Epidemiology of fractures in type 2 diabetes

Obesity and Skeletal Fragility

Skeletal fracture has recently emerged as a complication of obesity. Given the normal or better than normal bone mineral density (BMD), the skeletal fragility of these patients appears to be a problem of bone quality rather than quantity. Type 2 diabetes mellitus (T2DM), the incidence of which increases with increasing body mass index, is also associated with an increased risk for fractures despite a normal or high BMD. With the additional bone pathology from diabetes itself, patients with both obesity and T2DM could have a worse skeletal profile. Clinically, however, there are no available methods for identifying those who are at higher risk for fractures or preventing fractures in this subgroup of patients. Weight loss, which is the cornerstone in the management of obesity (with or without T2DM), is also associated with an increased risk of bone loss. This review of the literature will focus on the skeletal manifestations associated with obesity, its interrelationship with the bone defects associated with T2DM, and the available approach to the bone health of patients suffering from obesity.

The effect of starting metformin on bone mineral density among women with type 2 diabetes in the Study of Women's Health Across the Nation (SWAN)

We examined longitudinal changes in BMD among women in the mid-life starting metformin. Study subjects were 57 years old (mean), and 36% were White. Women initiating metformin were similar to noninitiators. During the 3-year follow-up, BMD loss at all anatomic areas was similar between groups and in subgroups including baseline fasting blood glucose.

PURPOSE/INTRODUCTION

Women with type 2 diabetes have higher bone mineral density (BMD), experience slower BMD loss, but have increased fracture risk. Data regarding the effect of metformin on BMD remain discordant. We examined longitudinal changes in BMD among women in the mid-life starting metformin.

METHODS

Participants in the Study of Women's Health Across the Nation (SWAN), a diverse community-based US cohort, with BMD measurements were evaluated. Propensity score matching helped balance baseline characteristics of metformin initiators versus noninitiators. Mixed model regression tested the change in BMD between groups.

RESULTS

Subjects (n = 248) were 57.4 years old (mean), and 35.9% were White. Women initiating metformin (n = 124) were similar to noninitiators (n = 124) in age and race/ethnicity. During the median 3-year follow-up, BMD loss at all anatomic areas was similar between the metformin initiators and nonusers (all p > 0.3). Subgroup analyses including baseline fasting blood glucose showed no between-group differences. Initiation of metformin (vs. not) in peri-menopausal women was not associated with BMD changes.

CONCLUSIONS

Women in the mid-life starting metformin had longitudinal changes in BMD very similar to other women not starting metformin.

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.

The complex pathophysiology of bone fragility in obesity and type 2 diabetes mellitus: therapeutic targets to promote osteogenesis

Fractures associated with Type2 diabetes (T2DM) are major public health concerns in an increasingly obese and aging population. Patients with obesity or T2DM have normal or better than normal bone mineral density but at an increased risk for fractures. Hence it is crucial to understand the pathophysiology and mechanism of how T2DM and obesity result in altered bone physiology leading to increased fracture risk. Although enhanced osteoclast mediated bone resorption has been reported for these patients, the most notable observation among patients with T2DM is the reduction in bone formation from mostly dysfunction in osteoblast differentiation and survival. Studies have shown that obesity and T2DM are associated with increased adipogenesis which is most likely at the expense of reduced osteogenesis and myogenesis considering that adipocytes, osteoblasts, and myoblasts originate from the same progenitor cells. Furthermore, emerging data point to an inter-relationship between bone and metabolic homeostasis suggesting that these physiologic processes could be under the control of common regulatory pathways. Thus, this review aims to explore the complex mechanisms involved in lineage differentiation and their effect on bone pathophysiology in patients with obesity and T2DM along with an examination of potential novel pharmacological targets or a re-evaluation of existing drugs to improve bone homeostasis.

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).

Morphometric Changes of Osteocyte Lacunar in Diabetic Pig Mandibular Cancellous Bone

Osteocytes play an important role in bone metabolism. The interactions of osteocytes with the surrounding microenvironment can alter cellular and lacunar morphological changes. However, objective quantification of osteocyte lacunae is challenging due to their deep location in the bone matrix. This project established a novel method for the analytical study of osteocytes/lacunae, which was then used to evaluate the osteocyte morphological changes in diabetic pig mandibular bone. Eight miniature pigs were sourced, and diabetes was randomly induced in four animals using streptozotocin (STZ) administration. The mandibular tissues were collected and processed. The jawbone density was evaluated with micro-CT. Osteocyte lacunae were effectively acquired and identified using backscattered electron scanning microscopy (BSE). A significantly decreased osteocyte lacunae size was found in the diabetic group. Using the acid etching method, it was demonstrated that the area of osteocyte and lacunae, and the pericellular areas were both significantly reduced in the diabetes group. In conclusion, a standard and relatively reliable method for analyzing osteocyte/lacunae morphological changes under compromised conditions has been successfully established. This method demonstrates that diabetes can significantly decrease osteocyte/lacunae size in a pig's mandibular cancellous bone.

The association between peripheral arterial disease and risk for hip fractures in elderly men is not explained by low hip bone mineral density. Results from the MrOS Sweden study

In this prospective study in Swedish elderly men, PAD based on an ABI < 0.9 was associated with an increased risk of hip fracture, independent of age and hip BMD. However, after further adjustments for comorbidity, medications, physical function, and socioeconomic factors, the association diminished and was no longer statistically significant.

INTRODUCTION

To examine if peripheral arterial disease (PAD) is associated with an increased risk for hip fracture in men independent of hip BMD.

METHODS

Ankle-brachial index (ABI) was assessed in the Swedish MrOS (Osteoporotic Fractures in Men) study, a prospective observational study including 3014 men aged 69-81 years at baseline. PAD was defined as ABI < 0.90. Incident fractures were assessed in computerized X-ray archives. The risk for hip fractures was calculated using Cox proportional hazard models. At baseline, BMD was assessed using DXA (Lunar Prodigy and Hologic QDR 4500) and functional measurements and blood samples were collected. Standardized questionnaires were used to collect information about medical history, falls, and medication.

RESULTS

During 10 years of follow-up, 186 men had an incident hip fracture. The hazard ratio (HR) for hip fracture in men with PAD was 1.70 (95% CI 1.14-2.54), adjusted for age and study site. Additional adjustment for total hip BMD marginally affected this association (HR 1.64; 95% CI 1.10-2.45). In a final multivariate model, the HR attenuated to a non-significant HR 1.38 (95% CI 0.91-2.11) adjusted for age, site, hip BMD, BMI, falls, smoking, eGFR, handgrip strength, walking speed, former hip fracture, antihypertensive treatment, diabetes, education, and history of cardiovascular disease.

CONCLUSION

This study suggests that PAD is associated with an increased risk for hip fracture independently of hip BMD in elderly Swedish men. However, the high frequency of comorbidity and lower physical performance among men with PAD might partly explain this association.

The extracellular matrix of human bone marrow adipocytes and glucose concentration differentially alter mineralization quality without impairing osteoblastogenesis

Bone marrow adipocytes (BMAds) accrue in various states of osteoporosis and interfere with bone remodeling through the secretion of various factors. However, involvement of the extracellular matrix (ECM) produced by BMAds in the impairment of bone marrow mesenchymal stromal cell (BM-MSC) osteoblastogenesis has received little attention. In type 2 diabetes (T2D), skeletal fragility is associated with several changes in bone quality that are incompletely understood, and BMAd quantity increases in relationship to poor glycemic control. Considering their altered phenotype in this pathophysiological context, we aimed to determine the contribution of the ECM of mature BMAds to osteoblastogenesis and mineralization quality in the context of chronic hyperglycemia.

Human BM-MSCs were differentiated for 21 days in adipogenic medium containing either a normoglycemic (LG, 5.5 mM) or a high glucose concentration (HG, 25 mM). The ECM laid down by BMAds were devitalized through cell removal to examine their impact on the proliferation and differentiation of BM-MSCs toward osteoblastogenesis in LG and HG conditions. Compared to control plates, both adipocyte ECMs promoted cell adhesion and proliferation. As shown by the unmodified RUNX2 and osteocalcin mRNA levels, BM-MSC commitment in osteoblastogenesis was hampered by neither the hyperglycemic condition nor the adipocyte matrices. However, adipocyte ECMs or HG condition altered the mineralization phase with perturbed expression levels of type 1 collagen, MGP and osteopontin. Despite higher ALP activity, mineralization levels per cell were decreased for osteoblasts grown on adipocyte ECMs compared to controls. Raman spectrometry revealed that culturing on adipocyte matrices specifically prevents type-B carbonate substitution and favors collagen crosslinking, in contrast to exposure to HG concentration alone. Moreover, the mineral to organic ratio was disrupted according to the presence of adipocyte ECM and the glucose concentration used for adipocyte or osteoblast culture. HG concentration and adipocyte ECM lead to different defects in mineralization quality, recapitulating contradictory changes reported in T2D osteoporosis.

Our study shows that ECMs from BMAds do not impair osteoblastogenesis but alter both the quantity and quality of mineralization partly in a glucose concentration-dependent manner. This finding sheds light on the involvement of BMAds, which should be considered in the compromised bone quality of T2D and osteoporosis patients more generally.

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Glucose level alters the Extracellular Matrix composition of Bone Marrow adipocytes.

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Osteoblastogenesis on adipocyte ECMs is unaltered but produced less mineral amount.

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The quality of the mineral is altered differently by adipocyte ECMs or glucose levels.

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The presence of BM adipocytes should be valued in damaged osteoporosis bone quality.

Bone, fat, and muscle interactions in health and disease

Energy metabolism is a point of integration among the various organs and tissues of the human body, not only in terms of consumption of energy substrates but also because it concentrates a wide interconnected network controlled by endocrine factors. Thus, not only do tissues consume substrates, but they also participate in modulating energy metabolism. Soft mesenchymal tissues, in particular, play a key role in this process. The recognition that high energy consumption is involved in bone remodeling has been accompanied by evidence showing that osteoblasts and osteocytes produce factors that influence, for example, insulin sensitivity and appetite. Additionally, there are significant interactions between muscle, adipose, and bone tissues to control mutual tissue trophism. Not by chance, trophic and functional changes in these tissues go hand in hand from the beginning of an individual's development until aging. Likewise, metabolic and nutritional diseases deeply affect the musculoskeletal system and adipose tissue. The present narrative review highlights the importance of the interaction of the mesenchymal tissues for bone development and maintenance and the impact on bone from diseases marked by functional and trophic disorders of adipose and muscle tissues.

Evaluation of Quality and Bone Microstructure Alterations in Patients with Type 2 Diabetes: A Narrative Review

Bone fragility is a common complication in subjects with type 2 diabetes mellitus (T2DM). However, traditional techniques for the evaluation of bone fragility, such as dual-energy X-ray absorptiometry (DXA), do not perform well in this population. Moreover, the Fracture Risk Assessment Tool (FRAX) usually underestimates fracture risk in T2DM. Importantly, novel technologies for the assessment of one microarchitecture in patients with T2DM, such as the trabecular bone score (TBS), high-resolution peripheral quantitative computed tomography (HR-pQCT), and microindentation, are emerging. Furthermore, different serum and urine bone biomarkers may also be useful for the evaluation of bone quality in T2DM. Hence, in this article, we summarize the limitations of conventional tools for the evaluation of bone fragility and review the current evidence on novel approaches for the assessment of quality and bone microstructure alterations in patients with T2DM.

Polypharmacy and bone fracture risk in patients with type 2 diabetes: The Fukuoka Diabetes Registry

AIMS

To prospectively investigate the association between the number of prescribed drugs and the fracture risk in patients with type 2 diabetes.

METHODS

Japanese participants with type 2 diabetes (n = 4,706; 2,755 men, 1,951 postmenopausal women; mean age, 66 years) were followed for a median of 5.3 years and grouped on the basis of the number of prescribed drugs at baseline. The main outcomes were fractures at any anatomic site and fragility fractures (fractures at hip and spine sites).

RESULTS

During follow-up, any fracture occurred in 662 participants. The overall age- and sex-adjusted fracture incidence rates per 1,000 person-years were 21.2 (0-2 drugs), 28.1 (3-5 drugs), 37.7 (6-8 drugs), and 44.0 (≥9 drugs) (p for trend < 0.001). Compared with 0-2 drugs, the multivariate-adjusted hazard ratios (HRs) (95% confidence intervals [CIs]) for fractures were 1.34 (1.07-1.68) for 3-5 drugs, 1.76 (1.37-2.26) for 6-8 drugs, and 1.71 (1.27-2.31) in ≥ 9 drugs. The multivariate-adjusted HR (95% CI) per increment in drugs was 1.05 (1.02-1.08) (p < 0.001). Similar tendencies were observed for fragility fractures.

CONCLUSIONS

A greater number of prescribed drugs is associated with an increased bone fracture risk in patients with type 2 diabetes.

Effect of Dipeptidyl Peptidase-4 Inhibitors on Bone Health in Patients with Type 2 Diabetes Mellitus

Patients with type 2 diabetes (T2DM) have a higher risk of bone fracture even when bone mineral density (BMD) values are normal. The trabecular bone score (TBS) was recently developed and used for evaluating bone strength in various diseases. We investigated the effect of DPP-4 inhibitors on bone health using TBS in patients with T2DM. This was a single-center, retrospective case-control study of 200 patients with T2DM. Patients were divided into two groups according to whether they were administered a DPP-4 inhibitor (DPP-4 inhibitor group vs. control group). Parameters related to bone health, including BMD, TBS, and serum markers of calcium homeostasis, were assessed at baseline and after one year of treatment. We found TBS values increased in the DPP-4 group and decreased in the control, indicating a significant difference in delta change between them. The BMD increased in both groups, with no significant differences in delta change between the two groups observed. Serum calcium and 25-hydroxy vitamin D3 increased only in the DPP-4 inhibitor group, while other glycemic parameters did not show significant differences between the two groups. Treatment with DPP-4 inhibitors was associated with favorable effects on bone health evaluated by TBS in patients with T2DM.

The Incidence of Fractures Among the Adult Population of Germany – and Analysis From 2009 through 2019

BACKGROUND

Detailed analyses of epidemiological data on fractures are an important resource for persons and institutions providing health care services, as they yield information on the effects of current treatment strategies and on the need for preventive measures. The epidemiology of fractures in Germany, however, is unknown. The goal of this study is to determine the nationwide fracture burden from 2009 through 2019, as a function of anatomical site, age, and sex.

METHODS

Annual compilations of ICD-10 diagnosis codes for the years 2009-2019 were made available to us by the German Federal Statistical Office. The prevalence and incidence of fractures at 30 different sites were quantified, and standardized sex and age distributions were calculated.

RESULTS

A total of 688 403 fractures was registered in 2019. From 2009 to 2019, the incidence of fractures rose by 14%, to 1014 fractures per 100 000 persons per year. The most common fracture types were femoral neck fractures (120 per 100 000 persons per year), pertrochanteric femural fractures (109 per 100 000 persons per year), and distal radius fractures (106 per 100 000 persons per year). All types were more common in women, with incidences that rose with age. The highest incidence was of pertrochanteric femoral fractures in women over age 90, with an incidence of 2550 per 100 000 persons per year. The largest rises in incidence were seen with regard to acetabular fractures (+ 58.16%) and clavicular fractures (+ 44.02%).

CONCLUSION

The increasing frequency of fractures, particularly among the elderly, presents a challenge to the health care system. Given the high frequency of geriatric fractures, prophylactic measures against fractures ought to be intensified.

Marantodes pumilum Var Alata (Kacip Fatimah) ameliorates derangement in RANK/RANKL/OPG pathway and reduces inflammation and oxidative stress in the bone of estrogen-deficient female rats with type-2 diabetes

BACKGROUND

M. pumilum has been claimed to protect the bone against the adverse effect of estrogen deficiency. Additionally, it also exhibits anti-diabetic activity. In view of these, this study aims to identify the mechanisms underlying the bone protective effect of M. pumilum in the presence of both estrogen deficiency and diabetes mellitus (DM).

METHODS

Ovariectomized, diabetic female rats were given M. pumilum leave aqueous extract (MPLA) (50 and 100 mg/kg/day), estrogen, glibenclamide and estrogen plus glibenclamide for 28 consecutive days. At the end of the treatment, fasting blood glucose (FBG), serum insulin, Ca²⁺, PO₄^3- and bone alkaline phosphatase (BALP) levels were measured. Rats were sacrificed and femur bones were harvested for determination of expression level and distribution of RANK, RANKL, OPG and oxidative stress and inflammatory proteins by molecular biological techniques.

RESULTS

100 mg/kg/day MPLA treatment decreased the FBG and BALP levels but increased the serum insulin, Ca²⁺ and PO₄^3- levels in estrogen deficient, diabetic rats. Expression and distribution of RANKL, NF-κB p65, IKKβ, IL-6, IL-1β and Keap-1 decreased however expression and distribution of RANK, OPG, BMP-2, Type-1 collagen, Runx2, TRAF6, Nrf2, NQO-1, HO-1, SOD and CAT increased in the bone of estrogen deficient, diabetic rats which received 100 mg/kg/day MPLA with greater effects than estrogen-only, glibenclamide-only and estrogen plus glibenclamide treatments.

CONCLUSION

MPLA helps to overcome the adverse effect of estrogen deficiency and DM on the bone and thus this herb could potentially be used for the treatment and prevention of osteoporosis in postmenopausal women with diabetes.

Falls and fractures associated with type 2 diabetic polyneuropathy: A cross-sectional nationwide questionnaire study

AIMS/INTRODUCTION

To examine the prevalence of falls and fractures, and the association with symptoms of diabetic polyneuropathy (DPN) in patients with recently diagnosed type 2 diabetes.

MATERIALS AND METHODS

A detailed questionnaire on neuropathy symptoms and falls was sent to 6,726 patients enrolled in the Danish Center for Strategic Research in Type 2 Diabetes cohort (median age 65 years, diabetes duration 4.6 years). Complete data on fractures and patient characteristics were ascertained from population-based health registries. We defined possible DPN as a score ≥4 on the Michigan Neuropathy Screening Instruments questionnaire. Using Poisson regression analyses, we estimated the adjusted prevalence ratio (aPR) of falls and fractures, comparing patients with and without DPN.

RESULTS

In total, 5,359 patients (80%) answered the questions on the Michigan Neuropathy Screening Instruments questionnaire and falls. Within the year preceding the questionnaire response, 17% (n = 933) reported at least one fall and 1.4% (n = 76) suffered from a fracture. The prevalence ratio of falls was substantially increased in patients with possible DPN compared with those without (aPR 2.33, 95% confidence interval [CI] 2.06-2.63). The prevalence ratio increased with the number of falls from aPR 1.51 (95% CI 1.22-1.89) for one fall to aPR 5.89 (95% CI 3.84-9.05) for four or more falls within the preceding year. Possible DPN was associated with a slightly although non-significantly increased risk of fractures (aPR 1.32, 95% CI 0.75-2.33).

CONCLUSIONS

Patients with recently diagnosed type 2 diabetes and symptoms of DPN had a highly increased risk of falling. These results emphasize the need for preventive interventions to reduce fall risk among patients with type 2 diabetes and possible DPN.

Risk Factors for Incident Fracture in Older Adults With Type 2 Diabetes: The Framingham Heart Study

OBJECTIVE

To identify risk factors for fracture in type 2 diabetes.

RESEARCH DESIGN AND METHODS

This prospective study included members of the Framingham Original and Offspring Cohorts. Type 2 diabetes was defined as fasting plasma glucose >125 mg/dL or use of type 2 diabetes therapy. We used repeated-measures Cox proportional hazards regression to calculate hazard ratios (HRs) and 95% CIs for associations between potential predictors and incidence of fragility fracture.

RESULTS

Participants included 793 individuals with type 2 diabetes. Mean ± SD age was 70 ± 10 years; 45% were women. A total of 106 incident fractures occurred over 1,437 observation follow-up intervals. Fracture incidence increased with age (adjusted HRs 1.00, 1.44 [95% CI 0.65, 3.16], and 2.40 [1.14, 5.04] for <60, 60-70, and >70 years, respectively; P _trend = 0.02), female sex (2.23 [1.26, 3.95]), HbA_1c (1.00, 2.10 [1.17, 3.75], and 1.29 [0.69, 2.41] for 4.45-6.46% [25-47 mmol/mol], 6.50-7.49% [48-58 mmol/mol], and 7.50-13.86% [58-128 mmol/mol]; P _trend =0.03), falls in past year (1.00, 1.87 [0.82, 4.28], and 3.29 [1.34, 8.09] for no falls, one fall, and two or more falls; P _trend =0.03), fracture history (2.05 [1.34, 3.12]), and lower grip strength (0.82 [0.69, 0.99] per 5-kg increase). Femoral neck bone mineral density, BMI, smoking, physical function, chronic diseases, medications, and physical function were not associated with fracture incidence.

CONCLUSIONS

Prior falls, fractures, low grip strength, and elevated HbA_1c are risk factors for fractures in older adults with type 2 diabetes. Evaluation of these factors may improve opportunities for early intervention and reduce fractures in this high-risk group.

The diabetes-fracture association in women with type 1 and type 2 diabetes is partially mediated by falls: a 15-year longitudinal study

This study evaluated mediators of fracture risk in postmenopausal women with type 1 (T1D) and type 2 diabetes (T2D), over a 15-year follow-up period. This study provides evidence that the increased fracture risk in women with T1D or T2D is partially explained by falls. Furthermore, a shorter reproductive lifespan in women with T1D contributes modestly to fracture risk in this cohort.

PURPOSE

Skeletal fragility is associated with diabetes mellitus, while limited estrogen exposure during the reproductive years also predisposes to lower bone mass and higher fracture risk. We aimed to determine osteoporosis diagnosis, fall and fracture rates in women with type 1 (T1D) and type 2 (T2D) diabetes mellitus, and explore mediators of the diabetes-fracture relationship.

METHODS

Prospective observational data drawn from the Australian Longitudinal Study in Women's Health (ALSWH) from 1996 to 2010. Women were randomly selected from the national health insurance database. Standardized data collection occurred at six survey time points, with main outcome measures being self-reported osteoporosis, incident fracture, falls, and reproductive lifespan. Mediation analyses were performed to elucidate relevant intermediaries in the diabetes-fracture relationship.

RESULTS

Exactly 11,313 women were included at baseline (T1D, n = 107; T2D, n = 333; controls, n = 10,873). A total of 885 new cases of osteoporosis and 1099 incident fractures were reported over 15 years. Women with T1D or T2D reported more falls and fall-related injuries; additionally, women with T1D had a shorter reproductive lifespan. While fracture risk was increased in women with diabetes (T1D: OR 2.28, 95% CI 1.53-3.40; T2D: OR 2.40, 95% CI 1.90-3.03), compared with controls, adjustment for falls attenuated the risk of fracture by 10% and 6% in T1D and T2D, respectively. In women with T1D, reproductive lifespan modestly attenuated fracture risk by 4%.

CONCLUSION

Women with T1D and T2D have an increased risk of fracture, which may be partially explained by increased falls, and to a lesser extent by shorter reproductive lifespan, in T1D.

The Clinical Value of the RA-Adjusted Fracture Risk Assessment Tool in the Fracture Risk Prediction of Patients with Type 2 Diabetes Mellitus in China

Objective

This study aimed to explore the clinical value of the fracture risk assessment tool (FRAX) in the fracture risk prediction of Chinese patients after replacing rheumatoid arthritis (RA) with type 2 diabetes mellitus (T2DM) in the FRAX algorithm.

Methods

A total of 1,047 patients with T2DM from the Endocrinology Department of the Third Affiliated Hospital of Nanchang University were enrolled in this study. Dual-energy X-ray absorptiometry (DXA) was then used to detect their bone density. RA in the FRAX algorithm was replaced with T2DM, and the new RA-adjusted FRAX was used to assess the fracture risk of the patients.

Results

The sensitivity, specificity, and Youden’s index of the RA-adjusted FRAX to the treatment opinions on T2DM-associated hip fractures were 0.4761, 0.9642, and 0.4403, respectively, while the sensitivity, specificity, and Youden’s index of RA-adjusted FRAX to the treatment opinions on T2DM-associated major bone osteoporotic fractures were 0.0080, 1.0000, 0.0080, respectively. The DXA and RA-adjusted FRAX both showed acceptable consistency in the treatment recommendations for hip fractures in patients with T2DM (κ = 0.49) but had poor consistency in treatment recommendations for major bone osteoporotic fractures (κ = 0.010). The body mass index (BMI) scores, femoral neck-bone mineral densities, and number of males in the same treatment opinion group were significantly higher than in the different treatment opinions group (P < 0.001).

Conclusion

RA-adjusted FRAX is a useful clinical tool for evaluation of hip fracture risk for Chinese patients with T2DM, and the accuracy of fracture risk prediction for male patients with T2DM and patients with T2DM with high BMI scores or high femoral neck-bone mineral density is higher.

Hyperglycemia Is Not Associated With Higher Volumetric BMD in a Chinese Health Check-up Cohort

BACKGROUND AND PURPOSE

Type 2 diabetes mellitus patients have an increased fracture risk despite having higher areal bone mineral density (aBMD) measured by DXA. This apparent paradox might be explained by the overestimation of BMD by DXA due to the higher fat mass in type 2 diabetes mellitus patients. Volumetric BMD (vBMD) as assessed by quantitative CT (QCT) is not influenced by fat mass. We assessed the association of vBMD and fasting plasma glucose in a large cohort of Chinese subjects and compared the vBMD in healthy and diabetic subjects. In addition, we compared the relation between aBMD, vBMD, glucose and fat mass in a subset of this cohort.

MATERIALS AND METHODS

10309 participants from the China Biobank project underwent QCT based on chest low dose CT to compute vBMD of L1 and L2 vertebrae and FPG measurements between 2018 and 2019. Among them, 1037 subjects also had spine DXA scans. Data was analyzed using linear regression models.

RESULTS

In the total cohort (5889 men and 4420 women, mean age 53 years, range 30-96), there was no significant association between vBMD and FPG after adjustment for age (women: p=0.774; men: p=0.149). 291 women and 606 men fitted the diagnostic criteria of diabetes. Both women and men with diabetes had lower vBMD compared to non-diabetic subjects, but this became non-significant after adjusting for age in the total cohort (women: p=0.817; men: p=0.288) and after propensity score matching based on age (women: p=0.678; men: p=0.135). In the DXA subcohort, aBMD was significantly higher in men with diabetes after adjusting for age and this difference disappeared after further adjusting for total fat area (p=0.064).

CONCLUSION

We did not find any effect of fasting plasma glucose or diabetes on the volumetric BMD measured with QCT after adjustment for age. Therefore, vBMD measured with QCT might be a more reliable measurement to diagnose osteoporosis and assess fracture risk than aBMD measured with DXA in diabetic patients.

Different Stages of Alveolar Bone Repair Process Are Compromised in the Type 2 Diabetes Condition: An Experimental Study in Rats

Simple Summary

Type 2 diabetes (T2D) affects more than 90% of all patients diagnosed with diabetes, and among its risk factors, unhealthy eating habits are worth mentioning. With the notorious increase in the incidence of diabetic patients, there has also been an increase in surgical complications in dentistry, so this work presents a study model that mimics the T2D condition in rats, where animals receive a diet composed of foods rich in sugar and fat equivalent to the poor diet of the current population. The animals were submitted to dental extraction to perform analyzes at different stages of the alveolar bone. It is important to highlight that with the development of this experimental model it will be possible to simulate different conditions that are observed in clinics and in consequence and improve the characterization of the cellular responses involved in this complex condition of T2D. The scientific evidence presented in this study shows that T2D prolongs the local inflammatory process, which impairs the organization and maturation of collagen fibers, delaying bone formation and bone turnover. This fact implies in a series of disorders in dental practice, that would need to compensate in other ways, either with systemic medications or local therapies.

Abstract

The aim of this study was to analyze the stages of the alveolar bone repair in type 2 diabetic rats evaluating the mechanism of mineralization and bone remodeling processes after dental extraction. Forty-eight rats were divided into normoglycemic (NG) and type 2 diabetes (T2D) groups. The upper right incisor was extracted and after 3, 7, 14 and 42 days the animals were euthanized. The following analyses were performed: immunolabeling against antibodies TNFα, TGFβ, IL6, WNT, OCN and TRAP, collagen fibers maturation, microtomography and confocal microscopy. Data were submitted to statistical analysis. The immunolabeling analysis showed that the T2D presented a more pronounced alveolar inflammation than NG. Labeling of proteins responsible for bone formation and mineralization was higher in NG than T2D, which presented greater resorptive activity characterized by TRAP labeling. Also, T2D group showed a decrease in the amount of collagen fibers. Micro-CT analysis showed that T2D causes a decrease in bone volume percentage due to deficient trabecular parameters and higher porosity. The T2D bone dynamics show a loss in bone remodeling process. T2D prolongs the local inflammatory process, which impairs the organization and maturation of collagen fibers, delaying bone formation that generates impact on mineralization and bone turnover.

Bone Marrow Metabolism Is Impaired in Insulin Resistance and Improves After Exercise Training

CONTEXT

Exercise training improves bone mineral density, but little is known about the effects of training on bone marrow (BM) metabolism. BM insulin sensitivity has been suggested to play an important role in bone health and whole-body insulin sensitivity.

OBJECTIVE

To study the effects of exercise training on BM metabolism.

DESIGN

Randomized controlled trial.

SETTING

Clinical research center.

PARTICIPANTS

Sedentary healthy (n = 28, 40-55 years, all males) and insulin resistant (IR) subjects (n = 26, 43-55 years, males/females 16/10).

INTERVENTION

Two weeks of sprint interval training or moderate-intensity continuous training.

MAIN OUTCOME MEASURES

We measured femoral, lumbar, and thoracic BM insulin-stimulated glucose uptake (GU) and fasting free fatty acid uptake (FFAU) using positron-emission tomography and bone turnover markers from plasma.

RESULTS

At baseline, GU was highest in lumbar, followed by thoracic, and lowest in femoral BM (all Ps < 0.0001). FFAU was higher in lumbar and thoracic than femoral BM (both Ps < 0.0001). BM FFAU and femoral BM GU were higher in healthy compared to IR men and in females compared to males (all Ps < 0.05). Training increased femoral BM GU similarly in all groups and decreased lumbar BM FFAU in males (all Ps < 0.05). Osteocalcin and PINP were lower in IR than healthy men and correlated positively with femoral BM GU and glycemic status (all Ps < 0.05).

CONCLUSIONS

BM metabolism differs regarding anatomical location. Short-term training improves BM GU and FFAU in healthy and IR subjects. Bone turnover rate is decreased in insulin resistance and associates positively with BM metabolism and glycemic control.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01344928.

Risk of fragility fractures in obesity and diabetes: a retrospective analysis on a nation-wide cohort

This study aims to investigate the role of obesity and diabetes on bone health in a nation-wide cohort of women with high risk of fracture.

INTRODUCTION

The role of obesity and diabetes on fracture risk is yet poorly understood. Body mass index (BMI) and bone mineral density (BMD) are strongly correlated; however, patients with elevated BMI are not protected against fractures, configuring the obesity paradox. A similar controversial association has been also found in diabetic patients. Herein, we present a retrospective analysis on 59,950 women.

METHODS

Using a new web-based fracture risk-assessment tool, we have collected demographic (including BMI), densitometric, and clinical data (including history of vertebral or hip and non-vertebral, non-hip fractures, presence of comorbidities). We performed a propensity score generation with 1:1 matching for patients in the obese (BMI ≥ 30) and non-obese (BMI < 30) groups, in the diabetics and non-diabetics. Propensity score estimates were estimated using a logistic regression model derived from the clinical variables: age, lumbar spine T-score, and femoral neck T-score.

RESULTS

We found an association between diabetes and fractures of any kind (OR 1.3, 95% CI 1.1-1.4 and 1.3, 95% CI 1.2-1.5 for vertebral or hip fractures and non-vertebral, non-hip fractures, respectively). Obesity, on the other hand, was significantly associated only with non-vertebral, non-hip fractures (OR 1.3, 95% CI 1.1-1.6). To estimate the individual effect of obesity and diabetes on bone health, we ran sensitivity analyses which included obese non-diabetic patients and non-obese diabetic patients, respectively.

CONCLUSIONS

Non-obese diabetics had the highest risk of vertebral or hip fracture, whereas obese non-diabetics predominantly had non-vertebral, non-hip fracture's risk. These results should raise awareness in clinical practice when evaluating diabetic and/or obese patients.

Individuals with type 2 diabetes mellitus show dimorphic and heterogeneous patterns of loss in femoral bone quality

Type 2 diabetes mellitus (T2DM), a metabolic disease on the rise, is associated with substantial increase in bone fracture risk. Because individuals with T2DM have normal or high bone mineral density (BMD), osteodensitometric measurements of BMD do not predict fracture risk with T2DM. Here, we aim to identify the underlying mechanism of the diabetes-induced fracture risk using a high-resolution multi-scale analysis of human cortical bone with special emphasis on osseous cellular activity. Specifically, we show increased cortical porosity in a subgroup of T2DM individuals accompanied by changed mineralization patterns and glycoxidative damage to bone protein, caused by non-enzymatic glycation of bone by reducing sugar. Furthermore, the high porosity T2DM subgroup presents with higher regional mineralization heterogeneity and lower mineral maturity, whereas in the T2DM subgroup regional higher mineral-to-matrix ratio was observed. Both T2DM groups show significantly higher carboxymethyl-lysine accumulation. Our results show a dimorphic pattern of cortical bone reorganization in individuals afflicted with T2DM and hence provide new insight into the diabetic bone disease leading to increased fracture risk.

Time Course of Immune Response and Immunomodulation During Normal and Delayed Healing of Musculoskeletal Wounds

Single trauma injuries or isolated fractures are often manageable and generally heal without complications. In contrast, high-energy trauma results in multi/poly-trauma injury patterns presenting imbalanced pro- and anti- inflammatory responses often leading to immune dysfunction. These injuries often exhibit delayed healing, leading to fibrosis of injury sites and delayed healing of fractures depending on the intensity of the compounding traumas. Immune dysfunction is accompanied by a temporal shift in the innate and adaptive immune cells distribution, triggered by the overwhelming release of an arsenal of inflammatory mediators such as complements, cytokines and damage associated molecular patterns (DAMPs) from necrotic cells. Recent studies have implicated this dysregulated inflammation in the poor prognosis of polytraumatic injuries, however, interventions focusing on immunomodulating inflammatory cellular composition and activation, if administered incorrectly, can result in immune suppression and unintended outcomes. Immunomodulation therapy is promising but should be conducted with consideration for the spatial and temporal distribution of the immune cells during impaired healing. This review describes the current state of knowledge in the spatiotemporal distribution patterns of immune cells at various stages during musculoskeletal wound healing, with a focus on recent advances in the field of Osteoimmunology, a study of the interface between the immune and skeletal systems, in long bone fractures. The goals of this review are to (1) discuss wound and fracture healing processes of normal and delayed healing in skeletal muscles and long bones; (2) provide a balanced perspective on temporal distributions of immune cells and skeletal cells during healing; and (3) highlight recent therapeutic interventions used to improve fracture healing. This review is intended to promote an understanding of the importance of inflammation during normal and delayed wound and fracture healing. Knowledge gained will be instrumental in developing novel immunomodulatory approaches for impaired healing.

Lessons learned with Bone Health TeleECHO: making treatment decisions when guidelines conflict

Clinical practice guidelines provide helpful information for managing patients with metabolic bone disease. Good guidelines are based on the best available medical evidence; however, guidelines from different societies can conflict. Additionally, it is not possible for a guideline to anticipate the vast variability of circumstances, comorbidities, previous medical experiences, cultural differences, and preferences in real-world patients. Bone Health TeleECHO is a strategy for sharing knowledge on the care of patients with skeletal diseases through ongoing interactive videoconferences. We report three cases based on those presented at Bone Health TeleECHO, where, through discussion, treatment outside of commonly used guidelines was ultimately recommended. Guidelines developed by different organizations may provide "evidence-based" or "informed" recommendations which do not account for the variability of clinical circumstances encountered in the care of individual patients. This highlights the importance of Bone Health TeleECHO, where healthcare professionals can share knowledge, individualize treatment decisions, and improve patient care.Learning objectives At the end of this activity participants should be able to:• Distinguish between the onset and off of bisphosphonates versus other medications used in the prevention and treatment of osteoporosis and how this affects choice of a "drug holiday."• Understand the limitations of clinical practices guidelines in the care of an individual patient and how interactive video conferencing can assist with decision making.• Recognize that patients treated with glucocorticoids at high risk for fracture can benefit from more aggressive interventions for osteoporosis.

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.

Obesity, Bariatric Surgery, and Fractures

CONTEXT

Obesity and its associated comorbidities are a recognized and growing public health problem. For a long time, obesity-associated effects on bone were considered to strengthen the bone, mainly because of the known relationship between body weight and bone mass and the long-term weight-bearing load effect on bone. However, recent epidemiologic studies have shown that obesity may not have a fully protective effect on the occurrence of fragility fractures. The goal of this article is to review updated information on the link between obesity, bariatric surgery, and fractures.

METHODS

The primary source literature for this review was acquired by searching a published database for reviews and articles up to January 2018. Additional references were selected through the in-depth analysis of the relevant studies.

RESULTS

We present data showing that overweight and obesity are often encountered in fracture cases. We also analyzed possible reasons and risk factors for fractures associated with overweight and patients with obesity. In addition, this review focuses on the complex effects of dramatic changes in body composition when interpreting dual-energy X-ray absorptiometry readings and findings. Finally, we review the data on the effects and consequences of bariatric surgery on bone metabolism and the risk of fractures in patients undergoing these procedures.

CONCLUSION

Because of various adiposity-induced effects, patients with obesity are at risk for fracture in certain sites. Bariatric surgery increases the risk of fractures in patients undergoing malabsorptive procedures.

Nutrient Intake Prior to Exercise Is Necessary for Increased Osteogenic Marker Response in Diabetic Postmenopausal Women

Type 2 diabetes increases bone fracture risk in postmenopausal women. Usual treatment with anti-resorptive bisphosphonate drugs has some undesirable side effects, which justified our interest in the osteogenic potential of nutrition and exercise. Since meal eating reduces bone resorption, downhill locomotion increases mechanical stress, and brief osteogenic responsiveness to mechanical stress is followed by several hours of refractoriness, we designed a study where 40-min of mechanical stress was manipulated by treadmill walking uphill or downhill. Exercise preceded or followed two daily meals by one hour, and the meals and exercise bouts were 7 hours apart. Fifteen subjects each performed two of five trials: No exercise (SED), uphill exercise before (UBM) or after meals (UAM), and downhill exercise before (DBM) or after meals (DAM). Relative to SED trial, osteogenic response, defined as the ratio of osteogenic C-terminal propeptide of type I collagen (CICP) over bone-resorptive C-terminal telopeptide of type-I collagen (CTX) markers, increased in exercise-after-meal trials, but not in exercise-before-meal trials. CICP/CTX response rose significantly after the first exercise-after-meal bout in DAM, and after the second one in UAM, due to a greater CICP rise, and not a decline in CTX. Post-meal exercise, but not the pre-meal exercise, also significantly lowered serum insulin response and homeostatic model (HOMA-IR) assessment of insulin resistance.

The differences in the relationship between obstructive sleep apnea severity and trabecular bone score in men and women with type 2 diabetes

Aims

Type 2 diabetes mellitus (T2DM) and obstructive sleep apnea (OSA) may adversely affect bone. Gender is a well-established factor influencing bone health. We investigated the impact of OSA on bone mineral density (BMD) and trabecular bone score (TBS) in T2DM.

Methods

Eighty-one T2DM patients [33 men and 48 women] participated. OSA was diagnosed using an overnight monitor, with its severity assessed by an apnea hypopnia index (pAHI). The measurements of hypoxia, including the percentage of total sleep time in which oxygen saturation remains below 90% (pT90), the oxygen desaturation index (pODI) and minimum O₂ (min O₂), were reported. Lumbar spine (L1-4) and femoral neck (FN) BMD were measured using dual-energy X-ray absorptiometry (DXA). TBS was computed from DXA images.

Results

Sixty-five patients (80.2%) had OSA. pAHI, pT90, pODI and min O₂ were not correlated to L1-4 BMD, FN BMD or TBS in all participants by multiple regression analyses adjusting for age, gender and BMI. However, an interaction between gender and pAHI, and gender and pODI were significantly associated with TBS (b = 0.003, p = 0.034 and b = 0.004, p = 0.046, respectively). We therefore reassessed an association between pAHI or pODI and TBS separately between men and women. After adjusting for age and BMI, more severe OSA (higher pAHI) and higher pODI significantly associated with lower TBS (b = -0.002, p = 0.034 and b = -0.003, p = 0.021, respectively) in men. On the other hand, higher pAHI non-significantly associated with better trabecular microarchitecture as indicated by higher TBS (b = 0.002, p = 0.059) in women. When considered only postmenopausal (n = 33), higher pAHI and higher pODI were significantly associated with higher TBS (b = 0.004, p = 0.003 and b = 0.004, p = 0.008, respectively).

Conclusions

In T2DM patients, there is a complex interrelationship among OSA severity, gender and TBS. More severe OSA predicted lower TBS in men, but predicted higher TBS in postmenopausal women.

Microcomputed tomography of the femur of diabetic rats: alterations of trabecular and cortical bone microarchitecture and vasculature-a feasibility study

BACKGROUND

To better understand bone fragility in type 2 diabetes mellitus and define the contribution of microcomputed tomography (micro-CT) to the evaluation of bone microarchitecture and vascularisation, we conducted an in vitro preliminary study on the femur of Zucker diabetic fatty (ZDF) rats and Zucker lean (ZL) rats. We first analysed bone microarchitecture, then determined whether micro-CT allowed to explore bone vascularisation, and finally looked for a link between these parameters.

METHODS

Eight ZDF and six ZL rats were examined for bone microarchitecture (group 1), and six ZDF and six ZL rats were studied for bone vascularisation after Microfil® perfusion which is a radiopaque casting agent (group 2). In group 1, we used micro-CT to examine the trabecular and cortical bone microarchitecture of the femoral head, neck, shaft, and distal metaphysis. In group 2, micro-CT was used to study the blood vessels in the head, neck, and distal metaphysis.

RESULTS

Compared to ZL rats, the ZDF rats exhibited significantly lower trabecular bone volume and number and higher trabecular separation in the three locations (p = 0.02, p = 0.02, p = 0.003). Cortical porosity was significantly higher in the ZDF rats at the neck and shaft (p = 0.001 and p = 0.005). We observed a dramatically poorer bone vascularisation in the femur of ZDF rats, especially in distal metaphysis (p < 0.047).

CONCLUSIONS

Micro-CT demonstrated not only significant alterations in the bone microarchitecture of the femurs of ZDF rats, but also significant alterations in bone vascularisation. Further studies are required to demonstrate the causal link between poor vascularisation and impaired bone architecture.

Bone collagen network integrity and transverse fracture toughness of human cortical bone

Greater understanding of the determinants of skeletal fragility is highly sought due to the great burden that bone affecting diseases and fractures have on economies, societies and health care systems. Being a complex, hierarchical composite of collagen type-I and non-stoichiometric substituted hydroxyapatite, bone derives toughness from its organic phase. In this study, we tested whether early observations that a strong correlation between bone collagen integrity measured by thermomechanical methods and work to fracture exist in a more general and heterogeneous sampling of the population. Neighboring uniform specimens from an established, highly characterized and previously published collection of human cortical bone samples (femur mid-shaft) were decalcified in EDTA. Fifty-four of the original 62 donors were included (26 male and 28 females; ages 21-101 years; aging, osteoporosis, diabetes and cancer). Following decalcification, bone collagen was tested using hydrothermal isometric tension (HIT) testing in order to measure the collagen's thermal stability (denaturation temperature, T_d) and network connectivity (maximum rate of isometric tension generation; Max.Slope). We used linear regression and general linear models (GLMs) with several explanatory variables to determine whether relationships between HIT parameters and generally accepted bone quality factors (e.g., cortical porosity, pentosidine content [pen], pyridinoline content [pyd]), age, and measures of fracture toughness (crack initiation fracture toughness, K_init, and total energy release/dissipation rate evaluated at the point of unstable fast fracture, J-int) were significant. Bone collagen connectivity (Max.Slope) correlated well with the measures of fracture toughness (R² = 24-35%), and to a lesser degree with bound water fraction (BW; R² = 7.9%) and pore water fraction (PW; R² = 9.1%). Significant correlations with age, apparent volumetric bone mineral density (vBMD), and mature enzymatic [pyd] and non-enzymatic collagen crosslinks [pen] were not detected. GLMs found that Max.Slope and vBMD (or BW), with or without age as additional covariate, all significantly explained the variance in Kinit (adjusted-R² = 36.7-49.0%). Also, the best-fit model for J-int (adjusted-R² = 35.7%) included only age and Max.Slope as explanatory variables with Max.Slope contributing twice as much as age. Max.Slope and BW without age were also significant predictors of J-int (adjusted-R² = 35.5%). In conclusion, bone collagen integrity as measured by thermomechanical methods is a key factor in cortical bone fracture toughness. This study further demonstrates that greater attention should be paid to degradation of the overall organic phase, rather than a specific biomarker (e.g. [pen]), when seeking to understand elevated fracture rates in aging and disease.

Effect of pioglitazone on bone mineral density in patients with nonalcoholic steatohepatitis: A 36-month clinical trial

BACKGROUND

The effects of pioglitazone on bone metabolism are unclear. This study evaluated the long-term effects of pioglitazone on bone mineral density (BMD) and bone metabolism in patients with prediabetes or type 2 diabetes mellitus (T2DM) and non-alcoholic steatohepatitis (NASH).

METHODS

Ninety-two patients with prediabetes or T2DM and biopsy-proven NASH with BMD and baseline biochemical bone measurements were included. Patients (mean [±SEM] age 51 ± 1 years, 71% male, mean body mass index 34.5 ± 0.5 kg/m² ) were randomly assigned to pioglitazone (45 mg/day) or placebo for 18 months, followed by an 18-month open-label pioglitazone treatment phase. Baseline, 18- and 36-month evaluations included plasma vitamin D and bone turnover biomarker levels, and BMD measurements at the spine, femoral neck, total hip, and one-third radius.

RESULTS

After 18 months of pioglitazone treatment, there were no differences in BMD versus placebo at either the femoral neck (P =0.87), total hip (P =0.78), or one-third radius (P =0.44); however, bone density decreased at the level of the spine with pioglitazone (-3.5%; P =0.002). During the extension phase (18-36 months), patients had no further decreases in BMD or plasma biomarkers of bone turnover during pioglitazone treatment. No patient experienced a low-energy bone fracture.

CONCLUSIONS

Treatment of patients with prediabetes or T2DM with pioglitazone for up to 3 years was associated with decreased BMD at the level of the lumbar spine. This reduction in BMD at the lumbar spine at 18 months versus placebo suggests an early deleterious effect of pioglitazone on bone metabolism.

Self-reported low-energy fractures and associated risk factors in people with diabetes: A national population-based study

AIMS

Clinical risk factors and bone mineral densitometry underestimate low-energy fracture (LEF) risk in people with diabetes. We aim to estimate the prevalence of LEF in diabetics, compare with nondiabetics; and evaluate possible predictors of LEF in people with diabetes.

METHODS

Cross-sectional, population-based study in Portuguese subjects over 40 years-old. Estimates computed as weighted proportions/means, considering sample design. Multivariate logistic regression models to evaluate the association of diabetes and LEF; and predictors of LEF in diabetics.

RESULTS

7675 subjects were analysed, of which 1173 reported diabetes. Diabetics were older (mean age 66.0 ± 11.49y), more frequently reported osteoporosis and falls in the previous 12 months (32.4% vs. 22.9%). Prevalence of self-reported LEF was 16.2% (95% CI:13.68-19.13) among diabetics (vs. 13.3%, 95% CI:12.14-14.57, in nondiabetics); OR for the association diabetes and LEF:1.26, 95% CI:1.01-1.58, p = 0.045 (in women, adjusted OR:1.41, 95% CI:1.05-1.89, p = 0.02). Thirty percent of diabetics reported at least one major LEF and 70% in other sites. In diabetics, LEF was independently associated with self-reported osteoporosis and falls in the previous 12 months.

CONCLUSION

People with diabetes reported more falls and had higher prevalence of self-reported LEF. Self-reported osteoporosis and falls were associated with LEF in diabetics. Our findings emphasize the need for fracture and falls preventive measures in diabetics.

Multi-Scale Approach for the Evaluation of Bone Mineralization in Strontium Ranelate-Treated Diabetic Rats

Long-term diabetes mellitus can induce osteopenia and osteoporosis, an increase in the incidence of low-stress fractures, and/or delayed fracture healing. Strontium ranelate (SrR) is a dual-action anti-osteoporotic agent whose use in individuals with diabetic osteopathy has not been adequately evaluated. In this study, we studied the effects of an oral treatment with SrR and/or experimental diabetes on bone composition and biomechanics. Young male Wistar rats (half non-diabetic, half with streptozotocin/nicotinamide-induced diabetes) were either untreated or orally administered 625 mg/kg/day of SrR for 6 weeks. After sacrifice, femora from all animals were evaluated by a multi-scale approach (X-ray diffraction, Fourier transform infrared spectroscopy, inductively coupled plasma optical-emission spectrometry, static histomorphometry, pQCT, and mechanical testing) to determine chemical, crystalline, and biomechanical properties. Untreated diabetic animals (versus untreated non-diabetic) showed a decrease in femoral mineral carbonate content, in cortical thickness and BMC, in trabecular osteocyte density, in maximum load supported at rupture and at yield point, and in overall toughness at mid-shaft. Treatment of diabetic animals with SrR further affected several parameters of bone (some already impaired by diabetes): crystallinity index (indicating less mature apatite crystals); trabecular area, BMC, and vBMD; maximum load at yield point; and structural elastic rigidity. However, SrR was also able to prevent the diabetes-induced decreases in trabecular osteocyte density (completely) and in bone ultimate strength at rupture (partially). Our results indicate that SrR treatment can partially but significantly prevent some bone structural mechanical properties as previously affected by diabetes, but not others (which may even be worsened).

The serum creatinine to cystatin C ratio predicts bone fracture in patients with type 2 diabetes: The Fukuoka Diabetes Registry

AIMS

Sarcopenia is involved in the pathogenesis of increased fracture risk associated with diabetes. The serum creatinine to cystatin C (Cr/CysC) ratio has been reported as a surrogate marker for muscle mass. We aimed to prospectively investigate the relationship between the Cr/CysC ratio and fracture risk.

METHODS

We followed 1911 postmenopausal women and 2689 men with type 2 diabetes (mean age, 66 years) for a median of 5.3 years, and divided into Cr/CysC ratio quartiles by sex. The primary outcome was fragility fractures and the secondary outcome was any fracture.

RESULTS

Fragility fractures occurred in 192 participants, and any fracture occurred in 645 participants. Multivariate-adjusted hazard ratios (95% CI) for fragility fractures were 2.15 (1.19-3.88) (Q1), 1.63 (0.89-2.98) (Q2), 1.34 (0.72-2.51) (Q3) and 1.0 (ref.) (Q4) in postmenopausal women, and 1.75 (0.64-4.50) (Q1), 2.09 (0.83-5.26) (Q2), 1.56 (0.58-4.18) (Q3) and 1.0 (ref.) (Q4) in men. Those for any fracture were 1.46 (1.07-1.98) (Q1), 1.33 (0.98-1.81) (Q2), 1.40 (1.03-1.88) (Q3) and 1.0 (ref.) (Q4) in postmenopausal women, and 2.33 (1.54-3.54) (Q1), 2.02 (1.54-3.04) (Q2), 1.13 (0.71-1.78) (Q3) and 1.0 (ref.) (Q4) in men.

CONCLUSIONS

A lower Cr/CysC ratio is a significant risk factor for fractures in patients with type 2 diabetes.

MECHANISMS IN ENDOCRINOLOGY: Bone marrow adiposity and bone, a bad romance?

Bone marrow adipocytes (BMA-) constitute an original and heterogeneous fat depot whose development appears interlinked with bone status throughout life. The gradual replacement of the haematopoietic tissue by BMA arises in a well-ordered way during childhood and adolescence concomitantly to bone growth and continues at a slower rate throughout the adult life. Importantly, BM adiposity quantity is found well associated with bone mineral density (BMD) loss at different skeletal sites in primary osteoporosis such as in ageing or menopause but also in secondary osteoporosis consecutive to anorexia nervosa. Since BMA and osteoblasts originate from a common mesenchymal stem cell, adipogenesis is considered as a competitive process that disrupts osteoblastogenesis. Besides, most factors secreted by bone and bone marrow cells (ligands and antagonists of the WNT/β-catenin pathway, BMP and others) reciprocally regulate the two processes. Hormones such as oestrogens, glucocorticoids, parathyroid and growth hormones that control bone remodelling also modulate the differentiation and the activity of BMA. Actually, BMA could also contribute to bone loss through the release of paracrine factors altering osteoblast and/or osteoclast formation and function. Based on clinical and fundamental studies, this review aims at presenting and discussing these current arguments that support but also challenge the involvement of BMA in the bone mass integrity.

FRAX tool in type 2 diabetic subjects: the use of HbA1c in estimating fracture risk

AIMS

Patients with type 2 diabetes mellitus (T2DM) have an increased risk of fractures, despite having greater bone mineral density (BMD) than non-diabetic subjects. This has led to the hypothesis that the presence of impaired bone quality among diabetics reduces bone strength. The Fracture Risk Assessment Score (FRAX) algorithm, introduced to facilitate the evaluation of fracture risk, underestimates the risk of fracture in diabetic patients. The purpose of this study is to confirm the relationship between the degree of metabolic compensation and the 10-year probability of a major fracture or a hip osteoporotic fracture observed in our previous study and to ascertain whether glycosylated hemoglobin (HbA_1c) can improve the predictive value of FRAX in patients with T2DM.

METHODS

Our data derive from a retrospective clinical study conducted at the "Tor Vergata" Polyclinic in Rome on 6355 subjects over 50 years of age evaluated for osteoporosis. All available clinical records were examined. HbA_1c was available for 242 of these subjects and all had had a Dual-energy X-ray Absorption (DXA) scan of the lumbar spine and femoral neck. The risk of fracture was estimated using the Italian version of the FRAX algorithm.

RESULT

Patients with T2DM had BMD and T-scores higher than those of non-diabetic subjects, while FRAX average values were higher in the non-diabetic group. HbA_1c and FRAX are inversely correlated with each other: for each incremental percentage point of HbA_1c growth, the FRAX major osteoporotic fracture probability is reduced by 0.915 points and the FRAX hip osteoporotic fracture probability by 1.438 points. The introduction of a correction factor derived from HbA_1c, resulted in mean FRAX values of diabetic patients equivalent to those of non-diabetic subjects.

CONCLUSIONS

We propose a correction factor derived from HbA_1c that could enhance the predictive ability of fracture risk estimated by the FRAX algorithm in subjects with T2DM.

Type 2 diabetes impairs angiogenesis and osteogenesis in calvarial defects: MicroCT study in ZDF rats

OBJECTIVES

The present study was motivated by the fact that bone regeneration in the compromised vascular microenvironment of T2DM is challenging and the factors that determine the adverse bone regeneration outcomes are poorly understood. For this purpose the effect of T2DM on osteogenic and angiogenic healing potential of calvarial bone, was evaluated in Zucker diabetic fatty (ZDF) rats, an established rat model for obese T2DM.

MATERIALS AND METHODS

The study used 16-week-old ZDF rats and their age-matched controls, Zucker Lean (ZL). Circular defects of different sizes were created on the animal calvaria, either a single 8-mm-diameter (n = 6) defect, or 6-4-2-mm-diameter multidefects (n = 6). Bone regeneration was evaluated at 0, 4, 6 and 8 weeks post surgery using in vivo micro-CT and after animal sacrifice using ex vivo micro-CT. Vascular network parameters within the defects, were quantified by perfusing the animal vasculature with microfil® and scanning it after decalcification.

RESULTS

Compared to results obtained from the ZL rats, defects of 8-mm-diameter in ZDF rats displayed impaired healing kinetics and significantly reduced newly formed bone volume (p < 0.01) and surface area (p < 0.01), 8 weeks post surgery. Defects of 6-4-2-mm-diameter exhibited bone formation, which was independent of either the size or the diabetic condition. Compared to results from the ZL, in the ZDF rats, vasculature volume and surface area were significantly (p < 0.05) reduced in all size-defects.

CONCLUSION

The present study provided evidence that T2DM impairs bone formation in critical-size calvarial defects and markedly reduces angiogenesis in all defects regardless of the defect size tested.

The Role of Matrix Composition in the Mechanical Behavior of Bone

PURPOSE OF REVIEW

While thinning of the cortices or trabeculae weakens bone, age-related changes in matrix composition also lower fracture resistance. This review summarizes how the organic matrix, mineral phase, and water compartments influence the mechanical behavior of bone, thereby identifying characteristics important to fracture risk.

RECENT FINDINGS

In the synthesis of the organic matrix, tropocollagen experiences various post-translational modifications that facilitate a highly organized fibril of collagen I with a preferred orientation giving bone extensibility and several toughening mechanisms. Being a ceramic, mineral is brittle but increases the strength of bone as its content within the organic matrix increases. With time, hydroxyapatite-like crystals experience carbonate substitutions, the consequence of which remains to be understood. Water participates in hydrogen bonding with organic matrix and in electrostatic attractions with mineral phase, thereby providing stability to collagen-mineral interface and ductility to bone. Clinical tools sensitive to age- and disease-related changes in matrix composition that the affect mechanical behavior of bone could potentially improve fracture risk assessment.

Low bone toughness in the TallyHO model of juvenile type 2 diabetes does not worsen with age

Fracture risk increases as type 2 diabetes (T2D) progresses. With the rising incidence of T2D, in particular early-onset T2D, a representative pre-clinical model is needed to study mechanisms for treating or preventing diabetic bone disease. Towards that goal, we hypothesized that fracture resistance of bone from diabetic TallyHO mice decreases as the duration of diabetes increases. Femurs and lumbar vertebrae were harvested from male, TallyHO mice and male, non-diabetic SWR/J mice at 16weeks (n≥12 per strain) and 34weeks (n≥13 per strain) of age. As is characteristic of this model of juvenile T2D, the TallyHO mice were obese and hyperglycemic at an early age (5weeks and 10weeks of age, respectively). The femur mid-shaft of TallyHO mice had higher tissue mineral density and larger cortical area, as determined by micro-computed tomography, compared to the femur mid-shaft of SWR/J mice, irrespective of age. As such, the diabetic rodent bone was structurally stronger than the non-diabetic rodent bone, but the higher peak force endured by the diaphysis during three-point (3pt) bending was not independent of the difference in body weight. Upon accounting for the structure of the femur diaphysis, the estimated toughness at 16weeks and 34weeks was lower for the diabetic mice than for non-diabetic controls, but neither toughness nor estimated material strength and resistance to crack growth (3pt bending of contralateral notched femur) decreased as the duration of hyperglycemia increased. With respect to trabecular bone, there were no differences in the compressive strength of the L6 vertebral strength between diabetic and non-diabetic mice at both ages despite a lower trabecular bone volume for the TallyHO than for the SWR/J mice at 34weeks. Amide I sub-peak ratios as determined by Raman Spectroscopy analysis of the femur diaphysis suggested a difference in collagen structure between diabetic and non-diabetic mice, although there was not a significant difference in matrix pentosidine between the groups. Overall, the fracture resistance of bone in the TallyHO model of T2D did not progressively decrease with increasing duration of hyperglycemia. However, given the variability in hyperglycemia in this model, there were correlations between blood glucose levels and certain structural properties including peak force.

Impact of Body Weight Loss From Maximum Weight on Fragility Bone Fractures in Japanese Patients With Type 2 Diabetes: The Fukuoka Diabetes Registry

OBJECTIVE

There is growing evidence that weight loss is associated with increased fracture risk in the general population. As patients with diabetes often lose weight intentionally or unintentionally, we aimed to investigate prospectively the relationship between weight loss from maximum body weight and fracture risk.

RESEARCH DESIGN AND METHODS

A total of 4,706 Japanese participants with type 2 diabetes (mean age 66 years), including 2,755 men and 1,951 postmenopausal women, were followed for a median of 5.3 years and were divided according to weight loss from maximum weight: <10%, 10% to <20%, 20% to <30%, and ≥30%. The primary outcomes were fragility fractures defined as fractures at sites of hip and spine.

RESULTS

During the follow-up period, fragility fractures occurred in 198 participants. The age- and sex-adjusted incidence rates per 1,000 person-years in all participants were 6.4 (<10% weight loss from maximum body weight), 7.8 (10% to <20%), 11.7 (20% to <30%), and 19.2 (≥30%) (P for trend <0.001). Multivariate-adjusted hazard ratios for fragility fractures compared with reference (<10% weight loss) were 1.48 (95% CI 0.79-2.77) in the 10% to <20% group, 2.23 (1.08-4.64) in 20% to <30%, and 5.20 (2.15-12.57) in ≥30% in men, and 1.19 (0.78-1.82) in 10% to <20%, 1.62 (0.96-2.73) in 20% to <30%, and 1.97 (0.84-4.62) in ≥30% in postmenopausal women.

CONCLUSIONS

The current study demonstrates that ≥20% body weight loss from maximum weight is a significant risk factor for fragility fractures in patients with type 2 diabetes, especially in men.

Trabecular Bone Score in Men and Women with Impaired Fasting Glucose and Diabetes

Diabetes is associated with increased skeletal fragility, despite higher bone mineral density (BMD). Alternative measures are necessary to more accurately determine fracture risk in individuals with diabetes. Therefore, we aimed to describe the relationship between trabecular bone score (TBS) and normoglycaemia, impaired fasting glucose (IFG) and diabetes and determine whether TBS-adjusted FRAX (Aus) score differed between these groups. This study included 555 men (68.7 ± 12.2 years) and 514 women (62.0 ± 12.0 years), enrolled in the observational Geelong Osteoporosis Study. IFG was considered as fasting plasma glucose (FPG) ≥ 5.5 mmol/L and diabetes as FPG ≥ 7.0 mmol/L, with the use of antihyperglycaemic medication and/or self-report. Using multivariable regression, the relationship between groups and TBS was determined. Men and women (all ages) with diabetes had lower mean TBS compared to those with normoglycaemia, in models adjusted for age, height and weight/waist circumference (all p < 0.05). Men with IFG had lower mean TBS in the age-adjusted models only (all p < 0.05). The addition of TBS to the FRAX score improved the discrimination between glycaemia groups, particularly for younger women (< 65 years). There was no difference in TBS detected between normoglycaemia and IFG; however, those with diabetes had lower TBS. Thus, the increased fracture risk in men and women with diabetes may be a result of BMD-independent bone deterioration. TBS adjustment of FRAX scores may be useful for younger women (< 65 years) with diabetes. This suggests that halting or reversing progression from IFG to diabetes could be important to prevent skeletal fragility in diabetes.

The risks of sarcopenia, falls and fractures in patients with type 2 diabetes mellitus

Fracture risk in patients with type 2 diabetes mellitus (T2DM) is increased, and the mechanism is multifactorial. Recent research on T2DM-induced bone fragility shows that bone mineral density (BMD) is often normal or even slightly elevated. However, bone turnover may be decreased and bone material and microstructural properties are altered, especially when microvascular complications are present. Besides bone fragility, extra-skeletal factors leading to an increased propensity to experience falls may also contribute to the increased fracture risk in T2DM, such as peripheral neuropathy, retinopathy and diabetes medication (e.g. insulin use). One of the probable additional contributing factors to the increased fall and fracture risks in T2DM is sarcopenia, the age-related decline in skeletal muscle mass, quality and function. Although the association between sarcopenia, fall risk, and fracture risk has been studied in the general population, few studies have examined the association between T2DM and muscle tissue and the risks of falls and fractures. This narrative review provides an overview of the literature regarding the multifactorial mechanisms leading to increased fracture risk in patients with T2DM, with a focus on sarcopenia and falls.

Obesity and type 2 diabetes, not a diet high in fat, sucrose, and cholesterol, negatively impacts bone outcomes in the hyperphagic Otsuka Long Evans Tokushima Fatty rat

BACKGROUND

Obesity and type 2 diabetes (T2D) increase fracture risk; however, the association between obesity/T2D may be confounded by consumption of a diet high in fat, sucrose, and cholesterol (HFSC).

OBJECTIVE

The study objective was to determine the main and interactive effects of obesity/T2D and a HFSC diet on bone outcomes using hyperphagic Otuska Long Evans Tokushima Fatty (OLETF) rats and normophagic Long Evans Tokushima Otsuka (LETO) controls.

METHODS

At 8weeks of age, male OLETF and LETO rats were randomized to either a control (CON, 10 en% from fat as soybean oil) or HFSC (45 en% from fat as soybean oil/lard, 17 en% sucrose, and 1wt%) diet, resulting in four treatment groups. At 32weeks, total body bone mineral content (BMC) and density (BMD) and body composition were measured by dual-energy X-ray absorptiometry, followed by euthanasia and collection of blood and tibiae. Bone turnover markers and sclerostin were measured using ELISA. Trabecular microarchitecture of the proximal tibia and geometry of the tibia mid-diaphysis were measured using microcomputed tomography; whole-bone and tissue-level biomechanical properties were evaluated using torsional loading of the tibia. Two-factor ANOVA was used to determine main and interactive effects of diet (CON vs. HFSC) and obesity/T2D (OLETF vs. LETO) on bone outcomes.

RESULTS

Hyperphagic OLEFT rats had greater final body mass, body fat, and fasting glucose than normophagic LETO, with no effect of diet. Total body BMC and serum markers of bone formation were decreased, and bone resorption and sclerostin were increased in obese/T2D OLETF rats. Trabecular bone volume and microarchitecture were adversely affected by obesity/T2D, but not diet. Whole-bone and tissue-level biomechanical properties of the tibia were not affected by obesity/T2D; the HFSC diet improved biomechanical properties only in LETO rats.

CONCLUSIONS

Obesity/T2D, regardless of diet, negatively impacted the balance between bone formation and resorption and trabecular bone volume and microarchitecture in OLETF rats.

Abnormal subchondral bone remodeling and its association with articular cartilage degradation in knees of type 2 diabetes patients

Type 2 diabetes (T2D) is associated with systemic abnormal bone remodeling and bone loss. Meanwhile, abnormal subchondral bone remodeling induces cartilage degradation, resulting in osteoarthritis (OA). Accordingly, we investigated alterations in subchondral bone remodeling, microstructure and strength in knees from T2D patients and their association with cartilage degradation. Tibial plateaus were collected from knee OA patients undergoing total knee arthroplasty and divided into non-diabetic (n=70) and diabetes (n=51) groups. Tibial plateaus were also collected from cadaver donors (n=20) and used as controls. Subchondral bone microstructure was assessed using micro-computed tomography. Bone strength was evaluated by micro-finite-element analysis. Cartilage degradation was estimated using histology. The expression of tartrate-resistant acidic phosphatase (TRAP), osterix, and osteocalcin were calculated using immunohistochemistry. Osteoarthritis Research Society International (OARSI) scores of lateral tibial plateau did not differ between non-diabetic and diabetes groups, while higher OARSI scores on medial side were detected in diabetes group. Lower bone volume fraction and trabecular number and higher structure model index were found on both sides in diabetes group. These microstructural alterations translated into lower elastic modulus in diabetes group. Moreover, diabetes group had a larger number of TRAP⁺ osteoclasts and lower number of Osterix⁺ osteoprogenitors and Osteocalcin⁺ osteoblasts. T2D knees are characterized by abnormal subchondral bone remodeling and microstructural and mechanical impairments, which were associated with exacerbated cartilage degradation. In regions with intact cartilage the underlying bone still had abnormal remodeling in diabetes group, suggesting that abnormal bone remodeling may contribute to the early pathogenesis of T2D-associated knee OA.

Serum adiponectin predicts fracture risk in individuals with type 2 diabetes: the Fukuoka Diabetes Registry

AIMS/HYPOTHESIS

Serum adiponectin has been reported to impact upon fracture risk in the general population. Although type 2 diabetes is associated with increased fracture risk, it is unclear whether serum adiponectin predicts fractures in individuals with type 2 diabetes. The aim of the study was to prospectively investigate the relationship between serum adiponectin and fracture risk in individuals with type 2 diabetes.

METHODS

In this study, data was obtained from The Fukuoka Diabetes Registry, a multicentre prospective study designed to investigate the influence of modern treatments on the prognoses of patients with diabetes mellitus. We followed 4869 participants with type 2 diabetes (mean age, 65 years), including 1951 postmenopausal women (defined as self-reported amenorrhea for >1 year) and 2754 men, for a median of 5.3 years. The primary outcomes were fractures at any site and major osteoporotic fractures (MOFs).

RESULTS

During the follow-up period, fractures at any site occurred in 682 participants, while MOFs occurred in 277 participants. Age-adjusted HRs (95% CIs) of any fracture and MOFs for 1 SD increment in log _e -transformed serum adiponectin were 1.27 (1.15, 1.40) and 1.35 (1.17, 1.55) in postmenopausal women and 1.22 (1.08, 1.38) and 1.40 (1.15, 1.71) in men, respectively. HRs (95% CIs) of MOFs for hyperadiponectinaemia (≥ 20 μg/ml) were 1.72 (1.19, 2.50) in postmenopausal women and 2.19 (1.23, 3.90) in men. The per cent attributable risk of hyperadiponectinaemia for MOFs was as high as being age ≥70 years or female sex.

CONCLUSIONS/INTERPRETATION

Higher serum adiponectin levels were significantly associated with an increased risk of fractures at any site and with an increased risk of MOFs in individuals with type 2 diabetes, including postmenopausal women.

Increased blood cadmium levels were not associated with increased fracture risk but with increased total mortality in women: the Malmö Diet and Cancer Study

This study aimed to investigate if high levels of blood cadmium at baseline were associated with increased fracture risk during follow-up in middle-aged women. No increased fracture risk was observed during follow-up, but women with higher levels of cadmium had an increased overall mortality.

INTRODUCTION

Exposure to high levels of cadmium has been associated with an increased fracture risk. The aim was to investigate a perceived association between low levels of blood cadmium (B-Cd) at baseline and risk of first incident fracture.

METHODS

From the population-based Malmö Diet and Cancer Study Cardiovascular cohort, 2920 middle-aged women with available background questionnaire and B-Cd measurements were included. Women were divided into quartiles (Q) according to their cadmium levels (Cd-Q1 <0.18 μg/L, Cd-Q2 0.18-0.28 μg/L, Cd-Q3 0.28-0.51 μg/L, and Cd-Q4 >0.51 μg/L). National registries were analysed for prospective risk of fractures or death. Associations between B-Cd and fracture risk were assessed by survival analysis (Cox regression analysis).

RESULTS

In total, 998 first incident fractures occurred in women during a follow-up lasting 20.2 years (median) (12.5-21.2 years) (25th-75th percentile). Women in Cd-Q4 were more often current smokers than in Cd-Q1 78.4 vs. 3.3% (p < 0.001) and the number of cigarettes smoked per day correlated with B-Cd (r = 0.49; p < 0.001). The risk of fracture was not associated with baseline B-Cd in adjusted models. The hazard ratio (HR) Cd-Q4 vs. Cd-Q1 was 1.06 (95% confidence interval (CI) 0.89-1.27). In the multivariate Cox regression, independent variables for increased fracture risk were history of gastric ulcer and increasing age, whereas increasing body mass index (BMI) lowered fracture risk. Overall mortality was significantly higher for women with high B-Cd, HR 2.06 (95% CI 1.57-2.69).

CONCLUSIONS

Higher blood levels of cadmium did not increase fracture risk in middle-aged women but reduced overall survival.