosis is required. Bone quality indicators closely related to bone fragility are required to be identified to establish a diagnostic method for osteoporosis in patients with diabetes mellitus.

Increased fracture risk in patients with type 2 diabetes mellitus: an overview of the underlying mechanisms and the usefulness of imaging modalities and fracture risk assessment tools

Type 2 diabetes mellitus has recently been linked to an increased fracture risk. Since bone mass seems to be normal to elevated in patient with type 2 diabetes, the increased fracture risk is thought to be due to both an increased falling frequency and decreased bone quality. The increased falling frequency is mainly a result of complications of the disease such as a retinopathy and polyneuropathy. Bone quality is affected through changes in bone shape, bone micro-architecture, and in material properties such as bone mineralization and the quality of collagen. Commonly used methods for predicting fracture risk such as dual energy X-ray absorptiometry and fracture risk assessment tools are helpful in patients with type 2 diabetes mellitus, but underestimate the absolute fracture risk for a given score. New imaging modalities such as high resolution peripheral quantitative computed tomography are promising for giving insight in the complex etiology underlying the fragility of the diabetic bone, as they can give more insight into the microarchitecture and geometry of the bone. We present an overview of the contributing mechanisms to the increased fracture risk and the usefulness of imaging modalities and risk assessment tools in predicting fracture risk in patients with type 2 diabetes.

More radial shortening after low-energy Colles' fractures is associated with type 2 diabetes mellitus among postmenopausal women, irrespective of bone mineral density

BACKGROUND

Recent meta-analysis data reveal that patients with type 2 diabetes mellitus (DM) have a higher risk of fracture, despite higher bone mineral density (BMD), than patients without type 2 DM. The purpose of this study was to compare BMD and distal radial shortening after low-energy Colles' fractures among Japanese postmenopausal women aged ≥50 years with type 2 DM with those in women without it (non-DM).

METHODS

One-hundred and ten postmenopausal women aged ≥50 years with distal radius fractures resulting from a fall were enrolled in this study. Twelve patients had DM. BMD, type I collagen cross-linked N-telopeptide (NTX), undercarboxylated osteocalcin (ucOC), estimated glomerular filtration rate (eGFR), grip strength of the unfractured hand, unipedal standing time, and the degree of radial shortening were measured.

RESULTS

There were no significant differences in age and body height between the two groups. The DM group had significantly greater body weight and body mass index than the non-DM group. BMDs of the lumbar spine and proximal hip were significantly higher in the DM group than in the non-DM group. NTX, ucOC, grip strength, and the percentage of women with unipedal standing time <15 s did not differ between the two groups. Stepwise regression analysis identified DM and shorter unipedal standing time as significant factors associated with more radial shortening, and identified more radial shortening and lower eGFR as significant factors associated with DM.

CONCLUSIONS

More radial shortening after low-energy Colles' fractures was significantly associated with type 2 DM among postmenopausal women aged ≥50 years, irrespective of BMD.

Effects of raloxifene on lipid and bone metabolism in postmenopausal women with type 2 diabetes

Evidence suggests that bone quality is poorer and fracture risk is higher in patients with diabetes, even those with normal bone mineral density. The aim of this study was to determine the effects of raloxifene on lipid, bone, and glucose metabolism in postmenopausal women with type 2 diabetes. The study subjects (144 postmenopausal women aged less than 80 years with type 2 diabetes) were randomly assigned into three groups: no medication, alfacalcidol 1 μg/day, or raloxifene hydrochloride 60 mg/day. The primary endpoint was the change in LDL-C at 6 months. Raloxifene significantly decreased the levels of bone metabolism markers NTX and BAP at 6 months in patients with diabetes. The primary endpoint, LDL-C at 6 months, was significantly lower in the raloxifene group than in the other two groups. However, percent changes in HDL-C were not significantly different among the three groups. Although glucose metabolism was unaffected, homocysteine, a bone quality marker, was significantly decreased at 6 months in the raloxifene group. The percent improvement in LDL-C did not correlate with percent improvement in any bone metabolism or bone quality markers. Raloxifene, unlike estrogen, improved LDL-C and decreased homocysteine, indicating that raloxifene can potentially improve LDL-C as well as bone quality in postmenopausal women with type 2 diabetes.

Type 2 diabetes and bone

There is a growing body of research showing that diabetes is an independent risk factor for fracture. Type 2 diabetes (T2D), which predominates in older individuals and is increasing globally as a consequence of the obesity epidemic, is associated with normal or even increased dual-energy x-ray absorptiometry (DXA)-derived areal bone mineral density (BMD). Therefore, the paradoxical increase in fracture risk has led to the hypothesis that there are diabetes-associated alterations in material and structural properties. An overly glycated collagen matrix, confounded by a low turnover state, in the setting of subtle cortical abnormalities, may lead to compromised biomechanical competence. In current clinical practice, because BMD is central to fracture prediction, a consequence of this paradox is a lack of suitable methods, including FRAX, to predict fracture risk in older adults with T2D. The option of adding diabetes to the FRAX algorithm is appealing but requires additional data from large population-based cohorts. The need for improved methods for identification of fracture in older adults with T2D is an important priority for osteoporosis research.

Characteristics of diabetic osteopenia in KK-Ay diabetic mice

We examined the bone mineral density (BMD) of the proximal region and the mid-diaphysis of the femur using dual energy X-ray absorption (DXA), the blood osteocalcin level and the blood glucose level every five weeks from 8 to 23 weeks old in KK-Ay diabetic mice. The BMD of the proximal region after 18 weeks old was significantly lower when compared with that at 8 weeks old (p<0.05), whereas there was no significant difference in the BMD of the mid-diaphysis at each week. The BMD of the proximal region at 18 weeks old was significantly lower than that in ddY mice, used as controls (p<0.05). The blood osteocalcin level at 18 weeks old was significantly lower than that at 8 weeks old and that in 18-week-old ddY mice (p<0.05). There was significant negative correlation between the blood glucose level and the BMD of the proximal region (r=-0.64, p<0.05). These results suggest that type 2 diabetes exerts an influence only on spongy bone, not on cortical bone, and that the BMD in the proximal region of the femur seems to be affected by blood glucose level, parallel with the progression of diabetes, through the blood osteocalcin level. In the present study, we show the characteristics of diabetic osteopenia in KK-Ay mice, an animal model of type 2 diabetes.

Association between bone mineral density and type 2 diabetes mellitus: a meta-analysis of observational studies

Type 2 diabetes mellitus (T2DM) influences bone metabolism, but the relation of T2DM with bone mineral density (BMD) remains inconsistent across studies. The objective of this study was to perform a meta-analysis and meta-regression of the literature to estimate the difference in BMD (g/cm²) between diabetic and non-diabetic populations, and to investigate potential underlying mechanisms. A literature search was performed in PubMed and Ovid extracting data from articles prior to May 2010. Eligible studies were those where the association between T2DM and BMD measured by dual energy X-ray absorptiometry was evaluated using a cross-sectional, cohort or case–control design, including both healthy controls and subjects with T2DM. The analysis was done on 15 observational studies (3,437 diabetics and 19,139 controls). Meta-analysis showed that BMD in diabetics was significantly higher, with pooled mean differences of 0.04 (95% CI: 0.02, 0.05) at the femoral neck, 0.06 (95% CI: 0.04, 0.08) at the hip and 0.06 (95% CI: 0.04, 0.07) at the spine. The differences for forearm BMD were not significantly different between diabetics and non-diabetics. Sex-stratified analyses showed similar results in both genders. Substantial heterogeneity was found to originate from differences in study design and possibly diabetes definition. Also, by applying meta-regression we could establish that younger age, male gender, higher body mass index and higher HbA_1C were positively associated with higher BMD levels in diabetic individuals. We conclude that individuals with T2DM from both genders have higher BMD levels, but that multiple factors influence BMD in individuals with T2DM.

Bone metabolism and fracture risk in type 2 diabetes mellitus

Osteoporosis and type 2 diabetes mellitus (T2DM), both prevalent in aging and westernized societies, adversely affect the health of elderly people by causing fractures and vascular complications, respectively. Recent experimental and clinical studies show that the disorders are etiologically related through the actions of osteocalcin and adiponectin. Meta-analyses of multiple clinical studies show that the hip fracture risk of T2DM patients is increased 1.4-1.7-fold compared with non-DM controls, even though the patients' bone mineral density (BMD) is not diminished. Vertebral fracture risk of the T2DM patients is also increased, and BMD measurement is not sensitive enough to assess this risk. These findings suggest that bone fragility in T2DM patients depends on bone quality deterioration rather than bone mass reduction. Surrogate markers are therefore needed to supplement the partial effectiveness of BMD testing in assessing the fracture risk of the T2DM patients. Markers related to advanced glycation end products may be candidates. These substances modulate bone quality in DM. Until research establishes the usefulness of surrogate markers, physicians should assess fracture risk in T2DM patients not only by measuring the BMD, but also by taking a fracture history and evaluating prior vertebral fractures using spinal X-rays.

Association between bone mineral density and type 2 diabetes mellitus: a meta-analysis of observational studies

Type 2 diabetes mellitus (T2DM) influences bone metabolism, but the relation of T2DM with bone mineral density (BMD) remains inconsistent across studies. The objective of this study was to perform a meta-analysis and meta-regression of the literature to estimate the difference in BMD (g/cm(2)) between diabetic and non-diabetic populations, and to investigate potential underlying mechanisms. A literature search was performed in PubMed and Ovid extracting data from articles prior to May 2010. Eligible studies were those where the association between T2DM and BMD measured by dual energy X-ray absorptiometry was evaluated using a cross-sectional, cohort or case-control design, including both healthy controls and subjects with T2DM. The analysis was done on 15 observational studies (3,437 diabetics and 19,139 controls). Meta-analysis showed that BMD in diabetics was significantly higher, with pooled mean differences of 0.04 (95% CI: 0.02, 0.05) at the femoral neck, 0.06 (95% CI: 0.04, 0.08) at the hip and 0.06 (95% CI: 0.04, 0.07) at the spine. The differences for forearm BMD were not significantly different between diabetics and non-diabetics. Sex-stratified analyses showed similar results in both genders. Substantial heterogeneity was found to originate from differences in study design and possibly diabetes definition. Also, by applying meta-regression we could establish that younger age, male gender, higher body mass index and higher HbA(1C) were positively associated with higher BMD levels in diabetic individuals. We conclude that individuals with T2DM from both genders have higher BMD levels, but that multiple factors influence BMD in individuals with T2DM.

Association between bone mineral density and type 2 diabetes mellitus: a meta-analysis of observational studies

Type 2 diabetes mellitus (T2DM) influences bone metabolism, but the relation of T2DM with bone mineral density (BMD) remains inconsistent across studies. The objective of this study was to perform a meta-analysis and meta-regression of the literature to estimate the difference in BMD (g/cm(2)) between diabetic and non-diabetic populations, and to investigate potential underlying mechanisms. A literature search was performed in PubMed and Ovid extracting data from articles prior to May 2010. Eligible studies were those where the association between T2DM and BMD measured by dual energy X-ray absorptiometry was evaluated using a cross-sectional, cohort or case-control design, including both healthy controls and subjects with T2DM. The analysis was done on 15 observational studies (3,437 diabetics and 19,139 controls). Meta-analysis showed that BMD in diabetics was significantly higher, with pooled mean differences of 0.04 (95% CI: 0.02, 0.05) at the femoral neck, 0.06 (95% CI: 0.04, 0.08) at the hip and 0.06 (95% CI: 0.04, 0.07) at the spine. The differences for forearm BMD were not significantly different between diabetics and non-diabetics. Sex-stratified analyses showed similar results in both genders. Substantial heterogeneity was found to originate from differences in study design and possibly diabetes definition. Also, by applying meta-regression we could establish that younger age, male gender, higher body mass index and higher HbA(1C) were positively associated with higher BMD levels in diabetic individuals. We conclude that individuals with T2DM from both genders have higher BMD levels, but that multiple factors influence BMD in individuals with T2DM.

Prevalence of osteoporosis and vertebral fractures in postmenopausal women with type 2 diabetes mellitus and their relationship with duration of the disease and chronic complications

Controversial data suggest that patients with type 2 diabetes mellitus have an increased risk of fractures despite having, in some studies, higher bone mineral density.

METHODS

The aim of this study was to determine the prevalence of osteoporosis and morphometric vertebral fractures in 148 postmenopausal diabetic women, aged 61.87±7.85 years, and their relationship with clinical and metabolic factors and chronic complications of the disease.

RESULTS

The prevalence of osteoporosis was 30.4% at lumbar spine (LS) and 9.5% at femoral neck (FN). The prevalence of vertebral fractures was 23%, mostly mild and located at the thoracic spine. Patients with fractures were older (P<.001), had been in the menopause for a long period (P=.005), had lower creatinine clearance (P=.026) had and lower bone mineral density at LS (P=.01) and FN (P=.042). The frequency of fractures increased with age (P<.001), with the duration of the disease (P=.037) and with the presence of retinopathy (P=.030). In patients with fractures, the prevalence of osteoporosis increased to 40% at LS (P=.004) and to 35.7% at FN (P=.049). After logistic regression adjustment, it was observed that the likelihood of presenting vertebral fractures was significantly increased at the age of 60 years or older (P<.001) and with the presence of osteoporosis at LS (P=.006), irrespective of blood glucose control.

CONCLUSION

We found a high prevalence of osteoporosis and vertebral fractures in postmenopausal women with type 2 diabetes mellitus, irrespective of blood glucose control, and these conditions were more frequent in long-standing disease and in patients with retinopathy and impaired renal function.

Association of BMD and FRAX score with risk of fracture in older adults with type 2 diabetes

CONTEXT

Type 2 diabetes mellitus (DM) is associated with higher bone mineral density (BMD) and paradoxically with increased fracture risk. It is not known if low BMD, central to fracture prediction in older adults, identifies fracture risk in patients with DM.

OBJECTIVE

To determine if femoral neck BMD T score and the World Health Organization Fracture Risk Algorithm (FRAX) score are associated with hip and nonspine fracture risk in older adults with type 2 DM.

DESIGN, SETTING, AND PARTICIPANTS

Data from 3 prospective observational studies with adjudicated fracture outcomes (Study of Osteoporotic Fractures [December 1998-July 2008]; Osteoporotic Fractures in Men Study [March 2000-March 2009]; and Health, Aging, and Body Composition study [April 1997-June 2007]) were analyzed in older community-dwelling adults (9449 women and 7436 men) in the United States.

MAIN OUTCOME MEASURE

Self-reported incident fractures, which were verified by radiology reports.

RESULTS

Of 770 women with DM, 84 experienced a hip fracture and 262 a nonspine fracture during a mean (SD) follow-up of 12.6 (5.3) years. Of 1199 men with DM, 32 experienced a hip fracture and 133 a nonspine fracture during a mean (SD) follow-up of 7.5 (2.0) years. Age-adjusted hazard ratios (HRs) for 1-unit decrease in femoral neck BMD T score in women with DM were 1.88 (95% confidence interval [CI], 1.43-2.48) for hip fracture and 1.52 (95% CI, 1.31-1.75) for nonspine fracture, and in men with DM were 5.71 (95% CI, 3.42-9.53) for hip fracture and 2.17 (95% CI, 1.75-2.69) for nonspine fracture. The FRAX score was also associated with fracture risk in participants with DM (HRs for 1-unit increase in FRAX hip fracture score, 1.05; 95% CI, 1.03-1.07, for women with DM and 1.16; 95% CI, 1.07-1.27, for men with DM; HRs for 1-unit increase in FRAX osteoporotic fracture score, 1.04; 95% CI, 1.02-1.05, for women with DM and 1.09; 95% CI, 1.04-1.14, for men with DM). However, for a given T score and age or for a given FRAX score, participants with DM had a higher fracture risk than those without DM. For a similar fracture risk, participants with DM had a higher T score than participants without DM. For hip fracture, the estimated mean difference in T score for women was 0.59 (95% CI, 0.31-0.87) and for men was 0.38 (95% CI, 0.09-0.66).

CONCLUSIONS

Among older adults with type 2 DM, femoral neck BMD T score and FRAX score were associated with hip and nonspine fracture risk; however, in these patients compared with participants without DM, the fracture risk was higher for a given T score and age or for a given FRAX score.

Bone metabolism and fracture risk in type 2 diabetes mellitus [Review]

Osteoporosis and type 2 diabetes mellitus (T2DM) are now prevalent in aging and westernized societies, and adversely affect the health of the elderly people by causing fractures and vascular complications, respectively. Recent experimental and clinical studies show that both disorders are etiologically related to each other through the actions of osteocalcin and adiponectin. Meta-analyses of multiple clinical studies show that hip fracture risk of T2DM patients is increased to 1.4 to 1.7-folds, although BMD of the patients is not diminished. Vertebral fracture risk of T2DM patients is also increased, and BMD is not useful for assessing its risk. These findings suggest that bone fragility in T2DM depends on bone quality deterioration rather than bone mass reduction. Thus, surrogate markers are needed to replace the insensitivity of BMD in assessing fracture risks of T2DM patients. Markers related to advanced glycation end products as well as insulin-like growth factor-I may be such candidates, because these substances were experimentally shown to modulate bone quality in DM. In practice, it is important for physicians to assess fracture risk in T2DM patients by evaluating prior VFs and fracture histories using spine X-ray and interview, respectively, until the usefulness of surrogate markers is established.

Bone fragility in type 2 diabetes mellitus

The number of patients with osteoporosis or type 2 diabetes mellitus (T2DM) is increasing in aging and westernized societies. Both disorders predispose elderly people to disabling conditions by causing fractures and vascular complications, respectively. It is well documented that bone metabolism and glucose/fat metabolism are etiologically related to each other through osteocalcin action and Wnt signaling. Bone fragility in T2DM, which is not reflected by bone mineral density (BMD), depends on bone quality deterioration rather than bone mass reduction. Thus, surrogate markers are needed to replace the insensitivity of BMD in assessing fracture risks of T2DM patients. Pentosidine, the endogenous secretory receptor for advanced glycation endproducts, and insulin-like growth factor-I seem to be such candidates, although further studies are required to clarify whether or not these markers could predict the occurrence of new fractures of T2DM patients in a prospective fashion.

Metformin reverses the deleterious effects of high glucose on osteoblast function

An association has been previously established between uncompensated diabetes mellitus and the loss of bone mineral density and/or quality. In the present study, we examined the effects of different concentrations of glucose (5.5, 11, 22, and 44 mmol/L) with or without metformin (10-640 micromol/L) on rat primary osteoblasts cultured in an osteogenic medium. With 11 mmol/L glucose, cellular proliferation, alkaline phosphatase (ALP) activity, the number of nodules formed, and calcium deposition in mineralized nodules were increased significantly; intracellular reactive oxygen species (ROS) and apoptosis were slightly reduced, although these reductions were not statistically significant. At higher concentrations of glucose (22 and 44 mmol/L), cellular proliferation, ALP activity, the number of nodules formed, and calcium deposition were greatly reduced; ROS and apoptosis were significantly increased in a dose-dependent manner. Metformin markedly increased cellular proliferation, ALP activity, calcium deposition, and the number of nodules formed and inhibited ROS and apoptosis in all glucose groups. Moreover, we assessed the gene expression levels of Runx2, IGF-1, and IGF-1R. Eleven micromole per liter glucose stimulated Runx2 and IGF-1 expression; 44 mmol/L glucose inhibited Runx2, IGF-1, and IGF-1R expression. Metformin stimulated the expression of Runx2 and IGF-1 in three glucose groups, but it did not affect IGF-1R. In conclusion, our findings suggest that the dual effects of glucose on cell proliferation and development are dose dependent. Metformin not only significantly decreased intracellular ROS and apoptosis, but also had a direct osteogenic effect on osteoblasts at all glucose concentrations, which could be partially mediated via promotion of Runx2 and IGF-1 expression.

The impact of diabetes mellitus on vitamin D metabolism in predialysis patients

Although diabetes mellitus (DM) disturbs bone metabolism, little is known concerning its effects on laboratory abnormalities in chronic kidney disease-mineral and bone disorders (CKD-MBD). We extracted data for 602 patients from the Osaka Vitamin D Study in patients with CKD (OVIDS-CKD), an observational study enrolling predialysis outpatients. No enrolled patients received vitamin D, bisphosphonate, estrogen or raloxifene. We measured 1- 84 PTH, 25-hydroxyvitamin D (25D), calcitriol, fibroblast growth factor-23 (FGF-23), calcium (Ca), and phosphate (P). Since there were 112 DM patients (group D), we extracted 112 age-, sex-, and eGFR-matched non-DM counterparts (group N). We compared biochemical markers between groups, and then performed multiple regression analyses for all 602 subjects to confirm the results obtained. Group D had significantly higher corrected Ca and P than group N throughout all stages of CKD. In group D, 25D decreased as renal function declined, while in group N it remained constant (interaction P<0.05). Despite higher P and poorer vitamin D status in DM, there were no differences in 1- 84 PTH level between group D and group N stratified by stage of CKD, resulting in significantly lower calcitriol levels in group D in late CKD. Multiple regression analyses revealed that DM was significantly associated with low vitamin D status even with adjustment for urinary protein, and that this poorer vitamin D status in DM was responsible for lower calcitriol level associated with DM. Despite higher P, lower FGF-23 in early CKD (stages 1 + 2) and comparable level of FGF-23 in late stages of CKD (stages 3, 4, and 5) were observed in group D. We interpreted these results to indicate that inappropriate production of FGF-23 in DM might explain higher serum phosphate in DM. Multiple regression analysis with adjustment for covariates confirmed an independent relationship between DM and low FGF-23, implying the existence of dysfunction or decreased density of osteocytes in DM. Given the origin of these phosphaturic hormones, DM may thus have markedly deleterious effects on parathyroid and bone. Poorer vitamin D status and higher CaP product might be partly responsible for functional and structural changes of vasculature, respectively, in DM.

Serum osteocalcin/bone-specific alkaline phosphatase ratio is a predictor for the presence of vertebral fractures in men with type 2 diabetes

We examined whether or not BMD or bone markers were useful for assessing the risk of vertebral fractures in 248 Japanese men with type 2 diabetes. We analyzed the relationships between bone markers (osteocalcin [OC], bone-specific alkaline phosphatase [BAP], urinary N-terminal cross-linked telopeptide of type-I collagen) or BMD and HbA(1c), urinary C-peptide, insulin-like growth factor-I (IGF-I), parathyroid hormone, 1,25(OH)(2) vitamin D, and the presence of prevalent vertebral fractures. Multiple regression analysis adjusted for age, body height, weight, duration of diabetes, and serum creatinine showed that serum OC and OC/BAP ratio were correlated negatively with HbA(1c) (P < 0.01) and positively with IGF-I (P < 0.01). Multivariate logistic regression analysis adjusted for the above parameters showed that serum OC/BAP ratio was inversely associated with the presence of vertebral fractures (odds ratio = 0.695, P < 0.05). This association was still significant after additional adjustment for lumbar or femoral neck BMD. Our results suggest that poor diabetic control and lower IGF-I level are linked to impaired bone formation and resultant reduction in OC/BAP ratio in men with type 2 diabetes. The OC/BAP ratio could be clinically useful for assessing the risk of vertebral fractures independent of BMD in diabetic men.

Skeletal changes associated with the onset of type 2 diabetes in the ZDF and ZDSD rodent models

The incidence and prevalence of type 2 diabetes (T2D) continue to escalate at an unprecedented rate in the United States, particularly among populations with high rates of obesity. The impact of T2D on bone mass, geometry, architecture, strength, and resistance to fracture has yet to be incontrovertibly characterized because of the complex and heterogeneous nature of this disease. This study utilized skeletally mature male diabetic rats of the commonly used Zucker diabetic fatty (ZDF) and Zucker diabetic Sprague-Dawley (ZDSD) strains as surrogate models to assess alterations in bone attributable to T2D-like states. After the animals were euthanized, bone data were collected using dual-energy X-ray absorptiometry, peripheral quantitative tomography, and micro-CT imaging modalities and via three-point bending or compression mechanical testing methods. ZDF and ZDSD diabetic rats exhibited lower bone mineral densities, which coincided with declines in structural strength and increased fragility at the femoral midshaft and the L4 vertebral body in response to monotonic loading. Vertebral trabecular morphology was compromised in both diabetic rodent strains, and ZDSD diabetic rats exhibited additional phenotypic impairments to bone material properties at the spine. Because the metabolic origin of the T2D-like state that develops in the ZDSD rat strain is highly relevant to adult-onset diabetes, it is a particularly attractive novel model for future preclinical research.

Bone mineral density and its relationship with body mass index in postmenopausal women with type 2 diabetes mellitus in mainland China

Bone mineral density (BMD) and its association with body mass index (BMI) are uncertain in postmenopausal women with type 2 diabetes mellitus (T2DM) in mainland China. This study was performed to assess this association including 1,042 postmenopausal women with T2DM and 919 non-diabetic control subjects. Bone mineral density of the posteroanterior spine and of the left hip was measured by use of dual-energy X-ray absorptiometry. Diabetic participants were divided into three groups according to BMI, i.e. low BMI (DML < 18.5 kg/m(2)), intermediate BMI (DMM 18.5-24.9 kg/m(2)), and high BMI (DMH >or= 25 kg/m(2)). The BMD values of diabetic subjects between groups exhibited a significant gradient difference, with DML < DMM < DMH. On the fitting curves, where BMD in various skeletal regions varied with age, BMDs of DML were approximately 15% lower than those of DMM, and those of DMM were approximately 10% lower than those of DMH. For prevalence and risks of osteoporosis a gradient difference was observed among diabetic groups, DML > DMM approximately control > DMH. The osteoporosis risk was higher for the hip than for the lumbar spine, especially in DML. This study indicated that postmenopausal women with T2DM had higher BMD and lower osteoporosis risk in the lumbar spine, and that lower BMI was an indicator of osteoporosis in mainland China.

Assessment of clinical risk factors to validate the probability of osteoporosis and subsequent fractures in Korean women

This cross-sectional, observational study was designed to identify clinical risk factors of osteoporosis and fractures in Korean women to validate the probability of osteoporosis and subsequent fractures. A total of 1541 Korean women were recruited nationally. Fracture history of any site, risk factors of osteoporosis, and fall-related risk factors were surveyed and physical performance tests were conducted. Peripheral dual-energy X-ray absorptiometry was used to measure calcaneus bone mineral density (BMD). The number of positive responses on the modified 1-min osteoporosis risk test was related to the risk of osteoporosis. The frequency of osteoporosis was higher in those with a height reduction of >4 cm and a reduced body mass index (BMI). Multivariate analysis showed that older age and lower BMI were related to higher relative risk of osteoporosis. Time required to stand up from a chair and questions related to fall injury were significantly related to clinical fracture history of any site. Multivariate analysis showed that the relative risk of fractures at any site was higher in older subjects with a lower T-score and parental hip fracture history. This study shows that age and BMI are the most significant clinical risk factors for osteoporosis and that age, BMD, and parental history of hip fracture are highly applicable risk factors for validating the probability of osteoporotic fractures in Korean women.

Combination of obesity with hyperglycemia is a risk factor for the presence of vertebral fractures in type 2 diabetic men

Although patients with type 2 diabetes show no bone mineral density (BMD) reduction, fracture risks are known to increase. It is unclear why the patients have an increased risk of fracture despite sufficient BMD. We investigated the relationships of body mass index (BMI), HbA(1c), and urinary C-peptide (uC-peptide) versus BMD, bone metabolic markers, serum adiponectin, and prevalent vertebral fracture (VF). A total of 163 Japanese type 2 diabetic men were consecutively recruited, and radiographic and biochemical data were collected. BMI was positively correlated with BMD at the whole body, lumbar spine, and femoral neck (P < 0.05) and negatively correlated with osteocalcin and urinary N-terminal cross-linked telopeptide of type-I collagen (uNTX) (P < 0.01). HbA(1c) was negatively correlated with osteocalcin (P < 0.01) but not BMD at any site. Subjects were classified into four groups based on BMI and HbA(1c) (group LL BMI < 24 and HbA(1c) < 9, group LH BMI < 24 and HbA(1c) > or = 9, group HL BMI > or = 24 and HbA(1c) < 9, group HH BMI > or = 24 and HbA(1c) > or = 9). Serum adiponectin, osteocalcin, and uNTX were lower and the incidence of VF was higher despite sufficient BMD in the HH group. Multivariate logistic regression analysis adjusted for age, duration of diabetes, uC-peptide, and estimated glomerular filtration rate showed that the HH group was associated with the presence of a VF and multiple VFs (odds ratio [OR] = 3.056, 95% confidence interval [CI] 1.031-9.056, P = 0.0439, and OR = 5.415, 95% CI 1.126-26.040, P = 0.0350, respectively). Combination of obesity with hyperglycemia was a risk factor for VF despite sufficient BMD in diabetic men.

Serum pentosidine levels are positively associated with the presence of vertebral fractures in postmenopausal women with type 2 diabetes

CONTEXT

Although type 2 diabetic patients are at increased risk of fractures, bone mineral density (BMD) may not be useful for assessing the risk. Recent studies have reported that increased bone content of pentosidine (PEN) is associated with its plasma concentration and bone fragility.

OBJECTIVE AND METHODS

To examine the association between serum PEN levels and vertebral fractures (VFs) in Japanese type 2 diabetic patients (77 males older than 50 yr and 76 postmenopausal females), we compared parameters including BMD, PEN, serum bone-specific alkaline phosphatase, and urinary levels of N-telopeptide between those with and without VFs.

RESULTS

Comparison of diabetic subjects with and without VFs revealed no significant differences in BMD values or bone metabolic markers in either gender. In contrast, PEN levels in women with VFs were significantly higher than in those without VFs (0.0440+/-0.0136 vs. 0.0321+/-0.0118 microg/ml; P<0.001). Multivariate logistic regression analysis adjusted for age, height, weight, hemoglobin A1c, estimated glomerular filtration rate, the presence of diabetic complications, histories of taking insulin or pioglitazone, risk factors for osteoporosis, and lumbar BMD identified PEN levels as a factor associated with the presence of VFs in postmenopausal diabetic women independent of BMD, risk factors for osteoporosis, diabetic status, and renal function (odds ratio 2.50, 95% confidential interval 1.09-5.73 per sd increase; P=0.0302).

CONCLUSION

PEN levels, but not BMD, may be useful for assessing the risk of prevalent VFs in postmenopausal diabetic women and may reflect bone quality in this group.

Serum insulin-like growth factor-I level is associated with the presence of vertebral fractures in postmenopausal women with type 2 diabetes mellitus

Multivariate logistic regression analysis showed that serum IGF-I level was significantly lower in postmenopausal diabetic women with vertebral fractures than in those without fractures. Serum IGF-I level could be clinically useful for assessing the risk of vertebral fractures independent of BMD in postmenopausal women with type 2 diabetes.

INTRODUCTION

We investigated the relationships among serum IGF-I and C-peptide levels, BMD, and vertebral fractures in postmenopausal women with type 2 diabetes.

METHODS

A total of 131 postmenopausal women with type 2 diabetes were consecutively recruited, and radiographic and biochemical characteristics were collected.

RESULTS

Either IGF-I or C-peptide was not correlated with BMD at any site or bone metabolic markers, such as osteocalcin (OC) and urinary N-terminal cross-linked telopeptide of type-I collagen (uNTX). However, serum IGF-I level was significantly lower in subjects with vertebral fractures than in those without fractures (mean +/- SD: 106.9 +/- 50.0 vs. 142.8 +/- 50.8 ng/ml, p = 0.0006). When multivariate logistic regression analysis was performed with the presence of vertebral fractures as a dependent variable and serum IGF-I adjusted for the parameters described above as independent variables, IGF-I was selected as an index affecting the presence of vertebral fractures [odds ratio = 0.436, 95% confidential interval 0.234-0.814 per SD increase, p = 0.0092]. This significance was almost the same after additional adjustment for lumbar BMD or C-peptide.

CONCLUSIONS

Serum IGF-I level could be clinically useful for assessing the risk of vertebral fractures independent of BMD in postmenopausal women with type 2 diabetes.

Effects of high glucose on mesenchymal stem cell proliferation and differentiation

High glucose (HG) concentrations impair cellular functions and induce apoptosis. Exposition of mesenchymal stem cells (MSC) to HG was reported to reduce colony forming activity and induce premature senescence. We characterized the effects of HG on human MSC in vitro using telomerase-immortalized MSC (hMSC-TERT) and primary MSC (hMSC). HG (25mM) enhanced hMSC-TERT proliferation in long-term studies in contrast to hMSC where proliferation was unchanged. Thioredoxin-interacting protein, which is involved in apoptosis regulation, was stimulated by glucose in hMSC-TERT. However, apoptosis was not influenced by HG in both cell types. MSC treatment with HG favored osteogenic differentiation. MSC are resistant to HG toxicity, depending on the stemness of MSC. Proliferation and osteogenic differentiation are stimulated by HG. Effects of HG on the transient amplifying compartment of MSC may differ from those in mature cells. Further research is needed to unravel the molecular mechanisms of HG resistance of MSC.