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

Changes in Testing and Treatment Methods in Osteoporosis Care

Osteoporosis treatment plays a crucial role in preventing fractures, particularly in bedridden patients. We conducted a questionnaire survey presenting hypothetical clinical cases in 2015 and 2020 to investigate trends over a 5-year period. The target population included physicians working in clinics and hospitals within our neighbourhood. The cases were presented, and the questionnaire was administered in a confidential format. The orthopaedic surgeons were matched for age and practice, resulting in 74 cases being included in the analysis. Comparing the 2015 and 2020 results, we observed a notable increase in physicians who would perform "bone mineral density measurements of the lumbar spine and hip." Furthermore, there was a significant rise in the percentage of respondents willing to test for bone metabolic markers, such as serum type I collagen cross-linked N-telopeptide (NTX), procollagen I N-terminal propeptide (P1NP), and tartrate-resistant acid phosphatase 5b (TRACP-5b). Regarding therapeutic agents, bisphosphonates decreased in usage, whereas parathyroid hormone and romosozumab witnessed an increase. In conclusion, the percentage of physicians requesting bone mineral density measurements of the lumbar spine and hip increased over the five-year period. In addition, more physicians chose to utilise bone metabolic markers due to their ease of measurement through blood tests and reduced diurnal variation. Finally, there was a marked trend towards the administration of drugs capable of rapidly and effectively increasing bone mineral density at an early stage of treatment.

Characteristics of bone metabolism in the male patients with diabetic neuropathy

BACKGROUND

This study aimed to evaluate the characteristics of bone metabolism and fracture risk in the type 2 diabetes mellitus (T2DM) patients with distal symmetric polyneuropathy (DSPN).

METHODS

A total of 198 T2DM individuals were recruited from January 2017 to December 2020. Patients with DSPN were evaluated by strict clinical and sensory thresholds. Biochemical parameters and bone mineral density (BMD) were measured. The BMD, bone turnover markers, and probability of fracture were compared between two groups, and the factors related to BMD and probability of hip fracture in 10 years were further explored.

RESULTS

Compared with type 2 diabetes mellitus without distal symmetric polyneuropathy (T2DN-) patients, type 2 diabetes mellitus with distal symmetric polyneuropathy (T2DN+) patients had lower level of cross-linked C-telopeptide (CTX) (0.32 ± 0.19 vs 0.38 ± 0.21 ng/mL, p = 0.038) and higher level of bone-specific alkaline phosphatase (BALP) (15.28 ± 5.56 vs 12.58 ± 4.41 μg/mL, p = 0.003). T2DN+ patients had higher BMD of lumbar L1-L4 (1.05 ± 0.19 vs 0.95 ± 0.37, p = 0.027) and higher probability of hip fracture (0.98 ± 0.88 vs 0.68 ± 0.63, p = 0.009) as compared to T2DN- individuals. Univariate correlation analysis showed that BALP level (coefficient (coef) = -0.054, p = 0.038), CTX level (coef = -2.28, p = 0.001), and hip fracture risk (coef = -1.02, p < 0.001) were negatively related to the BMD of L1-L4. As for the risk of hip fracture evaluated by WHO Fracture Risk Assessment Tool (FRAX), age (coef = 0.035, p < 0.001), use of insulin (coef = 0.31, p =0.015), and levels of BALP (coef = 0.031, p = 0.017) and CTX (coef = 0.7, p = 0.047) were positively related to the risk of hip fracture. Multivariate regression analysis showed that CTX level (coef = -1.41, p = 0.043) was still negatively related to BMD at the lumbar spine.

CONCLUSION

This study indicates that T2DM patients with DSPN have special bone metabolism represented by higher BALP level and lower CTX level which may increase BMD at the lumbar spine.

The impact of diabetes, anemia, and renal function in the relationship between osteoporosis and fasting blood glucose among Taiwanese women: a cross-sectional study

BACKGROUND

The aim of this study was to investigate the association between fasting blood glucose and osteoporosis in women with diabetes, anemia, and renal function.

METHODS

The medical records of women who underwent a general health examination at a regional hospital in southern Taiwan were retrospectively reviewed. Logistic regression analysis was performed to assess the association between osteoporosis and fasting blood glucose separately for the eight subgroups (diabetes or non-diabetes, anemia or non-anemia, normal or decreased renal function), adjusting for other clinical characteristics and laboratory findings.

RESULTS

A total of 11,872 women were included in the study. Among women with diabetes, anemia, and decreased renal function, an increment of 10 mg/dL in fasting blood glucose was associated with an increased risk of osteoporosis (adjusted odds ratio [aOR] = 1.57, p = 0.004). Among women without diabetes, fasting blood glucose was significantly associated with an increased risk of osteoporosis in those with anemia and normal renal function (OR = 1.14, p = 0.023) and those without anemia and normal renal function (OR = 1.04, p = 0.015), but these associations were not significant after adjusting for other covariates.

CONCLUSIONS

Higher fasting blood glucose levels in women with diabetes, anemia, and decreased renal function were associated with an increased risk of osteoporosis. Clinicians should be vigilant about glucose control in patients with diabetes to reduce the risk of fracture.

Risk Factors for Fractures in Renal Transplantation: A Population-Based Cohort Study

INTRODUCTION

Kidney transplant recipients are at an increased risk of fractures, and targeted preventive strategies are needed. Therefore, in this retrospective cohort study, we investigated a large population-based cohort to identify the transplant recipient-specific risk factors for fractures in Taiwanese kidney transplant recipients.

METHODS

We conducted a retrospective cohort study using the National Health Insurance Research Database. Patients who underwent renal transplantation between 2003 and 2015 were identified and followed until December 31, 2015, to observe the development of fractures. Variables associated with the development of post-transplant fractures were identified by calculating hazard ratios in a Cox regression model.

RESULTS

5,309 renal transplant recipients were identified, of whom 553 (10.4%) were diagnosed with post-transplant fractures. Independent predictors of post-transplant fractures included an age at transplant ≥65 years (p < 0.001), female sex (p < 0.001), fractures within 3 years prior to transplantation (p < 0.001), and diabetes mellitus (p < 0.001). In addition, daily prednisolone doses >2.9–5.3 mg/day (p < 0.001), >5.3–8.7 mg/day (p < 0.001), and >8.7 mg/day (p < 0.001) were also independent predictors of post-transplant fractures. Conversely, the use of peritoneal dialysis before renal transplantation (p = 0.021), hypertension (p = 0.005), and the use of tacrolimus (p < 0.001), azathioprine (p = 0.006), mycophenolate mofetil/mycophenolic acid (p = 0.002), mTOR inhibitors (p = 0.004), and calcium supplements (p = 0.009) were inversely correlated with post-transplant fractures.

CONCLUSION

We recommend minimizing daily glucocorticoids as early and as far as possible in conjunction with immunosuppressive regimens such as tacrolimus, azathioprine, mycophenolate mofetil/mycophenolic acid, mTOR inhibitors, and calcium supplements, especially in older female recipients and in recipients with diabetes and a history of prior fractures.

Underlying mechanisms and molecular targets of genistein in the management of type 2 diabetes mellitus and related complications

Diabetes mellitus (DM) is a chronic metabolic disease caused by a complex interaction of genetic and environmental factors and is characterized by persistent hyperglycemia. Long-term hyperglycemia can cause macrovascular and microvascular damage, and compromise the heart, brain, kidney, peripheral nerves, eyes and other organs, leading to serious complications. Genistein, a phytoestrogen derived from soybean, is known for its various biological activities and therapeutic properties. Recent studies found that genistein not only has hypoglycemic activity but can also decrease insulin resistance. In addition, genistein has particular activity in the prevention and treatment of diabetic complications, such as nephropathy, cardiovascular disease, osteoarthrosis, encephalopathy and retinopathy. Therefore, the purpose of this review is to summarize the latest medical research and progress of genistein in DM and related complications and highlights its potential molecular mechanisms and therapeutic targets. Meanwhile, evidence is provided for the development and application of genistein as a potential drug or functional food in the prevention and treatment of diabetes and its related complications.

Diabetes Is Predictive of Postoperative Outcomes and Readmission Following Posterior Lumbar Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The present study analyzes complication rates and episode-based costs for patients with and without diabetes mellitus (DM) following posterior lumbar fusion (PLF).

METHODS

PLF cases at a single institution from 2008 to 2016 were queried (n = 3226), and demographic and perioperative data were analyzed. Patients with and without the diagnosis of DM were compared using chi-square, Student's t test, and multivariable regression modeling.

RESULTS

Patients with diabetes were older (63.10 vs 56.48 years, P < .001) and possessed a greater number of preoperative comorbidities (47.84% of patients had Elixhauser Comorbidity Index >0 vs 42.24%, P < .001) than did patients without diabetes. When controlling for preexisting differences, diabetes remained a significant risk factor for prolonged length of stay (OR = 1.59, 95% CI 1.26-2.01, P < .001), intensive care unit stay (OR = 1.52, 95% CI 1.07-2.17, P = .021), nonhome discharge (OR = 1.86, 95% CI 1.46-2.37, P < .001), 30-day readmission (OR = 2.15, 95% CI 1.28-3.60, P = .004), 90-day readmission (OR = 1.65, 95% CI 1.05-2.59, P = .031), 30-day emergency room visit (OR = 2.15, 95% CI 1.27-3.63, P = .004), and 90-day emergency room visit (OR = 2.27, 95% CI 1.41-3.65, P < .001). Cost modeling controlling for overall comorbidity burden demonstrated that diabetes was associated with a $1709 increase in PLF costs (CI $344-$3074, P = .014).

CONCLUSIONS

The present findings indicate a correlation between diabetes and a multitude of postoperative adverse outcomes and increased costs, thus illustrating the substantial medical and financial burdens of diabetes for PLF patients. Future studies should explore preventive measures that may mitigate these downstream effects.

Balance and motion coordination parameters can be improved in patients with type 2 diabetes with physical balance training: non-randomized controlled trial

BACKGROUND

Type 2 diabetes (T2D) is a cause of multiple complications, including retinopathy and peripheral neuropathy. These complications are well understood and believed to contribute to gait instability. Poor balance control and increased falling risk have also been reported in people with diabetic peripheral neuropathy (DPN). Patients with DPN have increased risk of falling due to decreased proprioceptive feedback. Effective balance training should improve postural control in patients with DPN. For this purpose further evaluation was conducted and balance training was designed.

METHODS

The goal of our study was to determine values of proprioception, balance, muscle coordination and strength in patients with T2D and analyze whether biofeedback balance training with use of the Biodex Balance System could improve these parameters. To assess the fall risk the general stability index (GSI), the index of frontal-posterior (FPI) and medial-lateral (MLI) stability were evaluated. 37 patients with diagnosed type 2 diabetes mellitus were recruited to this study. Their results were compared with control group consisting of 41 healthy participants who were homogenic to the study group in terms of age and body mass index (BMI).

RESULTS

There were statistically significant differences between patients with diabetes compared to healthy subjects in GSI (2.79 vs 1.1), FPI (1.66 vs 0.7), MLI (0.88 vs 0.52) and risk of falling (5.18 vs 2.72) p < 0.05. There were also statistically significant changes before and after training in all stability indices (GSI: 2.79 vs 1.26, FPI: 1.66 vs 0.77, MLI: 0.88 vs 0.54 accordingly) p < 0.05 and risk of falling (5.18 vs 3.87) p < 0.05 in the study group who had undergone training with biofeedback.

CONCLUSIONS

This study found that there is a decreased balance and motor coordination and an increased risk of falling in patients with type 2 diabetes. These parameters improved in patients who have undergone training programme with biofeedback. Furthermore, an age-dependent deprivation of static balance was observed along with an increased risk of falling as a result of increasing BMI.

Hypogonadism, Type-2 Diabetes Mellitus, and Bone Health: A Narrative Review

One of the complications from chronic hyperglycemia and insulin resistance due to type 2 diabetes mellitus (T2DM) on the hypothalamic-pituitary-gonadal axis in men is the high prevalence of hypogonadotropic hypogonadism (HH). Both T2DM and hypogonadism are associated with impaired bone health and increased fracture risk but whether the combination results in even worse bone disease than either one alone is not well-studied. It is possible that having both conditions predisposes men to an even greater risk for fracture than either one alone. Given the common occurrence of HH or hypogonadism in general in T2DM, a significant number of men could be at risk. To date, there is very little information on the bone health men with both hypogonadism and T2DM. Insulin resistance, which is the primary defect in T2DM, is associated with low testosterone (T) levels in men and may play a role in the bidirectional relationship between these two conditions, which together may portend a worse outcome for bone. The present manuscript aims to review the available evidences on the effect of the combination of hypogonadism and T2DM on bone health and metabolic profile, highlights the possible metabolic role of the skeleton, and examines the pathways involved in the interplay between bone, insulin resistance, and gonadal steroids.

The effects of non-surgical periodontal therapy on glycemic control in diabetic patients: A randomized controlled trial

AIM

The present study aimed to monitor the clinical outcomes and the metabolic response of periodontal therapy (non-surgical) in patients with periodontitis (chronic) and uncontrolled diabetes (type 2).

METHODS

Eighty-eight subjects with periodontitis (chronic) and uncontrolled diabetes (type 2) were enrolled in this controlled trial and allocated randomly to the test group (44 patients were received immediate periodontal therapy) or the control group (44 patients were received delayed periodontal therapy). The metabolic and clinical evaluations were conducted at baseline and 3 months. This included clinical attachment level, glycated hemoglobin (HbA1c), bleeding on probing, visible plaque, and pocket depth. The periodontal therapy in this study consists of one-stage scaling and root planning, a combination of systemic antibiotics (amoxicillin 500 mg and metronidazole 400 mg), and oral hygiene instructions.

RESULTS

Regarding clinical and metabolic parameters at baseline, no statistically significant differences were displayed between the two groups. However, at 3-month follow-up period the patients within the test group demonstrated significantly better clinical and metabolic outcomes than patients in the control group.

CONCLUSION

The non-surgical periodontal treatment using a combination of metronidazole and amoxicillin significantly improved the metabolic outcome in addition to periodontal health in diabetic subjects with chronic periodontitis.

FRAX (Australia) scores in women with impaired fasting glucose and diabetes

BACKGROUND

Diabetes is associated with higher fracture risk despite higher bone mineral density (BMD), with FRAX® underestimating risk. This study aimed to investigate FRAX score with and without BMD for women with normoglycaemia, impaired fasting glucose (IFG) and diabetes.

METHODS

Among 566 women, aged 40-90 years, enrolled in the Geelong Osteoporosis Study, IFG was defined as fasting plasma glucose (FPG) ≥5.5 mmol/L and diabetes as FPG ≥ 7.0 mmol/L, use of antihyperglycaemic medication and/or self-report. FRAX (Australia) 10-year probabilities of major osteoporotic (MOF) and hip fracture were calculated, with and without BMD, producing four FRAX scores per participant. Kruskal-Wallis test for non-parametric data was used to examine differences between the three glycaemia groups. Fractures over 10 years were ascertained using radiological reports. The number of fractures predicted by FRAX was compared with the number of fractures observed using Chi-square tests.

RESULTS

For MOF FRAX calculated without BMD, women with diabetes (n = 67) tended to have a higher median score 7.1 (IQR 2.7-12.0) than normoglycaemia (n = 252) (4.3 (IQR 1.9-9.9) and IFG (n = 247) (5.1 (IQR 2.2-9.6)). For hip FRAX without BMD, diabetes tended to have a higher score (2.5 (IQR 06-4.3)) than normoglycaemia (1.2 (IQR 0.3-4.1)) and IFG (1.3 (IQR 0.3-4.1)). In the normoglycaemia and IFG groups, MOFs were underestimated; 15 predicted vs 28 observed, p = 0.038; and 16 predicted vs 31 observed, p = 0.021, respectively. Fractures were accurately estimated in all other groups.When including BMD, the association with diabetes was non-significant for both MOF FRAX (normoglycaemia 3.7 (IQR 1.9-8.0), IFG 4.3 (IQR 2.2-8.1) and diabetes 5.3 (IQR 2.7-9.4)) and hip FRAX scores (normoglycaemia 0.6 (IQR 0.2-2.5), IFG 0.8 (IQR 0.2-2.7) and diabetes 1.0 (IQR 0.3-3.0)). For normoglycaemia and IFG, MOFs were underestimated (normoglycaemia: 13 predicted vs 28 observed and IFG: 13 vs 31). For diabetes, both MOFs and hip fractures tended to be underestimated by FRAX with BMD (MOF: 4 predicted vs 11 observed, p = 0.055, hip: 1 predicted vs 6 observed, p = 0.052). Hip fractures were accurately estimated in the normoglycaemia and IFG groups.

CONCLUSIONS

Compared with women who had normoglycaemia or IFG, women with diabetes tended to have a higher FRAX score for both MOF and hip fractures when BMD was not included. When BMD was included, there was no difference. Fractures in diabetes tended to be underestimated by FRAX with BMD. This suggests that FRAX calculations including BMD may not be accurate for estimating fractures in those with diabetes.

Fracture Risk in Women with Dysglycaemia: Assessing Effects of Baseline and Time-Varying Risk Factors

Although individuals with diabetes appear to have a higher fracture risk compared to those without diabetes, fracture risk in impaired fasting glucose (IFG) has not been thoroughly explored. This study determined associations between glycaemia status and fracture risk. Women (n = 575, aged 50 + years) enrolled in the Geelong Osteoporosis Study, were followed from baseline (1993-1997), to date of first fracture, death or December 31, 2010, whichever occurred first (median 13.7 years, IQR 7.4-14.8). Hazard ratios (HRs) for any fracture (excluding fingers, toes, skull/face), as well as major osteoporotic fracture (MOF, clinical spine, hip, proximal humerus, wrist), in diabetes (n = 69), IFG (n = 250) and normoglycaemia (n = 256), were calculated using a Cox proportional hazards model. Normoglycaemia was set as the reference category. A Cox proportional hazards model with time-varying covariates was also used to assess change in baseline risk factors at the 10-year follow-up visit (2004-2008). During follow-up (6433 person-years), 162 women sustained any fracture and 104 had a MOF. Unadjusted fracture risk was higher in diabetes (HR 1.64; 95% CI 1.02-2.63) compared to normoglycaemia, but IFG and normoglycaemia had similar risk (HR 1.06; 95% CI 0.76-1.47). Age- and BMD-adjusted any-fracture risk in diabetes compared to normoglycaemia was greater (HR 1.59; 95% CI 0.98-2.58); IFG was similar to normoglycaemia (HR 1.01; 95% CI 0.72-1.41). For MOF, unadjusted and age- and BMD-adjusted fracture risk in IFG was similar to normoglycaemia HR 1.02; 95% CI 0.74-1.40 and HR 0.95; 95% CI 0.69-1.32, respectively, but diabetes was higher compared to normoglycaemia (unadjusted HR 1.64; 95% CI 1.04-2.60; adjusted HR 1.57; 95% CI 0.98-2.51). In the time-varying model, there was no difference between IFG in either the unadjusted or adjusted models, for both any fracture and MOF (p > 0.05). For diabetes, there was a significant difference between normoglycaemia in the adjusted model for any fracture (p = 0.046), but not for MOF (p = 0.103). An increased risk of fracture for women with diabetes was observed after accounting for time-varying risk factors. There was no difference in fracture risk detected for women with IFG.

Bone turnover and bone mineral density in old persons with type 2 diabetes

AIMS

To understand the paradox of an increased fracture risk despite increased bone mineral density (BMD) in persons with type 2 diabetes (DM2).

PATIENTS AND METHODS

We studied 80 old persons with DM2. Mineral metabolism, parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHD), bone turnover - osteocalcin, procollagen type 1 N-terminal propeptide (P1NP) and C-terminal telopeptide of type 1 collagen (CTX) - were measured and BMD was assessed at the lumbar spine (LS) and femoral neck (FN). Data was analyzed with the Statistical Package for the Social Sciences Program.

RESULTS

Low levels of 25OHD (84%) and high values of PTH (20%) were found. Osteocalcin was directly related to CTX, p < 0.001, with increased bone formation and increased BMD (z-score) at LS and FN. PTH was directly related to osteocalcin and CTX and inversely related to BMD at the FN, p < 0.05. Patients with dyslipidemia presented higher P1NP, p < 0.05 and patients with hypertension presented higher BMD at LS and FN, p < 0.01.

CONCLUSION

Old type 2 diabetics present increased bone formation, PTH-driven. Low grade secondary hyperparathyroidism may explain the paradox of an increased fracture risk despite increased BMD.

Effect of duration of diabetes on bone mineral density: a population study on East Asian males

BACKGROUND

The aim of the present study is to evaluate the association between BMD and type 2 DM status in middle-aged and elderly men. To investigate a possible correlation, the present study used the BMD dataset of the Korea National Health and Nutrition Examination Survey (KNHANES) from 2008 to 2011.

METHODS

In total, 37,753 individuals participated in health examination surveys between 2008 and 2011. A total of 3383 males aged ≥50 years were eligible. They underwent BMD measurement through dual-energy X-ray absorptiometry (DXA). The fasting plasma glucose and insulin levels of participants were also measured.

RESULTS

Men with prediabetes and diabetes had significantly higher mean BMD at all measured sites than control men did, irrespective of DM status. This was confirmed by multivariable linear regression analyses. DM duration was an important factor affecting BMD. Patients with DM for > 5 years had lower mean BMD in the total hip and femoral neck than those with DM for ≤5 years. Per multivariable linear regression analyses, patients with DM for > 5 years had significantly lower mean BMD at the femoral neck than those with DM ≤5 years.

CONCLUSIONS

DM duration was significantly associated with reduced femoral neck BMD.

Mechanical Characterization of Bone: State of the Art in Experimental Approaches-What Types of Experiments Do People Do and How Does One Interpret the Results?

PURPOSE OF REVIEW

The mechanical integrity of bone is determined by the direct measurement of bone mechanical properties. This article presents an overview of the current, most common, and new and upcoming experimental approaches for the mechanical characterization of bone. The key outcome variables of mechanical testing, as well as interpretations of the results in the context of bone structure and biology are also discussed.

RECENT FINDINGS

Quasi-static tests are the most commonly used for determining the resistance to structural failure by a single load at the organ (whole bone) level. The resistance to crack initiation or growth by fracture toughness testing and fatigue loading offers additional and more direct characterization of tissue material properties. Non-traditional indentation techniques and in situ testing are being increasingly used to probe the material properties of bone ultrastructure. Destructive ex vivo testing or clinical surrogate measures are considered to be the gold standard for estimating fracture risk. The type of mechanical test used for a particular investigation depends on the length scale of interest, where the outcome variables are influenced by the interrelationship between bone structure and composition. Advancement in the sensitivity of mechanical characterization techniques to detect changes in bone at the levels subjected to modifications by aging, disease, and/or pharmaceutical treatment is required. As such, a number of techniques are now available to aid our understanding of the factors that contribute to fracture risk.

Effects of voluntary running exercise on bone histology in type 2 diabetic rats

The incidence of obesity in children and adolescents, which may lead to type 2 diabetes, is increasing. Exercise is recommended to prevent and improve diabetes. However, little is known about the bone marrow environment at the onset of diabetes in the young, and it is unclear whether exercise training is useful for maintaining bone homeostasis, such as mechanical and histological properties. Thus, this study clarified the histological properties of bone and whether exercise contributes to maintaining bone homeostasis at the onset of type 2 diabetes in rats. Four-week-old male Otsuka Long-Evans Tokushima Fatty (OLETF; n = 21) rats as a diabetic model and Long-Evans Tokushima Otsuka (LETO; n = 18) rats as a control were assigned randomly to four groups: the OLETF sedentary group (O-Sed; n = 11), OLETF exercise group (O-Ex; n = 10), LETO sedentary group (L-Sed; n = 9), and LETO exercise group (L-Ex; n = 9). All rats in the exercise group were allowed free access to a steel running wheel for 20 weeks (5-25 weeks of age). In the glucose tolerance test, blood glucose level was higher in the O-Sed group than that in the L-Sed and L-Ex groups, and was markedly suppressed by the voluntary running exercise of O-Ex rats. The energy to fracture and the two-dimensional bone volume at 25 weeks of age did not differ significantly among the groups, though the maximum breaking force and stiffness were lower in OLETF rats. However, bone marrow fat volume was greater in O-Sed than that in L-Sed and L-Ex rats, and was markedly suppressed by wheel running in the O-Ex rats. Our results indicate that exercise has beneficial effects not only for preventing diabetes but also on normal bone remodeling at an early age.

The association between risk of limb fracture and type 2 diabetes mellitus

Background

Recently, increasing reports showed that the risk of fracture may be correlated with type 2 diabetes mellitus (T2DM). However, their results still remained controversial. Thus we performed a meta-analysis including 11 studies to estimate the risk factor of limb fracture in type 2 diabetes mellitus.

Materials and Methods

Databases including PubMed, Embase, Cochrane Library and Web of Science were searched to September, 2017. Risk Ratio (RR) with its 95% confidence intervals (CI) was used to evaluate the association between risk of limb fracture and type 2 diabetes mellitus. Two reviewers assessed the quality of all the included studies and extracted data for analysis independently.

Results

A total of 11 studies including 663,923 participants were included in this meta-analysis. Our analysis results showed that patients with type 2 diabetes mellitus had a significant association with risk of limb fracture (RR 1.18; 95% CI 1.02–1.35), including leg or ankle fracture (RR 1.80; 95% CI 1.13–2.87). Subgroup analysis showed individuals with type 2 diabetes had almost two-fold excessive risk of leg/ankle fracture in women and the pooled RR of leg/ankle fracture was 2.03 (95% CI 1.36–3.05; P = 0.0006).

Conclusions

The results of the present meta-analysis showed that individuals with type 2 diabetes mellitus had higher risk of limb fractures, and this relationship is more pronounced in leg or ankle fracture.

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.

Molecular Modulation of Osteoblasts and Osteoclasts in Type 2 Diabetes

Diabetes is a common disease affecting majority of populations worldwide. Since 1980, there has been an increase in the number of people diagnosed as prediabetic and diabetic. Diabetes is characterized by high levels of circulating glucose and leads to most microvascular and macrovascular complications such as retinopathy, nephropathy, neuropathy, stroke, and myocardial infarction. Bone marrow vascular disruption and increased adiposity are also linked to various complications in type II diabetes mellitus. In addition to these complications, type 2 diabetic patients also have fragile bones caused by faulty mineralization mainly due to increased adiposity among diabetic patients that affects both osteoblast and osteoclast functions. Other factors that increase fracture risk in diabetic patients are increased oxidative stress, inflammation, and drugs administered to diabetic patients. This review reports the modulation of different pathways that affect bone metabolism in diabetic conditions.

Bazedoxifene Ameliorates Homocysteine-Induced Apoptosis and Accumulation of Advanced Glycation End Products by Reducing Oxidative Stress in MC3T3-E1 Cells

Elevated plasma homocysteine (Hcy) level increases the risk of osteoporotic fracture by deteriorating bone quality. However, little is known about the effects of Hcy on osteoblast and collagen cross-links. This study aimed to investigate whether Hcy induces apoptosis of osteoblastic MC3T3-E1 cells as well as affects enzymatic and nonenzymatic collagen cross-links and to determine the effects of bazedoxifene, a selective estrogen receptor modulator, on the Hcy-induced apoptosis and deterioration of collagen cross-links in the cells. Hcy treatments (300 μM, 3 mM, and 10 mM) increased intracellular reactive oxygen species (ROS) production in a dose-dependent manner. Propidium iodide staining showed that 3 and 10 mM Hcy induced apoptosis of MC3T3-E1 cells. Moreover, the activities of caspases-8, 9, and 3 were increased by 3 mM Hcy. The detrimental effects of 3 mM Hcy on apoptosis and ROS production were partly reversed by bazedoxifene and 17β estradiol. In addition, real-time PCR, immunostaining and Western blot showed that 300 μM Hcy decreased the expression of lysyl oxidase (Lox). Furthermore, 300 μM Hcy increased extracellular accumulation of pentosidine, an advanced glycation end product. Treatment with bazedoxifene ameliorated Hcy-induced suppression of Lox expression and increase in pentosidine accumulation. These findings suggest that high-dose Hcy induces apoptosis of osteoblasts by increasing oxidative stress, and low-dose Hcy decreases enzymatic collagen cross-links and increases pentosidine accumulation, resulting in the deterioration of bone quality. Bazedoxifene treatment effectively prevents the Hcy-induced detrimental reactions of osteoblasts. Thus, bazedoxifene may be a potent therapeutic drug for preventing Hcy-induced bone fragility.

Role of cortical bone in hip fracture

In this review, I consider the varied mechanisms in cortical bone that help preserve its integrity and how they deteriorate with aging. Aging affects cortical bone in two ways: extrinsically through its effects on the individual that modify its mechanical loading experience and 'milieu interieur'; and intrinsically through the prolonged cycle of remodelling and renewal extending to an estimated 20 years in the proximal femur. Healthy femoral cortex incorporates multiple mechanisms that help prevent fracture. These have been described at multiple length scales from the individual bone mineral crystal to the scale of the femur itself and appear to operate hierarchically. Each cortical bone fracture begins as a sub-microscopic crack that enlarges under mechanical load, for example, that imposed by a fall. In these conditions, a crack will enlarge explosively unless the cortical bone is intrinsically tough (the opposite of brittle). Toughness leads to microscopic crack deflection and bridging and may be increased by adequate regulation of both mineral crystal size and the heterogeneity of mineral and matrix phases. The role of osteocytes in optimising toughness is beginning to be worked out; but many osteocytes die in situ without triggering bone renewal over a 20-year cycle, with potential for increasing brittleness. Furthermore, the superolateral cortex of the proximal femur thins progressively during life, so increasing the risk of buckling during a fall. Besides preserving or increasing hip BMD, pharmaceutical treatments have class-specific effects on the toughness of cortical bone, although dietary and exercise-based interventions show early promise.

Metformin Prevents Nonunion after Three-Cannulated-Screw Fixation in Displaced Femoral Neck Fractures: A Retrospective Study

Patients aged from 40 to 60 with displaced fractures of the femoral neck (Garden III or IV) who received fixation with three cannulated screws from January 2005 to December 2012 were evaluated retrospectively for the development of nonunion. Plasma HbA1C, a marker for long-term plasma glucose level, anti-T2DM medication, and other potential risk factors were recorded for the purpose of this study. There were no differences between the union and nonunion groups with respect to age, gender, Garden classification, Pauwel's angle, reduction quality, and T2DM presence. There were significant differences in reduction quality and preoperative plasma HbA1C level between patients with and those without union. The odds ratio (OR) for fracture nonunion was 2.659 (95% confidence interval [CI], 1.530–4.620) in subjects with anatomical reduction compared with those without anatomical reduction, 4.797 (95% CI, 1.371–16.778), in subjects with poor blood glucose control (HbA1C > 10%). The metformin usage showed a preventive effect on nonunion development (OR: 0.193 and CI: 0.060–0.616). The nonunion rate of metformin group (6.7%, 6/89) was even much lower than that of patients without T2DM (17.4%, 80/460).

Luteolin alleviates methylglyoxal-induced cytotoxicity in osteoblastic MC3T3-E1 cells

Methylglyoxal (MG), a reactive sugar-derived metabolite, exerts harmful effects by inducing oxidative stress, which aggravates a series of diabetic complications, including osteoporosis. The present study was performed to examine the effects of luteolin, a dietary polyphenolic flavonoid, on MG-induced cytotoxicity in MC3T3-E1 osteoblastic cells. Pretreatment of MC3T3-E1 osteoblastic cells with luteolin prevented MG-induced cell death and production of tumor necrosis factor-alpha, intracellular reactive oxygen species, mitochondrial superoxide, and cardiolipin peroxidation. In addition, luteolin increased the levels of glutathione and nuclear factor erythroid 2-related factor 2 (Nrf2) and decreased the inhibition of heme oxygenase-1 activity by MG. Pretreatment with luteolin prior to MG exposure reduced MG-induced mitochondrial dysfunction and increased the peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α) and nitric oxide levels, suggesting that luteolin may induce mitochondrial biogenesis. Taken together, these observations indicated that luteolin has potential as a preventive agent against the development of diabetic osteopathy related to MG-induced oxidative stress in diabetes.

Glycemic control and fracture risk in elderly patients with diabetes

AIMS

Elderly patients with diabetes are at increased fracture risk. Although long exposure to hyperglycemia may increase fracture risk via adverse effects on bone metabolism, tight glycemic control may increase risk via trauma subsequent to hypoglycemia. We tested the prospective relationship between glycemic control and fracture risk in 10,572 elderly patients (age ≥65) with diabetes.

METHODS

Geriatric patients with diabetes were drawn from Vanderbilt University Medical Center's Electronic Health Record. Baseline was defined as age at first HbA1c after the latter of age 65 or ICD 9 code for diabetes. Cox analysis was used to test the relationship of updated mean HbA1c (average HbA1c over follow-up) with time to first fracture since baseline. HbA1c was categorized as follows: <6.5% [<48mmol/mol]; 6.5-6.9% [48-52mmol/mol]; 7-7.9% [53-63mmol/mol]; 8-8.9% [64-74 mmol-mol]; ≥9% [≥75mmol/mol]. The number of BMI measurements was used as a surrogate for relative frequency of outpatient visits, i.e. patient-provider contacts.

RESULTS

During follow-up, there were 949 fracture events. HbA1c demonstrated a cubic relationship with fracture risk (p<0.05). In analyses accounting for age, sex, race, and number of BMI measures (a surrogate for patient-provider interaction), compared to an HbA1c of 7-7.9%, HRs (95% CIs) were: HbA1c<6.5% HR=0.97 (0.82-1.14), 6.5-6.9% HR=0.80 (0.66-0.97), 8-8.9% HR=1.13 (0.92-1.40), ≥9% HR=1.19 (0.93-1.54).

CONCLUSIONS

An HbA1c of 6.5-6.9% is associated with the lowest risk of fracture in elderly patients with diabetes. Risk associated with an HbA1c ≥9% may be a marker of infrequent patient-provider interaction.

Plasminogen activator inhibitor-1 concentrations and bone mineral density in postmenopausal women with type 2 diabetes mellitus

BACKGROUND

Women with type 2 diabetes mellitus (T2DM) have a higher risk of fractures despite increased bone mineral density (BMD). In experimental studies a potential role of plasminogen activator inhibitor-1 (PAI-1) in bone remodeling is suggested but studies in humans are lacking. This is a first study in humans investigating whether circulated levels of PAI-1 in postmenopausal women with T2DM are related to BMD and adiposity.

METHODS

Anthropometric variables, PAI-1 and insulin levels, serum lipids and bone turnover markers were measured in 127 postmenopausal women with T2DM. A total of 117 female patients were divided according to lumbar spine BMD measurements via dual-energy x-ray absorptiometry in three groups: 47 with osteopenia, 21 with osteoporosis and 49 with normal BMD.

RESULTS

Diabetic patients with normal BMD had significantly higher BMI, greater waist circumference and lower bone turnover markers than diabetics with osteopenia and osteoporosis. PAI-1 was lower in diabetics with osteoporosis and osteopenia compared with diabetics with normal BMD. Multiple regression analysis revealed insulin, triglycerides levels, pyrilinks and beta blocker therapy to be the strongest predictors of PAI-1 levels. PAI-1 levels correlated with both L-BMD and hip BMD, but after adjustment for age and BMI association was no longer significant.

CONCLUSION

Our findings suggest that elevated PAI-1 levels are associated with higher BMD in obese diabetic patients but the possible implications of this finding and underlying mechanisms still remain unclear. Obviously, metabolic parameters, may affect both BMD and PAI-levels, and association of PAI-1 and BMD could be indirect. However, as pyrilinks is also independently and significantly negatively correlated to PAI-1 its direct involvement in bone metabolism is also plausible. Further investigations are needed to elucidate the nature of interaction of this matrix modulator in relation to energy and bone metabolism in humans.

Impact of Diabetic Complications on Balance and Falls: Contribution of the Vestibular System

Diabetes causes many complications, including retinopathy and peripheral neuropathy, which are well understood as contributing to gait instability and falls. A less understood complication of diabetes is the effect on the vestibular system. The vestibular system contributes significantly to balance in static and dynamic conditions by providing spatially orienting information. It is noteworthy that diabetes has been reported to affect vestibular function in both animal and clinical studies. Pathophysiological changes in peripheral and central vestibular structures due to diabetes have been noted. Vestibular dysfunction is associated with impaired balance and a higher risk of falls. As the prevalence of diabetes increases, so does the potential for falls due to diabetic complications. The purpose of this perspective article is to present evidence on the pathophysiology of diabetes-related complications and their influence on balance and falls, with specific attention to emerging evidence of vestibular dysfunction due to diabetes. Understanding this relationship may be useful for screening (by physical therapists) for possible vestibular dysfunction in people with diabetes and for further developing and testing the efficacy of interventions to reduce falls in this population.

Lifestyle-Related Diseases Affect Surgical Outcomes after Posterior Lumbar Interbody Fusion

Study Design Retrospective study. Objective Hyperlipidemia (HL) and hypertension (HT) lead to systemic atherosclerosis. Not only atherosclerosis but also bone fragility and/or low bone mineral density result from diabetes mellitus (DM) and chronic kidney disease (CKD). The purpose of this study was to examine whether these lifestyle-related diseases affected surgical outcomes after posterior lumbar interbody fusion (PLIF). Methods The subjects comprised 122 consecutive patients who underwent single-level PLIF for degenerative lumbar spinal disorders. The clinical results were assessed using the Japanese Orthopaedic Association (JOA) score before surgery and at 2 years postoperatively. The fusion status was graded as union in situ, collapsed union, or nonunion at 2 years after surgery. The abdominal aorta calcification (AAC) score was assessed using preoperative lateral radiographs of the lumbar spine. Results HL did not significantly affect the JOA score recovery rate. On the other hand, HT and CKD (stage 3 to 4) had a significant adverse effect on the recovery rate. The recovery rate was also lower in the DM group than in the non-DM group, but the difference was not significant. The AAC score was negatively correlated with the JOA score recovery rate. The fusion status was not significantly affected by HL, HT, DM, or CKD; however, the AAC score was significantly higher in the collapsed union and nonunion group than in the union in situ group. Conclusions At 2 years after PLIF, the presence of HT, CKD, and AAC was associated with significantly worse clinical outcomes, and advanced AAC significantly affected fusion status.

Effect of type 2 diabetes-related non-enzymatic glycation on bone biomechanical properties

There is clear evidence that patients with type 2 diabetes mellitus (T2D) have increased fracture risk, despite having high bone mineral density (BMD) and body mass index (BMI). Thus, poor bone quality has been implicated as a mechanism contributing to diabetic skeletal fragility. Poor bone quality in T2D may result from the accumulation of advanced glycation end-products (AGEs), which are post-translational modifications of collagen resulting from a spontaneous reaction between extracellular sugars and amino acid residues on collagen fibers. This review discusses what is known and what is not known regarding AGE accumulation and diabetic skeletal fragility, examining evidence from in vitro experiments to simulate a diabetic state, ex vivo studies in normal and diabetic human bone, and diabetic animal models. Key findings in the literature are that AGEs increase with age, affect bone cell behavior, and are altered with changes in bone turnover. Further, they affect bone mechanical properties and microdamage accumulation, and can be inhibited in vitro by various inhibitors and breakers (e.g. aminoguanidine, N-Phenacylthiazolium Bromide, vitamin B6). While a few studies report higher AGEs in diabetic animal models, there is little evidence of AGE accumulation in bone from diabetic patients. There are several limitations and inconsistencies in the literature that should be noted and studied in greater depth including understanding the discrepancies between glycation levels across reported studies, clarifying differences in AGEs in cortical versus cancellous bone, and improving the very limited data available regarding glycation content in diabetic animal and human bone, and its corresponding effect on bone material properties in T2D.

Relationship of the Serum CRP Level With the Efficacy of Metformin in the Treatment of Type 2 Diabetes Mellitus: A Meta-Analysis

BACKGROUND

Metformin, an anti-diabetes drug, is always used as a first-line agent for the management of T2DM. This meta-analysis was conducted to investigate whether CRP was sensitive in predicting the efficacy of metformin in the treatment of T2DM.

METHODS

Potential relevant studies were identified covering the following databases: MEDLINE, Science Citation Index database, the Cochrane Library Database, PubMed, EMBASE, CINAHL, Current Contents Index, the Chinese Biomedical Database, the Chinese Journal Full-Text Database, and the Weipu Journal Database. Data from eligible studies were extracted and included into the meta-analysis using a random effects model. Statistical analyses were calculated using the version 12.0 STATA software.

RESULTS

A total of 33 articles including 1,433 subjects were collected for analysis. Pooled SMD of those studies revealed that serum levels of CRP and hs-CRP significantly decreased in patients with T2DM after receiving the metformin treatment. Subgroup analysis by country yielded significant different estimates in the serum levels of CRP between the baseline and after metformin treatment in the China, Israel and India subgroups; but only detected only in the China subgroup considering serum levels of hs-CRP. Follow-up time-stratified analyses indicated that serum levels of CRP were markedly reduced in the metformin-treated group in all subgroups. While differences in serum hs-CRP levels were not observed in two subgroups.

CONCLUSION

Decreased serum levels of CRP and hs-CRP may contribute to a more sensitive prediction in providing a more accurate efficacy reference in the metformin drug in T2DM patients.

Fracture Risk in Type 2 Diabetes: Current Perspectives and Gender Differences

Type 2 diabetes mellitus (T2DM) is associated with an increased risk of osteoporotic fractures, resulting in disabilities and increased mortality. The pathophysiological mechanisms linking diabetes to osteoporosis have not been fully explained, but alterations in bone structure and quality are well described in diabetic subjects, likely due to a combination of different factors. Insulin deficiency and dysfunction, obesity and hyperinsulinemia, altered level of oestrogen, leptin, and adiponectin as well as diabetes-related complications, especially peripheral neuropathy, orthostatic hypotension, or reduced vision due to retinopathy may all be associated with an impairment in bone metabolism and with the increased risk of fractures. Finally, medications commonly used in the treatment of T2DM may have an impact on bone metabolism and on fracture risk, particularly in postmenopausal women. When considering the impact of hypoglycaemic drugs on bone, it is important to balance their potential direct effects on bone quality with the risk of falling-related fractures due to the associated hypoglycaemic risk. In this review, experimental and clinical evidence connecting bone metabolism and fracture risk to T2DM is discussed, with particular emphasis on hypoglycaemic treatments and gender-specific implications.

Two-year outcomes on bone density and fracture incidence in patients with T2DM randomized to bariatric surgery versus intensive medical therapy

OBJECTIVE

To determine the 2-year outcomes of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) vs. intensive medical therapy (IMT) on lean body mass, total bone mass, and bone mineral density (BMD) measures from the STAMPEDE trial.

METHODS

54 subjects (BMI: 36 ± 1 kg/m(2) , age: 48 ± 4 years) with type 2 diabetes (T2DM) (HbA1c : 9.7 ± 2%) were randomized to IMT, RYGB, or SG and underwent DXA at baseline and at 1 and 2 years.

RESULTS

At 2 years, the reduction in BMI was similar after RYGB and SG and was greater than IMT (P < 0.001). Lean mass was reduced by ∼10%, total bone mineral content reduced by ∼8%, and hip BMD reduced by ∼9% in both surgical groups and was significantly greater than IMT despite increases in vitamin D intake in all groups. The change in hip BMD correlated with weight loss (r = 0.84, P < 0.0001) and changes in lean mass (r = 0.74, P < 0.0001) and leptin (r = 0.53, P < 0.0001). Peripheral fractures were self-reported in RYGB (4/18 patients), SG (2/19 patients), and IMT (4/16 patients).

CONCLUSIONS

Surgically induced weight loss is associated with modest reductions in lean mass, bone mineral content, and BMD, despite calcium and vitamin D supplementation in patients with T2DM. Awareness for bone loss is indicated for patients undergoing bariatric procedures.

Effect of non-surgical periodontal treatment on glycemic control of patients with diabetes: a meta-analysis of randomized controlled trials

Objective

The present study aimed at investigating whether non-surgical periodontal treatment can reduce the Haemoglobin A1c (HbA1c) % level in type 2 diabetic patients.

Methods

A search of the literature on English publications was performed in Cochrane Central, Medline, ISI Web of Knowledge and EMBASE (until 06 February 2014). An RCT was selected if the subject was type 2 diabetic patients diagnosed with chronic periodontitis, and compared HbA1c% change after non-surgical periodontal treatment alone for at least three months of the study duration. Weighted mean difference for pooled data and large sample size strata were calculated. Heterogeneity and publication bias were explored.

Results

After the study selection process, only 9 RCTs were suitable. Compared to the control group, the pooled analysis (n=1082) showed −0.27 % (95 % CI:-0.46 % to −0.07 %, p= 0.007) absolute difference in HbA1c % with treatment while studies with sufficient sample size had HbA1c % change of −0.014 % (95 % CI:-0.18 % to 0.16 %, p= 0.87). Publication bias was marginally significant with Egger’s teat (p=0.045) but not with Begg’s test (p=0.72).

Conclusion

The moderate reduction in HbA1c after the non-surgical therapy in patients with type 2 diabetes is consistent with previous systematic reviews. However, more large scale and high-quality RCTs are necessitated to confirm these results.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-015-0810-2) contains supplementary material, which is available to authorized users.

Chronic ingestion of advanced glycation end products induces degenerative spinal changes and hypertrophy in aging pre-diabetic mice

Intervertebral disc (IVD) degeneration and pathological spinal changes are major causes of back pain, which is the top cause of global disability. Obese and diabetic individuals are at increased risk for back pain and musculoskeletal complications. Modern diets contain high levels of advanced glycation end products (AGEs), cyto-toxic components which are known contributors to obesity, diabetes and accelerated aging pathologies. There is little information about potential effects of AGE rich diet on spinal pathology, which may be a contributing cause for back pain which is common in obese and diabetic individuals. This study investigated the role of specific AGE precursors (e.g. methylglyoxal-derivatives (MG)) on IVD and vertebral pathologies in aging C57BL6 mice that were fed isocaloric diets with standard (dMG+) or reduced amounts of MG derivatives (dMG-; containing 60-70% less dMG). dMG+ mice exhibited a pre-diabetic phenotype, as they were insulin resistant but not hyperglycemic. Vertebrae of dMG+ mice displayed increased cortical-thickness and cortical-area, greater MG-AGE accumulation and ectopic calcification in vertebral endplates. IVD morphology of dMG+ mice exhibited ectopic calcification, hypertrophic differentiation and glycosaminoglycan loss relative to dMG- mice. Overall, chronic exposure to dietary AGEs promoted age-accelerated IVD degeneration and vertebral alterations involving ectopic calcification which occurred in parallel with insulin resistance, and which were prevented with dMG- diet. This study described a new mouse model for diet-induced spinal degeneration, and results were in support of the hypothesis that chronic AGE ingestion could be a factor contributing to a pre-diabetic state, ectopic calcifications in spinal tissues, and musculoskeletal complications that are more generally known to occur with chronic diabetic conditions.

Fracture risk in diabetic elderly men: the MrOS study

AIMS/HYPOTHESIS

Diabetes mellitus is associated with increased fracture risk in women but few studies are available in men. To evaluate the relationship between diabetes and prospective non-vertebral fractures in elderly men, we used data from the Osteoporotic Fractures in Men (MrOS) study.

METHODS

The MrOS enrolled 5,994 men (aged ≥65 years). Diabetes (ascertained by self-report, the use of medication for diabetes or an elevated fasting glucose level) was reported in 881 individuals, 80 of whom were using insulin. Hip and spine bone mineral density (BMD) was measured using dual x-ray absorptiometry (DXA). After recruitment, the men were followed for incident non-vertebral fractures using a triannual (3 yearly) questionnaire for an average of 9.1 (SD 2.7) years. The Cox proportional hazards model was used to assess the incident risk of fractures.

RESULTS

In models adjusted for age, race, clinic site and total hip BMD, the risk of non-vertebral fracture was higher in men with diabetes compared with normoglycaemic men (HR 1.30, 95% CI 1.09, 1.54) and was elevated in men using insulin (HR 2.46, 95% CI 1.69, 3.59). Men with impaired fasting glucose did not have a higher risk of fracture compared with normoglycaemic men (HR 1.04, 95% CI 0.89, 1.21). After multivariable adjustment, the risk of non-vertebral fracture remained higher only among men with diabetes who were using insulin (HR 1.74, 95% CI 1.13, 2.69).

CONCLUSIONS/INTERPRETATION

Men with diabetes who are using insulin have an increased risk of non-vertebral fracture for a given age and BMD.

Decreased osteoclastogenesis, osteoblastogenesis and low bone mass in a mouse model of type 2 diabetes

The effect of type 2 diabetes mellitus (T2DM) on bone is controversial. Therefore, the present study investigated whether T2DM causes osteoporosis and explored the underlying mechanisms involved in this process. The effects of T2DM on bone physiology were analyzed in a mouse model of T2DM; KK/Upj‑Ay/J (KK‑Ay) mice develop diabetes after 8 weeks and exhibit stable diabetes symptoms and signs after 10 weeks when fed a KK‑Ay mouse maintenance fodder. Diabetic mice exhibited hyperglycemia, hyperinsulinemia and increased body and fat pad weight in comparison with C57BL/6 non-diabetic mice. Furthermore, diabetic mice demonstrated low bone weight and bone mineral density in the femur, tibia and fifth lumbar vertebra. Using von Kossa and tartrate-resistant acid phosphatase (TRAP) staining, alkaline phosphatase and TRAP activity analyses and gene profiling it was demonstrated that osteoblastogenesis and osteoclastogenesis were impaired in diabetic mice. To evaluate the bone biomechanics, the ultimate load of the bone was analyzed. It was found that the ultimate load of the tibia in diabetic mice was lower than that in the controls. The results from the present study suggest that bone metabolism is impaired in T2DM, resulting in decreased osteoblastogenesis, osteoclastogenesis and bone mass.

PHEX mimetic (SPR4-peptide) corrects and improves HYP and wild type mice energy-metabolism

CONTEXT

PHEX or DMP1 mutations cause hypophosphatemic-rickets and altered energy metabolism. PHEX binds to DMP1-ASARM-motif to form a complex with α5β3 integrin that suppresses FGF23 expression. ASARM-peptides increase FGF23 by disrupting the PHEX-DMP1-Integrin complex. We used a 4.2 kDa peptide (SPR4) that binds to ASARM-peptide/motif to study the DMP1-PHEX interaction and to assess SPR4 for the treatment of energy metabolism defects in HYP and potentially other bone-mineral disorders.

DESIGN

Subcutaneously transplanted osmotic pumps were used to infuse SPR4-peptide or vehicle (VE) into wild-type mice (WT) and HYP-mice (PHEX mutation) for 4 weeks.

RESULTS

SPR4 partially corrected HYP mice hypophosphatemia and increased serum 1.25(OH)2D3. Serum FGF23 remained high and PTH was unaffected. WT-SPR4 mice developed hypophosphatemia and hypercalcemia with increased PTH, FGF23 and 1.25(OH)2D3. SPR4 increased GAPDH HYP-bone expression 60× and corrected HYP-mice hyperglycemia and hypoinsulinemia. HYP-VE serum uric-acid (UA) levels were reduced and SPR4 infusion suppressed UA levels in WT-mice but not HYP-mice. SPR4 altered leptin, adiponectin, and sympathetic-tone and increased the fat mass/weight ratio for HYP and WT mice. Expression of perlipin-2 a gene involved in obesity was reduced in HYP-VE and WT-SPR4 mice but increased in HYP-SPR4 mice. Also, increased expression of two genes that inhibit insulin-signaling, ENPP1 and ESP, occurred with HYP-VE mice. In contrast, SPR4 reduced expression of both ENPP1 and ESP in WT mice and suppressed ENPP1 in HYP mice. Increased expression of FAM20C and sclerostin occurred with HYP-VE mice. SPR4 suppressed expression of FAM20C and sclerostin in HYP and WT mice.

CONCLUSIONS

ASARM peptides and motifs are physiological substrates for PHEX and modulate osteocyte PHEX-DMP1-α5β3-integrin interactions and thereby FGF23 expression. These interactions also provide a nexus that regulates bone and energy metabolism. SPR4 suppression of sclerostin and/or sequestration of ASARM-peptides improves energy metabolism and may have utility for treating familial rickets, osteoporosis, obesity and diabetes.

Differential pattern for regulating insulin secretion, insulin resistance, and lipid metabolism by osteocalcin in male and female T2DM patients

BACKGROUND

Osteocalcin has been reported to be relevant to glucose and lipid metabolism, indicating it may stimulate insulin secretion and improve insulin resistance. Yet the difference between male and female patients is still not clear. We aimed to investigate the difference in serum osteocalcin, and its association with glucose, lipid metabolism, pancreatic function, insulin sensitivity, and resistance in male and female middle-aged and elderly type 2 diabetic (T2DM) patients.

MATERIAL AND METHODS

739 T2DM patients were included. After measurement of body mass index (BMI), the levels of fasting plasma glucose (FPG), insulin (FINS), C peptide (FC-P), 2-h post-OGTT plasma glucose (2h-PG), HbA1C, and osteocalcin were determined. Homeostasis model assessment of β-cell function (HOMA-%B), homeostasis model assessment of insulin sensitivity (HOMA-%S), and homeostasis model assessment of insulin resistance (HOMA-IR) were calculated.

RESULTS

Females had higher osteocalcin concentration than males (P<0.05). In males, serum osteocalcin was negatively correlated with HbA1C, FPG, and 2-h PG (P<0.05), but positively with 2-h post-OGTT C peptide (2hC-P), 2-h post-OGTT serum insulin (2h-INS), and HOMA-%B (P<0.05). In females, serum osteocalcin was negatively correlated with HbA1C, FPG, triglyceride (TG), and HOMA-IR (P<0.05), but positively with 2-h C-P, 2-h INS, HOMA-%B, HOMA-%S, and high-density lipoprotein (HDL) (P<0.05). In all subjects, serum osteocalcin was inversely correlated with HbA1C, FPG, and 2-h PG (P<0.05), but positively with 2-h C-P, 2-h INS, HDL, and HOMA-%B (P<0.05).

CONCLUSIONS

Osteocalcin might improve glucose metabolism through enhancing insulin secretion in males, and through increasing insulin secretion and improving insulin resistance in females with T2DM. Osteocalcin probably also plays an important role in lipid metabolism.

The fragile elderly hip: mechanisms associated with age-related loss of strength and toughness

Every hip fracture begins with a microscopic crack, which enlarges explosively over microseconds. Most hip fractures in the elderly occur on falling from standing height, usually sideways or backwards. The typically moderate level of trauma very rarely causes fracture in younger people. Here, this paradox is traced to the decline of multiple protective mechanisms at many length scales from nanometres to that of the whole femur. With normal ageing, the femoral neck asymmetrically and progressively loses bone tissue precisely where the cortex is already thinnest and is also compressed in a sideways fall. At the microscopic scale of the basic remodelling unit (BMU) that renews bone tissue, increased numbers of actively remodelling BMUs associated with the reduced mechanical loading in a typically inactive old age augments the numbers of mechanical flaws in the structure potentially capable of initiating cracking. Menopause and over-deep osteoclastic resorption are associated with incomplete BMU refilling leading to excessive porosity, cortical thinning and disconnection of trabeculae. In the femoral cortex, replacement of damaged bone or bone containing dead osteocytes is inefficient, impeding the homeostatic mechanisms that match strength to habitual mechanical usage. In consequence the participation of healthy osteocytes in crack-impeding mechanisms is impaired. Observational studies demonstrate that protective crack deflection in the elderly is reduced. At the most microscopic levels attention now centres on the role of tissue ageing, which may alter the relationship between mineral and matrix that optimises the inhibition of crack progression and on the role of osteocyte ageing and death that impedes tissue maintenance and repair. This review examines recent developments in the understanding of why the elderly hip becomes fragile. This growing understanding is suggesting novel testable approaches for reducing risk of hip fracture that might translate into control of the growing worldwide impact of hip fractures on our ageing populations.

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 clinical utility of bone marker measurements in osteoporosis

Osteoporosis is characterised by low bone mass and structural deterioration of bone tissue, resulting in increased fragility and susceptibility to fracture. Osteoporotic fractures are a significant cause of morbidity and mortality. Direct medical costs from such fractures in the UK are currently estimated at over two billion pounds per year, resulting in a substantial healthcare burden that is expected to rise exponentially due to increasing life expectancy. Currently bone mineral density is the WHO standard for diagnosis of osteoporosis, but poor sensitivity means that potential fractures will be missed if it is used alone. During the past decade considerable progress has been made in the identification and characterisation of specific biomarkers to aid the management of metabolic bone disease. Technological developments have greatly enhanced assay performance producing reliable, rapid, non-invasive cost effective assays with improved sensitivity and specificity. We now have a greater understanding of the need to regulate pre-analytical sample collection to minimise the effects of biological variation. However, bone turnover markers (BTMs) still have limited clinical utility. It is not routinely recommended to use BTMs to select those at risk of fractures, but baseline measurements of resorption markers are useful before commencement of anti-resorptive treatment and can be checked 3–6 months later to monitor response and adherence to treatment. Similarly, formation markers can be used to monitor bone forming agents. BTMs may also be useful when monitoring patients during treatment holidays and aid in the decision as to when therapy should be recommenced. Recent recommendations by the Bone Marker Standards Working Group propose to standardise research and include a specific marker of bone resorption (CTX) and bone formation (P1NP) in all future studies. It is hoped that improved research in turn will lead to optimised markers for the clinical management of osteoporosis and other bone diseases.

Serum extracellular secreted antagonists of the canonical Wnt/β-catenin signaling pathway in patients with Cushing's syndrome

Patients with endogenous hypercortisolism have higher sclerostin, but do not differ in Dickkopf 1 (Dkk1) or secreted frizzled-related protein 1 (SFRP1) levels as compared to healthy control.

INTRODUCTION

Endogenous Cushing's syndrome (CS), usually affecting young and otherwise healthy patients, is a good model to validate the effects of supraphysiological levels of glucocorticoids in humans. This study evaluates circulating levels of extracellular antagonists of the Wnt/β-catenin signaling pathway (sclerostin, Dkk1, SFRP1) in patients with CS versus healthy individuals.

METHODS

Forty patients with clinically and biochemically evident CS and 40 sex-, age-, and body mass index-matched healthy subjects provided fasting serum samples for sclerostin, SFRP1 and Dkk1, along with bone turnover markers.

RESULTS

Patients with CS had higher sclerostin levels (34.5 (30.3-37.1) pmol/L) versus healthy individuals (29.9 (24.3-36.8) pmol/L) (p = 0.032). Differences in sclerostin were due to the lack of lower sclerostin values rather than an increase in protein levels above the upper limits of the healthy control. The odds of sclerostin levels being higher than 30 pmol/L were greater in patients with CS as compared with the odds in healthy subjects (odds ratio = 3.81 95 % confidence interval 1.45-10.02) (p = 0.01). It coexisted with suppressed bone formation and unchanged bone resorption markers. Dkk1, SFRP1 did not differ from the control group.

CONCLUSIONS

Of all the tested proteins (sclerostin, Dkk1, SFRP1), only sclerostin showed a significant difference when contrasting CS with healthy subjects. Hypercortisolism might prevent the down-regulation of sclerostin. Targeting sclerostin seems to be a promising therapeutic approach to treating osteoporosis in patients with CS.

Osteoporosis and treatments in Japan: management for preventing subsequent fractures

Prevalent fractures are major contributors to an increased risk of subsequent fractures, particularly in people with osteoporosis. While many studies have been conducted to assess the incidence of fracture in Japanese people with osteoporosis, far fewer have been conducted to assess the risk of subsequent fractures. This article reviews the morbidity, mortality, and risk of fracture in patients who are at high risk of subsequent fracture in Japan and the current treatment options available for these patients. Osteoporotic fractures in Japan are associated with high morbidity and mortality that result in significant financial and social costs. The rise in the proportion of elderly women in the Japanese population is contributing to a greater proportion of people with osteoporotic fractures and the high cost of osteoporosis. Although hip fractures have a significant effect on costs, a greater proportion of the Japanese population experience vertebral fractures. An increase in the incidence of vertebral fractures is concerning because preexisting vertebral fractures in older patients are associated with an increased risk of subsequent fractures. Hence, there is a clear rationale for pharmacological treatment of patients with prevalent vertebral fractures, or for those who are hospitalized or undergo surgery for osteoporotic fractures. Several pharmacological therapies are now available in Japan for the treatment of patients with osteoporosis. Understanding the consequences of subsequent fractures and the treatment options available for patients at high risk of subsequent fractures may contribute to clinical decision-making and improved outcomes for patients with osteoporosis.

High bone mineral density and fracture risk in type 2 diabetes as skeletal complications of inadequate glucose control: the Rotterdam Study

OBJECTIVE

Individuals with type 2 diabetes have increased fracture risk despite higher bone mineral density (BMD). Our aim was to examine the influence of glucose control on skeletal complications.

RESEARCH DESIGN AND METHODS

Data of 4,135 participants of the Rotterdam Study, a prospective population-based cohort, were available (mean follow-up 12.2 years). At baseline, 420 participants with type 2 diabetes were classified by glucose control (according to HbA1c calculated from fructosamine), resulting in three comparison groups: adequately controlled diabetes (ACD; n = 203; HbA1c <7.5%), inadequately controlled diabetes (ICD; n = 217; HbA1c ≥ 7.5%), and no diabetes (n = 3,715). Models adjusted for sex, age, height, and weight (and femoral neck BMD) were used to test for differences in bone parameters and fracture risk (hazard ratio [HR] [95% CI]).

RESULTS

The ICD group had 1.1-5.6% higher BMD, 4.6-5.6% thicker cortices, and -1.2 to -1.8% narrower femoral necks than ACD and ND, respectively. Participants with ICD had 47-62% higher fracture risk than individuals without diabetes (HR 1.47 [1.12-1.92]) and ACD (1.62 [1.09-2.40]), whereas those with ACD had a risk similar to those without diabetes (0.91 [0.67-1.23]).

CONCLUSIONS

Poor glycemic control in type 2 diabetes is associated with fracture risk, high BMD, and thicker femoral cortices in narrower bones. We postulate that fragility in apparently "strong" bones in ICD can result from microcrack accumulation and/or cortical porosity, reflecting impaired bone repair.

Sex-specific relationships between insulin resistance and bone mineral content in Korean adolescents

The aim of this study was to examine sex-specific relationships between insulin resistance (IR) and bone mineral content (BMC) according to age group and weight status. A population-based sample of 618 Korean adolescents (315 male and 303 female), aged 10-19 years from the Fourth Korea National Health and Nutrition Examination Survey, 2009. They were divided into three age groups (10-12; 13-16; 17-19 years) and two weight groups (non-overweight vs. overweight). IR was assessed using the homeostatic model of assessment of IR (HOMA-IR). Soft tissue composition (fat and lean mass) and BMC of the whole body, proximal femur, and lumbar spine were measured by dual energy X-ray absorptiometry. Adiposity (body mass index, waist circumference, or soft tissue composition), age, height, total cholesterol, triglycerides, high density lipoprotein cholesterol, alkaline phosphatase, serum vitamin D, dietary calcium and energy intake, and menarche for females were adjusted using general linear models of a complex sampling design. Higher HOMA-IR was associated with a decrease in BMC in male adolescents aged 13-19 years after adjustment for adiposity and other confounders, while the associations were not significant in male adolescents aged 10-12 years and female adolescents. After adjustment for adiposity and confounders, the inverse associations between HOMA-IR and BMC were more consistent in non-overweight male adolescents than in other weight groups (overweight males and non-overweight and overweight females). The unfavorable effect of IR on BMC appears to be more obvious in males aged 13-19 years or non-overweight males than in females.

Bone density, bone quality, and FRAX: changing concepts in osteoporosis management

Bone densitometry was originally developed to diagnose a high risk for fragility fractures in older postmenopausal women who may have primary osteoporosis. Its widespread availability, however, has led to its use in healthy peri- and premenopausal patients and the unexpected findings of low bone density in this group of patients. Their low bone density caused much uncertainty about the likelihood of fracture risk and what treatment might be needed. Conceptually, bone density reflected bone strength, and so a low density reflected increased fracture risk. Clinical experience and the results of pivotal studies of therapy for osteoporosis suggested that bone density was only partly responsible for skeletal strength. Many structural and material properties of bone, not measured by bone density, made it resist fracturing. Clinical risk factors helped determine these characteristics, albeit imperfectly, and aided clinicians decide whether and what treatment was needed. But now, new fracture risk assessment protocols (namely, FRAX, the WHO risk assessment tool) are available to help resolve this dilemma. This paper reviews some of the clinical observations that led to rethinking the concept bone density and bone strength and how it changes the clinical approach to therapy for the healthy young patient.