Hyperinsulinemia and bone mineral density in an elderly population: The Rotterdam Study

Association between dietary insulin index and postmenopausal osteoporosis in Iranian women: a case-control study

BACKGROUND

The relationship between the dietary insulin index (DII) and the disease's risk is unknown, despite the fact that hyperinsulinemia is presumed to contribute to osteoporosis. The insulin response of various diets determines the DII. This study aimed to investigate the connection between postmenopausal Iranian women's adherence to a diet with a higher insulinemic potential and osteoporosis.

METHODS

A total of 380 postmenopausal women were included in the current case-control study. A 168-item food frequency questionnaire (FFQ) with established validity and reliability was used to evaluate individuals' daily calorie intake. The standard formula was employed to determine the dietary insulin load of each product. Subsequently, the calculation of DII was performed by dividing the dietary insulin load by the total energy consumed for each individual. In order to investigate the relationship between osteoporosis and DII, logistic regression was implemented.

RESULTS

The results of the current study demonstrated a substantial inverse relationship between osteoporosis and the DII, even after accounting for confounding variables (OR = 0.927; 95% CI = 0.888-0.967). The mean scores of DII (P < 0.001) was significantly higher in control group (36.82 ± 8.98) compared to the case group (33.53 ± 6.28).

CONCLUSIONS

Our findings suggest that keeping a diet high in insulin index and low in foods that are insulinogenic may improve bone mass density. Consequently, it may be essential for postmenopausal women to consume nutrients that stimulate insulin production in order to prevent osteoporosis.

Correlation between bone mineral density and type 2 diabetes mellitus in elderly men and postmenopausal women

The relationship between bone mineral density and type 2 diabetes is still controversial. The aim of this study is to investigate the relationship between type 2 diabetes mellitus (T2DM) and bone mineral density (BMD) in elderly men and postmenopausal women. The participants in this study included 692 postmenopausal women and older men aged ≥ 50 years, who were divided into the T2DM group and non-T2DM control group according to whether or not they had T2DM. The data of participants in the two groups were collected from the inpatient medical record system and physical examination center systems, respectively, of the Tertiary Class A Hospital. All data analysis is performed in SPSS Software. Compared with all T2DM group, the BMD and T scores of lumbar spines 1-4 (L1-L4), left femoral neck (LFN) and all left hip joints (LHJ) in the non-T2DM group were significantly lower than those in the T2DM group (P < 0.05), and the probability of major osteoporotic fracture in the next 10 years (PMOF) was significantly higher than that in T2DM group (P < 0.001). However, with the prolongation of the course of T2DM, the BMD significantly decreased, while fracture risk and the prevalence of osteoporosis significantly increased (P < 0.05). We also found that the BMD of L1-4, LFN and LHJ were negatively correlated with homeostatic model assessment-insulin resistance (HOMA-IR) (P = 0.028, P = 0.01 and P = 0.047, respectively). The results also showed that the BMD of LHJ was positively correlated with indirect bilirubin (IBIL) (P = 0.018). Although the BMD was lower in the non-T2DM group than in the T2DM group, the prolongation of the course of T2DM associated with the lower BMD. And the higher prevalence of osteoporosis and fracture risk significantly associated with the prolongation of the course of T2DM. In addition, BMD was significantly associated with insulin resistance (IR) and bilirubin levels in T2DM patients.Registration number: China Clinical Trials Registry: MR-51-23-051741; https://www.medicalresearch.org.cn/search/research/researchView?id=c0e5f868-eca9-4c68-af58-d73460c34028 .

IRTKS promotes osteogenic differentiation by inhibiting PTEN phosphorylation

Insulin stimulates osteoblast proliferation and differentiation as an anabolic agent in bone. Insulin Receptor Tyrosine Kinase Substrate (IRTKS) is involved in insulin signaling as an adapter for insulin receptors (IR). Here, we showed that IRTKS levels were significantly decreased in bone marrow mesenchymal stem cells (BMSCs) derived from the bone marrow of patients with osteoporosis. Based on relevant experiments, we observed that IRTKS promoted the proliferation, migration, and osteoblast differentiation of BMSCs and MC3T3-E1 cells. In addition, we identified a Phosphatase and Tensin homolog deleted on chromosome 10 (PTEN) as a potential active substrate of IRTKS. We demonstrated a direct interaction between IRTKS and PTEN using co-immunoprecipitation. Subsequently, we confirmed that the SH3 domain of IRTKS directly binds to the C-terminal tail of PTEN. Further experimental results demonstrated that PTEN attenuated the promoting effects of IRTKS on the proliferation, migration, and osteoblast differentiation of BMSCs and MC3T3-E1 cells. In conclusion, this study suggests that IRTKS contributes to osteogenic differentiation by inhibiting PTEN phosphorylation and provides a potential therapeutic target for osteoporosis patients.

Relative Contribution of Metabolic Syndrome Components in Relation to Obesity and Insulin Resistance in Postmenopausal Osteoporosis

Introduction. Osteoporosis (OP) affects 30% of postmenopausal women, often complicated by metabolic syndrome (MetS) with a still controversial role. We aimed to characterize MetS and its components in relation to bone mineral density (BMD), body mass index (BMI), and insulin resistance. Methods. Patients (n = 188) underwent DEXA scans, spine X-rays, and metabolic and hormonal investigations, including bone biomarkers, muscular strength, and physical performance tests, while insulin resistance was evaluated by the Homeostasis Model Assessment (HOMA-IR). Results. Patients with a normal BMD or osteopenia (n = 68) and with OP (n = 120) displayed 51.5% and 30.8% of MetS, but without differences in insulin resistance. When BMD was studied as a function of the cumulative MetS criteria and centiles of BMI, lower levels of BMD were observed beyond an inflection point of 27.2 kg/m2 for BMI, allowing for further stratification as lean and overweight/obese (OW/OB) subjects. In contrast with lean individuals (n = 74), in OW/OB patients (n = 46), MetS was associated with HbA1c (p < 0.0037, OR 9.6, 95% CI [1.64-55.6]) and insulin resistance (p < 0.0076, OR 6.7, 95% CI [1.49-30.8]) in the context where BMD values were lower than those predicted from BMI in non-OP subjects. In OP patients with fragility fractures (31% of MetS), glycemia also appeared to be the dominant factor for MetS (p < 0.0005, OR 4.1, 95% CI [1.63-10.39]). Conclusions. These data indicate a detrimental effect of insulin resistance in MetS on OP patients, while the prevalence of the syndrome depends on the proportion of obesity. These findings provide new insights into the pathogenic role of MetS and reveal the need to consider different strata of BMI and insulin resistance when studying postmenopausal OP.

Use of noninvasive imaging to identify causes of skeletal fragility in adults with diabetes: a review

Diabetes, a disease marked by consistent high blood glucose levels, is associated with various complications such as neuropathy, nephropathy, retinopathy, and cardiovascular disease. Notably, skeletal fragility has emerged as a significant complication in both type 1 (T1D) and type 2 (T2D) diabetic patients. This review examines noninvasive imaging studies that evaluate skeletal outcomes in adults with T1D and T2D, emphasizing distinct skeletal phenotypes linked with each condition and pinpointing gaps in understanding bone health in diabetes. Although traditional DXA-BMD does not fully capture the increased fracture risk in diabetes, recent techniques such as quantitative computed tomography, peripheral quantitative computed tomography, high-resolution quantitative computed tomography, and MRI provide insights into 3D bone density, microstructure, and strength. Notably, existing studies present heterogeneous results possibly due to variations in design, outcome measures, and potential misclassification between T1D and T2D. Thus, the true nature of diabetic skeletal fragility is yet to be fully understood. As T1D and T2D are diverse conditions with heterogeneous subtypes, future research should delve deeper into skeletal fragility by diabetic phenotypes and focus on longitudinal studies in larger, diverse cohorts to elucidate the complex influence of T1D and T2D on bone health and fracture outcomes.

The nonlinear association between triglyceride glucose-body mass index and femoral neck BMD in nondiabetic elderly men: NHANES 2005-March 2020

BACKGROUND

The triglyceride glucose-body mass index (TyG-BMI) has been considered a surrogate marker for assessing insulin resistance. We aimed to correlate the TyG-BMI, triglyceride glucose combined with body mass index, with femoral neck bone mineral density (FN BMD) in non-diabetic elderly men.

METHODS

Using data from the National Health and Nutrition Examination Survey (NHANES) database, totally, 1182 eligible men aged ≥ 50 years without diabetes were included in the current study. Smoothed curves were obtained by a two-piecewise linear regression model and the threshold effects were explored by using a smoothing function.

RESULTS

TyG-BMI was positive related with and FN BMD with or without adjustment for confounders. However, no typical dose-dependent positive association between TyG-BMI and FN BMD was observed across the TyG-BMI tertiles, indicating a non-linear association. Further analysis by the weighted two-piecewise linear regression model and recursive algorithm suggested that per SD increase in TyG-BMI increased FN BMD by 0.266 gm/cm2 when TyG-BMI lower than 168.20. However, when TyG-BMI is higher than 168.20, FN BMD only increased 0.046 gm/cm2 for per SD increase of TyG-BMI after fully adjustment (OR = 11.258, 95%CI: 6.034, 16.481). Moreover, subgroup analyses showed that higher TyG-BMI levels were related to elevated FN BMD in all groups, suggesting the consistency of the positive association within these stratas.

CONCLUSIONS

This study demonstrated that TyG-BMI is positively associated with FN BMD in a nonlinear fashion among elderly men without diabetes, which may be a reliable marker for the early identification of individuals with lower FN BMD.

Diabetes and Osteoporosis

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

Risk of fracture in adults with type 2 diabetes in Sweden: A national cohort study

BACKGROUND

Type 2 diabetes mellitus (T2DM) is considered a risk factor for fracture but the evidence regarding the impact of T2DM on fracture risk is conflicting. The objective of the study was to determine if patients with T2DM have increased fracture risk and if T2DM-related risk factors could be identified.

METHODS AND FINDINGS

In this national cohort study in Sweden, we investigated the risk of fracture in 580,127 T2DM patients, identified through the national diabetes register including from both primary care and hospitals, and an equal number of population-based controls without diabetes matched for age, sex, and county from 2007 to 2017. The mean age at entry was 66.7 years and 43.6% were women. During a median follow-up time of 6.6 (interquartile range (IQR) 3.1 to 9.8) years, patients with T2DM had a marginally but significantly increased risk of major osteoporotic fracture (MOF) (hazard ratio (HR) 1.01 (95% confidence interval [CI] 1.00 to 1.03)) and hip fracture (HR 1.06 (95% CI 1.04 to 1.08)) compared to controls, associations that were only minimally affected (HR 1.05 (95% CI 1.03 to 1.06) and HR 1.11 (95% CI 1.09 to 1.14), respectively) by multivariable adjustment (age, sex, marital status, and an additional 20 variables related to general morbidity, cardiovascular status, risk of falls, and fracture). In a multivariable-adjusted Cox model, the proportion of the risk for all fracture outcomes (Heller's R2) explained by T2DM was below 0.1%. Among the T2DM patients, important risk factors for fracture were a low BMI (<25 kg/m2), long diabetes duration (≥15 years), insulin treatment, and low physical activity. In total, 55% of the T2DM patients had none of these risk factors and a significantly lower fracture risk than their respective controls. The relatively short mean duration of T2DM and lack of bone density data, constitute limitations of the analysis.

CONCLUSION

In this study, we observed only a marginally increased fracture risk in T2DM, a condition that explained less than 0.1% of the fracture risk. Consideration of the herein identified T2DM-related risk factors could be used to stratify T2DM patients according to fracture risk.

Diabetes Mellitus is Associated with Poor Bone Microarchitecture in Older Adults Residing in Long-Term Care Facilities

OBJECTIVES

Both diabetes mellitus (DM) and osteoporosis are very common in older adults who reside in long-term care (LTC) facilities. Nevertheless, few studies have examined the relationship between diabetes and bone quality in this population. The purpose of this study is to determine if bone mineral density (BMD) or trabecular bone score (TBS) is a better measure of bone quality and skeletal health, in LTC residents with and without a history of DM. Methodology. In this longitudinal cohort study, we examined baseline BMD (lumbar spine, total hip, and femoral neck), TBS, DM, and functional status in 511 LTC residents who were enrolled in two ongoing randomized placebo-controlled osteoporosis clinical trials.

RESULTS

On average, participants were older than 80 years and majority were prefrail or frail. Women with DM had greater lumbar spine BMD (1.106 vs 1.017, adjusted difference ± standard error = 0.084 ± 0.023 g/cm², p = 0.0003) and femoral neck BMD (0.695 vs 0.651, 0.027 ± 0.013 g/cm², p = 0.0463), but lesser lumbar spine TBS (1.211 vs 1.266, -0.036 ± 0.016, p = 0.0299) compared to women without DM. Total hip BMD was also higher based on descriptive statistics (0.780 vs 0.734, p = 0.6255) in diabetic women, although the difference was not statistically significant. Men had similar but attenuated findings.

CONCLUSIONS

Among LTC residents, those with DM have greater BMD but lower bone quality measured by TBS. TBS should be considered in assessing older patients with DM. However, further studies are required to confirm the findings with respect to fractures.

Longitudinal associations of insulin resistance with change in bone mineral density in midlife women

BACKGROUNDThe effects of insulin resistance on bone mineral density (BMD) are unclear.METHODSIn Study of Women's Health Across the Nation (SWAN) participants, we used multivariable regression to test average insulin resistance (homeostatic model assessment of insulin resistance, HOMA-IR) and rate of change in insulin resistance as predictors of rate of change in lumbar spine (LS) and femoral neck (FN) BMD in 3 stages: premenopause (n = 861), menopause transition (MT) (n = 571), and postmenopause (n = 693). Models controlled for age, average BW, change in BW, cigarette use, race and ethnicity, and study site.RESULTSThe relation between HOMA-IR and BMD decline was biphasic. When average log2HOMA-IR was less than 1.5, greater HOMA-IR was associated with slower BMD decline; i.e., each doubling of average HOMA-IR in premenopause was associated with a 0.0032 (P = 0.01, LS) and 0.0041 (P = 0.004, FN) g/cm2 per year slower BMD loss. When greater than or equal to 1.5, average log2HOMA-IR was not associated with BMD change. In women in whom HOMA-IR decreased in premenopause, the association between the HOMA-IR change rate and BMD change rate was positive; i.e, slower HOMA-IR decline was associated with slower BMD loss. In women in whom insulin resistance increased in premenopause, the association was negative; i.e, faster HOMA-IR rise was associated with faster BMD decline. Associations of average HOMA-IR and HOMA-IR change rate with BMD change rate were similar in postmenopause, but weaker during the MT.CONCLUSIONWhen it decreases, insulin resistance is associated with BMD preservation; when it increases, insulin resistance is associated with BMD loss.FUNDINGThe SWAN has grant support from the NIH of the Department of Health and Human Services (DHHS) through the NIH National Institute on Aging (NIA), National Institute of Nursing Research (NINR), and Office of Research on Women's Health (ORWH) (grants U01NR004061, U01AG012505, U01AG012535, U01AG012531, U01AG012539, U01AG012546, U01AG012553, U01AG012554, U01AG012495, and U19AG063720).

Triglyceride Glucose-Body Mass Index Is a Reliable Indicator of Bone Mineral Density and Risk of Osteoporotic Fracture in Middle-Aged and Elderly Nondiabetic Chinese Individuals

(1) Background: This study aimed to investigate the relationship of triglyceride glucose−body mass index (TyG-BMI) with bone mineral density (BMD), femoral neck geometry, and risk of fracture in middle-aged and elderly Chinese individuals. (2) Methods: A total of 832 nondiabetic individuals were selected from the prospective population-based HOPE cohort. All individuals underwent DXA for assessment of BMD at the lumbar spine, femoral neck, and total hip, as well as femoral neck geometry. The 10-year probabilities of both major osteoporotic (MOFs) and hip fractures (HFs) were calculated. (3) Results: Cortical thickness, compression strength index, cross-sectional moment of inertia, cross-sectional area, section modulus, and 25(OH)D levels were significantly lower in women (all p < 0.001). The presence of osteoporosis was related to age, BMI, BMD and femoral neck geometry, TyG-BMI, MOF, and HF. TyG-BMI was positively correlated with BMD. In men, TyG-BMI showed significant negative correlation with HF but not with MOF, the correlation exists only after adjusting for other variables in women. Femoral neck geometries were significantly impaired in individuals with low TyG-BMI. (4) Conclusion: TyG-BMI is positively associated with BMD and geometry, and negatively associated with risk of fracture in nondiabetic middle-aged and elderly Chinese men and women.

Distributions of Microdamage Are Altered Between Trabecular Rods and Plates in Cancellous Bone From Men With Type 2 Diabetes Mellitus

Individuals with type 2 diabetes mellitus (T2DM) have an increased risk of fragility fracture despite exhibiting normal to high bone mineral density (BMD). Conditions arising from T2DM, such as reduced bone turnover and alterations in microarchitecture, may contribute to skeletal fragility by influencing bone morphology and microdamage accumulation. The objectives of this study were (i) to characterize the effect of T2DM on microdamage quantity and morphology in cancellous bone, and (ii) relate the accumulation of microdamage to the cancellous microarchitecture. Cancellous specimens from the femoral neck were collected during total hip arthroplasty (T2DM: n = 22, age = 65 ± 9 years, glycated hemoglobin [HbA1c] = 7.00% ± 0.98%; non-diabetic [non-DM]: n = 25, age = 61 ± 8 years, HbA1c = 5.50% ± 0.4%), compressed to 3% strain, stained with lead uranyl acetate to isolate microdamage, and scanned with micro-computed tomography (μCT). Individual trabeculae segmentation was used to isolate rod-like and plate-like trabeculae and their orientations with respect to the loading axis. The T2DM group trended toward a greater BV/TV (+27%, p = 0.07) and had a more plate-like trabecular architecture (+8% BV_plates , p = 0.046) versus non-DM specimens. Rods were more damaged relative to their volume compared to plates in the non-DM group (DV_rods /BV_rods versus DV_plates /BV_plates : +49%, p < 0.0001), but this difference was absent in T2DM specimens. Longitudinal rods were more damaged in the non-DM group (DV_{longitudinal rods} /BV_{longitudinal rods} : +73% non-DM versus T2DM, p = 0.027). Total damage accumulation (DV/BV) and morphology (DS/DV) did not differ in T2DM versus non-DM specimens. These results provide evidence that cancellous microarchitecture does not explain fracture risk in T2DM, pointing to alterations in material matrix properties. In particular, cancellous bone from men with T2DM may have an attenuated ability to mitigate microdamage accumulation through sacrificial rods. © 2022 American Society for Bone and Mineral Research (ASBMR).

Markers of insulin resistance in Polycystic ovary syndrome women: An update

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders, affecting 5%-10% of women of reproductive age. The importance of this syndrome lies in the magnitude of associated comorbidities: infertility, metabolic dysfunction, cardiovascular disease (CVD), plus psychological and oncological complications. Insulin resistance (IR) is a prominent feature of PCOS with a prevalence of 35%-80%. Without adequate management, IR with compensatory hyperinsulinemia contributes directly to reproductive dysfunction in women with PCOS. Furthermore, epidemiological data shows compelling evidence that PCOS is associated with an increased risk of impaired glucose tolerance, gestational diabetes mellitus and type 2 diabetes. In addition, metabolic dysfunction leads to a risk for CVD that increases with aging in women with PCOS. Indeed, the severity of IR in women with PCOS is associated with the amount of abdominal obesity, even in lean women with PCOS. Given these drastic implications, it is important to diagnose and treat insulin resistance as early as possible. Many markers have been proposed. However, quantitative assessment of IR in clinical practice remains a major challenge. The gold standard method for assessing insulin sensitivity is the hyperinsulinemic euglycemic glucose clamp. However, it is not used routinely because of the complexity of its procedure. Consequently, there has been an urgent need for surrogate markers of IR that are more applicable in large population-based epidemiological investigations. Despite this, many of them are either difficult to apply in routine clinical practice or useless for women with PCOS. Considering this difficulty, there is still a need for an accurate marker for easy, early detection and assessment of IR in women with PCOS. This review highlights markers of IR already used in women with PCOS, including new markers recently reported in literature, and it establishes a new classification for these markers.

Bone fragility in diabetes: novel concepts and clinical implications

Increased fracture risk represents an emerging and severe complication of diabetes. The resulting prolonged immobility and hospitalisations can lead to substantial morbidity and mortality. In type 1 diabetes, bone mass and bone strength are reduced, resulting in up to a five-times greater risk of fractures throughout life. In type 2 diabetes, fracture risk is increased despite a normal bone mass. Conventional dual-energy x-ray absorptiometry might underestimate fracture risk, but can be improved by applying specific adjustments. Bone fragility in diabetes can result from cellular abnormalities, matrix interactions, immune and vascular changes, and musculoskeletal maladaptation to chronic hyperglycaemia. This Review summarises how the bone microenvironment responds to type 1 and type 2 diabetes, and the mechanisms underlying fragility fractures. We describe the value of novel imaging technologies and the clinical utility of biomarkers, and discuss current and future therapeutic approaches that protect bone health in people with diabetes.

Common Dietary Modifications in Preclinical Models to Study Skeletal Health

Bone is a highly dynamic tissue that undergoes continuous remodeling by bone resorbing osteoclasts and bone forming osteoblasts, a process regulated in large part by osteocytes. Dysregulation of these coupled catabolic and anabolic processes as in the case of menopause, type 2 diabetes mellitus, anorexia nervosa, and chronic kidney disease is known to increase fracture risk. Recent advances in the field of bone cell metabolism and bioenergetics have revealed that maintenance of the skeleton places a high energy demand on these cells involved in bone remodeling. These new insights highlight the reason that bone tissue is the beneficiary of a substantial proportion of cardiac output and post-prandial chylomicron remnants and requires a rich supply of nutrients. Studies designed for the specific purpose of investigating the impact of dietary modifications on bone homeostasis or that alter diet composition and food intake to produce the model can be found throughout the literature; however, confounding dietary factors are often overlooked in some of the preclinical models. This review will examine some of the common pre-clinical models used to study skeletal biology and its pathologies and the subsequent impact of various dietary factors on these model systems. Furthermore, the review will include how inadvertent effects of some of these dietary components can influence bone cell function and study outcomes.

Associations of insulin resistance and insulin secretion with bone mineral density and osteoporosis in a general population

We investigated the associations of insulin resistance and β-cell secretion with bone mineral density (BMD) and osteoporosis using data from the National Health and Nutrition Examination Survey. Data on BMD assessed using dual-energy x-ray absorptiometry from 5292 participants were analyzed. Insulin resistance and β-cell secretion were assessed using the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) and β-cell function (HOMA-β), respectively. We divided the study population into four groups according to HOMA-IR (<2 vs. ≥ 2) and HOMA-β (<100 vs. ≥ 100). BMD and T score at the lumbar spine, hip joint, and femur were used for analyses. Osteoporosis was defined as a T score ≤ -2.5. Logistic regression analyses were conducted to examine the associations of HOMA-IR and HOMA-β with osteoporosis, and the joint effects of HOMA-IR and HOMA-β on osteoporosis. We found a positive association between HOMA-IR and osteoporosis in participants with a HOMA-β ≥ 100 (OR 8.773, 95% CI 2.160-35.637, p=0.002 at the femoral neck). A negative association between HOMA-β and osteoporosis was noted in those with a HOMA-IR <2 (OR 0.183, 95% CI 0.038-0.882, p=0.034 at the femoral neck). Compared with participants who had HOMA-IR <2 and HOMA-β <100, those with HOMA-IR <2 and HOMA-β ≥ 100 had a lower risk of osteoporosis (OR 0.126, 95% CI 0.020-0.805, p=0.032 at the femoral neck). In conclusion, the association between HOMA-β and BMD/osteoporosis changed as HOMA-IR increased. HOMA-β was negatively associated with osteoporosis when HOMA-IR <2. The association was not significant when HOMA-IR ≥ 2.

Update on the pathogenesis and treatment of skeletal fragility in type 2 diabetes mellitus

Fracture risk is increased in patients with type 2 diabetes mellitus (T2DM). In addition, these patients sustain fractures despite having higher levels of areal bone mineral density, as measured by dual-energy X-ray absorptiometry, than individuals without T2DM. Thus, additional factors such as alterations in bone quality could have important roles in mediating skeletal fragility in patients with T2DM. Although the pathogenesis of increased fracture risk in T2DM is multifactorial, impairments in bone material properties and increases in cortical porosity have emerged as two key skeletal abnormalities that contribute to skeletal fragility in patients with T2DM. In addition, indices of bone formation are uniformly reduced in patients with T2DM, with evidence from mouse studies published over the past few years linking this abnormality to accelerated skeletal ageing, specifically cellular senescence. In this Review, we highlight the latest advances in our understanding of the mechanisms of skeletal fragility in patients with T2DM and suggest potential novel therapeutic approaches to address this problem.

Comparing the bone mineral density among male patients with latent autoimmune diabetes and classical type 1 and type 2 diabetes, and exploring risk factors for osteoporosis

AIMS

This study aimed to compare the bone mineral densities (BMDs) among male patients with latent autoimmune diabetes in adults (LADA), classical type 1 diabetes (T1DM), and type 2 diabetes (T2DM), and to examine the risk factors for developing low BMD in these patients.

PATIENTS AND METHODS

Between January 2017 and October 2020, a total of 57, 67, and 223 male patients with LADA, classical T1DM, and T2DM, respectively, were recruited from the endocrinology department of Shanghai Tenth People's Hospital. Hormonal markers of bone metabolism, lipid profiles, uric acid, glycosylated hemoglobin A1c (HbA1c), and beta-cell function were measured using blood samples. BMD was measured at the lumbar spine, femoral neck, and right hip by dual-energy X-ray absorptiometry.

RESULTS

The mean BMD values from all three skeletal sites in male patients with LADA were comparable to those with classical T1DM but were much lower than those with T2DM. After adjusting for confounding factors, multiple linear regression analysis demonstrated that in all male patients with diabetes, body mass index (BMI), uric acid, and fasting C-peptide showed significant positive associations with BMD at all three skeletal sites; however, osteocalcin showed a negative association at all three sites.

CONCLUSIONS

Compared with male patients with T2DM, lower BMDs were observed in patients with LADA and T1DM. Low BMI, uric acid, C-peptide levels, and high osteocalcin levels are risk factors for developing low BMD in male patients with diabetes.

On the Relationship Between Non-alcoholic Fatty Liver Disease with Body Composition and Bone Mineral Density in Overweight/Obese Adolescents

Background: Nonalcoholic fatty liver disease (NAFLD) is a health problem growing in line with the rising prevalence of obesity in children and adolescents, which may be correlated with different metabolic abnormalities such as osteoporosis. Objectives: This study aimed to evaluate the possible relationship between NAFLD with body composition and bone mineral density (BMD) in obese and overweight adolescents. Methods: This cross-sectional study encompassed 70 adolescents aged 11 - 18 years and was conducted during March 2016 and September 2016 in Mashhad, Iran. Anthropometric parameters and blood biomarkers were measured. Fat mass, fat-free mass, and BMD were determined using dual-energy X‐ray absorptiometry (DXA) scans, and NAFLD was also assessed using Fibroscan. All statistical data were analyzed using SPSS software version 21. Multivariate linear regression assessed the relationship between liver fat content with bone-related indicators, and multivariate logistic regression detected the relationship between body composition and NAFLD. Results: Total and trunk fat mass were significantly correlated with higher NAFLD even after controlling for intervening factors (total fat mass, OR = 1.27; 95% CI, 1.016 to 1.59, P = 0.036; trunk fat mass, OR = 1.35; 95% CI, 0.97 to 1.88, P = 0.045). Moreover, liver fat content was significantly correlated with lower BMD Z-score after adjusting for gender, BMI Z-score, ALT, fat mass index, total lean mass, and physical activity (β = -0.285, P = 0.048). Conclusions: The findings of the present study suggest that excess adipose tissue is correlated with higher NAFLD. Moreover, liver steatosis may be correlated with decreased BMD Z-score in overweight/obese adolescents.

Very high bone mineral density in a monogenic form of obesity-associated insulin resistance

INTRODUCTION

Alström syndrome (ALMS) is an ultra-rare metabolic disorder caused by biallelic loss-of-function in the Alms1 gene which encodes a ubiquitously expressed centrosomal protein of the primary cilium. Although ALMS is characterised by several metabolic and hormonal dysfunctions that can lead to an increased risk of developing osteoporosis and bone fracture, an increased BMD have been observed. The aim of this study was to characterise the anthropometric, clinical, genetic and densitometric features of bone health in a large adult UK cohort of subjects with ALMS.

METHODS

Twenty-three patients with ALMS and 23 age-matched male control subjects were recruited. Lumbar spine (LS) and total hip (TH) bone mineral density (BMD) were evaluated by DXA in all subjects. A CT scan to assess the spinal bone architecture was performed in ALMS patients with raised lumbar density. Blood analysis for biochemical parameters and thyroid and sex hormones was performed in all ALMS patients.

RESULTS

LS Z-score levels were higher than +2 SD in 35% of all ALMS study participants, of whom 75% were men and 25% were women. TH Z-scores were higher than +1 SD 13% of patients and all of them have higher than expected lumbar Z-score. An extremely high BMD was found in two of the oldest patients (LS Z-score +10.8 and +15.3 SD).

CONCLUSION

ALMS patients tend to have high levels of BMD that increase with age, in particular of the trabecular bones. Although obesity and lifelong IR can be responsible for the increase in BMD, at least in part, of a possible signalling role of Alms1 protein as a bone-forming factor is plausible.

Effect of vitamin D therapy on bone mineral density in patients with diabetic nephropathy; a randomized, double-blind placebo controlled clinical trial

Purpose

Diabetes compromises bone strength resulting increased risk of osteoporosis. Objective of this study was to determine the effect of vitamin D given to patients with early diabetic renal disease on BMD and BMC.

Methods

Patients with diabetic nephropathy were recruited. Treatment group received 50,000 IU of vitamin D3 intramuscularly and the control group was given an equal volume of distilled water (0.25 mL) monthly for six months. Baseline BMD, BMC in the total body, lumbar spine and proximal femur were measured by DXA. After six months measurements were repeated. When trial period was over, a randomly selected subgroup of patients (25 from each group) was followed up for further six-months and measurements were repeated.

Results

Selected patients were randomly assigned to two groups. After six months, the treatment group total body BMD, total body BMC and BMDs of spine, femoral neck and total hip regions increased by 2.0%, 2.2%, 1.8%, 2.1% and 2.6% (P < 0.05 for all within-group differences), respectively. In the Control group, BMD or BMC of any region mentioned above did not change significantly during the initial 6 months (P < 0.05 for the between-groups differences). After 6 months of stopping treatment, a statistically significant reduction of total BMD and BMC was observed in the treatment group (P = 0.009).

Conclusion

This study showed that treatment with high dose vitamin D significantly influences total body BMC, total body BMD, BMDs of spine, femoral neck and hip among patients with diabetic nephropathy.

Thyroid Hormones, Glucocorticoids, Insulin, and Bone

Several endocrine systems have important effects on bone tissue. Thyroid hormones are essential for normal growth and development. Excess of these hormones will result in clinically significant changes that may require intervention. Glucocorticoids also have a marked effect on bone metabolism by several pathways. Their endogenous or exogenous excess will induce pathological processes that might elevate the risk of fractures. Insulin and the carbohydrate metabolism elicit a physiological effect on bone; however, the lack of insulin (type 1 diabetes) or insulin resistance (type 2 diabetes) have deleterious influence on bone tissue.

Comparative transcriptome analysis identifies CARM1 and DNMT3A as genes associated with osteoporosis

To identify new candidate genes in osteoporosis, mainly involved in epigenetic mechanisms, we compared whole gene-expression in osteoblasts (OBs) obtained from women undergoing hip replacement surgery due to fragility fracture and severe osteoarthritis. Then, we analyzed the association of several SNPs with BMD in 1028 women. Microarray analysis yielded 2542 differentially expressed transcripts belonging to 1798 annotated genes, of which 45.6% (819) were overexpressed, and 54.4% (979) underexpressed (fold-change between - 7.45 and 4.0). Among the most represented pathways indicated by transcriptome analysis were chondrocyte development, positive regulation of bone mineralization, BMP signaling pathway, skeletal system development and Wnt signaling pathway. In the translational stage we genotyped 4 SNPs in DOT1L, HEY2, CARM1 and DNMT3A genes. Raw data analyzed against inheritance patterns showed a statistically significant association between a SNP of DNMT3A and femoral neck-(FN) sBMD and primarily a SNP of CARM1 was correlated with both FN and lumbar spine-(LS) sBMD. Most of these associations remained statistically significant after adjusting for confounders. In analysis with anthropometric and clinical variables, the SNP of CARM1 unexpectedly revealed a close association with BMI (p = 0.000082), insulin (p = 0.000085), and HOMA-IR (p = 0.000078). In conclusion, SNPs of the DNMT3A and CARM1 genes are associated with BMD, in the latter case probably owing to a strong correlation with obesity and fasting insulin levels.

Determinants of Bone Material Strength and Cortical Porosity in Patients with Type 2 Diabetes Mellitus

CONTEXT

Reduced bone material strength index (BMSi) and increased cortical porosity (CtPo) have emerged as potentially contributing to fracture risk in type 2 diabetes mellitus (T2DM) patients.

OBJECTIVE

To determine whether BMSi or CtPo are related to other diabetic complications.

DESIGN

Cross-sectional observational study.

SETTING

Subjects recruited from a random sample of southeast Minnesota residents.

PARTICIPANTS

A total of 171 T2DM patients (mean age, 68.8 years) and 108 age-matched nondiabetic controls (mean age, 67.3 years).

MAIN MEASURES

Bone material strength index was measured using microindentation, skin advanced glycation end-products (AGEs) measured using autofluorescence, high-resolution peripheral quantitative computed tomography at the distal radius and tibia, assessment of diabetic microvascular complications including urine microalbuminuria, retinopathy, neuropathy, and vascular disease (ankle brachial index and transcutaneous oxygen tension [TcPO2]). All analyses were adjusted for age, sex, and body mass index.

RESULTS

Skin AGEs were negatively correlated with the BMSi in both T2DM (r = -0.30, P < 0.001) and control (r = -0.23, P = 0.020) subjects. In relating diabetic complications to CtPo, we found that T2DM patients with clinically significant peripheral vascular disease (TcPO2 ≤ 40 mm Hg) had higher (+21.0%, P = 0.031) CtPo at the distal tibia as compared to controls; in these subjects, CtPo was negatively correlated with TcPO2 at both the distal tibia (r = -0.39, P = 0.041) and radius (r = -0.41, P = 0.029).

CONCLUSIONS

Our findings demonstrate that bone material properties are related to AGE accumulation regardless of diabetes status, while CtPo in T2DM patients is linked to TcPO2, a measure of microvascular blood flow.

Wrist circumference: A new marker for insulin resistance in African women with polycystic ovary syndrome

BACKGROUND

Insulin resistance (IR) is the main complication found in 35%-80% of women with polycystic ovary syndrome (PCOS). However, there is no definite consensus regarding which marker to use for its assessment in PCOS women. Research has shown that hyperinsulinemia is correlated with increased bone mass. Given that most women with PCOS are insulin resistant, which is independent from body fat and characterized by hyperinsulinemia, it could be hypothesized that there would be an increased bone mass in the patient as a result. Subsequently, increased bone mass could be measured using the wrist circumference method.

AIM

To assess the wrist circumference as an easy-to-detect marker of IR in Congolese women with PCOS.

METHODS

Seventy-two Congolese women with PCOS and seventy-one controls from the same ethnic group, were enrolled in the study (mean age 24.33 ± 5.36 years). Fasting biochemical parameters, and the Homeostasis Model Assessment of insulin resistance (HOMA-IR) and body composition were evaluated. The non-dominant wrist circumference was measured manually, as was the waist circumference (WC), hip circumference, height and weight. Calculated measures included evaluation of body mass index (BMI), Waist-to-Height (WHtR) and Waist-to-hip ratio (WHR). In addition, body composition was assessed by Bioelectrical Impedance Analysis using a body fat analyzer.

RESULTS

The non-dominant wrist circumference was more closely correlated with HOMA-IR (r = 0.346; P = 0.003) and was the best anthropometrical marker correlated with IR (P = 0.011 ) compared with other anthropometrical markers in women with PCOS: Dominant Wrist Circumference (r = 0.315; P = 0.007), Waist Circumference (WC) (r = 0.259; P = 0.028), BMI (r = 0.285; P = 0.016), WHR (r = 0.216; P = 0,068) and WHtR (r = 0.263; P = 0.027). The diagnostic accuracy of the non-dominant wrist circumference for the presence or absence of IR using Receiver-operating characteristic (ROC) curve analysis showed that the area under the ROC curve was 0.72. A cutoff value for the non-dominant wrist circumference of 16.3 cm was found to be the best predictor of IR in Congolese women with PCOS.

CONCLUSION

Non-dominant wrist circumference is, to date, the best anthropometrical marker of IR in Sub-Saharan African women with PCOS. It could be suggested as an easy-to-detect marker for assessing IR.

Lipids in the Bone Marrow: An Evolving Perspective

Because of heavy energy demands to maintain bone homeostasis, the skeletal system is closely tied to whole-body metabolism via neuronal and hormonal mediators. Glucose, amino acids, and fatty acids are the chief fuel sources for bone resident cells during its remodeling. Lipids, which can be mobilized from intracellular depots in the bone marrow, can be a potent source of fatty acids. Thus, while it has been suggested that adipocytes in the bone marrow act as "filler" and are detrimental to skeletal homeostasis, we propose that marrow lipids are, in fact, essential for proper bone functioning. As such, we examine the prevailing evidence regarding the storage, use, and export of lipids within the skeletal niche, including from both in vitro and in vivo model systems. We also highlight the numerous challenges that remain to fully appreciate the relationship of lipid turnover to skeletal homeostasis.

Risk of Fractures Associated with Dipeptidyl Peptidase-4 Inhibitor Treatment: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

INTRODUCTION

More and more studies suggest that type 2 diabetes mellitus (T2DM) can lead to an increased fracture risk. Some previous clinical studies and experimental data have shown that some antidiabetic drugs can increase or decrease the incidence of fractures.

METHODS

We searched Medline, Embase, Cochrane Library, and the ClinicalTrials.gov website ( https://www.clinicaltrials.gov ) for published or unpublished randomized controlled trials (RCTs) from inception through 2 December 2018 to compare the effects of dipeptidyl peptidase-4 (DDP-4) inhibitors with active control drugs or placebo in T2DM patients. All RCTs had a duration of at least 12 weeks, and the ultimate measure was whether a fracture occurs or not. We calculated odds ratios and their 95% confidence intervals by the fixed effect Mantel-Haenszel model. Publication bias was investigated firstly through visual observation of funnel plot asymmetry and then through Begg's test or Egger's test. The Cochrane bias risk tools were used to assess the quality of included studies.

RESULTS

Eighty-seven eligible RCTs were included in this study. Of 93,772 participants, 49,270 patients received therapy and 44,502 were control patients. Five kinds of DDP-4 inhibitors were included: sitagliptin, saxagliptin, alogliptin, linagliptin and vildagliptin. There were 676 fractures in the DDP-4 inhibitor treatment group and 646 in the control group. The median average glycosylated hemoglobin level was 8.2%. DDP-4 inhibitor treatment did not seem to influence the fracture risk, no matter whether compared with placebo or active comparators in T2DM patients (Mantel-Haenszel odds ratio (MH-OR) = 1.01, 95% CI 0.90-1.12, P = 0.92). After three subgroup analyses which were defined by drug type, control regimen and duration, the results were still stable.

CONCLUSION

This systematic review and meta-analysis shows that DDP-4 inhibitors do not affect the fracture risk when compared with antidiabetic drugs or placebo in T2DM patients.

Effect of Insulin Resistance on BMD and Fracture Risk in Older Adults

CONTEXT

Adults with type 2 diabetes (T2D) have higher fracture risk compared with nondiabetics, despite having higher bone mineral density (BMD). Insulin resistance (IR) has been associated with increased BMD. It is not known if IR increases fracture risk.

OBJECTIVE

We investigated the relationship among IR HOMA-IR, BMD, and incident nonspine fractures in nondiabetic individuals.

DESIGN

Participants included 2398 community-dwelling, nondiabetic older adults (age 74 ± 3 years, 53% women, 38% black) in the Health, Aging and Body Composition Prospective Cohort Study [median follow-up: 12 (interquartile range: 6) years].

RESULTS

The cut-off values for the HOMA-IR quartiles were 1.05, 1.54, and 2.33. Total hip BMD was 0.104 g/cm2 higher in the fourth vs the first HOMA-IR quartile (P < 0.001). This difference was attenuated after adjustment for BMI (adjusted mean difference 0.007 g/cm2; P = 0.371). In unadjusted models, fracture risk was lower in those with higher HOMA-IR [hazard ratio (HR) 0.86 (95% CI 0.73 to 1.01) and 0.65 (95% CI 0.47 to 0.89) for the third and fourth quartile, respectively, vs the first quartile]. However, after adjustment for BMD and BMI, fracture risk was significantly higher in the third quartile (HR 1.19, 95% CI 1.00 to 1.41) and tended to be increased in the fourth quartile (HR 1.12, 95% CI 0.87 to 1.46) vs the first quartile.

CONCLUSIONS

Greater IR is associated with higher BMD in nondiabetic older adults. In contrast to the relationship between T2D and fracture risk, we did not find consistent evidence that greater IR is associated with increased fracture risk after adjustment for BMI and BMD.

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

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

Altered Tissue Composition, Microarchitecture, and Mechanical Performance in Cancellous Bone From Men With Type 2 Diabetes Mellitus

People with type 2 diabetes mellitus (T2DM) have normal-to-high BMDs, but, counterintuitively, have greater fracture risks than people without T2DM, even after accounting for potential confounders like BMI and falls. Therefore, T2DM may alter aspects of bone quality, including material properties or microarchitecture, that increase fragility independently of bone mass. Our objective was to elucidate the factors that influence fragility in T2DM by comparing the material properties, microarchitecture, and mechanical performance of cancellous bone in a clinical population of men with and without T2DM. Cancellous specimens from the femoral neck were collected during total hip arthroplasty (T2DM: n = 31, age = 65 ± 8 years, HbA1c = 7.1 ± 0.9%; non-DM: n = 34, age = 62 ± 9 years, HbA1c = 5.5 ± 0.4%). The T2DM specimens had greater concentrations of the advanced glycation endproduct pentosidine (+ 36%, P < 0.05) and sugars bound to the collagen matrix (+ 42%, P < 0.05) than the non-DM specimens. The T2DM specimens trended toward a greater bone volume fraction (BV/TV) (+ 24%, NS, P = 0.13) and had greater mineral content (+ 7%, P < 0.05) than the non-DM specimens. Regression modeling of the mechanical outcomes revealed competing effects of T2DM on bone mechanical behavior. The trend of higher BV/TV values and the greater mineral content observed in the T2DM specimens increased strength, whereas the greater values of pentosidine in the T2DM group decreased postyield strain and toughness. The long-term medical management and presence of osteoarthritis in these patients may influence these outcomes. Nevertheless, our data indicate a beneficial effect of T2DM on cancellous microarchitecture, but a deleterious effect of T2DM on the collagen matrix. These data suggest that high concentrations of advanced glycation endproducts can increase fragility by reducing the ability of bone to absorb energy before failure, especially for the subset of T2DM patients with low BV/TV. © 2019 American Society for Bone and Mineral Research.

Update on the impact of type 2 diabetes mellitus on bone metabolism and material properties

The prevalence of type 2 diabetes mellitus (T2DM) is increasing worldwide, especially as a result of our aging society, high caloric intake and sedentary lifestyle. Besides the well-known complications of T2DM on the cardiovascular system, the eyes, kidneys and nerves, bone strength is also impaired in diabetic patients. Patients with T2DM have a 40-70% increased risk for fractures, despite having a normal to increased bone mineral density, suggesting that other factors besides bone quantity must account for increased bone fragility. This review summarizes the current knowledge on the complex effects of T2DM on bone including effects on bone cells, bone material properties and other endocrine systems that subsequently affect bone, discusses the effects of T2DM medications on bone and concludes with a model identifying factors that may contribute to poor bone quality and increased bone fragility in T2DM.

Relationship between non-alcoholic steatohepatitis, PNPLA3 I148M genotype and bone mineral density in adolescents

BACKGROUND & AIMS

It is uncertain whether non-alcoholic steatohepatitis (NASH) is a risk factor for low bone mineral density (BMD). Our aim was to investigate: (a) associations between NASH and BMD values and (b) associations between PNPLA3 I148M genotypes and BMD, in children with histologically proven non-alcoholic fatty liver disease (NAFLD).

METHODS

BMD area (g/cm² ) was measured using dual-energy X-ray absorptiometry (DEXA). NASH was diagnosed by a Steatosis, Activity and Fibrosis (SAF) score and FLIP algorithm. Genotyping for patatin-like phospholipase domain containing-3 (PNPLA3) I148M genotype (rs738409) (CC, CG and GG) was undertaken using the TaqMan SNP genotyping allelic discrimination method. Logistic regression was used to test associations [OR (95% CIs)] between low BMD, and both NASH and PNPLA3 I148M genotypes.

RESULTS

Thirty-four adolescents (mean age 13.8 ± 1.1 years) with histologically confirmed NAFLD were studied. Subjects with NASH (n = 25) had a lower BMD (means (SDs) 0.87 ± 0.06 vs 0.97 ± 0.12, P = 0.005), compared to subjects without NASH. Subjects with PNPLA3 CG+GG genotypes had a lower BMD compared with subjects with PNPLA3-CC genotype (means (SDs) 0.79 ± 0.20 vs 0.92 ± 0.10, P = 0.009). PNPLA3 CG+GG genotypes were independently associated with NASH [OR (95% CIs 1.78, 1.24, 2.99)], and low BMD was associated with both PNPLA3 CG+GG (OR 3.62 (95% CIs 1.21, 5.53), P = 0.028) and with SAF score (OR 2.76 (95% CIs 1.12, 5.41), P = 0.045).

CONCLUSIONS

Taken together the independent associations between: (a) low BMD and PNPLA3 CG+GG genotype; (b) low BMD and NASH; and (c) PNPLA3 CG+GG genotype and NASH, provide support for a causal relationship between NASH and low BMD.

Sex hormone-binding globulin and risk of fracture in older adults: systematic review and meta-analysis of observational studies

We conducted a meta-analysis of observational study to clarify the association between sex hormone-binding globulin (SHBG) levels and the risk of fracture in older adults. We found that higher SHBG levels were associated with an increased risk of fracture in older adults.

INTRODUCTION

The association between SHBG levels and the risk of fracture in older adults remains elusive. We aim to clarify this association by conducting a meta-analysis of observational studies.

METHODS

PubMed and Web of Science databases were searched for relevant observational studies investigating the association between SHBG levels and the risk of fracture in older adults. The relative risks (RRs) with 95% confidence intervals (CIs) from each study were transformed into a continuous variable for each 1 μg/dL increase in SHBG and were pooled under a random-effects model.

RESULTS

A total of 16 observational studies were included in the present meta-analysis. The summary RR of fracture risk associated with each 1 μg/dL increase in SHBG was 1.18 (95% CI 1.11, 1.26); no statistically significant heterogeneity was observed across studies (I² = 0%, P = 0.67). The positive association was also evident in men (RR 1.22, 95% CI 1.12, 1.33) and women (RR 1.15, 95% CI, 1.05, 1.26). By site of fracture, higher SHBG levels were positively associated with higher risks of hip fracture (RR 1.43, 95% CI 1.23, 1.65), vertebral fracture (RR 1.31, 95% CI 1.12, 1.54), and non-vertebral fracture (RR 1.21, 95% CI 1.06, 1.38).

CONCLUSIONS

The present meta-analysis suggests that higher SHBG levels predict an increased risk of fracture in older adults. Further studies should aim to elucidate the complex biological mechanisms by which SHBG may affect fracture risk.

Dipeptidyl peptidase-4 inhibitor use is associated with decreased risk of fracture in patients with type 2 diabetes: a population-based cohort study

AIMS

The aim of this study was to investigate the putative link between dipeptidyl peptidase-4 inhibitor (DPP-4i) use and the risk of fracture in patients with type 2 diabetes.

METHODS

This propensity-score-matched population-based cohort study was performed between 2009 and 2013 on patients with type 2 diabetes who were stable metformin users. A total of 3996 patients with type 2 diabetes used DPP-4i as a second-line antidiabetic drug. The same number of matched non-DPP-4i users were followed up until fracture occurrence, health insurance policy termination, or the end of 2013. The incidence rates of overall and cause-specific fractures were estimated based on the Poisson assumption. A multiple Cox proportional hazard model was used to estimate the covariate-adjusted hazard ratio (HR) and 95% confidence interval (CI) to determine the association between DPP-4i use and overall and cause-specific fractures stratified by age and sex.

RESULTS

Over a maximum follow-up period of 5 years, 340 DPP-4i users and 419 non-DPP-4i users were newly diagnosed with fractures, yielding incidence rates of 28.03 and 32.04 per 1000 people per year, respectively. The Cox proportional hazard model revealed that DPP-4i use significantly reduced the risk of all-cause fractures and upper extremity fractures, with adjusted HRs of 0.86 (95% CI: 0.74-0.99) and 0.75 (95% CI: 0.59-0.95), respectively. The aforementioned associations of DDP-4i use with fracture were sustained across sex and age stratifications.

CONCLUSIONS

The results of this study supported the premise that DPP-4i usage is associated with a reduced risk of all-cause fractures and upper extremity fractures in patients with type 2 diabetes.

Inverse association between sympathetic nervous system activity and bone mass in middle aged overweight individuals

BACKGROUND/PURPOSE

Sympathetic nervous system activation in obesity is associated with impaired cardiovascular and metabolic function. Animal studies have shown a direct link between sympathetic nervous activation and bone health but little is known about this link in humans. This study examined whether sympathetic activation may impact bone health in overweight adults.

METHODS

This cross sectional study included 96 overweight or obese middle-aged adults (51 males, mean body mass index: 32.8 kg/m², mean age: 55.3 years). Multivariate linear regression models evaluated associations between whole body and leg bone mineral density (BMD) and bone mineral content (BMC) derived from dual-energy X-ray absorptiometry and muscle sympathetic nervous system activity (MSNA) measured by microneurography.

RESULTS

Older age, male sex and higher weight were associated with higher leg and body BMC and BMD. After adjustment for age, sex and weight, MSNA was significantly inversely associated with total BMC (p = 0.012) and with leg BMC (p < 0.01) but was not associated with either total or leg BMD (p = 0.159 and p = 0.063 respectively). When the analysis was sex specific, the relationships between MSNA and total and leg BMC were only significant in males.

CONCLUSIONS

Our study indicates that in middle aged overweight or obese males, sympathetic activation may have a deleterious effect on bone mineral content.

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

Background:

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

Objective:

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

Method:

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

Results:

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

Conclusion:

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

Comparison of fractal dimension analysis and panoramic-based radiomorphometric indices in the assessment of mandibular bone changes in patients with type 1 and type 2 diabetes mellitus

OBJECTIVES

This study compared the fractal dimension (FD) and radiomorphometric indices in the assessment of mandibular bone of patients with type 1 (T1 DM) and type 2 diabetes mellitus (T2 DM).

STUDY DESIGN

Panoramic radiographs of 104 patients were evaluated to calculate FD, mandibular cortical width (MCW), panoramic mandibular index (PMI), and mandibular cortical index (MCI) in the mandible.

RESULTS

No statistically significant differences were found in FD when T1 DM and T2 DM groups were compared with controls (P ≥ .168). Patients with T1 DM had significantly lower MCW (P < .001) and PMI (P = .030) compared with controls. Patients with T2 DM had no significant differences in MCW (P = .228) or PMI (P = .137) compared with controls. No significant differences were observed between patients with T1 DM and those with T2 DM for FD, MCW, and PMI (P > .05). In the T1 DM and T2 DM groups, there was a significant correlation between MCW and FD (P ≤ .011). No correlation was observed between FD and PMI in either the T1 DM group or the T2 DM group (P ≥ .142). No significant differences in MCI were observed between the DM groups and controls (P = .740) or between the T1 DM and T2 DM groups (P = 1.000).

CONCLUSIONS

The cortical and trabecular bone architectures of patients with T1 DM and T2 DM were not different. Patients with T1 DM had lower cortical measurements compared with controls.

Insulin resistance and bone: a biological partnership

Despite a clear association between type 2 diabetes (T2D) and fracture risk, the pathogenesis of bone fragility in T2D has not been clearly elucidated. Insulin resistance is the primary defect in T2D. Insulin signalling regulates both bone formation and bone resorption, but whether insulin resistance can affect bone has not been established. On the other hand, evidence exists that bone might play a role in the regulation of glucose metabolism. This article reviews the available experimental and clinical evidence on the interplay between bone and insulin resistance. Interestingly, a bilateral relationship between bone and insulin resistance seems to exist that unites them in a biological partnership.

Positive Association of Obesity and Insulin Resistance With Bone Mineral Density in Tunisian Postmenopausal Women

The association of bone mineral density (BMD) with obesity and insulin resistance remains unclear. This study aimed to explore these associations in Tunisian menopausal women. Eighty-one postmenopausal women were recruited. Data were analyzed for obese (N = 57) and non-obese women (N = 24) and for insulin-resistant (N = 43) and non insulin-resistant women (N = 36). Anthropometric and biochemical parameters were recorded. BMD in different sites and body composition were measured using dual-energy X-ray absorptiometry. Higher BMD was observed in obese women than those non-obese in the left femur (p = 0.0067), right femur (p = 0.0108), total hip (p = 0.0077), and the whole body (p = 0.0276). Also BMD was significantly greater in insulin-resistant women than in non-insulin-resistant women when measured in the left femur and total hip. Positive correlations were recorded between BMD and anthropometric parameters, body composition parameters, and glycemia (r = 0.249, p < 0.05). Multiple linear regression analysis shows that only trunk fat (p < 0.05) and lean mass (p < 0.05) were independently and positively related to BMD, and the waist circumference was the only anthropometric parameter independently and negatively associated to BMD. BMD is improved in obese and insulin-resistant women. Also, trunk fat and lean mass are likely to be key positive independent factors for BMD.

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.

Type 2 diabetes mellitus and bone

Type 2 diabetes (T2DM) is a rapidly growing public health problem. It is associated with an increased risk of fracture, particularly of the hip, despite normal or high bone mineral density. Longer duration of disease and poor glycaemic control are both associated with higher fracture risk. The factors underlying increased fracture risk have not been clearly established, but increased falls risk, obesity, sarcopenia and co-morbidities are likely to contribute. The basis for reduced bone strength despite higher bone mineral density remains to be fully elucidated. Bone turnover is reduced in individuals with T2DM, with evidence of impaired bone formation. Most studies indicate normal or superior trabecular bone structure although reduced lumbar spine trabecular bone score (TBS) has been reported. Deficits in cortical bone structure have been demonstrated in some, but not all, studies whilst reduced bone material strength index (BMSi), as assessed by microindentation, has been a consistent finding. Accumulation of advanced glycation end products in bone may also contribute to reduced bone strength. The use of FRAX in individuals with T2DM underestimates fracture probability. Clinical management should focus on falls prevention strategies, avoidance of known risk factors, maintenance of good glycaemic control and bone protective intervention in individuals at high risk of fracture. Dietary and surgical strategies to reduce weight have beneficial effects on diabetes but may have adverse effects on skeletal health. Future research priorities include better definition of the mechanisms underlying increased fracture risk in T2DM and optimal strategies for identifying and treating those at high risk.

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

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

Association of insulin resistance with near peak bone mass in the femur and lumbar spine of Korean adults aged 25-35: The Korean National Health and Nutrition Examination Survey 2008-2010

Objective

This study aimed to evaluate the relationship between insulin resistance and the bone mineral density (BMD) of femur and lumbar spine in Korean adults who are expected to exhibit near peak bone mass.

Methods

Data from the Korean National Health and Nutrition Examination Survey 2008–2010 were analyzed. A total of 2,750 participants aged 25−35 years were included. Insulin resistance was assessed using a homeostatic model assessment of insulin resistance (HOMA-IR) and serum fasting insulin.

Results

In a multivariate linear regression analysis, the HOMA-IR was significantly inversely associated with the BMD of the total hip (TH, β = −0.052, P = 0.002), femoral neck (FN, β = −0.072, P<0.001), femoral trochanter (FTr, β = −0.055, P = 0.003), femoral intertrochanter (FITr, β = −0.041, P = 0.015), and lumbar spine (LS, β = −0.063, P = 0.001) among all study subjects after adjustment for gender, age, height, weight, whole body fat mass percentage, systolic blood pressure, diastolic blood pressure, total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, vitamin D, smoking, alcohol intake, physical activity, education level, and household income in both genders as well as labor, the use of oral contraceptives, and age at menarche in females. The serum fasting insulin was significantly inversely associated with the BMD of the TH (β = −0.055, P = 0.001), FN (β = −0.072, P<0.001), FTr (β = −0.055, P = 0.003), FITr (β = −0.045, P = 0.009), and LS (β = −0.064, P = 0.001) among all subjects in a multivariate linear regression analysis.

Conclusion

Our results suggest that insulin resistance may be independently and inversely associated with the near peak bone mass of the femur and lumbar spine.

Pathophysiology of Bone Fragility in Patients with Diabetes

It has been well established that bone fragility is one of the chronic complications of diabetes mellitus, and both type 1 and type 2 diabetes are risk factors for fragility fractures. Diabetes may negatively affect bone health by unbalancing several pathways: bone formation, bone resorption, collagen formation, inflammatory cytokine, muscular and incretin system, bone marrow adiposity and calcium metabolism. The purpose of this narrative review is to explore the current understanding of pathophysiological pathways underlying bone fragility in diabetics. In particular, the review will focus on the peculiar cellular and molecular system impairment that may lead to increased risk of fracture in type 1 and type 2 diabetes.

Boning up on DPP4, DPP4 substrates, and DPP4-adipokine interactions: Logical reasoning and known facts about bone related effects of DPP4 inhibitors

Dipeptidyl peptidase 4 (DPP4) is a conserved exopeptidase with an important function in protein regulation. The activity of DPP4, an enzyme which can either be anchored to the plasma membrane or circulate free in the extracellular compartment, affects the glucose metabolism, cellular signaling, migration and differentiation, oxidative stress and the immune system. DPP4 is also expressed on the surface of osteoblasts, osteoclasts and osteocytes, and was found to play a role in collagen metabolism. Many substrates of DPP4 have an established role in bone metabolism, among which are incretins, gastrointestinal peptides and neuropeptides. In general, their effects favor bone formation, but some effects are complex and have not been completely elucidated. DPP4 and some of its substrates are known to interact with adipokines, playing an essential role in the energy metabolism. The prolongation of the half-life of incretins through DPP4 inhibition led to the development of these inhibitors to improve glucose tolerance in diabetes. Current literature indicates that the inhibition of DPP4 activity might also result in a beneficial effect on the bone metabolism, but the long-term effect of DPP4 inhibition on fracture outcome has not been entirely established. Diabetic as well as postmenopausal osteoporosis is associated with an increased activity of DPP4, as well as a shift in the expression levels of DPP4 substrates, their receptors, and adipokines. The interactions between these factors and their relationship in bone metabolism are therefore an interesting field of study.

Association between bone mineral density and nonalcoholic fatty liver disease in Korean adults

PURPOSE

Nonalcoholic fatty liver disease (NAFLD) is associated with various metabolic abnormalities that can increase the risk of an osteoporotic fracture. Across the few previous studies of the association between NAFLD and bone mineral density (BMD), the association was not consistent. We examined the association between BMD and NAFLD in generally healthy adults.

METHODS

The subjects who visited the Seoul National University Hospital for health checkup between 2005 and 2015 were included. Men aged more than 40 and postmenopausal women were included. Lumbar spine and femoral neck (FN) BMD were measured using dual-energy X-ray absorptiometry. Liver ultrasonography was conducted to evaluate the extent of fatty changes. After excluding subjects with a secondary cause of liver disease such as heavy drinking or viral hepatitis, multivariable linear regression analysis adjusted for possible cofactors was performed to investigate the association between BMD and NAFLD.

RESULTS

A total of 6634 subjects was included in this study (men:women = 3306:3328). Multivariate regression analysis revealed a significant negative association between FN BMD and NAFLD in men (β = -0.013, p = 0.029). However, there was a positive correlation between lumbar spine BMD and NAFLD in postmenopausal women (β = 0.022, p = 0.005).

CONCLUSIONS

Moderate or severe NAFLD exerted a detrimental effect on FN BMD in men. However, moderate or severe NAFLD had a positive effect on lumbar spine BMD in postmenopausal women. Potential sex-specific differences of the effect of NAFLD on BMD need to be elucidated further.

Methodological considerations when studying the skeletal response to glucose intolerance using the diet-induced obesity model

The prevalence of obesity and type 2 diabetes mellitus (T2DM) continues to rise, and as a result, research aimed at understanding the molecular basis for the co-morbidities has become an area of much scientific interest. Among the more recently recognized chronic complications of T2DM is the increased risk of fracture, especially hip fracture, that has been reported independent of bone mineral density (BMD). A widely used animal model to study how the development and progression of impaired glucose tolerance affect the skeleton has been the diet-induce obesity (DIO) model. As the name implies, this model employs the use of a version of high-fat diets to induce obesity and the subsequent metabolic perturbations that occur with T2DM. Although the model offers a number of advantages, the literature reveals some inconsistent results. Upon further review, discrepancies in the choice of the experimental high-fat diets and the control diets have become a point of major concern. The variability between diets and study design has made it difficult to compare data and results across studies. Therefore, this review aims to provide guidelines that should be employed when designing studies using DIO models of T2DM.

Association Between Insulin Resistance and Bone Structure in Nondiabetic Postmenopausal Women

CONTEXT

The clinical consequences of insulin resistance and hyperinsulinemia on bone remain largely unknown.

OBJECTIVE

The objective of the study was to evaluate the effect of insulin resistance on peripheral bone geometry, volumetric bone mineral density (vBMD), bone microarchitecture, and estimated bone strength.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study included 146 postmenopausal, nondiabetic Caucasian women (mean age 60.3 ± 2.7 y) who were participating in the Study of Women's Health Across the Nation.

INTERVENTIONS

There were no interventions.

MAIN OUTCOME MEASURES

High-resolution peripheral quantitative computed tomography was used to assess bone density and microstructure at the distal radius and tibia. Fasting insulin and glucose were measured and insulin resistance was estimated using homeostasis model assessment of insulin resistance (HOMA-IR), with higher values indicating greater insulin resistance.

RESULTS

There was a negative association between HOMA-IR and bone size and a positive association between HOMA-IR and total vBMD, trabecular vBMD, trabecular thickness, and cortical thickness at the radius and tibia. These relationships remained, even after adjusting for body weight and other potential covariates (eg, time since menopause, cigarette smoking, physical activity, prior use of osteoporosis medications or glucocorticoids).

CONCLUSIONS

In nondiabetic, postmenopausal women, insulin resistance was associated with smaller bone size, greater volumetric bone mineral density, and generally favorable bone microarchitecture at weight-bearing and nonweight-bearing skeletal sites. These associations were independent of body weight and other potential covariates, suggesting that hyperinsulinemia directly affects bone structure independent of obesity and may explain, in part, the higher trabecular bone density and favorable trabecular microarchitecture seen in individuals with type 2 diabetes mellitus.

DPP-4 inhibitor therapy and bone fractures in people with Type 2 diabetes - A systematic review and meta-analysis

AIM

Fracture risk is higher in older adults with Type 2 diabetes mellitus (T2DM). Oral glucose-lowering medications have different effects on bone metabolism. The purpose of this study is to appraise the evidence from literature and determine the effect of dipeptidyl peptidase-4 (DPP-4) inhibitor on the risk of developing bone fractures.

METHODS

Using Boolean search terms, the search strategy combined synonyms of 'fracture' and 'DPP-4 inhibitor'. Comprehensive electronic databases which include EMBASE, MEDLINE, the EMA and the WHO ICTRP databases were searched for randomised controlled trial (RCT) studies which compared a DPP-4 inhibitor with an active comparator or placebo amongst patients with T2DM. Meta-analysis was performed to compare DPP-4 inhibitor with either an active comparator or a placebo. The outcome measure was the presence or absence of fracture.

RESULTS

The search yielded 5061 records relating to fractures and DPP-4 inhibitor, from which 51 eligible RCTs were selected for meta-analysis (N=36,402). Thirty-seven (37) studies compared DPP-4 inhibitor with placebo (n=23,974), while fourteen (14) studies (n=12,428) compared DPP-4 inhibitor with an active comparator. The mean age of patients was 57.5±5.4years, the average glycated haemoglobin (HbA1c) was 8.2%, while the average BMI was 30±2kg/m(2). Overall, there was no significant association of fracture events with the use of DPP-4 inhibitor when compared with placebo (OR; 0.82, 95% CI 0.57-1.16, P=0.9) or when DPP-4 inhibitor was compared against an active comparator (OR; 1.59, 95% CI 0.91-2.80, P=0.9).

CONCLUSION

This study offers a larger, up-to-date review of the subject. The meta-analysis showed that there was no significant association between DPP-4 inhibitor use and the incidence of fractures.