Osteopenia associated with non-insulin-dependent diabetes mellitus: what are the causes?

Diabetes and Osteoporosis

Bone fragility is an emerging complication of diabetes. People with diabetes are at a significantly higher risk of fractures compared to the general population. Bone fragility occurs in diabetes as a result of complex and poorly understood mechanisms occurring at the cellular level contributed by vascular, inflammatory and mechanical derangements. Bone mineral density (BMD) as assessed by DEXA is low in type 1 diabetes. Type 2 diabetes has a high risk of fracture despite a normal to raised BMD. DEXA thus underestimates the fracture risk in diabetes. Data are scare regarding the efficacy of the available therapies in this low bone turnover state.

Morroniside ameliorates glucocorticoid-induced osteoporosis and promotes osteoblastogenesis by interacting with sodium-glucose cotransporter 2

CONTEXT

Morroniside (MOR) possesses antiosteoporosis (OP) effects, but its molecular target and relevant mechanisms remain unknown.

OBJECTIVE

We investigated the effects of MOR on glucocorticoid-induced OP and osteoblastogenesis and its underlying mechanisms.

MATERIALS AND METHODS

The effects of MOR (10-100 μM) on the proliferation and differentiation of MC3T3-E1 cells were studied in vitro. The glucocorticoid-induced zebrafish OP model was treated with 10, 20 and 40 μM MOR for five days to evaluate its effects on vertebral bone density and related osteogenic markers. In addition, molecular targets prediction and molecular docking analysis were carried out to explore the binding interactions of MOR with the target proteins.

RESULTS

In cultured MC3T3-E1 cells, 20 μM MOR significantly increased cell viability (1.64 ± 0.12 vs. 0.95 ± 0.16; p < 0.01) and cell differentiation (1.57 ± 0.01 vs. 1.00 ± 0.04; p < 0.01) compared to the control group. MOR treatment significantly ameliorated vertebral bone loss in the glucocorticoid-induced OP zebrafish model (0.86 ± 0.02 vs. 0.40 ± 0.03; p < 0.01) and restored the expression of osteoblast-specific markers, including ALP, Runx2 and Col-І. Ligand-based target prediction and molecular docking revealed the binding interaction between MOR and the glucose pockets in sodium-glucose cotransporter 2 (SGLT2).

DISCUSSION AND CONCLUSIONS

These findings demonstrated that MOR treatment promoted osteoblastogenesis and ameliorated glucocorticoid-induced OP by targeting SGLT2, which may provide therapeutic potential in managing glucocorticoid-induced OP.

Development and validation of a risk prediction model for osteoporosis in elderly patients with type 2 diabetes mellitus: a retrospective and multicenter study

BACKGROUND

This study aimed to construct a risk prediction model to estimate the odds of osteoporosis (OP) in elderly patients with type 2 diabetes mellitus (T2DM) and evaluate its prediction efficiency.

METHODS

This study included 21,070 elderly patients with T2DM who were hospitalized at six tertiary hospitals in Southwest China between 2012 and 2022. Univariate logistic regression analysis was used to screen for potential influencing factors of OP and least absolute shrinkage. Further, selection operator regression (LASSO) and multivariate logistic regression analyses were performed to select variables for developing a novel predictive model. The area under the receiver operating characteristic curve (AUROC), calibration curve, decision curve analysis (DCA), and clinical impact curve (CIC) were used to evaluate the performance and clinical utility of the model.

RESULTS

The incidence of OP in elderly patients with T2DM was 7.01% (1,476/21,070). Age, sex, hypertension, coronary heart disease, cerebral infarction, hyperlipidemia, and surgical history were the influencing factors. The seven-variable model displayed an AUROC of 0.713 (95% confidence interval [CI]:0.697-0.730) in the training set, 0.716 (95% CI: 0.691-0.740) in the internal validation set, and 0.694 (95% CI: 0.653-0.735) in the external validation set. The optimal decision probability cut-off value was 0.075. The calibration curve (bootstrap = 1,000) showed good calibration. In addition, the DCA and CIC demonstrated good clinical practicality. An operating interface on a webpage ( https://juntaotan.shinyapps.io/osteoporosis/ ) was developed to provide convenient access for users.

CONCLUSIONS

This study constructed a highly accurate model to predict OP in elderly patients with T2DM. This model incorporates demographic characteristics and clinical risk factors and may be easily used to facilitate individualized prediction.

Advanced Glycation End Products, Bone Health, and Diabetes Mellitus

Advanced glycation end products (AGEs), the compounds resulting from the non-enzymatic glycosylation between reducing sugars and proteins, are derived from food or produced de novo. Over time, more and more endogenous and exogenous AGEs accumulate in various organs such as the liver, kidneys, muscle, and bone, threatening human health. Among these organs, bone is most widely reported. AGEs accumulating in bone reduce bone strength by participating in bone structure formation and breaking bone homeostasis by binding their receptors to alter the proliferation, differentiation, and apoptosis of cells involved in bone remodeling. In this review, we summarize the research about the effects of AGEs on bone health and highlight their associations with bone health in diabetes patients to provide some clues toward the discovery of new treatment and prevention strategies for bone-related diseases caused by AGEs.

Skin autofluorescence Is associated With low bone mineral density in type 2 diabetic patients

Although the risk of bone fracture is increased in type 2 diabetes (T2DM), bone mineral density (BMD) is increased rather than decreased. Accumulation of advanced glycation end products (AGEs) adversely influences the fracture resistance of bone in T2DM. We hypothesized that SAF is also associated with BMD levels in type 2 diabetic patients and aimed to evaluate the association of SAF with BMD and the presence of osteoporosis. This cross-sectional case-control study included 237 patients with T2DM (F/M: 133/104, 56.2±11.9 yrs) and 100 age- and sex-matched controls (F/M: 70/30, 54.8±8.8 yrs). Skin autofluorescence, a validated non-invasive measure of tissue AGEs, is used to detect the accumulation of AGEs in skin collagen using AGE Reader (DiagnOptics B.V., Groningen, The Netherlands). In addition, BMD was measured with DEXA (Lunar DPX-L). Patients with T2DM had higher SAF values compared to control group (2.21±0.53 AU vs. 1.79±0.33 AU, p < 0.001). Male subjects had higher SAF compared to women (2.34±0.53 AU vs. 2.11±0.50 AU, p < 0.001). Subjects with below -2.5 femoral neck or lumbar T scores had higher SAF measurements compared to subjects with normal T scores (2.46±0.53 AU vs. 2.18±0.52 AU, p = 0.006). Femoral neck BMD was lower in subjects with T2DM (0.946±0.345 g/cm² vs. 1.005±0.298 g/cm², p = 0.002). There was a negative correlation between SAF and femoral neck BMD (r=-0.24, p < 0.001), femoral neck T scores (r=-0.24, p < 0.001), L1-4 BMD (r=-0.10, p = 0.005), L1-4 T score (r=-0.16, p=0.001) and a positive correlation between SAF and age (r=0.44, p < 0.001), body mass index (r:0.16, p = 0.002) and HbA1c (r=0.37, p < 0.001). Accumulation of skin AGEs was increased, and BMD levels were decreased in diabetic patients. A negative association between SAF and BMD was detected, indicating a relationship between higher AGE accumulation and low BMD and osteoporosis in diabetic patients. Long-term prospective studies are needed to identify the practical use of SAF measurement in diabetic bone disease.

Risk Factors and Outcomes After Surgical Reconstruction of Charcot Neuroarthropathy in Fracture Versus Dislocation Patterns

The primary aim of this study is to compare the preoperative risk factors and postoperative outcomes between Charcot neuroarthropathy patients with dislocation versus purely fracture pattern breakdown. The secondary aim is to compare the same factors between Charcot neuroarthropathy patients with dislocation versus fracture-dislocation pattern breakdown. A total of 55 patients with forefoot, midfoot, or hindfoot Charcot Neuroarthopathy were assessed at a mean follow up of 2.99 years. Bivariate analysis compared preoperative risk factors and postoperative outcomes, and segmented multivariable regression analysis was performed. Dislocation pattern Charcot had statistically significant higher rates of broken hardware (p = .05), mean age (p = .01), and revisional exostectomy (p = .01) compared to pure fracture pattern Charcot. Dislocation pattern Charcot was 12 times more likely to have revisions exostectomy (odds ratio [OR] 12.0, 95% confidence interval [CI] 1.84-78.37), and was 8 times more likely to have osteomyelitis (OR 7.8, 95% CI 1.4-42.7, p = .02) compared to the fracture-dislocation pattern Charcot. The patients with pure fracture pattern Charcot were 58.8 times more likely to have Charcot breakdown involvement of the talonavicular joint compared to the dislocation pattern cohort (OR 58.83, 95% CI 1.1-3220.3). Involvement of the talonavicular joint, in the fracture pattern Charcot associate with medial column collapse occurring at the onset of Charcot breakdown. The dislocation pattern in Charcot Neuroarthropathy demonstrated a higher propensity for residual collapse as demonstrated by the higher rates of broken hardware, osteomyelitis, and need for revisional exostectomy.

The Interplay Between Bone and Glucose Metabolism

The multiple endocrine functions of bone other than those related to mineral metabolism, such as regulation of insulin sensitivity, glucose homeostasis, and energy metabolism, have recently been discovered. In vitro and murine studies investigated the impact of several molecules derived from osteoblasts and osteocytes on glucose metabolism. In addition, the effect of glucose on bone cells suggested a mutual cross-talk between bone and glucose homeostasis. In humans, these mechanisms are the pivotal determinant of the skeletal fragility associated with both type 1 and type 2 diabetes. Metabolic abnormalities associated with diabetes, such as increase in adipose tissue, reduction of lean mass, effects of hyperglycemia per se, production of the advanced glycation end products, diabetes-associated chronic kidney disease, and perturbation of the calcium-PTH-vitamin D metabolism, are the main mechanisms involved. Finally, there have been multiple reports of antidiabetic drugs affecting the skeleton, with differences among basic and clinical research data, as well as of anti-osteoporosis medication influencing glucose metabolism. This review focuses on the aspects linking glucose and bone metabolism by offering insight into the most recent evidence in humans.

The prevalence of osteoporosis among Iranian postmenopausal women with type 2 diabetes: A systematic review and meta-analysis

Osteoporosis is the most common metabolic bone disorder that is common in postmenopausal women with type 2 diabetes. Different studies have reported different prevalence of osteoporosis. This systematic review and meta-analysis was conducted to estimate the pooled prevalence of osteoporosis in Iranian postmenopausal women with type 2 diabetes. Search for eligible articles was performed using the keywords of osteoporosis, osteopenia, bone mineral density, OP, bone loss, Post menopaus*, diabetes, hyperglycemia, and Iran, and their possible combinations in the following databases: Scientific Information Database (SID), MagIran, PubMed, Scopus, and Web of Science. Heterogeneity between studies was examined with I². The data were analyzed using the meta-analysis method and random effects model with Stata version 11.0. The analysis of 4 papers with a sample size of 562 showed that the prevalence of osteoporosis in the lumbar spine and femoral neck of the Iranian post-menopausal women with type II diabetes was 25.26% (95% CI: 7.22-30.30) and 17.45% (95% CI: 0.25-34.65), respectively. Also, the prevalence of osteopenia in the lumbar spine and femoral neck of these patients was 45.23% (95% CI: 40.66-49.79) and 44.53% (95% CI: 36.60-52.47), respectively. There was no relationship between the prevalence of osteoporosis and osteopenia with sample size, year of publication, age and body mass index. Osteoporosis and osteopenia are prevalent in women, so healthy lifestyle education for these postmenopausal women are necessary to reduce the prevalence of these problems.

Risk of osteoporosis and fracture in victims with burn injury

Osteoporosis is a well-known bone disorder affecting people worldwide. Patients with osteoporosis have an increased risk of bone fracture. This study provides new information on the risk of developing osteoporosis post burn injury and the risk of fracture among those with osteoporosis developed.

INTRODUCTION

The relationship between burn injury and hip fracture risk is unclear. Population-based evaluation on relationships between burn injury and osteoporosis development and subsequent fractures is limited. We conducted a retrospective cohort study as the investigation.

METHODS

From the insurance data of Taiwan, we established a cohort of 43,532 patients with a burn injury in 2000-2012 and a comparison cohort of 174,124 individuals without such an injury, frequency matched by sex, age, and diagnosis date. Both cohorts were followed up to the end of 2013 to evaluate the occurrence of osteoporosis and hip fracture.

RESULTS

The incidence of osteoporosis was greater in the burn cohort than in the comparison cohort (6.40 vs. 4.75 per 1,000 person-years) with an adjusted IRR of 1.35 (95% confidence interval = 1.32-1.39). The incidence rates in both cohorts were greater in women than in men, increased with age, income, and Charlson comorbidity index. Patients with burns involving 20%-49% of total body surface area and with burns confined to the lower/upper limbs had the greatest incidence rates, 8.32 and 8.58 per 1,000 person-years, respectively. Osteoporosis incidence increased further to 22.7 per 1,000 person-years for burn victims with comorbid diabetes. The risk of fracture was over five-fold greater for burn victims with osteoporosis developed than for comparisons without osteoporosis.

CONCLUSION

Patients who have a burn injury deserve prevention intervention to reduce the risk of osteoporosis and fracture.

Investigation of diabetic patient's fingernail quality to monitor type 2 diabetes induced tissue damage

Long-term Type 2 Diabetes (T2D) affects the normal functioning of heart, kidneys, nerves, arteries, bones, and joints. The T2D gradually alters the intrinsic material properties, and structural integrity of the tissues and prolonged hyperglycemia causes chronic damages to these tissues quality. Clinically no such technique is available which can assess the altered tissues quality associated with T2D. In the present study, the microstructural characterization (surface morphology, surface roughness and density and calcium content), material characterization (modulus, hardness), and macromolecular characterization (disulfide bond content, protein content and its secondary structure) are investigated among healthy, diabetic controlled (DC) and uncontrolled diabetic (UC) group of fingernail plate. It is found that T2D has an adverse effect on the human fingernail plate quality. The parameters of nail plate quality are changing in a pattern among all the three groups. The properties mentioned above are degrading in DC group, but the degradation is even worst in the case of severity of T2D (UC group) as compared to the healthy group (Healthy Collapse

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MESH Headings

• Adult
• Aged
• Bone and Bones/metabolism
• Chronic Disease
• Diabetes Mellitus, Type 2/metabolism
• Female
• Humans
• Male
• Middle Aged
• Nails/metabolism
• Nails/pathology

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Grants

• IIT Ropar

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Affiliation(s)

Praveer Sihota Department of Mechanical Engineering, Indian Institute of Technology (IIT) Ropar, Rupnagar, Punjab, 140001, India
Ram Naresh Yadav Department of Mechanical Engineering, Indian Institute of Technology (IIT) Ropar, Rupnagar, Punjab, 140001, India
Vandana Dhiman Department of Endocrinology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, 160012, India
Sanjay Kumar Bhadada Department of Endocrinology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, 160012, India
Vishwajeet Mehandia Department of Mechanical Engineering, Indian Institute of Technology (IIT) Ropar, Rupnagar, Punjab, 140001, India
Navin Kumar Department of Mechanical Engineering, Indian Institute of Technology (IIT) Ropar, Rupnagar, Punjab, 140001, India.

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Type 2 Diabetes Mellitus Increases the Risk to Hip Fracture in Postmenopausal Osteoporosis by Deteriorating the Trabecular Bone Microarchitecture and Bone Mass

T2DM is linked to an increase in the fracture rate as compared to the nondiabetic population even with normal or raised bone mineral density (BMD). Hence, bone quality plays an important role in the pathogenesis of skeletal fragility due to T2DM. This study analyzed the changes in the trabecular bone microstructure due to T2DM at various time points in ovariectomized and nonovariectomized rats. Animals were divided into four groups: (I) control (sham), (II) diabetic (sham), (III) ovariectomized, and (IV) ovariectomized with diabetes. The trabecular microarchitecture of the femoral head was characterized using a micro-CT. The differences between the groups were analyzed at 8, 10, and 14 weeks of the onset of T2DM using a two-way analysis of variance and by post hoc multiple comparisons. The diabetic group with and without ovariectomies demonstrated a significant increase in trabecular separation and a decrease in bone volume fraction, trabecular number, and thickness. BMD decreased in ovariectomized diabetic animals at 14 weeks of the onset of T2DM. No significant change was found in connectivity density and degree of anisotropy among groups. The structural model index suggested a change towards a weaker rod-like microstructure in diabetic animals. The data obtained suggested that T2DM affects the trabecular structure within a rat's femoral heads negatively and changes are most significant at a longer duration of T2DM, increasing the risk to hip fractures.

Exploring the link between metabolic syndrome and risk of dysmobility syndrome in elderly population

Dysmobility syndrome (DMS) was considered as a comprehensive approach to evaluate the condition of musculoskeletal system and adverse health problems in older population. The objective of our study was to examine the association between metabolic syndrome (MetS) and DMS in a U.S. adult population. 1760 eligible participants from the National Health and Nutrition Examination Survey (NHANES) 1999-2002 were enrolled in the study. The criteria of DMS consisted of six domains including increased body fat, declined muscle mass, reduced muscle strength, osteoporosis, slow gait speed, and balance problem. A multivariate regression analysis was investigated to clarify the relationship among MetS and its components and DMS. A positive association between increased number of MetS components and the presence of DMS achieved significance (β = 0.142, 95%CI = 0.035, 0.249, p = 0.009). Among the components of MetS, hyperglycemia had a central place in the DMS after adjustment of clinical variables (β = 0.083, 95%CI = 0.030, 0.136, p = 0.002). Notably, insulin resistance assessed by homeostatic model assessment (HOMA-IR) was correlated to increased body fat (r = 0.092, p<0.05), osteoporosis (r = -0.105, p<0.05) and balance (r = 0.105, p<0.05) among these participants with MetS. Our study demonstrated a strong relationship between DMS and the presence of MetS and its components in elderly population, highlighting a possible mechanism through insulin resistance.

Characteristics of bone strength and metabolism in type 2 diabetic model Tsumura, Suzuki, Obese Diabetes mice

OBJECTIVE

Type 2 diabetes mellitus (T2DM) is a metabolic disease characterized by hyperglycemia, hyperinsulinemia, and complications such as obesity and osteoporosis. The Tsumura, Suzuki, Obese Diabetes (TSOD) mouse is an animal model of spontaneous obese T2DM. However, bone metabolism in TSOD mice is yet to be investigated. The objective of the present study was to investigate the effects of T2DM on bone mass, metabolism, microstructure, and strength in TSOD mice.

METHODS

We determined the following parameters in TSOD mice and Tsumura, Suzuki, Non-obesity (TSNO) mice (as controls): serum glucose levels; serum insulin levels; bone mass; bone microstructure; bone metabolic markers; and bone strength. We also performed the oral glucose tolerance test and examined histological sections of the femur. We compared these data between both groups at pre-diabetic (10 weeks) and established (20 weeks) diabetic conditions.

RESULTS

Bone strength, such as extrinsic mechanical properties, increased with age in the TSOD mice and intrinsic material properties decreased at both 10 weeks and 20 weeks. Bone resorption marker levels in TSOD mice were significantly higher than those in the control mice at both ages, but there was no significant difference in bone formation markers between the groups. Bone mass in TSOD mice was lower than that in controls at both ages. The trabecular bone volume at the femoral greater trochanter increased with age in the TSOD mice. The femoral mid-diaphysis in TSOD mice was more slender and thicker than that in TSNO mice at both ages.

CONCLUSIONS

Bone mass of the femur was lower in TSOD mice than in TSNO mice because hyperinsulinemia during pre-diabetic and established diabetic conditions enhanced bone resorption due to high bone turnover. In addition, our data suggest that the bone mass of the femur was significantly reduced as a result of chronic hyperglycemia during established diabetic conditions in TSOD mice. We suggest that bone strength in the femur deteriorated due to the reduction of bone mass and because the femoral mid-diaphysis was more slender in TSOD mice.

Metformin; an old antidiabetic drug with new potentials in bone disorders

The prevalence of diabetes mellitus especially type 2 diabetes mellitus is increasing all over the world. In addition to cardiomyopathy and nephropathy, diabetics are at higher risk of mortality and morbidity due to greater risk of bone fractures and skeletal abnormalities. Patients with diabetes mellitus have lower bone quality in comparison to their non-diabetic counterparts mainly because of hyperglycemia, toxic effects of advanced glycosylation end-products (AGEs) on bone tissue, and impaired bone microvascular system. AGEs may also contribute to the development of osteoarthritis further to osteoporosis. Therefore, glycemic control in diabetic patients is vital for bone health. Metformin, a widely used antidiabetic drug, has been shown to improve bone quality and decrease the risk of fractures in patients with diabetes in addition to glycemic control and improving insulin sensitivity. AMP activated protein kinase (AMPK), the key molecule in metformin antidiabetic mechanism of action, is also effective in signaling pathways involved in bone physiology. This review, discusses the molecules linking diabetes and bone turnover, role of AMPK in bone metabolism, and the effect of metformin as an activator of AMPK on bone disorders and malignancies.

Positive association between serum uric acid and bone mineral density in Chinese type 2 diabetes mellitus stratified by gender and BMI

Accumulating evidence has demonstrated that serum uric acid (UA), a natural powerful antioxidant, plays a beneficial role in bone health in the general population. However, few reports are available on the association between serum UA and bone in patients with type 2 diabetes mellitus (T2DM). We therefore investigated whether the benefit of serum UA for bone health was still present in those patients. 626 males and 609 postmenopausal females with T2DM were enrolled in this cross-sectional study. Serum UA concentrations and bone mineral density (BMD) measured at lumbar spine, femoral neck and total hip by dual-energy X-ray absorptiometry were obtained from all subjects. Meanwhile, data on osteoporosis prevalence, glucose metabolism, bone turnover markers and other serum biochemical indexes were collected. After adjustment for potential confounders, the results suggested that serum UA was positively associated with BMD in patients with normal weight, but this positive association varied by gender and skeletal sites in overweight T2DM patients [body mass index (BMI) ≥ 25 kg/m²]. Moreover, significantly lower odds ratios (ORs) for osteoporosis were found in postmenopausal patients with the highest UA tertile and male patients with medium UA tertile [adjusted OR 0.315, 95% confidence interval (CI) 0.170-0.581 for postmenopausal patients; adjusted OR 0.464, 95% CI 0.225-0.955 for male patients]. The positive association between serum UA and BMD found in Chinese T2DM patients may imply that relatively high UA is a protective factor for bone in these patients. Large intervention studies are needed to further confirm the outcomes and provide possible explanations.

The Prevalence of Osteopenia and Osteoporosis Among Malaysian Type 2 Diabetic Patients Using Quantitative Ultrasound Densitometer

Background:

Type 2 Diabetes Mellitus (T2DM) and osteoporosis are both chronic conditions and the relationship between them is complex.

Objective:

The aims of this study were to assess the prevalence of Low Bone Mineral density (LBMD, i.e., osteopenia and osteoporosis), as well as, the difference and associations between Quantitative Ultrasound Scan (QUS) parameters with socio-demographic data and clinical related data among T2DM in Penang, Malaysia.

Method:

An observational, cross-sectional study with a convenient sample of 450 T2DM patients were recruited from the outpatient diabetes clinic at Hospital Pulau Pinang (HPP) to measure Bone Mineral Density (BMD) at the heel bone using QUS. In addition, a self-reported structured questionnaire about the socio-demographic data and osteoporosis risk factors were collected. Moreover, the study included the retrospective collection of clinical data from patients’ medical records.

Results:

The mean value of T-score for normal BMD, osteopenic and osteoporotic patients’ were (-0.41±0.44), (-1.65±0.39) and (-2.76±0.27), respectively. According to QUS measurements, more than three quarters of T2DM patients (82%) were at high risk of abnormal BMD. The results showed that QUS scores were significantly associated with age, gender, menopausal duration, educational level and diabetic related data. Moreover, the QUS parameters and T-scores demonstrated significant negative correlation with age, menopausal duration, diabetic duration and glycaemic control, as well as, a positive correlation with body mass index and waist to hip ratio. The current study revealed that none of the cardiovascular disease risk factors appear to influence the prevalence of low BMD among T2DM Malaysian patients.

Conclusion:

The study findings revealed that the assessment of T2DM patients’ bone health and related factor are essential and future educational programs are crucial to improve osteoporosis management.

Irbesartan attenuates advanced glycation end products-mediated damage in diabetes-associated osteoporosis through the AGEs/RAGE pathway

AIMS

Diabetes-associated osteoporosis is mainly caused by the formation and accumulation of advanced glycation end products (AGEs). Angiotensin II type 1 receptor blocker (ARB) has anabolic bone effects on the physicochemical properties of the bone in diabetes. We hypothesized that ARB could inhibit AGEs-induced deleterious effects.

MAIN METHODS

In this study, we chose seven-week-old Leprdb/Lepr+ (db/+) and Leprdb/Leprdb (db/db) mice. After 12 week intervention by irbesartan, the microarchitecture and mechanical strength of the bone of seven-week-old db/db mice were investigated systematically. Meanwhile, the molecular mechanisms of the osteoblasts were analyzed, after AGEs or irbesartan were added to the culture. Also, intracellular formation of reactive oxygen species (ROS) was measured with DCF fluorescence.

KEY FOUNDINGS

Results showed that 12-week irbesartan treatment could dramatically improve trabecular bone microarchitecture through increasing BV/TV (p = 0.003, +46.7%), Tb.N (p = 0.020, +52.0%), and decreasing that of Tb.Sp (p = 0.005, -21.2%) and SMI (p = 0.007, -26.4%), comparing with the db/db group. Irbesartan could also substantially raise biomechanical parameters including max load (p = 0.013, +20.7%), fracture load (p = 0.014, +70.5%), energy absorption (p = 0.019, +99.4%). Besides, it could inhibit AGEs-induced damage of cell proliferation and osteogenic differentiation of osteoblasts, as well as suppressing the activation of apoptosis caused by AGEs. Moreover, co-incubation with irbesartan could prevent the AGEs-induced increase of intracellular oxidative stress and RAGE expression in osteoblasts.

SIGNIFICANCE

In conclusion, this study suggested that irbesartan might play a protective role in diabetes-related bone damages by blocking the deleterious effects of AGEs/RAGE-mediated oxidative stress. This may provide a revolutionary benefits to therapy with irbesartan on diabetic osteoporosis.

Does a Treadmill Running Exercise Contribute to Preventing Deterioration of Bone Mineral Density and Bone Quality of the Femur in KK-Ay Mice, a Type 2 Diabetic Animal Model?

Although it has been recently shown that type 2 diabetics have an increased risk of hip fracture, the effects of exercise therapy to prevent this have not been clarified. We examined whether a treadmill running exercise contributes to the bone mineral density (BMD) and bone microarchitecture of the femur and what kind of exercise intensity and duration are optimum in type 2 diabetes mellitus using KK-Ay diabetic mice. The mice were divided into two running groups, one fast speed and short duration (FS), the other slow speed and long duration (SL), and a group of controls with no running (CO). The running exercise was started when the mice were 8 weeks of age, and continued once a day 5 days per week for 10 weeks. Ten weeks after the start of the running exercise, the BMD of the proximal region and mid-diaphysis in the SL were significantly higher in comparison with that in the CO, whereas there was no difference in bone microarchitecture among the three groups. Blood glucose, insulin levels, and visceral fat contents in the SL were significantly lower than those in the CO and FS. Bone resorption protein and C-reactive protein levels in the SL were significantly lower than those in the CO. These results suggest that slow, long duration loading is better for both bone and glycemic control than fast, short duration loading in type 2 diabetes.

Thiazolidinedione drugs in the treatment of type 2 diabetes mellitus: past, present and future

Thiazolidinedione (TZD) drugs used in the treatment of type 2 diabetes mellitus (T2DM) have proven effective in improving insulin sensitivity, hyperglycemia, and lipid metabolism. Though well tolerated by some patients, their mechanism of action as ligands of peroxisome proliferator-activated receptors (PPARs) results in the activation of several pathways in addition to those responsible for glycemic control and lipid homeostasis. These pathways, which include those related to inflammation, bone formation, and cell proliferation, may lead to adverse health outcomes. As treatment with TZDs has been associated with adverse hepatic, cardiovascular, osteological, and carcinogenic events in some studies, the role of TZDs in the treatment of T2DM continues to be debated. At the same time, new therapeutic roles for TZDs are being investigated, with new forms and isoforms currently in the pre-clinical phase for use in the prevention and treatment of some cancers, inflammatory diseases, and other conditions. The aims of this review are to provide an overview of the mechanism(s) of action of TZDs, a review of their safety for use in the treatment of T2DM, and a perspective on their current and future therapeutic roles.

The association between insulin use and volumetric bone mineral density, bone micro-architecture and bone strength of the distal radius in patients with type 2 diabetes - The Maastricht study

Type 2 diabetes mellitus (T2DM) has been associated with an increased risk of fractures, despite normal to increased bone mineral density (BMD). Insulin use is one of the factors linked to this increased fracture risk. However, direct negative effects of insulin on bone quality are not expected since insulin is thought to be anabolic to bone. In this cross-sectional study the association between insulin use and volumetric BMD (vBMD), bone micro-architecture and bone strength of the distal radius, as measured with HR-pQCT, was examined. Data from 50 participants with T2DM of The Maastricht Study (mean age 62±7.5years, 44% women) was used. Participants were classified as insulin user (n=13) or non-insulin user (n=37) based on prescription data. Linear regression analysis was used to estimate the association between current insulin use and HR-pQCT derived parameters. After adjustment for age, sex, body mass index, glycated hemoglobin A1c and T2DM duration, insulin use was associated with lower total vBMD (standardized beta (β):-0.56 (95% CI:-0.89 to -0.24)), trabecular vBMD (β:-0.58 (95% CI:-0.87 to -0.30)), trabecular thickness (β:-0.55 (95% CI:-0.87 to -0.23)), cortical thickness (β:-0.41 (95% CI:-0.74 to -0.08)), log cortical pore volume (β:-0.43 (95% CI:-0.73 to -0.13)), bone stiffness (β:-0.39 (95% CI:-0.62 to -0.17)) and failure load (β:-0.39 (95% CI:-0.60 to -0.17)) when compared to the non-insulin users. Insulin use was not associated with cortical vBMD, trabecular number, trabecular separation, cortical porosity and cortical pore diameter. This study indicates that insulin use is negatively associated with bone density, bone micro-architectural and bone strength parameters. These findings may partly explain the previously observed increased fracture risk in insulin users, although there may be residual confounding by other factors related to disease severity in insulin users.

Type 2 diabetes and risk of low-energy fractures in postmenopausal women: meta-analysis of observational studies

Background

Observational studies on osteoporotic fractures in patients with type 2 diabetes indicate their increased incidence compared to those without diabetes, but results are inconsistent. Currently, type 2 diabetes is not considered as an independent risk factor for low-energy fractures in elder subjects. The aim of the study was to assess the association between type 2 diabetes and risk for hip and vertebral fractures in postmenopausal women.

Materials and methods

We searched Medline, Web of Science and Cochrane databases for articles published before September 2013. Studies assessing fractures in women aged >50 diagnosed with type 2 diabetes, regardless of the diabetes treatment, were deemed eligible. To estimate fracture risk meta-analysis in a random effect model was performed. The results were shown by the odds ratio (OR) and 95 % confidence interval (CI). Heterogeneity was tested using a Q-Cochrane test (significance was analyzed with p < 0.10) and I² measure.

Results

A total of 15 observational studies (11 cohort and 4 cross-sectional, 263.006 diabetics and 502.115 controls) were included. Thirteen papers provided information on the incidence of hip fractures, and seven on vertebral ones. The meta-analysis revealed type 2 diabetes was associated with higher risk for hip fracture (OR 1.296, 95 % CI (1.069–1.571), but not vertebral fracture (OR = 1.134, 95 % CI (0.936–1.374). There was significant heterogeneity between hip fracture studies. American origin was identified as a potential source of such heterogeneity.

Conclusions

The results of our meta-analysis indicate there is an increased risk for hip fracture in postmenopausal women with type 2 diabetes.

MECHANISMS IN ENDOCRINOLOGY: Diabetes mellitus, a state of low bone turnover - a systematic review and meta-analysis

OBJECTIVE

To investigate the differences in bone turnover between diabetic patients and controls.

DESIGN

A systematic review and meta-analysis.

METHODS

A literature search was conducted using the databases Medline at PubMed and EMBASE. The free text search terms 'diabetes mellitus' and 'bone turnover', 'sclerostin', 'RANKL', 'osteoprotegerin', 'tartrate-resistant acid' and 'TRAP' were used. Studies were eligible if they investigated bone turnover markers in patients with diabetes compared with controls. Data were extracted by two reviewers.

RESULTS

A total of 2881 papers were identified of which 66 studies were included. Serum levels of the bone resorption marker C-terminal cross-linked telopeptide (-0.10 ng/mL (-0.12, -0.08)) and the bone formation markers osteocalcin (-2.51 ng/mL (-3.01, -2.01)) and procollagen type 1 amino terminal propeptide (-10.80 ng/mL (-12.83, -8.77)) were all lower in patients with diabetes compared with controls. Furthermore, s-tartrate-resistant acid phosphatase was decreased in patients with type 2 diabetes (-0.31 U/L (-0.56, -0.05)) compared with controls. S-sclerostin was significantly higher in patients with type 2 diabetes (14.92 pmol/L (3.12, 26.72)) and patients with type 1 diabetes (3.24 pmol/L (1.52, 4.96)) compared with controls. Also, s-osteoprotegerin was increased among patients with diabetes compared with controls (2.67 pmol/L (0.21, 5.14)).

CONCLUSIONS

Markers of both bone formation and bone resorption are decreased in patients with diabetes. This suggests that diabetes mellitus is a state of low bone turnover, which in turn may lead to more fragile bone. Altered levels of sclerostin and osteoprotegerin may be responsible for this.

The impact of SGLT2 inhibitors, compared with insulin, on diabetic bone disease in a mouse model of type 1 diabetes

Skeletal co-morbidities in type 1 diabetes include an increased risk for fracture and delayed fracture healing, which are intertwined with disease duration and the presence of other diabetic complications. As such, chronic hyperglycemia is undoubtedly a major contributor to these outcomes, despite standard insulin-replacement therapy. Therefore, using the streptozotocin (STZ)-induced model of hypoinsulinemic hyperglycemia in DBA/2J male mice, we compared the effects of two glucose lowering therapies on the fracture resistance of bone and markers of bone turnover. Twelve week-old diabetic (DM) mice were treated for 9weeks with: 1) oral canagliflozin (CANA, dose range ~10-16mg/kg/day), an inhibitor of the renal sodium-dependent glucose co-transporter type 2 (SGLT2); 2) subcutaneous insulin, via minipump (INS, 0.125units/day); 3) co-therapy (CANA+INS); or 4) no treatment (STZ, without therapy). These groups were also compared to non-diabetic control groups. Untreated diabetic mice experienced increased bone resorption and significant deficits in cortical and trabecular bone that contributed to structural weakness of the femur mid-shaft and the lumbar vertebra, as determined by three-point bending and compression tests, respectively. Treatment with either canagliflozin or insulin alone only partially rectified hyperglycemia and the diabetic bone phenotype. However, when used in combination, normalization of glycemic control was achieved, and a prevention of the DM-related deterioration in bone microarchitecture and bone strength occurred, due to additive effects of canagliflozin and insulin. Nevertheless, CANA-treated mice, whether diabetic or non-diabetic, demonstrated an increase in urinary calcium loss; FGF23 was also increased in CANA-treated DM mice. These findings could herald ongoing bone mineral losses following CANA exposure, suggesting that certain CANA-induced skeletal consequences might detract from therapeutic improvements in glycemic control, as they relate to diabetic bone disease.

Evaluation of bone mineral density among type 2 diabetes mellitus patients in South Karnataka

Background:

Diabetes is one of the world's biggest health problems and the disease affects almost all organ systems. The relationship between type 2 diabetes mellitus (T2DM) and bone mineral density (BMD) has been controversial. Early identification of reduction in bone mass in a diabetic patient may be helpful in preventing the bone loss and future fracture risks.

Objective:

The aim is to study the effect of T2DM on BMD among patients in South Karnataka.

Materials and Methods:

A cross-sectional study was conducted on 150 patients between 40 and 70 years of age which included 75 diabetic and 75 nondiabetic subjects. BMD was measured using qualitative ultrasound and the data were compared among age-matched subjects of both the groups. Statistical analysis was performed using unpaired Student's t-test and test of equality of proportions.

Results:

No significant difference was observed in bone density of both the groups. On further analyzing the data, incidence of osteoporosis was higher among diabetic subjects, whereas incidence of osteopenia was higher among nondiabetic subjects.

Conclusion:

Although significant difference in bone mineral density was not observed in both the groups, the incidence of osteoporosis was higher among type 2 diabetics. Hence, all type 2 diabetics should be evaluated for the risk of osteoporosis and should be offered appropriate preventive measures.

Type 2 diabetes and the skeleton: new insights into sweet bones

Substantial evidence shows that skeletal fragility should be considered among the complications associated with type 2 diabetes. Individuals with type 2 diabetes have increased fracture risk, despite normal bone mineral density (BMD) and high BMI-factors that are generally protective against fractures. The mechanisms underlying skeletal fragility in diabetes are not completely understood, but are multifactorial and likely include effects of obesity, hyperglycaemia, oxidative stress, and accumulation of advanced glycation end products, leading to altered bone metabolism, structure, and strength. Clinicians should be aware that BMD measurements underestimate fracture risk in people with type 2 diabetes, and that new treatments for diabetes, with neutral or positive effects on skeletal health, might play a part in the management of diabetes in those at high risk of fracture. Data for the optimum management of osteoporosis in patients with type 2 diabetes are scarce, but in the absence of evidence to the contrary, physicians should follow guidelines established for postmenopausal osteoporosis.

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

OBJECTIVE AND DESIGN

Patients with type 2 diabetes mellitus (T2D) have an increased fracture risk despite a normal or elevated bone mineral density (BMD). The aim of this cross-sectional in vivo study was to assess parameters of peripheral bone microarchitecture, estimated bone strength and bone remodeling in T2D patients with and without diabetic microvascular disease (MVD+ and MVD- respectively) and to compare them with healthy controls.

METHODS

Fifty-one T2D patients (MVD+ group: n=25) were recruited from Funen Diabetic Database and matched for age, sex and height with 51 healthy subjects. High-resolution peripheral quantitative tomography (HR-pQCT) was used to assess bone structure at the non-dominant distal radius and tibia. Estimated bone strength was calculated using finite element analysis. Biochemical markers of bone turnover were measured in all participants.

RESULTS

After adjusting for BMI, MVD+ patients displayed lower cortical volumetric BMD (P=0.02) and cortical thickness (P=0.02) and higher cortical porosity at the radius (P=0.02) and a trend towards higher cortical porosity at the tibia (P=0.07) compared to controls. HR-pQCT parameters did not differ between MVD- and control subjects. Biochemical markers of bone turnover were significantly lower in MVD+ and MVD- patients compared to controls (all P<0.01). These were no significant correlations between disease duration, glycemic control (average glycated hemoglobin over the previous 3 years) and HR-pQCT parameters.

CONCLUSION

Cortical bone deficits are not a characteristic of all T2D patients but of a subgroup characterized by the presence of microvascular complications. Whether this influences fracture rates in these patients needs further investigation.

Effect of exenatide, insulin and pioglitazone on bone metabolism in patients with newly diagnosed type 2 diabetes

AIM

Preclinical studies suggested that insulin, incretin and thiazolidinediones had effect on regulation of bone metabolism. But clinical evidence is limited. We assessed the effects of these antihyperglycemic agents on bone metabolism in patients with newly diagnosed type 2 diabetes.

METHODS

The present study was a two-center, randomized, parallel-group clinical trial. Sixty-two newly diagnosed and drug-naïve patients with type 2 diabetes were randomized to exenatide (EXE, n = 20), mixed protamine zinc recombinant human insulin lispro injection (25R; INS, n = 21) or pioglitazone (PIO, n = 21) group for a 24-week treatment. Glycosylated hemoglobin A1c (HbA1c), body weight, body mineral density (BMD) and fasting serum concentration of bone turnover markers including osteocalcin (OC), C-telopeptide of type I collagen (CTX) and tartrate-resistant alkaline phosphatase 5b (TRAcP5b) were assessed at baseline and week 24.

RESULTS

Baseline characteristics were similar among groups. At week 24, HbA1c improved in all patients (EXE:-2.4 ± 0.3 %, INS:-2.4 ± 0.3 %, PIO:-2.0 ± 0.2 %; p > 0.05 among groups). Patients treated with exenatide lost body weight remarkably (-4.7 ± 0.8 kg). In spite of the amelioration of glucose control, no significant improvement of OC, CTX or TRAcP5b was observed at week 24 (EXE: OC -0.619 ± 0.728 ng/ml, CTX 0.147 ± 0.046 ng/ml, TRAcP5b 0.302 ± 0.149 U/L;INS: OC 0.637 ± 0.787 ng/ml, CTX -0.012 ± 0.074 ng/ml, TRAcP5b 0.124 ± 0.395 U/L; PIO: OC -0.150 ± 0.691 ng/ml, CTX 0.073 ± 0.094 ng/ml, TRAcP5b 0.586 ± 0.183 U/L; p > 0.05), as well as BMD measurement, regardless of the treatments.

CONCLUSIONS

Twenty-four-week treatment with exenatide, insulin and pioglitazone improved glucose control in patients with newly diagnosed type 2 diabetes, but had no impact on bone turnover markers or BMD.

Type 2 diabetes mellitus and fracture risk

Increased fracture risk, traditionally associated with type 1 diabetes, has lately been of great concern in patients with type 2 diabetes. A variable increase in fracture risk has been reported, ranging from 20% to 3-fold, depending on skeletal site, diabetes duration and study design. Longer disease duration, the presence of diabetic complications, inadequate glycemic control, insulin use and increased risk for falls are all reported to increase fracture risk. Patients with type 2 diabetes display a unique skeletal phenotype with either normal or more frequently increased, bone mineral density and impaired structural and geometric properties. Recently, alterations in bone material properties seem to be the predominant defect leading to increased bone fragility. Accumulation of advanced glycation end-products and changes in collagen cross-linking along with suppression of bone turnover seem to be significant factors impairing bone strength. FRAX score has been reported to underestimate fracture risk and lumbar spine BMD is inadequate in predicting vertebral fractures. Anti-diabetic medications, apart from thiazolidinediones, appear to be safe for the skeleton, although more data are needed. Optimal strategies to reduce skeletal fragility in type 2 diabetic patients are yet to be determined.

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.

Osteoporosis, fractures, and diabetes

It is well established that osteoporosis and diabetes are prevalent diseases with significant associated morbidity and mortality. Patients with diabetes mellitus have an increased risk of bone fractures. In type 1 diabetes, the risk is increased by ∼6 times and is due to low bone mass. Despite increased bone mineral density (BMD), in patients with type 2 diabetes the risk is increased (which is about twice the risk in the general population) due to the inferior quality of bone. Bone fragility in type 2 diabetes, which is not reflected by bone mineral density, depends on bone quality deterioration rather than bone mass reduction. Thus, surrogate markers and examination methods are needed to replace the insensitivity of BMD in assessing fracture risks of T2DM patients. One of these methods can be trabecular bone score. The aim of the paper is to present the present state of scientific knowledge about the osteoporosis risk in diabetic patient. The review also discusses the possibility of problematic using the study conclusions in real clinical practice.

The Effects of an Educational Self-Efficacy Intervention on Osteoporosis Prevention and Diabetes Self-Management Among Adults With Type 2 Diabetes Mellitus

Background:

Prevalence of osteoporosis (OP) is high among Chinese adults with diabetes. Assessment of OP and fracture risk as well as patient education should be included as part of the management of diabetes.

Purpose:

The purpose of this pilot study was to test the effectiveness of an educational self-efficacy intervention on knowledge about OP, dietary calcium intake, the importance of physical activity (PA), and glycemic control among Chinese adults with type 2 diabetes residing in Wuhan, China.

Method:

A quasi-experimental design with repeated measures was employed. Participants were assigned to either the intervention ( n = 23) or the control group ( n = 23). Intervention participants attended 6 weekly 1-hr educational sessions comprising presentations, demonstration, and discussions. Control participants received standard care. Data were collected via questionnaires at pre- and postintervention and at 3-month follow-up, and blood was drawn at preintervention and 3-month follow-up.

Results:

Participants in the intervention group had significant improvement in OP knowledge, F(2, 43) = 11.504, p < .001; OP self-efficacy, F(2, 43) = 6.915, p = .003; dietary calcium intake, F(2, 43) = 7.856, p = .002; level of PA, F(2, 43) = 4.787, p = .011; diabetes self-care activities, F(2, 43) = 14.009, p < .001; diabetes self-efficacy, F(2, 43) = 19.722, p < .001; and glycemic control (A1C level; t = 2.809, p = .010) compared to the control group at the 3-month follow-up.

Conclusion:

The results demonstrate the effectiveness of OP prevention education based on self-efficacy theory among Chinese adults with type 2 diabetes.

The alliance of mesenchymal stem cells, bone, and diabetes

Bone fragility has emerged as a new complication of diabetes. Several mechanisms in diabetes may influence bone homeostasis by impairing the action between osteoblasts, osteoclasts, and osteocytes and/or changing the structural properties of the bone tissue. Some of these mechanisms can potentially alter the fate of mesenchymal stem cells, the initial precursor of the osteoblast. In this review, we describe the main factors that impair bone health in diabetic patients and their clinical impact.

Intensive glycemic control and thiazolidinedione use: effects on cortical and trabecular bone at the radius and tibia

Factors that contribute to bone fragility in type 2 diabetes are not well understood. We assessed the effects of intensive glycemic control, thiazolidinediones (TZDs), and A1C levels on bone geometry and strength at the radius and tibia. In a substudy of the Action to Control Cardiovascular Risk in Diabetes trial, peripheral quantitative computed tomographic (pQCT) scans of the radius and tibia were obtained 2 years after randomization on 73 participants (intensive n = 35, standard n = 38). TZD use and A1C levels were measured every 4 months during the trial. Effects of intervention assignment, TZD use, and A1C on pQCT parameters were assessed in linear regression models. Intensive, compared with standard, glycemic control was associated with 1.3 % lower cortical volumetric BMD at the tibia in men (p = 0.02) but not with other pQCT parameters. In women, but not men, each additional year of TZD use was associated with an 11 % lower polar strength strain index (SSIp) at the radius (p = 0.04) and tibia (p = 0.002) in models adjusted for A1C levels. In women, each additional 1 % increase in A1C was associated with an 18 % lower SSIp at the ultradistal radius (p = 0.04) in models adjusted for TZD use. There was no consistent evidence of an effect of intensive, compared with standard, glycemic control on bone strength at the radius or tibia. In women, TZD use may reduce bone strength at these sites. Higher A1C may also be associated with lower bone strength at the radius, but not tibia, in women.

Rosiglitazone decreases bone mineral density and increases bone turnover in postmenopausal women with type 2 diabetes mellitus

CONTEXT

Postmenopausal status and type 2 diabetes mellitus (T2DM) are independent risk factors for fractures. An increased fracture risk has been observed with rosiglitazone (RSG), a thiazolidinedione, in patients with T2DM.

DESIGN AND SETTING

This was a randomized, double-blind study in postmenopausal women with T2DM. A 52-week double-blind phase (RSG or metformin [MET]) was followed by a 24-week open-label phase, during which time all patients received MET.

MAIN OUTCOME MEASURES

The primary endpoint was to assess the mean percentage change in bone mineral density (BMD) at the femoral neck (FN) by dual-energy x-ray absorptiometry from baseline to week 52 in the RSG treatment group. Key secondary objectives included assessment of changes in BMD at the total hip, trochanter, and lumbar spine and to evaluate RSG effects on bone turnover markers.

RESULTS

From baseline to week 52, RSG was associated with a reduction in FN BMD by dual-energy x-ray absorptiometry (-1.47%). During the open-label phase (weeks 52-76), no further loss in FN BMD was observed. A decrease in BMD occurred at the total hip during RSG or MET treatment at 52 weeks (-1.62 and -0.72%, respectively). Total hip BMD loss by RSG was attenuated after switching to MET and was similar between treatment groups at the end of the open-label phase. From baseline to week 52, bone turnover markers significantly increased with RSG compared with MET, but decreased significantly during the open-label phase.

CONCLUSIONS

RSG for 52 weeks in postmenopausal women with T2DM was associated with small reductions in FN, total hip, and lumbar spine BMD and increased bone turnover markers. These effects are attenuated after cessation of RSG treatment.

Prevalence of Osteoporosis and Its Associated Factors among Older Men with Type 2 Diabetes

This study investigated the prevalence of osteoporosis and its associated factors in old men with T2DM to identify risk factors for low BMD. We enrolled 93 old men (≥60 years of age) with T2DM and 125 healthy old men (controls) and collected data of their lifestyle, medical history, bone densitometry, body weight, height, and blood pressure. Blood samples were collected for biochemical analyses. Urine samples were collected to determine 24 h urinary creatinine, albumin, and protein. Although no differences in age, blood pressure, waist-to-hip ratio, body mass index (BMI), and testosterone levels were observed, the prevalence of low BMD was significantly higher in the T2DM group compared to the control group. The risk of developing low BMD and fracture in T2DM subjects was increased by 46- and 26-fold, respectively, compared to control subjects. BMD of total spine and hip was positively correlated with BMI and negatively correlated with age, duration of diabetes, creatinine, and 24 h urinary albumin. So old men with T2DM have a greater risk of developing low BMD than old men without T2DM.

Diabetes, biochemical markers of bone turnover, diabetes control, and bone

Diabetes mellitus is known to have late complications including micro vascular and macro vascular disease. This review focuses on another possible area of complication regarding diabetes; bone. Diabetes may affect bone via bone structure, bone density, and biochemical markers of bone turnover. The aim of the present review is to examine in vivo from humans on biochemical markers of bone turnover in diabetics compared to non-diabetics. Furthermore, the effect of glycemic control on bone markers and the similarities and differences of type 1- and type 2-diabetics regarding bone markers will be evaluated. A systematic literature search was conducted using PubMed, Embase, Cinahl, and SveMed+ with the search terms: "Diabetes mellitus," "Diabetes mellitus type 1," "Insulin dependent diabetes mellitus," "Diabetes mellitus type 2," "Non-insulin dependent diabetes mellitus," "Bone," "Bone and Bones," "Bone diseases," "Bone turnover," "Hemoglobin A Glycosylated," and "HbA1C." After removing duplicates from this search 1,188 records were screened by title and abstract and 75 records were assessed by full text for inclusion in the review. In the end 43 records were chosen. Bone formation and resorption markers are investigated as well as bone regulating systems. T1D is found to have lower osteocalcin and CTX, while osteocalcin and tartrate-resistant acid are found to be lower in T2D, and sclerostin is increased and collagen turnover markers altered. Other bone turnover markers do not seem to be altered in T1D or T2D. A major problem is the lack of histomorphometric studies in humans linking changes in turnover markers to actual changes in bone turnover and further research is needed to strengthen this link.

Impact of common variation in bone-related genes on type 2 diabetes and related traits

Exploring genetic pleiotropy can provide clues to a mechanism underlying the observed epidemiological association between type 2 diabetes and heightened fracture risk. We examined genetic variants associated with bone mineral density (BMD) for association with type 2 diabetes and glycemic traits in large well-phenotyped and -genotyped consortia. We undertook follow-up analysis in ∼19,000 individuals and assessed gene expression. We queried single nucleotide polymorphisms (SNPs) associated with BMD at levels of genome-wide significance, variants in linkage disequilibrium (r(2) > 0.5), and BMD candidate genes. SNP rs6867040, at the ITGA1 locus, was associated with a 0.0166 mmol/L (0.004) increase in fasting glucose per C allele in the combined analysis. Genetic variants in the ITGA1 locus were associated with its expression in the liver but not in adipose tissue. ITGA1 variants appeared among the top loci associated with type 2 diabetes, fasting insulin, β-cell function by homeostasis model assessment, and 2-h post-oral glucose tolerance test glucose and insulin levels. ITGA1 has demonstrated genetic pleiotropy in prior studies, and its suggested role in liver fibrosis, insulin secretion, and bone healing lends credence to its contribution to both osteoporosis and type 2 diabetes. These findings further underscore the link between skeletal and glucose metabolism and highlight a locus to direct future investigations.

Intensive glycemic control is not associated with fractures or falls in the ACCORD randomized trial

OBJECTIVE

Older adults with type 2 diabetes are at high risk of fractures and falls, but the effect of glycemic control on these outcomes is unknown. To determine the effect of intensive versus standard glycemic control, we assessed fractures and falls as outcomes in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) randomized trial.

RESEARCH DESIGN AND METHODS

ACCORD participants were randomized to intensive or standard glycemia strategies, with an achieved median A1C of 6.4 and 7.5%, respectively. In the ACCORD BONE ancillary study, fractures were assessed at 54 of the 77 ACCORD clinical sites that included 7,287 of the 10,251 ACCORD participants. At annual visits, 6,782 participants were asked about falls in the previous year.

RESULTS

During an average follow-up of 3.8 (SD 1.3) years, 198 of 3,655 participants in the intensive glycemia and 189 of 3,632 participants in the standard glycemia group experienced at least one nonspine fracture. The average rate of first nonspine fracture was 13.9 and 13.3 per 1,000 person-years in the intensive and standard groups, respectively (hazard ratio 1.04 [95% CI 0.86-1.27]). During an average follow-up of 2.0 years, 1,122 of 3,364 intensive- and 1,133 of 3,418 standard-therapy participants reported at least one fall. The average rate of falls was 60.8 and 55.3 per 100 person-years in the intensive and standard glycemia groups, respectively (1.10 [0.84-1.43]).

CONCLUSIONS

Compared with standard glycemia, intensive glycemia did not increase or decrease fracture or fall risk in ACCORD.

Effect of 1 year of an intentional weight loss intervention on bone mineral density in type 2 diabetes: results from the Look AHEAD randomized trial

Intentional weight loss is an important component of treatment for overweight patients with type 2 diabetes, but the effects on bone density are not known. We used data from the Look AHEAD trial to determine the impact of an intensive lifestyle weight loss intervention (ILI) compared with diabetes support and education (DSE) on changes in bone mineral density (BMD) over 12 months. Overweight and obese adults with type 2 diabetes were randomly assigned to ILI or DSE. In a substudy of BMD conducted at 5 of 16 clinical centers, hip, spine, and whole body dual X-ray absorptiometry scans were obtained at baseline and 1-year later on 642 of 739 ILI and 632 of 740 DSE participants. At baseline, mean age was 58.4 years, and average body mass index was 35.2 kg/m(2). Total hip BMD T-score was <-2.5 in 1% and <-1.0 in 8%. At 1 year, weight loss was greater in ILI than DSE (-8.6% versus -0.7%), and glycemic control and fitness were also improved. Bone loss over 1 year was greater in ILI at the total hip (-1.4% versus -0.4%; p < 0.001) and femoral neck (-1.5% versus -0.8%; p = 0.009), but change in BMD for the lumbar spine and whole body did not differ between groups. In ILI, bone loss at the total hip was independently associated with weight loss in men and women and with poorer glycemic control in men, but was not associated with changes in fitness. One year of an intensive lifestyle intervention in adults with type 2 diabetes, resulting in weight loss, was associated with a modest increase in hip bone loss despite improved fitness and glycemic control.

Total and undercarboxylated osteocalcin predict changes in insulin sensitivity and β cell function in elderly men at high cardiovascular risk

BACKGROUND

Osteocalcin has been related to insulin secretion in experimental models. Few prospective studies have evaluated the association between circulating osteocalcin concentrations and insulin secretion and sensitivity in humans.

OBJECTIVE

The objective was to examine cross-sectional and longitudinal associations between circulating forms of osteocalcin and insulin secretion and sensitivity in elderly men at high cardiovascular risk.

DESIGN

We examined cross-sectional and longitudinal associations between serum measurements of total osteocalcin and undercarboxylated osteocalcin (ucOC) with fasting glucose, fasting insulin, HOMA-IR, and HOMA β cell function (HOMA-BCF) in 79 elderly men. We also examined the association between 2-y changes in osteocalcin and changes in fasting glucose, insulin, HOMA-IR, and HOMA-BCF.

RESULTS

In an adjusted multivariable linear regression analysis, increases in serum osteocalcin were significantly associated with an increase in HOMA-BCF (β coefficient: 2.87; 95% CI: 0.23, 5.52; P = 0.033), and changes in ucOC were linked to a decrease in HOMA-IR (β coefficient: -0.31; 95% CI: -0.60, 0.03; P = 0.032). Moreover, in subjects not taking oral antidiabetic drugs, baseline osteocalcin concentrations were positively associated with higher fasting insulin concentrations and HOMA-BCF even after adjustment for BMI, physical activity, intervention group, presence of type 2 diabetes mellitus, and baseline values of each dependent variable.

CONCLUSIONS

Changes in serum osteocalcin and ucOC are associated with an improvement in insulin secretion and sensitivity, which suggests a possible role of bone in the development of type 2 diabetes. This trial is registered at clinicaltrials.gov as ISRCTN35739639.

Osteoporosis and type 2 diabetes mellitus: what do we know, and what we can do?

Diabetes mellitus (DM) is a pandemic and chronic metabolic disorder with substantial morbidity and mortality. In addition, osteoporosis (OP) is a silent disease with a harmful impact on morbidity and mortality. Therefore, this systematic review focuses on the relationship between OP and type 2 diabetes mellitus (T2DM). Systematic reviews of full-length articles published in English from January 1950 to October 2010 were identified in PubMed and other available electronic databases on the Universiti Sains Malaysia Library Database. The following keywords were used for the search: T2DM, OP, bone mass, skeletal. Studies of more than 50 patients with T2DM were included. Forty-seven studies were identified. The majority of articles (26) showed increased bone mineral density (BMD), while 13 articles revealed decreased BMD; moreover, eight articles revealed normal or no difference in bone mass. There were conflicting results concerning the influence of T2DM on BMD in association with gender, glycemic control, and body mass index. However, patients with T2DM display an increased fracture risk despite a higher BMD, which is mainly attributable to the increased risk of falling. As a conclusion, screening, identification, and prevention of potential risk factors for OP in T2DM patients are crucial and important in terms of preserving a good quality of life in diabetic patients and decreasing the risk of fracture. Patients with T2DM may additionally benefit from early visual assessment, regular exercise to improve muscle strength and balance, and specific measures for preventing falls. Patient education about an adequate calcium and vitamin D intake and regular exercise is important for improving muscle strength and balance. Furthermore, adequate glycemic control and the prevention of diabetic complications are the starting point of therapy in diabetic patients.