Epidemiology of Fractures in Diabetes

Hip fractures and type 2 diabetes in the elderly: risk factors analysis of the Nedices cohort

AIM

- To analyze the association between type 2 diabetes (T2D) and the incidence of hip fractures in the elderly, while also considering the influence of socioeconomic status (SES), and other risk factors (RFs).

METHODS

- Data were collected from 5,278 participants aged ≥ 65 years. The study included a baseline and a follow-up survey 3 years later. Participants completed a questionnaire, anthropometric measurements, blood tests, and physical and cognitive tools. The research was conducted in three Spanish communities with different socioeconomic backgrounds.

RESULTS

- At baseline, there were 874 T2D and 4,494 controls. Body mass index (BMI) was slightly higher in individuals with hip fractures. Significant differences were observed in BMI, education level, physical activity, osteoporosis, cataracts, and osteoarthritis. In the follow-up survey, 96 newly, 615 previously T2D, and 2,985 controls were compared. Those with hip fractures were associated with lower educational attainment, sedentary life, and higher diagnoses of osteoporosis, cataracts, and osteoarthritis. Charlson index was higher in individuals with hip fractures. A higher proportion of fractures occurred in urban areas. The rate of incidence of T2D between individuals with and without fractures was not different.

CONCLUSION

- RFs for hip fractures in T2D are similar to those in the general population. Osteoporosis, being female, and advancing age were independent RFs for hip fractures. There was an inverse association between educational level, community allocation, and physical activity which may further contribute to hip fracture risk. These highlights the need for research to better understand the role of T2D and these RFs in hip fracture incidence.

The potential therapeutic effects of Panax notoginseng in osteoporosis: A comprehensive review

BACKGROUND

Accumulating evidence shows that Panax notoginseng, a well-known medicinal herb, has an ideal effect on prevention and treatment of skeletal diseases. In this study, we reviewed clinical applications of clinical application as well as phytochemistry, pharmacokinetics, pharmacology in improving bone quality and toxicity of Panax notoginseng.

PURPOSE

Review the phytochemistry, pharmacokinetics, pharmacology involved in the improving bone metabolism and toxicity of Panax notoginseng and evaluate its potential as a traditional Chinese herbal medicine for osteoporosis.

METHODS

Several databases were consulted, including PubMed, China National Knowledge Infrastructure, National Science and Technology Library and Web of Science. The following words or phrases were used alone or in combinations in the titles and/or abstracts: "","Panax notoginseng", "Sanqi", "osteoporosis", "bone", "osteoblast", "osteoclast", "phytochemistry", "pharmacology" and "pharmacokinetics". Altogether 160 papers were cited.

RESULTS

8 clinical trials of Panax notoginseng alone for the treatment of osteoporosis were identified, most of which used traditional Chinese patent medicines to treat osteoporosis fractures. In these clinical trials, Panax notoginseng preparations have achieved relatively good therapeutic effects. However, more rigorous large-scale experiments are expected to prove their efficacy. Phytochemistry study showed that saponins, flavonoids, polysaccharides are the main active ingredients extracted from Panax notoginseng and the transformation of saponins during the processing explains the different effects of raw and cooked Panax notoginseng. The pharmacokinetics data reveals that protopanaxdiol-type (ppd-type) saponins possesses higher bioavailability than protopanaxtriol-type(ppt-type) saponins and ppd-type saponins such as ginsenoside Ra3, Rb1, and Rd can represent suitable pharmacokinetic markers for Panax notoginseng extracts. The data from animal experiments demonstrates that Panax notoginseng can improve bone quality in ovariectomized, diabetic, hyperlipidemia, radiation-induced, and arthritis rats through the regulation of anti-adipogenesis, anti-inflammation, anti-oxidation, angiogenesis and estrogenic effects. In vitro experiments, the activities of improving bone quality of Panax notoginseng and its ingredients may be attributed to the regulation of multiple signaling pathways, including Wnt/β-catenin, BMP/BMP-R, AMPK/mTOR, GPER/PI3K/AKT, etc. Acute and chronic toxicity as well as genotoxicity studies show that Panax notoginseng is well tolerated while long term use may lead to liver and kidney toxicity.

CONCLUSIONS

Panax notoginseng is a superior medicinal herb that contains multiple active ingredients and could play a potential role in the prevention and treatment of osteoporosis. Further studies should concentrate on developing Panax notoginseng products with higher curative effect and bioavailability.

Association between diabetes of different durations and hip fracture in middle-aged and older people: a stratified cohort study from CHARLS 2011-2020

BACKGROUND

The effect of the duration of diabetes on hip fracture is inconsistent. The aim of this study was to analyze the association between different durations of diabetes and hip fracture.

METHODS

This cohort study included participants from the China Health and Retirement Longitudinal Study (CHARLS) 2011-2020. Diabetes was defined as glycated hemoglobin A1c ≥ 6.5%, fasting blood glucose ≥ 126 mg/dL, random blood glucose ≥ 200 mg/dL, or previous diagnosis of diabetes. Participants were stratified according to diabetes duration, and information was collected on their first hip fracture. The association between diabetes of different durations and hip fracture was assessed using Cox proportional risk models and Kaplan-Meier curves.

RESULTS

A total of 9,927 participants with a mean age of 58.4 ± 8.7 and 54.3% female were included, and 574 participants suffered a hip fracture. Compared with no diabetes, the associations between overall diabetes, newly diagnosed diabetes, diabetes with a duration of < 6 years, and hip fracture were all not significant, all P > 0.05. Known diabetes and diabetes of duration ≥ 6 years significantly increased the risk of hip fracture, with hazard ratios (HRs) and 95% confidence intervals (CIs) of 1.69 (1.19 ~ 2.4), P = 0.003, and 2.2 (1.34 ~ 3.61), P = 0.002.

CONCLUSIONS

Neither newly diagnosed diabetes nor diabetes with a disease duration of < 6 years was associated with hip fracture compared with no diabetes people. When the duration of diabetes is ≥ 6 years, the risk of hip fracture is significantly increased, and appropriate preventive measures are recommended.

Prediction model for low bone mass mineral density in type 2 diabetes: an observational cross-sectional study

PURPOSE

Considering the prevalence of type 2 diabetes (T2D), osteoporosis should be considered a serious complication. However, an effective tool for the assessment of low bone mass mineral density (BMD) in T2D patients is not currently available. Therefore, the aim of our study was to establish a simple-to-use risk assessment tool by exploring risk factors for low BMD in T2D patients.

METHODS

This study included 436 patients with a low BMD and 381 patients with a normal BMD. Multiple logistic regression analysis was performed to evaluate risk factors for low BMD in T2D patients. A nomogram was then developed from these results. A receiver operating characteristic (ROC) curve, calibration plot, and goodness-of-fit test were used to validate the nomogram. The clinical utility of the nomogram was also assessed.

RESULTS

Multivariate logistic regression indicated that age, sex, education, body mass index (BMI), fasting C-peptide, high-density cholesterol (HDL), alkaline phosphatase (ALP), estimated glomerular filtration rate (eGFR), and type I collagen carboxy terminal peptide (S-CTX) were independent predictors for low BMD in T2D patients. The nomogram was developed from these variables using both the unadjusted area under the curve (AUC) and the bootstrap-corrected AUC (0.828). Calibration plots and the goodness-of-fit test demonstrated that the nomogram was well calibrated.

CONCLUSIONS

The nomogram-illustrated model can be used by clinicians to easily predict the risk of low BMD in T2D patients. Our study also revealed that common factors are independent predictors of low BMD risk. Our results provide a new strategy for the prediction, investigation, and facilitation of low BMD in T2D patients.

The potential therapeutic role of curcumin in osteoporosis treatment: based on multiple signaling pathways

Osteoporosis is a common chronic metabolic bone disease caused by disturbances in normal bone metabolism and an imbalance between osteoblasts and osteoclasts. Osteoporosis is characterized by a decrease in bone mass and bone density, leading to increased bone fragility. Osteoporosis is usually treated with medications and surgical methods, but these methods often produce certain side effects. Therefore, the use of traditional herbal ingredients for the treatment of osteoporosis has become a focus of attention and a hot topic in recent years. Curcumin, widely distributed among herbs such as turmeric, tulip, and curcuma longa, contains phenolic, terpenoid, and flavonoid components. Modern pharmacological studies have confirmed that curcumin has a variety of functions including antioxidant and anti-inflammatory properties. In addition, curcumin positively regulates the differentiation and promotes the proliferation of osteoblasts, which play a crucial role in bone formation. Multiple studies have shown that curcumin is effective in the treatment of osteoporosis as it interacts with a variety of signaling pathway targets, thereby interfering with the formation of osteoblasts and osteoclasts and regulating the development of osteoporosis. This review summarized the key signaling pathways and their mechanisms of action of curcumin in the prevention and treatment of osteoporosis and analyzed their characteristics and their relationship with osteoporosis and curcumin. This not only proves the medicinal value of curcumin as a traditional herbal ingredient but also further elucidates the molecular mechanism of curcumin's anti-osteoporosis effect, providing new perspectives for the prevention and treatment of osteoporosis through multiple pathways.

Impact of High-Fat Diet and Exercise on Bone and Bile Acid Metabolism in Rats

Bile acids help facilitate intestinal lipid absorption and have endocrine activity in glucose, lipid and bone metabolism. Obesity and exercise influence bile acid metabolism and have opposite effects in bone. This study investigates if regular exercise helps mitigate the adverse effects of obesity on bone, potentially by reversing alterations in bile acid metabolism. Four-month-old female Sprague Dawley rats either received a high-fat diet (HFD) or a chow-based standard diet (lean controls). During the 10-month study period, half of the animals performed 30 min of running at moderate speed on five consecutive days followed by two days of rest. The other half was kept inactive (inactive controls). At the study's end, bone quality was assessed by microcomputed tomography and biomechanical testing. Bile acids were measured in serum and stool. HFD feeding was related to reduced trabecular (-33%, p = 1.14 × 10-7) and cortical (-21%, p = 2.9 × 10-8) bone mass and lowered femoral stiffness (12-41%, p = 0.005). Furthermore, the HFD decreased total bile acids in serum (-37%, p = 1.0 × 10-6) but increased bile acids in stool (+2-fold, p = 7.3 × 10-9). These quantitative effects were accompanied by changes in the relative abundance of individual bile acids. The concentration of serum bile acids correlated positively with all cortical bone parameters (r = 0.593-0.708), whilst stool levels showed inverse correlations at the cortical (r = -0.651--0.805) and trabecular level (r = -0.656--0.750). Exercise improved some trabecular and cortical bone quality parameters (+11-31%, p = 0.043 to 0.001) in lean controls but failed to revert the bone loss related to the HFD. Similarly, changes in bile acid metabolism were not mitigated by exercise. Prolonged HFD consumption induced quantitative and qualitative alterations in bile acid metabolism, accompanied by bone loss. Tight correlations between bile acids and structural indices of bone quality support further functional analyses on the potential role of bile acids in bone metabolism. Regular moderate exercise improved trabecular and cortical bone quality in lean controls but failed in mitigating the effects related to the HFD in bone and bile acid metabolism.

Nutrition-Based Support for Osteoporosis in Postmenopausal Women: A Review of Recent Evidence

Postmenopausal osteoporosis stands as the predominant bone disorder in the developed world, posing a significant public health challenge. Nutritional factors play a crucial role in bone health and may contribute to its prevention or treatment. Calcium and vitamin D, extensively studied with robust scientific evidence, are integral components of the non-pharmacological treatment for this disorder. Nevertheless, other less-explored nutritional elements appear to influence bone metabolism. This review provides a comprehensive summary of the latest evidence concerning the relationship between various nutrients, such as phosphorus, magnesium, vitamins, phytate, and phytoestrogens; specific foods like dairy or soy, and dietary patterns such as the Mediterranean diet with bone health and osteoporosis.

Sex- and Age Group-Specific Fracture Incidence Rates Trends for Type 1 and 2 Diabetes Mellitus

The incidence of major osteoporotic fractures has declined in men and women in Western countries over the last two decades. Although fracture risk is higher in persons with diabetes mellitus, trends of fractures remain unknown in men and women with diabetes. We investigated the trends in fracture incidence rates (IRs) in men and women with type 1 diabetes mellitus (T1D) and type 2 diabetes mellitus (T2D) in Denmark between 1997 and 2017. We identified men and women aged 18+ years who sustained a fracture (excluding skull and facial fractures) between 1997 and 2017 using the Danish National Patient Registry. We calculated sex-specific IRs of fractures per 10,000 person-years separately in persons with T1D, T2D, or without diabetes. Furthermore, we compared median IRs of the first 5 years (1997-2002) to the median IRs of the last 5 years (2012-2017). We identified 1,235,628 persons with fractures including 4863 (43.6% women) with T1D, 65,366 (57.5% women) with T2D, and 1,165,399 (54.1% women) without diabetes. The median IRs of fractures declined 20.2%, 19.9%, and 7.8% in men with T1D, T2D, and without diabetes, respectively (p-trend <0.05). The median IRs decreased 6.4% in women with T1D (p-trend = 0.35) and 25.6% in women with T2D (p-trend <0.05) but increased 2.3% in women without diabetes (p-trend = 0.08). Fracture IRs decreased in men with both diabetes types and only in women with T2D, highlighting the need for further attention behind the stable trend observed in women with T1D. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Advanced glycation and glycoxidation end products in bone

Hyperglycemia and oxidative stress, enhanced in diabetes and aging, result in excessive accumulation of advanced glycation and glycoxidation end products (AGEs/AGOEs) in bone. AGEs/AGOES are considered to be "the missing link" in explaining increased skeletal fragility with diabetes, aging, and osteoporosis where increased fracture risk cannot be solely explained by bone mass and/or fall incidences. AGEs/AGOEs disrupt bone turnover and deteriorate bone quality through alterations of organic matrix (collagen and non-collagenous proteins), mineral, and water content. AGEs and AGOEs are also associated with bone fragility in other conditions such as Alzheimer's disease, circadian rhythm disruption, and cancer. This review explains how AGEs and AGOEs accumulate in bone and impact bone quality and bone fracture, and how AGES/AGOEs are being targeted in preclinical and clinical investigations for inhibition or removal, and for prediction and management of diabetic, osteoporotic and insufficiency fractures.

Increased Advanced Glycation Endproducts, Stiffness, and Hardness in Iliac Crest Bone From Postmenopausal Women With Type 2 Diabetes Mellitus on Insulin

Individuals with type 2 diabetes mellitus (T2DM) have a greater risk of bone fracture compared with those with normal glucose tolerance (NGT). In contrast, individuals with impaired glucose tolerance (IGT) have a lower or similar risk of fracture. Our objective was to understand how progressive glycemic derangement affects advanced glycation endproduct (AGE) content, composition, and mechanical properties of iliac bone from postmenopausal women with NGT (n = 35, age = 65 ± 7 years, HbA1c = 5.8% ± 0.3%), IGT (n = 26, age = 64 ± 5 years, HbA1c = 6.0% ± 0.4%), and T2DM on insulin (n = 25, age = 64 ± 6 years, HbA1c = 9.1% ± 2.2%). AGEs were assessed in all samples using high-performance liquid chromatography to measure pentosidine and in NGT/T2DM samples using multiphoton microscopy to spatially resolve the density of fluorescent AGEs (fAGEs). A subset of samples (n = 14 NGT, n = 14 T2DM) was analyzed with nanoindentation and Raman microscopy. Bone tissue from the T2DM group had greater concentrations of (i) pentosidine versus IGT (cortical +24%, p = 0.087; trabecular +35%, p = 0.007) and versus NGT (cortical +40%, p = 0.003; trabecular +35%, p = 0.004) and (ii) fAGE cross-link density versus NGT (cortical +71%, p < 0.001; trabecular +44%, p < 0.001). Bone pentosidine content in the IGT group was lower than in the T2DM group and did not differ from the NGT group, indicating that the greater AGE content observed in T2DM occurs with progressive diabetes. Individuals with T2DM on metformin had lower cortical bone pentosidine compared with individuals not on metformin (-35%, p = 0.017). Cortical bone from the T2DM group was stiffer (+9%, p = 0.021) and harder (+8%, p = 0.039) versus the NGT group. Bone tissue AGEs, which embrittle bone, increased with worsening glycemic control assessed by HbA1c (Pen: R2  = 0.28, p < 0.001; fAGE density: R2  = 0.30, p < 0.001). These relationships suggest a potential mechanism by which bone fragility may increase despite greater tissue stiffness and hardness in individuals with T2DM; our results suggest that it occurs in the transition from IGT to overt T2DM. © 2022 American Society for Bone and Mineral Research (ASBMR).

Why Aboriginal and Torres Strait Islander Australians fall and fracture: the codesigned Study of Indigenous Muscle and Bone Ageing (SIMBA) protocol

OBJECTIVES

Aboriginal and Torres Strait Islander Australians have a substantially greater fracture risk, where men are 50% and women are 26% more likely to experience a hip fracture compared with non-Indigenous Australians. Fall-related injuries in this population have also increased by 10%/year compared with 4.3%/year in non-Indigenous Australians. This study aims to determine why falls and fracture risk are higher in Aboriginal and Torres Strait Islander Australians.

SETTING

All clinical assessments will be performed at one centre in Melbourne, Australia. At baseline, participants will have clinical assessments, including questionnaires, anthropometry, bone structure, body composition and physical performance tests. These assessments will be repeated at follow-up 1 and follow-up 2, with an interval of 12 months between each clinical visit.

PARTICIPANTS

This codesigned prospective observational study aims to recruit a total of 298 adults who identify as Aboriginal and Torres Strait Islander and reside within Victoria, Australia. Stratified sampling by age and sex will be used to ensure equitable distribution of men and women across four age-bands (35-44, 45-54, 55-64 and 65+ years).

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome is within-individual yearly change in areal bone mineral density at the total hip, femoral neck and lumbar spine assessed by dual energy X-ray absorptiometry. Within-individual change in cortical and trabecular volumetric bone mineral density at the radius and tibia using high-resolution peripheral quantitative computed tomography will be determined. Secondary outcomes include yearly differences in physical performance and body composition.

ETHICAL APPROVAL

Ethics approval for this study has been granted by the Monash Health Human Research Ethics Committee (project number: RES-19-0000374A).

TRIAL REGISTRATION NUMBER

ACTRN12620000161921.

The pattern of incident fractures according to fracture site in people with T1D

Higher incidences of fractures are seen in people with type 1 diabetes (T1D), but knowledge on different fracture sites is sparse. We found a higher incidence mainly for distal fracture sites in people with T1D compared to controls. It must be further studied which fractures attributed to the higher incidence rates (IRs) at specific sites.

INTRODUCTION

People with T1D have a higher incidence of fractures compared to the general population. However, sparse knowledge exists on the incidence rates of individual fracture sites. Therefore, we examined the incidence of various fracture sites in people with newly treated T1D compared to matched controls.

METHODS

All people from the UK Clinical Practice Research Datalink GOLD (1987-2017), of all ages with a T1D diagnosis code (n = 6381), were included. People with T1D were matched by year of birth, sex, and practice to controls (n = 6381). Fracture IRs and incidence rate ratios (IRRs) were calculated. Analyses were stratified by fracture site and sex.

RESULTS

The IR of all fractures was significantly higher in people with T1D compared to controls (IRR: 1.39 (CI95%: 1.24-1.55)). Compared to controls, the IRR for people with T1D was higher for several fracture sites including carpal (IRR: 1.41 (CI95%: 1.14-1.75)), clavicle (IRR: 2.10 (CI95%: 1.18-3.74)), foot (IRR: 1.70 (CI95%: 1.23-2.36)), humerus (IRR: 1.46 (CI95%: 1.04-2.05)), and tibia/fibula (IRR: 1.67 CI95%: 1.08-2.59)). In women with T1D, higher IRs were seen at the ankle (IRR: 2.25 (CI95%: 1.10-4.56)) and foot (IRR: 2.11 (CI95%: 1.27-3.50)), whereas in men with T1D, higher IRs were seen for carpal (IRR: 1.45 (CI95%: 1.14-1.86)), clavicle (IRR: 2.13 (CI95%: 1.13-4.02)), and humerus (IRR: 1.77 (CI95%: 1.10-2.83)) fractures.

CONCLUSION

The incidence of carpal, clavicle, foot, humerus, and tibia/fibula fractures was higher in newly treated T1D, but there was no difference at other fracture sites compared to controls. Therefore, the higher incidence of fractures in newly treated people with T1D has been found mainly for distal fracture sites.

Glucose variability and low bone turnover in people with type 2 diabetes

INTRODUCTION

Type 2 diabetes (T2D) is related to an increased fracture risk and low bone turnover. However, the mechanisms are not elucidated. In the present study we investigate the association between glycemic variability and bone turnover markers.

METHODS

100 participants with T2D and 100 age and gender matched controls were included in this cross-sectional study. All participants with T2D were equipped with a continuous glucose monitoring (CGM) sensor for 3 days (CGMS iPro Continuous Glucose Recorder; Medtronic MiniMed). The dawn glucose levels were defined as a morning period starting 1 h before breakfast ending 1 h post ingestion. On all participants serum (s)-C-terminal cross-linked telopeptide of type-I collagen (CTX), s-procollagen type 1 amino terminal propeptide (P1NP), and s-sclerostin were measured.

RESULTS

Participants with T2D displayed significantly lower levels of the bone resorption marker s-CTX and the bone formation marker s-P1NP compared to controls. S-CTX was significantly negatively associated with the mean amplitude of glycemic excursions (MAGE) and the dawn glucose levels whereas s-P1NP only was significantly negatively associated with the dawn glucose levels while it was borderline significantly associated with MAGE (p = 0.05). S-CTX and s-P1NP were significantly lower among the 50% with the highest dawn glucose levels compared to the 50% lowest dawn glucose levels also after adjustment for age, gender, glycated hemoglobin A1c (HbA1c), and body mass index (BMI).

CONCLUSION

We observed that the amplitude of glycemic excursions and rise in dawn glucose was negatively associated with bone turnover markers. Future research is needed to determine whether reduction of the amplitude of glycemic excursions increase bone turnover markers.

Diabetes increases the risk of bone fractures in patients on kidney replacement therapy: A Danish national cohort study

BACKGROUND

Patients treated with dialysis or living with a kidney transplant (kidney replacement therapy, KRT) have an increased risk of bone fracture. Patients with diabetes also have an increased risk of fracture. The aim of this study was to investigate whether the presence of diabetes in patients on KRT aggravates the risk of fracture.

METHODS

Nationwide Danish registries were used in this retrospective cohort study. All prevalent adult patients on hemodialysis (HD) or peritoneal dialysis (PD) on 1st of January 2000 and all incident patients starting KRT (HD, PD, kidney transplanted (KTX)) until 31st of December 2011 were included in the KRT group. Adult persons not on KRT and without diabetes on 1st of January 2000 were used as a reference group. Patients were separated in groups with and without (+/-) diabetes. They were followed until first fracture, emigration, death, or end-of-study on 31st of December 2016.

RESULTS

A total of 4,074,085 not on KRT +/- diabetes and 9053 patients on KRT +/- diabetes were included. Comparing the different groups with diabetes to the corresponding group without diabetes, the unadjusted HR (95% CI) for any first fracture were 1.2 (1.0-1.3) in the HD population, 1.4 (1.1-1.7) in the PD population, and 1.7 (1.4-2.2) in the KTX population. Further adjustments for age, sex, prior fractures, comorbidity and medication did not change these results significantly.

CONCLUSIONS

Diabetes increases the risk of fracture in patients on KRT.

Stress Hyperglycemia and Osteocalcin in COVID-19 Critically Ill Patients on Artificial Nutrition

We aimed to study the possible association of stress hyperglycemia in COVID-19 critically ill patients with prognosis, artificial nutrition, circulating osteocalcin, and other serum markers of inflammation and compare them with non-COVID-19 patients. Fifty-two critical patients at the intensive care unit (ICU), 26 with COVID-19 and 26 non-COVID-19, were included. Glycemic control, delivery of artificial nutrition, serum osteocalcin, total and ICU stays, and mortality were recorded. Patients with COVID-19 had higher ICU stays, were on artificial nutrition for longer (p = 0.004), and needed more frequently insulin infusion therapy (p = 0.022) to control stress hyperglycemia. The need for insulin infusion therapy was associated with higher energy (p = 0.001) and glucose delivered through artificial nutrition (p = 0.040). Those patients with stress hyperglycemia showed higher ICU stays (23 ± 17 vs. 11 ± 13 days, p = 0.007). Serum osteocalcin was a good marker for hyperglycemia, as it inversely correlated with glycemia at admission in the ICU (r = -0.476, p = 0.001) and at days 2 (r = -0.409, p = 0.007) and 3 (r = -0.351, p = 0.049). In conclusion, hyperglycemia in critically ill COVID-19 patients was associated with longer ICU stays. Low circulating osteocalcin was a good marker for stress hyperglycemia.

Effects of a whey protein pre-meal on bone turnover in participants with and without type 2 diabetes-A post hoc analysis of a randomised, controlled, crossover trial

AIMS

Whey protein may improve bone turnover and have anti-osteoporotic effects. The aim of the present randomised, controlled, crossover trial was to evaluate the effects of a whey protein pre-meal on bone turnover in people with type 2 diabetes and controls.

METHODS

Two groups, matched on sex, age and body mass index, comprising 12 participants with and 12 participants without type 2 diabetes were randomly given a pre-meal of whey protein (20 g) or water, which was consumed 15 min before a fat-rich meal or a fat-rich meal supplemented with 20 g whey protein. During a 360-min period, postprandial responses in bone turnover were examined.

RESULTS

Osteocalcin, P-procollagen type 1 amino terminal propeptide (P1NP), C-terminal cross-linked telopeptide of type-I collagen (CTX) and parathyroid hormone (PTH) were lower at baseline and PTH, osteocalcin and P1NP were lower during the entire postprandial phase in participants with type 2 diabetes than in participants without type 2 diabetes. We observed similar postprandial responses in bone turnover markers between persons with and without type 2 diabetes. We observed no effect of the whey protein or the water pre-meal on bone turnover markers. The changes were unrelated to secretion of hormones of the gut-bone axis.

CONCLUSION

Osteocalcin, P1NP, CTX and PTH all decreased following meal ingestion. We observed no convincing effect of a whey protein pre-meal on bone turnover. However, these results confirm that people with type 2 diabetes have low bone turnover and that the decreased bone formation markers are also extend into the postprandial responses.

Distinct Effects of a High Fat Diet on Bone in Skeletally Mature and Developing Male C57BL/6J Mice

Increased risks of skeletal fractures are common in patients with impaired glucose handling and type 2 diabetes mellitus (T2DM). The pathogenesis of skeletal fragility in these patients remains ill-defined as patients present with normal to high bone mineral density. With increasing cases of glucose intolerance and T2DM it is imperative that we develop an accurate rodent model for further investigation. We hypothesized that a high fat diet (60%) administered to developing male C57BL/6J mice that had not reached skeletal maturity would over represent bone microarchitectural implications, and that skeletally mature mice would better represent adult-onset glucose intolerance and the pre-diabetes phenotype. Two groups of developing (8 week) and mature (12 week) male C57BL/6J mice were placed onto either a normal chow (NC) or high fat diet (HFD) for 10 weeks. Oral glucose tolerance tests were performed throughout the study period. Long bones were excised and analysed for ex vivo biomechanical testing, micro-computed tomography, 2D histomorphometry and gene/protein expression analyses. The HFD increased fasting blood glucose and significantly reduced glucose tolerance in both age groups by week 7 of the diets. The HFD reduced biomechanical strength, both cortical and trabecular indices in the developing mice, but only affected cortical outcomes in the mature mice. Similar results were reflected in the 2D histomorphometry. Tibial gene expression revealed decreased bone formation in the HFD mice of both age groups, i.e., decreased osteocalcin expression and increased sclerostin RNA expression. In the mature mice only, while the HFD led to a non-significant reduction in runt-related transcription factor 2 (Runx2) RNA expression, this decrease became significant at the protein level in the femora. Our mature HFD mouse model more accurately represents late-onset impaired glucose tolerance/pre-T2DM cases in humans and can be used to uncover potential insights into reduced bone formation as a mechanism of skeletal fragility in these patients.

Understanding Bone Disease in Patients with Diabetic Kidney Disease: a Narrative Review

PURPOSE OF REVIEW

Both diabetes and kidney disease associate with the development of bone disease and an increased risk of fragility fractures. The etiologies of bone disease in patients with diabetic kidney disease (DKD) are multiple and complex. This review explores the association between DKD and bone disease and discusses how the presence of both diabetes and kidney disease may impair bone quality and increase fracture risk. Diagnostic tools as well as future research areas are also discussed.

RECENT FINDINGS

Patients with DKD have an increased risk of fragility fracture, most pronounced in patients with type 1 diabetes, and in DKD a high prevalence of adynamic bone disease is found. Recent studies have demonstrated disturbances in the interplay between bone regulating factors in DKD, such as relative hypoparathyroidism and alterations of bone-derived hormones including fibroblast growth factor-23 (FGF-23), sclerostin and klotho, which lead to bone disease. This review examines the current knowledge on bone disease in patients with DKD, clinical considerations for patient care, as well as subjects for future research.

Negligible Effect of Estrogen Deficiency on Development of Skeletal Changes Induced by Type 1 Diabetes in Experimental Rat Models

Although postmenopausal osteoporosis often occurs concurrently with diabetes, little is known about interactions between estrogen deficiency and hyperglycemia in the skeletal system. In the present study, the effects of estrogen deficiency on the development of biochemical, microstructural, and mechanical changes induced by streptozotocin-induced diabetes mellitus (DM) in the rat skeletal system were investigated. The experiments were carried out on nonovariectomized (NOVX) and ovariectomized (OVX) control and diabetic mature female Wistar rats. Serum levels of bone turnover markers (CTX-I and osteocalcin) and 23 cytokines, bone mass and mineralization, histomorphometric parameters, and mechanical properties of cancellous and compact bone were determined. The results were subjected to two-way ANOVA and principal component analysis (PCA). Estrogen deficiency induced osteoporotic changes, with increased bone resorption and formation, and worsening of microstructure (femoral metaphyseal BV/TV decreased by 13.0%) and mechanical properties of cancellous bone (the maximum load in the proximal tibial metaphysis decreased by 34.2%). DM in both the NOVX and OVX rats decreased bone mass, increased bone resorption and decreased bone formation, and worsened cancellous bone microarchitecture (for example, the femoral metaphyseal BV/TV decreased by 17.3% and 18.1%, respectively, in relation to the NOVX controls) and strength (the maximum load in the proximal tibial metaphysis decreased by 35.4% and 48.1%, respectively, in relation to the NOVX controls). Only in the diabetic rats, profound increases in some cytokine levels were noted. In conclusion, the changes induced by DM in female rats were only slightly intensified by estrogen deficiency. Despite similar effects on bone microstructure and strength, the influence of DM on the skeletal system was based on more profound systemic homeostasis changes than those induced by estrogen deficiency.

Potentially inappropriate medications in older individuals with diabetes: A population-based study in Quebec, Canada

AIM

To study the population-based prevalence of potentially inappropriate medication (PIM) among older individuals with diabetes, and to identify factors associated with their use.

METHODS

We used the Quebec Integrated Chronic Disease Surveillance System (QICDSS) database to conduct a population-based cohort study of individuals with diabetes ≥66 years between April 1st, 2014 and March 31st, 2015. PIMs were defined according to the 2015 Beers Criteria. Factors associated with PIM use were identified using robust Poisson regression models. Risk ratios (RR) and 99% confidence intervals (99%CI) were calculated.

RESULTS

More than half (56%) of the 286,962 older individuals with diabetes used at least one PIM over a year. Benzodiazepines (41%), proton pump inhibitors (27%) and endocrine medication (mainly glibenclamide) (25%) were the most common PIMs used. Factors associated with PIM use included female sex (RR: 1.17; 99%CI: 1.16-1.18), and comorbidities such as schizophrenia (1.48; 1.45-1.51), anxiety disorders (1.34; 1.33-1.35) and Alzheimer's disease (1.14; 1.13-1.25). Risks of using PIMs increased both with increasing comorbidities and number of medications.

CONCLUSION

PIM use is highly prevalent among older individuals with diabetes. Interventions to promote optimal medication use should particularly target individuals with comorbidities and polypharmacy who are most vulnerable to adverse drug events.

Adverse event profiles of dipeptidyl peptidase-4 inhibitors: data mining of the public version of the FDA adverse event reporting system

BACKGROUND

To describe and analyze the patterns of adverse events associated with dipeptidyl peptidase-4 inhibitors (DPP-4is) (sitagliptin, saxagliptin, linagliptin, vildagliptin, and alogliptin) from the FDA Adverse Event Reporting System (FAERS) and to highlight areas of safety concerns.

METHODS

Adverse events spontaneously submitted to the FAERS between 2004 Q1 to 2019 Q2 were included. The online tool OpenVigil 2.1 was used to query the database. The research relied on definitions of preferred terms (PTs) specified by the Medical Dictionary for Regulatory Activities (MedDRA) and the standardized MedDRA Queries (SMQ). The reporting odds ratio (ROR), with 95% confidence intervals (CIs) was calculated for disproportionality analysis.

RESULTS

Over 16 years, a total of 9706 adverse event reports were identified. Alogliptin was excluded from further analysis due to insufficient sample size. Compared with the non-insulin antidiabetic drugs, the four DPP-4is were all disproportionately associated with four SMQs: "gastrointestinal nonspecific inflammation and dysfunctional conditions," "hypersensitivity," "severe cutaneous adverse reactions," and "noninfectious diarrhoea". As for PT level analyses, DPP-4is are associated with higher reporting of the gastrointestinal tract, pancreas, malignancies, infection, musculoskeletal disorders, general disorders, hypersensitivity, and skin AEs.

CONCLUSIONS

Data mining of the FAERS is useful for examining DPP-4 inhibitors-associated adverse events. The findings of the present study are compatible with clinical experience, and it provides valuable information to decision-makers and healthcare providers in clinical practice.

Update on the Acute Effects of Glucose, Insulin, and Incretins on Bone Turnover In Vivo

PURPOSE OF REVIEW

To provide an update on the acute effects of glucose, insulin, and incretins on markers of bone turnover in those with and without diabetes.

RECENT FINDINGS

Bone resorption is suppressed acutely in response to glucose and insulin challenges in both healthy subjects and patients with diabetes. The suppression is stronger with oral glucose compared with intravenous delivery. Stronger responses with oral glucose may be related to incretin effects on insulin secretion or from a direct effect on bone turnover. Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-2 (GLP-2) infusion acutely suppresses bone resorption without much effect on bone formation. The bone turnover response to a metabolic challenge may be attenuated in type 2 diabetes, but this is an understudied area. A knowledge gap exists regarding bone turnover responses to a metabolic challenge in type 1 diabetes. The gut-pancreas-bone link is potentially an endocrine axis. This linkage is disrupted in diabetes, but the mechanism and progression of this disruption are not understood.

Incidence of fractures in patients with type 1 diabetes mellitus-a retrospective study with 4420 patients

This retrospective study investigated the incidence of fracture in 4420 type 1 diabetes (T1DM) patients. Our findings indicate that patients with T1DM have an increased incidence of fractures. Further studies and preventive measures are urgently needed.

INTRODUCTION

The aim of this study was to investigate the incidence of fracture in patients with type 1 diabetes mellitus (T1DM).

METHODS

This study is based on the German Disease Analyzer database and included 4258 adult individuals with a T1DM diagnosis documented between January 2000 and December 2015 in 1203 general practices in Germany. Individual matching of T1DM and non-diabetic patients was performed. The cumulative incidence of new fractures was shown for up to 10 years after the index date using Kaplan-Meier curves. Cox proportional hazard models (dependent variable: incident fracture) were used to estimate the effect of T1DM on fracture incidence, as well as the effect of predefined variables on fracture incidence.

RESULTS

After 10 years of follow-up, the cumulative fracture incidence was 18.4% for T1DM patients and 9.9% for non-diabetic patients (p < 0.001). A strong association between T1DM and fractures was found (HR, 2.01 (95% CI, 1.70-2.38) p < 0.001) in both female and male patients. Significant differences between T1DM and non-diabetes patients were found in lower leg/ankle, foot and toe, shoulder/upper arm, and rib(s), sternum and thoracic spine fractures. A significant association between higher age and fracture incidence was observed in T1DM patients.

CONCLUSIONS

In summary, we found that patients with T1DM have a twofold increased fracture rate compared with healthy controls. Furthermore, fractures were associated with increased age and high HbA1c values.

Relationship between Insulin Resistance (HOMA-IR), Trabecular Bone Score (TBS), and Three-Dimensional Dual-Energy X-ray Absorptiometry (3D-DXA) in Non-Diabetic Postmenopausal Women

BACKGROUND

Insulin may play a key role in bone metabolism, where the anabolic effect predominates. This study aims to analyze the relationship between insulin resistance and bone quality using the trabecular bone score (TBS) and three-dimensional dual-energy X-ray absorptiometry (3D-DXA) in non-diabetic postmenopausal women by determining cortical and trabecular compartments.

METHODS

A cross-sectional study was conducted in non-diabetic postmenopausal women with suspected or diagnosed osteoporosis. The inclusion criteria were no menstruation for more than 12 months and low bone mass or osteoporosis as defined by DXA. Glucose was calculated using a Hitachi 917 auto-analyzer. Insulin was determined using an enzyme-linked immunosorbent assay (EIA). Insulin resistance was estimated using a homeostasis model assessment of insulin resistance (HOMA-IR). DXA, 3D-DXA, and TBS were thus collected. Moreover, we examined bone parameters according to quartile of insulin, hemoglobin A1C (HbA1c), and HOMA-IR.

RESULTS

In this study, we included 381 postmenopausal women. Women located in quartile 4 (Q4) of HOMA-IR had higher values of volumetric bone mineral density (vBMD) but not TBS. The increase was higher in the trabecular compartment (16.4%) than in the cortical compartment (6.4%). Similar results were obtained for insulin. Analysis of the quartiles by HbA1c showed no differences in densitometry values, however women in Q4 had lower levels of TBS. After adjusting for BMI, statistical significance was maintained for TBS, insulin, HOMA-IR, and HbA1c.

CONCLUSIONS

In non-diabetic postmenopausal women there was a direct relationship between insulin resistance and vBMD, whose effect is directly related to greater weight. TBS had an inverse relationship with HbA1c, insulin, and insulin resistance unrelated to weight. This might be explained by the formation of advanced glycosylation products (AGEs) in the bone matrix, which reduces bone deformation capacity and resistance, as well as increases fragility.

Is Switching from Oral Antidiabetic Therapy to Insulin Associated with an Increased Fracture Risk?

BACKGROUND

Observational studies showed that exposure to exogenous insulin increases fracture risk. However, it remains unclear whether the observed association is a function of the severity of underlying type 2 diabetes mellitus, complications, therapies, comorbidities, or all these factors combined. That being so, and because of the relative infrequency of these events, it is important to study this further in a large-database setting. QUESTION/PURPOSES: (1) Is switching from oral antidiabetic agents to insulin associated with an increased fracture risk? (2) How soon after switching does the increased risk appear, and for how long does this increased risk persist?

METHODS

Data from healthcare utilization databases of the Italian region of Lombardy were used. These healthcare utilization databases report accurate, complete, and interconnectable information of inpatient and outpatient diagnoses, therapies, and services provided to the almost 10 million residents in the region. The 216,624 patients on treatment with oral antidiabetic therapy from 2005 to 2009 were followed until 2010 to identify those who modified their antidiabetic therapy (step 1 cohort). Among the 63% (136,307 patients) who experienced a therapy modification, 21% (28,420 patients) switched to insulin (active exposure), and the remaining 79% (107,887 patients) changed to another oral medication (referent exposure). A 1:1 high-dimension propensity score matching design was adopted for balancing patients on active and referent exposure. Matching failed for 3% of patients (926 patients), so the cohort of interest was formed by 27,494 insulin-referent couples. The latter were followed until 2012 to identify those who experienced hospital admission for fracture (outcome). A Cox proportional hazard model was fitted to estimate the hazard ratio (HR) for the outcome risk associated with active-exposure (first research question). Between-exposure comparison of daily fracture hazard rates from switching until the 24 successive months was explored through the Kernel-smoothed estimator (second research question).

RESULTS

Compared with patients on referent exposure, those who switched to insulin had an increased risk of experiencing any fracture (HR = 1.5 [95% CI 1.3 to 1.6]; p < 0.001). The same risk was observed for hip and vertebral fractures, with HRs of 1.6 (95% CI 1.4 to 1.8; p < 0.001) and 1.8 (95% 1.5 to 2.3; p < 0.001), respectively. Differences in the daily pattern of outcome rates mainly appeared the first 2 months after switching, when the hazard rate of patients on active exposure (9 cases for every 100,000 person-days) was higher than that of patients on referent exposure (4 cases for every 100,000 person-days). These differences persisted during the remaining follow-up, though with reduced intensity.

CONCLUSIONS

We found quantitative evidence that switching from oral antidiabetic therapy to insulin is associated with an increased fracture risk, mainly in the period immediately after the start of insulin therapy. The observed association may result from higher hypoglycemia risk among patients on insulin, which leads to a greater number of falls and resulting fractures. However, although our study was based on a large sample size and highly accurate data, its observational design and the lack of clinical data suggest that future research will need to replicate or refute our findings and address the issue of causality, if any. Until then, though, prescribers and patients should be aware of this risk. Careful control of insulin dosage should be maintained and measures taken to reduce fall risk in these patients.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Consumption of nutrients and insulin resistance suppress markers of bone turnover in subjects with abdominal obesity

OBJECTIVE

Abdominal obesity and type 2 diabetes are associated with insulin resistance and low bone turnover along with an increased fracture risk. The mode of action is poorly understood. The bone resorption marker, C-terminal telopeptide type 1 collagen (CTX), and to a lesser extent, the bone formation marker, Procollagen type 1 N-terminal propeptide (P1NP) appear to be inhibited by food consumption. The link between food consumption, insulin resistance and bone turnover remains to be clarified. Primarily we aimed to compare the postprandial CTX, P1NP and PTH responses by two frequently applied methods in assessing metabolic health; oral glucose tolerance test (OGTT) and mixed meal tolerance test. Secondly, we explored the effect of insulin resistance on bone marker responses.

METHODS

We enrolled 64 subjects with abdominal obesity. Following 10 h of fasting, subjects initially underwent a standard OGTT (300 kcal) and approximately one week later a mixed meal tolerance test (1130 kcal). Circulating CTX, P1NP and PTH were assessed on both days at time = 0, after 30 min and after 90 min for comparison of the two interventions. We analyzed glucose and insulin levels for the assessment of insulin resistance. Additionally, we measured plasma calcium levels along with the gut hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like-peptide 2 (GLP-2) in an attempt to identify possible mediators of the postprandial bone response.

RESULTS

CTX, P1NP and PTH were suppressed by OGTT and the mixed meal; the latter induced a more pronounced suppression after 90 min. Calcium levels were similar between OGTT and meal. GIP and GLP-2 levels increased after both interventions, although only the meal induced a sustained increase after 90 min. Fasting P1NP was inversely associated with insulin resistance. The meal-induced suppression of P1NP (but not CTX or PTH) was inversely associated with level of insulin resistance.

CONCLUSION

The acute postprandial suppression of bone turnover markers is extended after ingestion of a mixed meal compared to an OGTT. The response appears to be independent of gender and prompted by a reduction in PTH. The study additionally indicates a possible link between the development of insulin resistance and low bone turnover - which may be of key essence in the development of the fragile bone structure and increased fracture risk demonstrated in subjects with abdominal obesity and T2D.

Pilose antler peptide promotes osteoblast proliferation, differentiation and mineralization via the insulin signaling pathway

Osteoporosis is a severe bone disease characterized by a decrease in the density and structure of bones, with high risks of fractures. Pilose antler peptide (PAP), extracted and purified from deer antlers, can promote regeneration and fracture healing, and strengthen sinews and bone. To determine whether PAP can promote osteoblast development and to elucidate the molecular mechanisms underlying its functions, the present study investigated the effects of PAP on osteoblast proliferation, differentiation and mineralization, and the role of the insulin signaling pathway using MTT assay, alkaline phosphatase activity assay, western blot analysis and reverse transcription-quantitative PCR. The present results suggested that PAP promoted osteoblast proliferation, differentiation and mineralization in vitro via the insulin signaling pathway. The effect of PAP on insulin signaling in osteoblasts may be mediated via the ERK pathway and partially by the PI3K/Akt pathway. The present results indicated that PAP could potentially be developed as an alternative treatment strategy for bone diseases related to diabetes characterized by insulin signaling impairment.

Effects of Diabetes on Bone Material Properties

PURPOSE OF REVIEW

Individuals with type 1 and type 2 diabetes mellitus (T1DM, T2DM) have an increased risk of bone fracture compared to non-diabetic controls that is not explained by differences in BMD, BMI, or falls. Thus, bone tissue fracture resistance may be reduced in individuals with DM. The purpose of this review is to summarize work that analyzes the effects of T1DM and T2DM on bone tissue compositional and mechanical properties.

RECENT FINDINGS

Studies of clinical T2DM specimens revealed increased mineralization and advanced glycation endproduct (AGE) concentrations and significant relationships between mechanical performance and composition of cancellous bone. Specifically, in femoral cancellous tissue, compressive stiffness and strength increased with mineral content; and post-yield properties decreased with AGE concentration. In addition, cortical resistance to in vivo indentation (bone material strength index) was lower in patients with T2DM vs. age-matched non-diabetic controls, and this resistance decreased with worsening glycemic control. Recent studies on patients with T1DM and history of a prior fragility fracture found greater mineral content and concentrations of AGEs in iliac trabecular bone and correspondingly stiffer, harder bone at the nanosacle. Recent observational data showed greater AGE and mineral content in surgically retrieved bone from patients with T2DM vs. non-DM controls, consistent with reduced bone remodeling. Limited data on human T1DM bone tissue also showed higher mineral and AGE content in patients with prior fragility fractures compared to non-DM and non-fracture controls.

Skeletal Status, Body Composition, and Glycaemic Control in Adolescents with Type 1 Diabetes Mellitus

BACKGROUND

Disturbed bone turnover, osteoporosis, and increased fracture risk are late complications of insulin-dependent diabetes mellitus. Little is known about how far and to what extent can glycaemic control of type 1 diabetes mellitus (T1DM) prevent disturbances of bone health and body composition during the growth and maturation period.

OBJECTIVE

The aim of this cross-sectional study was to compare the skeletal status outcomes and body composition between patients stratified by glycaemic control (1-year HbA1c levels) into well- and poorly-controlled subgroups in a population of T1DM adolescents, that is, <8% and ≥8%, respectively.

SUBJECTS AND METHODS

Skeletal status and body composition were evaluated in 60 adolescents with T1DM (53.3% female; mean aged: 15.1 ± 1.9 years; disease duration: 5.1 ± 3.9 years) using dual energy X-ray absorptiometry (GE Prodigy). The results were compared to age- and sex-adjusted reference values for healthy controls. The calculated Z-scores of different metabolic control subgroups were compared. Clinical data was also assessed.

RESULTS

As evidenced by Z-scores, patients with T1DM revealed a significantly lower TBBMD (total body bone mineral density), TBBMC (total body bone mineral content), S24BMD (bone mineral density of lumbar spine L2-L4), and TBBMC/LBM ratio (total body bone mineral content/lean body mass), but higher FM (fat mass) and FM/LBM ratio (fat mass/lean body mass) values compared to an age- and sex-adjusted general population. The subset (43.3% patients) with poor metabolic control (HbA1c ≥ 8%) had lower TBBMD, TBBMC, and LBM compared to respective values noted in the HbA1c < 8% group, after adjusting for confounders (mean Z-scores: -0.74 vs. -0.10, p = 0.037; -0.67 vs. +0.01, p = 0.026; and -0.45 vs. +0.20, p = 0.043, respectively). Additionally, we found a significant difference in the TBBMC/LBM ratio (relative bone strength index) between the metabolic groups (-0.58 vs. -0.07; p = 0.021). A statistically significant negative correlation between 1-year HbA1c levels and Z-scores of TBBMD, TBBMC, and LBM was also observed. In patients with longer disease duration, a significant negative correlation was established only for TBBMD, after adjusting for confounders. The relationships between densitometric values and age at onset of T1DM and sex were not significant and showed no relation to any of the analysed parameters of the disease course.

CONCLUSION

Findings from this study of adolescents with T1DM indicate that the lower Z-scores of TBBMD, TBBMC, and LBM as well as the TBBMC/LBM ratio are associated with increased HbA1c levels. Their recognition can be crucial in directing strategies to optimise metabolic control and improve diabetes management for bone development and maintenance in adolescents with T1DM.

Skeletal Fragility in Type 2 Diabetes Mellitus

Type 2 diabetes (T2D) is associated with an increased risk of fracture, which has been reported in several epidemiological studies. However, bone mineral density in T2D is increased and underestimates the fracture risk. Common risk factors for fracture do not fully explain the increased fracture risk observed in patients with T2D. We propose that the pathogenesis of increased fracture risk in T2D is due to low bone turnover caused by osteocyte dysfunction resulting in bone microcracks and fractures. Increased levels of sclerostin may mediate the low bone turnover and may be a novel marker of increased fracture risk, although further research is needed. An impaired incretin response in T2D may also affect bone turnover. Accumulation of advanced glycosylation endproducts may also impair bone strength. Concerning antidiabetic medication, the glitazones are detrimental to bone health and associated with increased fracture risk, and the sulphonylureas may increase fracture risk by causing hypoglycemia. So far, the results on the effect of other antidiabetics are ambiguous. No specific guideline for the management of bone disease in T2D is available and current evidence on the effects of antiosteoporotic medication in T2D is sparse. The aim of this review is to collate current evidence of the pathogenesis, detection and treatment of diabetic bone disease.

Musculoskeletal health of Indigenous Australians

INTRODUCTION

Research on non-communicable diseases (NCD) in Indigenous Australians has mostly focused on diabetes mellitus and chronic kidney or cardiovascular disease. Osteoporosis, characterised by low bone mass and structural deterioration of bone tissue, and sarcopenia, the age-related loss of muscle mass and strength, often co-exist with these common NCDs-the combination of which will disproportionately increase bone fragility and fracture risk and negatively influence cortical and trabecular bone. Furthermore, the social gradient of NCDs, including osteoporosis and fracture, is well-documented, meaning that specific population groups are likely to be at greater risk of poorer health outcomes: Indigenous Australians are one such group.

PURPOSE

This review summarises the findings reported in the literature regarding the muscle and bone health of Indigenous Australians.

FINDINGS

There are limited data regarding the musculoskeletal health of Indigenous Australians; however, areal bone mineral density (aBMD) measured by dual-energy X-ray absorptiometry (DXA) is reported to be greater at the hip compared to non-Indigenous Australians. Falls are the leading cause of injury-related hospitalisations in older Australians, particularly Indigenous Australians, with a great proportion suffering from fall-related fractures. Despite sparse data, it appears that Indigenous men and women have a substantially higher risk of hip fracture at a much younger age compared to non-Indigenous Australians.

CONCLUSION

Data on more detailed musculoskeletal health outcomes are required in Indigenous Australians to better understand fracture risk and to formulate evidence-based strategies for fracture prevention and to minimise the risk of falls.

A review of bone metabolism and developments in medical treatment of the diabetic Charcot foot

Charcot foot is a rare but severe, and possibly limb-threatening, complication to neuropathy and diabetes mellitus. The current treatment consists of long-term off-loading, and has a large negative impact on the patient's life. Much research has gone into understanding the condition and its biochemical mechanisms, however, the underlying pathogenesis of a Charcot foot is not yet fully understood. In the recent decades several key advances in our understanding of the Charcot foot have been made, both in regards to the changes in bone metabolism and structure an acute Charcot foot can cause, and to the molecular pathways involved in this. This review summerizes the available research into the bone metabolism around a Charcot foot, with an emphasis on the biochemical profile. The existing data regarding attempts at medical treatment is also reviewed, including novel trials targetting specific inflammatory pathways upregulated in the acute diabetic Charcot foot.

Higher dietary glycemic index and glycemic load values increase the risk of osteoporotic fracture in the PREvención con DIeta MEDiterránea (PREDIMED)-Reus trial

BACKGROUND

High glucose and insulin concentrations seem to have a negative impact on bone health. However, the relation between the dietary glycemic index (DGI) and the dietary glycemic load (DGL), which has proved to be effective at modulating blood glucose concentrations after carbohydrate consumption, has yet to be explored in relation to bone health.

OBJECTIVE

The aim of the study was to examine the associations between the DGI or DGL and the risk of osteoporotic-related fractures in an elderly Mediterranean population.

DESIGN

The study was conducted in 870 subjects aged 55-80 y at high cardiovascular disease risk participating in the PREvención con DIeta MEDiterránea (PREDIMED)-Reus study. The DGI and DGL were estimated from validated food-frequency questionnaires with the use of the international glycemic index and glycemic load values, with glucose as reference. Data on osteoporotic fractures were acquired from a systematic review of medical records. We used Cox proportional hazard models to assess the risk of osteoporotic fracture according to tertiles of average DGI and DGL.

RESULTS

A total of 114 new cases of osteoporotic-related fractures were documented after a mean follow-up of 8.9 y. Participants in the highest tertile of DGI and DGL had a significantly higher risk of osteoporotic fractures than those in the lowest tertile after adjusting for potential confounders (HR: 1.80; 95% CI: 1.03, 3.15 and HR: 3.20; 95% CI: 1.25, 8.18, respectively).

CONCLUSIONS

A high DGI and DGL are associated with a higher risk of osteoporosis-related fractures in an elderly Mediterranean population at high cardiovascular disease risk. This trial was registered at isrctn.com as ISRCTN35739639.

Bone Turnover Markers in Patients With Nonalcoholic Fatty Liver Disease and/or Type 2 Diabetes During Oral Glucose and Isoglycemic Intravenous Glucose

CONTEXT

Nonalcoholic fatty liver disease (NAFLD) is associated with type 2 diabetes (T2D) and vice versa, and both conditions are associated with an increased risk of fractures and altered bone turnover. Although patients with NAFLD typically suffer from decreased bone mineral density (BMD), T2D is associated with normal to high BMD. The pathophysiology is uncertain but may involve the gut-bone axis.

OBJECTIVE

We investigated the influence of the gut on glucose-induced changes in plasma bone turnover markers in healthy controls and patients with T2D and/or biopsy-verified NAFLD.

DESIGN

Cross-sectional cohort study.

PATIENTS

Patients with NAFLD with normal glucose tolerance, patients with NAFLD and T2D, patients with T2D without liver disease, and healthy controls.

INTERVENTIONS

Four-hour 50-g oral glucose tolerance test (OGTT) and an isoglycemic intravenous glucose infusion (IIGI).

MAIN OUTCOME MEASURES

Collagen type 1 C-telopeptide (CTX), osteocalcin, procollagen type 1 N-terminal propeptide (P1NP), and parathyroid hormone.

RESULTS

Plasma glucose levels achieved during OGTTs were successfully matched on corresponding IIGI days. Patients with NAFLD and T2D exhibited similar CTX suppression during the two glucose challenges (P = 0.46) and pronounced suppression of P1NP during IIGI compared with OGTT. Conversely, remaining groups showed greater (P < 0.05) CTX suppression during OGTT and similar suppression of bone formation markers during IIGI and OGTT.

CONCLUSIONS

OGTT-induced CTX suppression seems to be impaired in patients with NAFLD and T2D, but preserved in patients with either NAFLD or T2D, suggesting that coexistence of T2D and NAFLD may affect gut-bone axis.

The relationship between bone turnover and insulin sensitivity and secretion: Cross-sectional and prospective data from the RISC cohort study

Bone metabolism appears to influence insulin secretion and sensitivity, and insulin promotes bone formation in animals, but similar evidence in humans is limited. The objectives of this study are to explore if bone turnover markers were associated with insulin secretion and sensitivity and to determine if bone turnover markers predict changes in insulin secretion and sensitivity. The study population encompassed 576 non-diabetic adult men with normal glucose tolerance (NGT; n=503) or impaired glucose regulation (IGR; n=73). Baseline markers of bone resorption (CTX) and formation (P1NP) were determined in the fasting state and after a 2-h hyperinsulinaemic, euglycaemic clamp. An intravenous glucose tolerance test (IVGTT) and a 2-h oral glucose tolerance test (OGTT) were performed at baseline, and the OGTT was repeated after 3years. There were no differences in bone turnover marker levels between NGT and IGR. CTX and P1NP levels decreased by 8.0% (p<0.001) and 1.9% (p<0.01) between baseline and steady-state during the clamp. Fasting plasma glucose was inversely associated with CTX and P1NP both before and after adjustment for recruitment centre, age, BMI, smoking and physical activity. However, baseline bone turnover markers were neither associated with insulin sensitivity (assessed using hyperinsulinaemic euglycaemic clamp and OGTT) nor with insulin secretion capacity (based on IVGTT and OGTT) at baseline or at follow-up. Although inverse associations between fasting glucose and markers of bone turnover were identified, this study cannot support an association between insulin secretion and sensitivity in healthy, non-diabetic men.

Insulin and osteocalcin: further evidence for a mutual cross-talk

PURPOSE

In the last few years, bone has been recognized as an endocrine organ that modulates glucose metabolism by secretion of osteocalcin, an osteoblast-specific hormone, that influences fat deposition and blood sugar levels. To date, however, very few in vitro models have been developed to investigate, at the molecular levels, the relationship between glucose, insulin and osteocalcin. This study aims at covering this gap.

METHODS

We studied osteogenic differentiation, osteocalcin gene expression, and osteblast-mediated insulin secretion, using cultured MG-63 human osteoblast-like cells that underwent glucotoxicity and insulin resistance. In addition, we investigated whether a correlation existed between hyperglycemia and/or insulin resistance and total osteocalcin serum concentrations in patients.

RESULTS

While insulin and low glucose increased osteocalcin gene expression, disruption of insulin signaling in MG-63 osteoblasts and high glucose concentration in cell culture medium decreased osteocalcin gene transcription and reduced osteogenic differentiation. Concomitantly, insulin secretion was significantly impaired in rat INS-1 β-cells treated with conditioned medium from insulin resistant MG-63 cells or cells exposed to high glucose concentrations. Also, chronic hyperglycemia, but not insulin resistance, inversely correlated with circulating osteocalcin levels in patients.

CONCLUSION

Our results further support the existence of an endocrine axis between bone, where osteocalcin is produced, and pancreatic β-cells, and add new insights into the molecular details of this relationship. These findings may contribute to the understanding of osteocalcin regulation and its role in metabolism.

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.

Effects of Lobeglitazone, a Novel Thiazolidinedione, on Bone Mineral Density in Patients with Type 2 Diabetes Mellitus over 52 Weeks

BACKGROUND

The aim of this multicenter, randomized, double-blind study was to examine the effect of lobeglitazone, a novel thiazolidinedione, on the changes in bone mineral density (BMD) in patients with type 2 diabetes mellitus.

METHODS

A 24-week, double-blinded phase was followed by a 28-week, open-label phase, in which the placebo group also started to receive lobeglitazone. A total of 170 patients aged 34 to 76 years were randomly assigned in a 2:1 ratio to receive lobeglitazone 0.5 mg or a matching placebo orally, once daily. BMD was assessed using dual-energy X-ray absorptiometry at week 24 and at the end of the study (week 52).

RESULTS

During the double-blinded phase, the femur neck BMD showed decreasing patterns in both groups, without statistical significance (-0.85%±0.36% and -0.78%±0.46% in the lobeglitazone and placebo groups, respectively). The treatment difference between the groups was 0.07%, which was also not statistically significant. Further, minimal, nonsignificant decreases were observed in both groups in the total hip BMD compared to values at baseline, and these differences also did not significantly differ between the groups. During the open-label phase, the BMD was further decreased, but not significantly, by -0.32% at the femur neck and by -0.60% at the total hip in the lobeglitazone group, and these changes did not significantly differ compared with the original placebo group switched to lobeglitazone.

CONCLUSION

Our results indicate that treatment with lobeglitazone 0.5 mg over 52 weeks showed no detrimental effect on the BMD compared to the placebo.

Fructus Ligustri Lucidi in Osteoporosis: A Review of its Pharmacology, Phytochemistry, Pharmacokinetics and Safety

Background: Fructus Ligustri Lucidi (FLL) has now attracted increasing attention as an alternative medicine in the prevention and treatment of osteoporosis. This study aimed to provide a general review of traditional interpretation of the actions of FLL in osteoporosis, main phytochemical constituents, pharmacokinetics, pharmacology in bone improving effect, and safety. Materials and Methods: Several databases, including PubMed, China National Knowledge Infrastructure, National Science and Technology Library, China Science and Technology Journal Database, and Web of Science were consulted to locate publications pertaining to FLL. The initial inquiry was conducted for the presence of the following keywords combinations in the abstracts: Fructus Ligustri Lucidi, osteoporosis, phytochemistry, pharmacokinetics, pharmacology, osteoblasts, osteoclasts, salidroside. About 150 research papers and reviews were consulted. Results: FLL is assumed to exhibit anti-osteoporotic effects by improving liver and kidney deficiencies and reducing lower back soreness in Traditional Chinese Medicine (TCM). The data from animal and cell experiments demonstrate that FLL is able to improve bone metabolism and bone quality in ovariectomized, growing, aged and diabetic rats through the regulation of PTH/FGF-23/1,25-(OH)₂D₃/CaSR, Nox4/ROS/NF-κB, and OPG/RANKL/cathepsin K signaling pathways. More than 100 individual compounds have been isolated from this plant. Oleanolic acid, ursolic acid, salidroside, and nuzhenide have been reported to exhibit the anti-osteoporosis effect. The pharmacokinetics data reveals that salidroside is one of the active constituents, and that tyrosol is hard to detect under physiological conditions. Acute and subacute toxicity studies show that FLL is well tolerated and presents no safety concerns. Conclusions: FLL provides a new option for the prevention and treatment of osteoporosis, which attracts rising interests in identifying potential anti-osteoporotic compounds and fractions from this plant. Further scientific evidences are expected from well-designed clinical trials on its bone protective effects and safety.

Imaging of the spectrum of bony injuries in the diabetic foot: a case series with emphasis on non-Charcot fractures

Diabetes mellitus is associated with an increased risk of lower limb injuries. Peripheral neuropathy, often associated with diabetes, has been demonstrated to increase the risk of fracture almost two-fold and is associated with complications related to fracture healing. Detection of neuropathy-related foot injury is frequently delayed owing to the paucity of symptoms and low degree of suspicion by the clinician. Early recognition of fracture or bone injury and appropriate treatment are critical in preventing debilitating foot deformity and disability. Therefore, the astute radiologist cognizant of these potential injuries plays an essential role in early diagnosis of bony injuries in the diabetic foot. We present a series of radiological images that depict a range of osseous injuries in the diabetic foot and emphasize the role of the radiologist in early recognition of these abnormalities.

Diabetes, bone and glucose-lowering agents: basic biology

Skeletal fragility often accompanies diabetes and does not appear to correlate with low bone mass or trauma severity in individuals with diabetes. Instead (and in contrast to those with osteoporotic bone disease), bone remodelling and bone turnover are compromised in both type 1 and type 2 diabetes, contributing to defective bone material quality. This review is one of a pair discussing the relationship between diabetes, bone and glucose-lowering agents; an accompanying review is provided in this issue of Diabetologia by Ann Schwartz (DOI: 10.1007/s00125-017-4283-6 ). This review presents basic science evidence that, alongside other organs, bone is affected in diabetes via impairments in glucose metabolism, toxic effects of glucose oxidative derivatives (advance glycation end-products [AGEs]), and via impairments in bone microvascular function and muscle endocrine function. The cellular and molecular basis for the effects of diabetes on bone are discussed, as is the impact of diabetes on the stem cell niche and fracture healing. Furthermore, the safety of clinically approved glucose-lowering therapies and the possibility of developing a single therapy that would be beneficial for both insulin sensitisation and diabetes bone syndrome are outlined.