Menopausal bone changes and incident fractures in diabetic women: a cohort study

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.

Prediabetes and Fracture Risk Among Midlife Women in the Study of Women's Health Across the Nation

Importance

Whether prediabetes is associated with fracture is uncertain.

Objective

To evaluate whether prediabetes before the menopause transition (MT) is associated with incident fracture during and after the MT.

Design, Setting, and Participants

This cohort study used data collected between January 6, 1996, and February 28, 2018, in the Study of Women's Health Across the Nation cohort study, an ongoing, US-based, multicenter, longitudinal study of the MT in diverse ambulatory women. The study included 1690 midlife women in premenopause or early perimenopause at study inception (who have since transitioned to postmenopause) who did not have type 2 diabetes before the MT and who did not take bone-beneficial medications before the MT. Start of the MT was defined as the first visit in late perimenopause (or first postmenopausal visit if participants transitioned directly from premenopause or early perimenopause to postmenopause). Mean (SD) follow-up was 12 (6) years. Statistical analysis was conducted from January to May 2022.

Exposure

Proportion of visits before the MT that women had prediabetes (fasting glucose, 100-125 mg/dL [to convert to millimoles per liter, multiply by 0.0555]), with values ranging from 0 (prediabetes at no visits) to 1 (prediabetes at all visits).

Main Outcomes and Measures

Time to first fracture after the start of the MT, with censoring at first diagnosis of type 2 diabetes, initiation of bone-beneficial medication, or last follow-up. Cox proportional hazards regression was used to examine the association (before and after adjustment for bone mineral density) of prediabetes before the MT with fracture during the MT and after menopause.

Results

This analysis included 1690 women (mean [SD] age, 49.7 [3.1] years; 437 Black women [25.9%], 197 Chinese women [11.7%], 215 Japanese women [12.7%], and 841 White women [49.8%]; mean [SD] body mass index [BMI] at the start of the MT, 27.6 [6.6]). A total of 225 women (13.3%) had prediabetes at 1 or more study visits before the MT, and 1465 women (86.7%) did not have prediabetes before the MT. Of the 225 women with prediabetes, 25 (11.1%) sustained a fracture, while 111 of the 1465 women without prediabetes (7.6%) sustained a fracture. After adjustment for age, BMI, and cigarette use at the start of the MT; fracture before the MT; use of bone-detrimental medications; race and ethnicity; and study site, prediabetes before the MT was associated with more subsequent fractures (hazard ratio for fracture with prediabetes at all vs no pre-MT visits, 2.20 [95% CI, 1.11-4.37]; P = .02). This association was essentially unchanged after controlling for BMD at the start of the MT.

Conclusions and Relevance

This cohort study of midlife women suggests that prediabetes was associated with risk of fracture. Future research should determine whether treating prediabetes reduces fracture risk.

Association of Body Mass Index and Fracture Risk Varied by Affected Bones in Patients with Diabetes: A Nationwide Cohort Study

BACKGROUND

Body mass index (BMI) is a risk factor for the type 2 diabetes (T2DM), and T2DM accompanies various complications, such as fractures. We investigated the effects of BMI and T2DM on fracture risk and analyzed whether the association varied with fracture locations.

METHODS

This study is a nationwide population-based cohort study that included all people with T2DM (n=2,746,078) who received the National Screening Program during 2009-2012. According to the anatomical location of the fracture, the incidence rate and hazard ratio (HR) were analyzed by dividing it into four categories: vertebra, hip, limbs, and total fracture.

RESULTS

The total fracture had higher HR in the underweight group (HR, 1.268; 95% CI, 1.228 to 1.309) and lower HR in the obese group (HR, 0.891; 95% CI, 0.882 to 0.901) and the morbidly obese group (HR, 0.873; 95% CI, 0.857 to 0.89), compared to reference (normal BMI group). Similar trends were observed for HR of vertebra fracture. The risk of hip fracture was most prominent, the risk of hip fracture increased in the underweight group (HR, 1.896; 95% CI, 1.178 to 2.021) and decreased in the obesity (HR, 0.643; 95% CI, 0.624 to 0.663) and morbidly obesity group (HR, 0.627; 95% CI, 0.591 to 0.665). Lastly, fracture risk was least affected by BMI for limbs.

CONCLUSION

In T2DM patients, underweight tends to increase fracture risk, and overweight tends to lower fracture risk, but association between BMI and fracture risk varied depending on the affected bone lesions.

The interplay between diabetes mellitus and menopause: clinical implications

The menopausal transition is an impactful period in women's lives, when the risk of cardiovascular disease is accelerated. Similarly, diabetes mellitus profoundly impacts cardiovascular risk. However, the interplay between menopause and diabetes mellitus has not been adequately studied. The menopausal transition is accompanied by metabolic changes that predispose to diabetes mellitus, particularly type 2 diabetes mellitus (T2DM), as menopause results in increased risk of upper body adipose tissue accumulation and increased incidence of insulin resistance. Equally, diabetes mellitus can affect ovarian ageing, potentially causing women with type 1 diabetes mellitus and early-onset T2DM to experience menopause earlier than women without diabetes mellitus. Earlier age at menopause has been associated with a higher risk of T2DM later in life. Menopausal hormone therapy can reduce the risk of T2DM and improve glycaemic control in women with pre-existing diabetes mellitus; however, there is not enough evidence to support the administration of menopausal hormone therapy for diabetes mellitus prevention or control. This Review critically appraises studies published within the past few years on the interaction between diabetes mellitus and menopause and addresses all clinically relevant issues, such as the effect of menopause on the development of T2DM, and the management of both menopause and diabetes mellitus.

Associations of hypertensive disorders of pregnancy and gestational diabetes mellitus with menopausal symptoms at midlife in Project Viva

OBJECTIVE

The aim of this study was to evaluate the associations of a lifetime history of hypertensive disorders of pregnancy (HDP) and gestational diabetes mellitus (GDM) with menopausal symptoms in midlife.

METHODS

This was a secondary analysis of women participating in Project Viva, an ongoing cohort enrolled during pregnancy. The exposure was lifetime history of HDP or GDM assessed for the index pregnancy by review of outpatient and hospital medical records and for all other pregnancies by interview or questionnaire at study entry (1999-2002) and the midlife visit (2017-2021). The primary outcome was the Menopause Rating Scale (MRS) applied at the midlife study visit. We used linear or logistic regression models adjusted for covariates such as baseline age, race/ethnicity, education, married/cohabiting, household income, baseline parity, age at menarche, and body mass index at midlife.

RESULTS

Of the 676 included participants, 120 (18%) had a history of HDP, and 47 (7%) had a history of GDM. The mean (SD) age was 52 (3.9) years at the midlife visit, and 48% of the participants had experienced menopause. There were no consistent differences in total, domain-specific, or individual symptoms in women with a history of HDP or GDM. A history of HDP and/or GDM was not associated with age at the onset of natural menopause.

CONCLUSIONS

Our findings do not support an association of a history of HDP or GDM with the severity of menopausal symptoms or age at the onset of natural menopause. Larger studies of women with a history of these pregnancy complications are needed to clarify their association with menopausal symptoms.

Prediabetes and insulin resistance are associated with lower trabecular bone score (TBS): cross-sectional results from the Study of Women's Health Across the Nation TBS Study

In pre- and early perimenopausal women, prediabetes (with blood glucose ≥ 110 mg/dL) and greater insulin resistance are associated with worse trabecular bone quality (as assessed by trabecular bone score).

PURPOSE

Diabetes mellitus (DM) is associated with lower trabecular bone score (TBS) and fracture; less certain is whether the precursor states of prediabetes and increased insulin resistance are also related to adverse bone outcomes. We examined, in women who do not have DM, the associations of glycemic status (prediabetes vs. normal) and insulin resistance with TBS.

METHODS

This was a cross-sectional analysis of baseline data collected from 42- to 52-year-old, pre- and perimenopausal participants in the Study of Women's Health Across the Nation (SWAN) TBS Study. Women with prediabetes were categorized as having either high prediabetes if their fasting glucose was between 110 and 125 mg/dL or low prediabetes if their fasting glucose was between 100 and 109 mg/dL. Normoglycemia was defined as a fasting glucose below 100 mg/dL.

RESULTS

In multivariable linear regression, adjusted for age, race/ethnicity, menopause transition stage, cigarette use, calcium and vitamin D supplementation, lumbar spine bone mineral density, and study site, women with high prediabetes had 0.21 (p < 0.0001) standard deviations (SD) lower TBS than those with normoglycemia. Low prediabetes was not associated with lower TBS. When HOMA-IR levels were ≥ 1.62, each doubling of HOMA-IR was associated with a 0.11 SD decrement in TBS (p = 0.0001).

CONCLUSION

Similar to diabetics, high prediabetics have lower TBS than normoglycemic individuals. Women with greater insulin resistance have lower TBS even in the absence of DM. Future studies should examine the associations of high prediabetes and insulin resistance with incident fracture.

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.

Dairy intake is not associated with improvements in bone mineral density or risk of fractures across the menopause transition: data from the Study of Women's Health Across the Nation

Objective:

Menopause represents a period in which bone deterioration is accelerated; thus, primary prevention strategies to address age-related bone loss are crucial. Dairy products contain more than a dozen essential nutrients, including calcium, phosphorus, vitamin D, and high-quality protein, as well as bioactive compounds that may promote bone mineralization. However, the relationship between dairy consumption and bone health across the menopause transition remains largely unknown. The purpose of this analysis was to estimate the change in lumbar spine and femoral neck bone mineral density and the risk of bone fracture by the frequency of dairy intakes among women across the menopausal transition using the publicly available data from the Study of Women's Health Across the Nation.

Methods:

We analyzed total dairy foods in four categories of <0.5, 0.5 to <1.5, 1.5 to <2.5, and ≥2.5 servings/d or <1.5 and ≥1.5 servings/d. A general linear model was used to estimate the association of dairy intake with the 10-year bone mineral density loss rate and a linear mixed model was used to estimate the annualized bone mineral density loss rate of the femoral neck and lumbar spine. A Cox proportional hazard model was applied to calculate hazard ratios and 95% confidence intervals of the nontraumatic fractures. Poisson regression was used to determine the relative risks and 95% confidence intervals of the nontraumatic fractures. The models were controlled for race/ethnicity, age, height, weight, smoking status, physical activity, alcohol consumption, calcium use, menopausal status, and total caloric intake.

Results:

No significant differences in bone mineral density change were observed, regardless of baseline menopausal status. No significant differences in the risk of nontraumatic fracture were observed.

Conclusions:

In this group of US women undergoing the menopausal transition, dairy food intake was neither associated with femoral and spine bone mineral density loss nor the risk of fractures.

The risk of hip fractures in individuals over 50 years old with prediabetes and type 2 diabetes - A longitudinal nationwide population-based study

BACKGROUND

The present study aimed to investigate the association between type 2 diabetes mellitus (T2DM) and hip fractures using a large-scale nationwide population-based cohort that is representative of the Republic of Korea. We determined the risks of hip fractures in individuals with prediabetes and T2DM with different diabetes durations, and compared them with the risks of hip fractures in individuals without T2DM.

METHODS

A total of 5,761,785 subjects over 50 years old who underwent the National Health Insurance Service medical checkup in 2009-2010 were included. Subjects were classified into 5 groups based on the diabetes status; Normal, Prediabetes, Newly-diagnosed T2DM, T2DM less than 5 years, and T2DM more than 5 years. They were followed from the date of the medical checkup to the end of 2016. The endpoint was a new development of hip fracture during follow-up. The hazard ratios (HRs) and 95% confidence intervals (CIs) of hip fractures for each group were analyzed using Cox proportional hazard regression models after adjusting for age, sex, smoking, alcohol drinking, regular exercise, body mass index, hypertension, dyslipidemia, and chronic kidney disease.

RESULTS

The HRs of hip fractures were 1 in the Normal group, 1.032 (95% CI: 1.009, 1.056) in the Prediabetes group, 1.168 (95% CI: 1.113, 1.225) in the Newly-diagnosed T2DM2, 1.543 (95% CI: 1.495, 1.592) in the T2DM less than 5 years and 2.105 (95% CI: 2.054, 2.157) in the T2DM more than 5 years. The secular trend of the HRs of hip fractures according to the duration of T2DM was statistically significant (P < .001). Subgroup analyses also showed the same increasing pattern of the HRs of hip fractures according to the duration of T2DM in both sexes and all age groups (50-64 years, 65-74 years, over 75 years).

CONCLUSIONS

In summary, this large-scale, retrospective, longitudinal, nationwide population-based cohort study of 5,761,785 subjects demonstrated that the risks of hip fractures started to increase in prediabetes and was associated linearly with the duration of T2DM. The secular trend of risks of hip fractures according to the duration of T2DM was consistent in both sexes and all age groups.

Evaluation of bone densitometry by dual-energy x-ray absorptiometry as a fracture prediction tool in women with chronic kidney disease

Background

The 2017 KDIGO guidelines establish a 2B grade recommendation in favor of testing Bone Mineral Density (BMD) by DXA to assess osteoporotic fracture (OPF) risk in patients with CKD G3a-G5D. Still, controversy remains because large studies evaluating it for this particular population are lacking.

Aim

To establish the clinical performance of BMD measured by DXA in the evaluation of fracture risk in women with CKD.

Methods

We conducted a 43 year retrospective cohort study with 218 women ≥18 years-old with CKD and BMD measurement by DXA of total hip and lumbar spine. Clinical (age, year of CKD onset, comorbidities, BMI, transplant status, treatment), and biochemical (PTH, corrected calcium, phosphate, vitamin D [25 (OH) D3], creatinine, and albumin), parameters were collected from hospital records. All osteoporotic fractures (as defined by the WHO) found in the clinical and radiologic files were registered.

Results

218 women with a median age of 60 years (40–73 IQ range) and a CKD evolution time of 12 years (7–18 IQ range) were evaluated. Forty-eight (28.23%) presented an OPF. These women were older (57 vs 69 years, p =0.0072) and had a lower BMD. CKD stage did not influence fracture incidence. In the multivariate analysis we found that for each standard deviation decrease in hip and lumbar spine T-Score, the overall fracture risk was 2.7 and 2.04 times higher, respectively. More than 50% of fractures took place within the first ten years of follow-up, especially with GFR <30 mL/min/m² and osteoporosis. Diabetes and hypothyroidism accelerated fracture onset, while renal transplant delayed it. In the ROC analysis, the AUC was largest with the total hip (0.7098, p =0.000) and lumbar spine (0.6916, p = 0.000).

Conclusions

BMD measured by DXA is a useful fracture prediction tool for women with CKD, having a sensibility and specificity similar to that in the general population. It seems to be appropriate for the diagnosis, treatment decisions, and follow-up of patients with renal failure.

Calcium Supplement Use Is Associated With Less Bone Mineral Density Loss, But Does Not Lessen the Risk of Bone Fracture Across the Menopause Transition: Data From the Study of Women's Health Across the Nation

Diet is a modifiable factor that is related to bone mass and risk for fractures; however, the use of calcium supplements for bone health is controversial, with little scientific agreement. The purpose of this analysis was to estimate the change in lumbar spine and femoral neck BMD and the risk of bone fracture by the use of calcium supplements among the Study of Women's Health Across the Nation (SWAN) participants. SWAN is a multicenter, multiethnic, community‐based longitudinal cohort designed to examine the health of women across the menopause transition (n = 1490; aged 42 to 52 years at baseline in 1996 to 1997 and followed annually until 2006 to 2008). A mixed‐effect model for repeated measures was used to estimate annualized BMD change across time between supplement users and nonusers, unadjusted or fully adjusted (age, race, height, weight, menopausal status [pre‐, early peri‐, late peri‐, and postmenopausal], DXA scanner mode, alcohol intake, vitamin D supplement use, smoking, and physical activity) and a log‐linear model with repeated measures was used to estimate the relative risk of fracture by calcium supplement use. All models were also stratified by baseline menopausal status. In fully adjusted models, calcium supplement use was associated with less annualized loss of femoral neck BMD (−0.0032 versus −0.0040 g/cm²/year; p < .001) and lumbar spine BMD (−0.0046 versus −0.0053 g/cm²/year, p = 0.021) in the complete cohort. However, this protective association of calcium supplement use with BMD loss was significant only among premenopausal women (femoral neck: −0.0032 versus −0.0042 g/cm²/year; p = 0.002; lumbar spine: −0.0038 versus −0.0050 g/cm²/year, p = 0.001); no significant differences in BMD were observed among women who were early perimenopausal by calcium supplement use at baseline. No significant differences in the relative risk of fracture were observed, regardless of baseline menopausal status. The use of calcium supplements was associated with less BMD loss over more than a decade, but was not related to the risk of incident bone fracture across the menopause transition. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Association of bone mineral density with a first-degree family history of diabetes in normoglycemic postmenopausal women

OBJECTIVE

A first-degree family history of diabetes (FHD) contributes to increased risks of metabolic and cardiovascular diseases. Bone is an insulin-resistant site and an organ susceptible to microvascular complications. The goal of the present study was to investigate the association of FHD with bone mineral density (BMD) in postmenopausal women.

METHODS

In all, 892 normoglycemic postmenopausal women were divided into subgroups of participants with or without a first-degree FHD. BMD was measured using dual-energy x-ray absorptiometry. Fasting plasma insulin and glucose levels were measured, and insulin resistance was evaluated using the Homeostasis Model Assessment-Insulin Resistance (HOMA-IR) index.

RESULTS

The BMD of the lumbar spine and femoral neck were much higher in the participants with a first-degree FHD than in those without an FHD (all P < 0.05). Lumbar spine BMD and femoral neck BMD were both positively associated with HOMA-IR (P = 0.041 and P = 0.005, respectively). Multiple stepwise regression analysis showed that a first-degree FHD was an independent factor that was positively associated with lumbar spine BMD (standardized β = 0.111, P = 0.001) and femoral neck BMD (standardized β = 0.078, P = 0.021). A first-degree FHD was associated with increased BMD, insulin resistance, and hyperinsulinemia.

CONCLUSIONS

Our study indicated that normoglycemic postmenopausal women with a first-degree FHD exhibit increased BMD with insulin resistance and hyperinsulinemia. A first-degree FHD was an independent factor associated with elevated BMD in Chinese women after menopause.

Frailty and Risk of Fractures in Patients With Type 2 Diabetes

OBJECTIVE

We aimed to explore whether frailty was associated with fracture risk and whether frailty could modify the propensity of type 2 diabetes toward increased risk of fractures.

RESEARCH DESIGN AND METHODS

Data were from a prospective cohort study. Our primary outcome was time to the first incident clinical fragility fracture; secondary outcomes included time to hip fracture and to clinical spine fracture. Frailty status was measured by a Frailty Index (FI) of deficit accumulation. The Cox model incorporating an interaction term (frailty × diabetes) was used for analyses.

RESULTS

The analysis included 3,149 (70% women) participants; 138 (60% women) had diabetes. Higher bone mineral density and FI were observed in participants with diabetes compared with control subjects. A significant relationship between the FI and the risk of incident fragility fractures was found, with a hazard ratio (HR) of 1.02 (95% CI 1.01-1.03) and 1.19 (95% CI 1.10-1.33) for per-0.01 and per-0.10 FI increase, respectively. The interaction was also statistically significant (P = 0.018). The HR for per-0.1 increase in the FI was 1.33 for participants with diabetes and 1.19 for those without diabetes if combining the estimate for the FI itself with the estimate from the interaction term. No evidence of interaction between frailty and diabetes was found for risk of hip and clinical spine fractures.

CONCLUSIONS

Participants with type 2 diabetes were significantly frailer than individuals without diabetes. Frailty increases the risk of fragility fracture and enhances the effect of diabetes on fragility fractures. Particular attention should be paid to diabetes as a risk factor for fragility fractures in those who are frail.

Bone Health During the Menopause Transition and Beyond

The menopause transition is a critical period for bone health, with rapid losses in bone mass and strength occurring in a 3-year window bracketing the date of the final menstrual period. Declines in bone mass are accompanied by deleterious changes in bone macrostructure and microarchitecture, which may be captured by changes in composite strength indices and indices of trabecular thickness and connectivity. The onset of the rapid bone loss phase is preceded by changes in sex steroid hormones and increases in markers of bone resorption, measurements of which may be clinically useful in predicting the onset of the rapid loss phase and in identifying the women who will lose the most bone strength over the menopause transition.

The effect of insulin on bone mineral density among women with type 2 diabetes: a SWAN Pharmacoepidemiology study

This was a longitudinal study examining the effects of insulin use on bone mineral density loss. Insulin use was found to be associated with greater bone mineral density loss at the femoral neck among women with diabetes mellitus.

INTRODUCTION

Women with diabetes mellitus (DM) have higher bone mineral density (BMD) and experience slower BMD loss but have an increased risk of fracture. The data regarding the effect of insulin treatment on BMD remains conflicted. We examined the impact of insulin initiation on BMD.

METHODS

We investigated the annual changes in BMD associated with the new use of insulin among women with DM in the Study of Women's Health Across the Nation (SWAN). Propensity score (PS) matching, which is a statistical method that helps balance the baseline characteristics of women who did and did not initiate insulin, was used. Covariates with a potential impact on bone health were included in all models. Mixed model regression was used to test the change in BMD between the two groups. Median follow-up time was 5.4 years.

RESULTS

The cohort consisted of 110 women, mean age, 53.6 years; 49% white and 51% black. Women using insulin (n = 55) were similar on most relevant characteristics to the 55 not using insulin. Median diabetes duration for the user group was 10 vs. 5.0 years for the non-user group. There was a greater loss of BMD at the femoral neck among insulin users (- 1.1%) vs non-users (- 0.77%) (p = 0.04). There were no differences in BMD loss at the spine - 0.30% vs - 0.32% (p = 0.85) or at the total hip - 0.31% vs - 0.25 (p = 0.71), respectively.

CONCLUSIONS

Women with T2DM who initiated insulin experienced a more rapid BMD loss at the femoral neck as compared to women who did use insulin.

Effects of obesity and diabetes on rate of bone density loss

In this large registry-based study, women with diabetes had marginally greater bone mineral density (BMD) loss at the femoral neck but not at other measurement sites, whereas obesity was not associated with greater BMD loss. Our data do not support the hypothesis that rapid BMD loss explains the increased fracture risk associated with type 2 diabetes and obesity observed in prior studies.

INTRODUCTION

Type 2 diabetes and obesity are associated with higher bone mineral density (BMD) which may be less protective against fracture than previously assumed. Inconsistent data suggest that rapid BMD loss may be a contributing factor.

METHODS

We examined the rate of BMD loss in women with diabetes and/or obesity in a population-based BMD registry for Manitoba, Canada. We identified 4960 women aged ≥ 40 years undergoing baseline and follow-up BMD assessments (mean interval 4.3 years) without confounding medication use or large weight fluctuation. We calculated annualized rate of BMD change for the lumbar spine, total hip, and femoral neck in relation to diagnosed diabetes and body mass index (BMI) category.

RESULTS

Baseline age-adjusted BMD was greater in women with diabetes and for increasing BMI category (all P < 0.001). In women with diabetes, unadjusted BMD loss was less at the lumbar spine (P = 0.017), non-significantly greater at the femoral neck (P = 0.085), and similar at the total hip (P = 0.488). When adjusted for age and BMI, diabetes was associated with slightly greater femoral neck BMD loss (- 0.0018 g/cm²/year, P = 0.012) but not at the lumbar spine or total hip. There was a strong linear effect of increasing BMI on attenuated BMI loss at the lumbar spine with negligible effects on hip BMD.

CONCLUSIONS

Diabetes was associated with slightly greater BMD loss at the femoral neck but not at other measurement sites. BMD loss at the lumbar spine was reduced in overweight and obese women but BMI did not significantly affect hip BMD loss.

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

Background

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

Materials and methods

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

Results

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

Conclusions

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

Zinc supplementation reduces RANKL/OPG ratio and prevents bone architecture alterations in ovariectomized and type 1 diabetic rats

Type 1 diabetes mellitus (T1DM) and estrogen deficiency are associated with several alterations in bone turnover. Zinc (Zn) is required for growth, development, and overall health. Zinc has been used in complementary therapy against bone loss in several diseases. We hypothesized that Zn supplementation represents a potential therapy against severe bone loss induced by the combined effect of estrogen deficiency and T1DM. We evaluated the protective effect of Zn against bone alterations in a chronic model of these disorders. Female Wistar rats were ramdomized into 3 groups (5 rats each): control, OVX/T1DM (ovariectomized rats with streptozotocin-induced T1DM), and OVX/T1DM+Zn (OVX/T1DM plus daily Zn supplementation). Serum biochemical, bone histomorphometric, and molecular analyses were performed. Histomorphometric parameters were similar between the control and OVX/T1DM+Zn groups, suggesting that Zn prevents bone architecture alterations. In contrast, the OVX/T1DM group showed significantly lower trabecular width and bone area as well as greater trabecular separation than the control. The OVX/T1DM and OVX/T1DM+Zn groups had significantly higher serum alkaline phosphatase activity than the control. The supplemented group had higher levels of serum-ionized calcium and phosphorus than the nonsupplemented group. The RANKL/OPG ratio was similar between the control and OVX/T1DM+Zn groups, whereas it was higher in the OVX/T1DM group. In conclusion, Zn supplementation prevents bone alteration in chronic OVX/T1DM rats, as demonstrated by the reduced RANKL/OPG ratio and preservation of bone architecture. The findings may represent a novel therapeutic approach to preventing OVX/T1DM-induced bone alterations.

Ovarian aging in women with diabetes: An overview

Type 2 diabetes is a global epidemic, and the prevalence and incidence of type 1 diabetes are increasing. The negative effects of diabetes on kidneys, nerves, and vessels are well established. The effect of diabetes on reproductive function is less well understood, but important to characterize, given the increasing numbers of young women with diabetes. In this review, we summarize the available literature on how women with diabetes experience ovarian aging, from menarche to menopause. We report that women with type 1 diabetes appear more likely to have ovarian dysfunction, manifested by delayed menses, menstrual irregularities, and possibly earlier menopause. Studies of women with type 2 diabetes are inconsistent but suggest increased anovulation and earlier menopause. Differences in reproductive aging between women with type 1 and type 2 diabetes raise questions about potential differences in the mechanisms contributing to ovarian aging. Although there is shared glycemic dysregulation, fundamental differences in insulin presence and processing distinguish the two diseases. This review suggests that insulin, age at diagnosis, and weight play a role in ovarian dysfunction. More long-term studies are needed to evaluate the multitude of factors that may disrupt hypothalamic, pituitary, and ovarian function in women with diabetes.

Triglyceride Levels and Fracture Risk in Midlife Women: Study of Women's Health Across the Nation (SWAN)

CONTEXT

Unfavorable lipid levels contribute to cardiovascular disease and may also harm bone health.

OBJECTIVE

Our objective was to investigate relationships between fasting plasma lipid levels and incident fracture in midlife women undergoing the menopausal transition.

DESIGN AND SETTING

This was a 13-year prospective, longitudinal study of multiethnic women in five US communities, with near-annual assessments.

PARTICIPANTS

At baseline, 2062 premenopausal or early perimenopausal women who had no history of fracture were included.

EXPOSURES

Fasting plasma total cholesterol, triglycerides (TG), low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol at baseline and follow-up visits 1 and 3-7.

MAIN OUTCOME MEASURE(S)

Incident nontraumatic fractures 1) 2 or more years after baseline, in relation to a single baseline level of lipids; and 2) 2-5 years later, in relation to time-varying lipid levels. Cox proportional hazards modelings estimated hazard ratios and 95% confidence interval (CI).

RESULTS

Among the lipids, TG levels changed the most, with median levels increased by 16% during follow-up. An increase of 50 mg/dl in baseline TG level was associated with a 1.1-fold increased hazards of fracture (adjusted hazard ratio, 1.11; 95% CI, 1.04-1.18). Women with baseline TG higher than 300 mg/dl had an adjusted 2.5-fold greater hazards for fractures (95% CI, 1.13-5.44) than women with baseline TG lower than 150 mg/dl. Time-varying analyses showed a comparable TG level-fracture risk relationship. Associations between total cholesterol, low-density lipoprotein cholesterol, or high-density lipoprotein cholesterol levels and fractures were not observed.

CONCLUSIONS

Midlife women with high fasting plasma TG had an increased risk of incident nontraumatic fracture. Secondary Abstract: Midlife women with fasting plasma triglyceride (TG) of at least 300 mg/dl had 2.5-fold greater hazards of fracture in 2 years later and onward, compared to those with TG below 150 mg/dl, in a multiethnic cohort. Time-varying analyses revealed comparable results.

Diabetes and Menopause

During menopause, women's body composition, sex hormone profile, and metabolic profile may change dramatically. In this review, we summarize studies examining whether the menopausal transition and physiologic factors characterizing the transition are associated with increased risk of diabetes. We review the evidence for estrogen therapy and diabetes risk and studies examining the relationship between diabetes and menarche, which represents an extension of the reproductive life span at the opposite end of the age spectrum. Although studied less extensively, the presence of type 1 or type 2 diabetes may increase the risk of ovarian failure, and we review this literature. In conclusion, we note that the evidence linking menopausal sex hormone changes with increased diabetes risk is weak, although rapid changes as observed with oophorectomy may increase risk. Further studies should investigate the contradictory effects of estrogen therapy upon hepatic and glucose metabolism in mid-life women.

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

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

Diabetes mellitus and risk of hip fractures: a meta-analysis

This meta-analysis revealed that diabetic adults had a twofold greater risk of hip fractures compared with non-diabetic populations, and this association was more pronounced in type 1 diabetes.

INTRODUCTION

The relationship between diabetes mellitus and risk of hip fracture yielded conflicting results. We conducted a meta-analysis to investigate the association between diabetes mellitus and the risk of hip fractures based on observational studies.

METHODS

We conducted a systematic literature search of PubMed and Embase databases through May 2015. We selected cohort and case-control studies providing at least age-adjusted risk ratio (RR) and corresponding 95 % confidence intervals (CI) of hip fractures among diabetic and non-diabetic subjects. Moreover, we pooled the female-to-male RR of hip fractures from studies that reported gender-specific risk estimate in a single study.

RESULTS

Twenty-one studies involving 82,293 hip fracture events among 6,995,272 participants were identified. Diabetes mellitus was associated with an increased risk of hip fractures (RR 2.07; 95 % CI 1.83-2.33) in a random effects model. Subgroup analysis indicated that excess risk of hip fracture was more pronounced in type 1 diabetes (RR 5.76; 95 % CI 3.66-9.07) than that in type 2 diabetes (RR 1.34; 95 % CI 1.19-1.51). The pooled female-to-male RR of hip fractures was 1.09 (95 % CI 0.93-1.28).

CONCLUSIONS

Individuals with diabetes mellitus have an excessive risk of hip fractures, and this relationship is more pronounced in type 1 diabetes. The association between diabetes and hip fracture risk is similar in men and women.

Epidemiology of fractures in type 2 diabetes

Type 2 diabetes affects an increasing proportion of older adults, the population that is also at elevated risk of fracture. Type 2 diabetes itself increases the risk of fracture, particularly in African-American and Latino populations. In Western countries, overweight and obesity, associated with reduced fracture risk, are highly prevalent in diabetic patients. Studies in East Asian countries that have a lower prevalence of obesity with diabetes may help to disentangle the effects of diabetes and obesity on the skeleton. Type 2 diabetes is also associated with higher bone density, and as a result standard tools for fracture prediction tend to underestimate fracture risk in this population, an important challenge for risk assessment in the clinical setting. Contributing factors to the increased fracture risk in type 2 diabetes include more frequent falls and deficits in diabetic bone, not captured by dual X-ray absorptiometry (DXA), that are as yet not clearly understood. Recent epidemiological studies indicate that poor glycemic control contributes to increased fracture risk although intensive lowering of A1C is not effective in preventing fracture. This article is part of a Special Issue entitled "Bone and diabetes".

Contributions of fat mass and fat distribution to hip bone strength in healthy postmenopausal Chinese women

The fat and bone connection is complicated, and the effect of adipose tissue on hip bone strength remains unclear. The aim of this study was to clarify the relative contribution of body fat accumulation and fat distribution to the determination of proximal femur strength in healthy postmenopausal Chinese women. This cross-sectional study enrolled 528 healthy postmenopausal women without medication history or known diseases. Total lean mass (LM), appendicular LM (ALM), percentage of lean mass (PLM), total fat mass (FM), appendicular FM (AFM), percentage of body fat (PBF), android and gynoid fat amount, android-to-gynoid fat ratio (AOI), bone mineral density (BMD), and proximal femur geometry were measured by dual energy X-ray absorptiometry. Hip structure analysis was used to compute some variables as geometric strength-related parameters by analyzing the images of the hip generated from DXA scans. Correlation analyses among anthropometrics, variables of body composition and bone mass, and geometric indices of hip bone strength were performed with stepwise linear regression analyses as well as Pearson's correlation analysis. In univariate analysis, there were significantly inverse correlations between age, years since menopause (YSM), hip BMD, and hip geometric parameters. Bone data were positively related to height, body weight, LM, ALM, FM, AFM, and PBF but negatively related to AOI and amount of android fat (all P < 0.05). AFM and AOI were significantly related to most anthropometric parameters. AFM was positively associated with height, body weight, and BMI. AFM was negatively associated with age and YSM. AOI was negatively associated with height, body weight, and BMI. AOI positively associated with age and YSM. LM, ALM, and FM had a positive relationship with anthropometric parameters (P < 0.05 for all). PLM had a negative relationship with those parameters. The correlation between LM, ALM, FM, PLM, ALM, age, and YSM was not significant. In multivariate linear regression analysis, the hip bone strength was observed to have a consistent and unchanged positive association with AFM and a negative association with AOI, whereas its association with other variables of body composition was not significant after adjusting for age, years since menopause, height, body weight, and BMI. AFM may be a positively protective effect for hip bone strength while AOI, rather than android fat, shows a strong negative association with hip bone strength after making an adjustment for confounders (age, YSM, height, body weight, and BMI) in healthy postmenopausal Chinese women. Rational weight control and AOI reduction during menopause may have vital clinical significance in decreasing postmenopausal osteoporosis.

Association between low C-peptide and low lumbar bone mineral density in postmenopausal women without diabetes

In this population-based, cross-sectional study in Italian postmenopausal females not affected by diabetes, we showed a link between serum C-peptide and lumbar bone mineral density, suggesting that C-peptide exerts an insulin-independent effect on bone mass.

INTRODUCTION

It is well known that type 1 (T1) diabetes, characterized by insulin and C-peptide deficiency, is associated with a low lumbar bone mineral density and an increased risk for fracture. While a role for insulin in the pathogenesis of osteoporosis has been demonstrated, the association between C-peptide and the bone mineral density has not been investigated. We conducted a study in a cohort of 84 postmenopausal women without diabetes to clarify the association between serum C-peptide and the lumbar bone mineral density.

METHODS

Participants underwent a bone mineral density evaluation by DXA and biochemical analysis including the C-peptide assay.

RESULTS

rteen percent of the population had osteoporosis and 38% had osteopenia. With ANOVA test, we showed that women with the lowest C-peptide concentration had lower lumbar mineral density in comparison to those in all other C-peptide concentration group (p = 0.02 among groups after adjustment). The univariate and multivariate analysis showed that C-peptide was positively associated with both lumbar T-score and Z-score besides other well-known factors like age (with T-score p < 0.001; beta = -0.38) and BMI (with T-score p = 0.009; beta = 0.34), while insulin was not correlated with the lumbar bone mineral density. The area under the receiver operating characteristic (ROC) curve for C-peptide to predict the absence of lumbar osteoporosis was 0.74 (SE = 0.073; p = 0.013).

CONCLUSIONS

These results suggest that C-peptide may exert an insulin- and BMI-independent effect on lumbar bone mineral density and that further large-scale studies are needed in order to clarify its role in bone mineralization especially in subjects without diabetes.

Increased fracture risk in patients with type 2 diabetes mellitus: an overview of the underlying mechanisms and the usefulness of imaging modalities and fracture risk assessment tools

Type 2 diabetes mellitus has recently been linked to an increased fracture risk. Since bone mass seems to be normal to elevated in patient with type 2 diabetes, the increased fracture risk is thought to be due to both an increased falling frequency and decreased bone quality. The increased falling frequency is mainly a result of complications of the disease such as a retinopathy and polyneuropathy. Bone quality is affected through changes in bone shape, bone micro-architecture, and in material properties such as bone mineralization and the quality of collagen. Commonly used methods for predicting fracture risk such as dual energy X-ray absorptiometry and fracture risk assessment tools are helpful in patients with type 2 diabetes mellitus, but underestimate the absolute fracture risk for a given score. New imaging modalities such as high resolution peripheral quantitative computed tomography are promising for giving insight in the complex etiology underlying the fragility of the diabetic bone, as they can give more insight into the microarchitecture and geometry of the bone. We present an overview of the contributing mechanisms to the increased fracture risk and the usefulness of imaging modalities and risk assessment tools in predicting fracture risk in patients with type 2 diabetes.

Biochemical markers of bone turnover in diabetes patients--a meta-analysis, and a methodological study on the effects of glucose on bone markers

This study examined whether markers of bone turnover differ between individuals with and without diabetes. Bone markers showed heterogeneity between studies and were discrepant for markers of bone creation and markers of bone degradation. Bone markers may be of lesser value in diabetes due to heterogeneity.

INTRODUCTION

The aim of this meta-analysis was to compare existing literature regarding changes in bone markers among diabetics compared to healthy controls. To exclude that blood glucose levels among diabetes patients could influence the assays used for determining bone turnover markers, a methodological study was performed.

METHODS

Medline at Pubmed Embase, Cinahl, Svemed+, Cochrane library, and Bibliotek.dk was searched in August 2012. The studies should examine biochemical bone turnover among diabetes patients in comparison to controls in an observational design. In the methodological study, fasting blood samples were drawn from two individuals. Glucose was added to the blood samples in different concentrations and OC, CTX, and procollagen type 1 amino terminal propeptide were measured after 0, 1, 2, and 3 h.

RESULTS

Twenty-two papers fulfilled the criteria for the meta-analysis. From the pooled data in the meta-analysis, the bone markers osteocalcin (OC) (-1.15 ng/ml [-1.78,-0.52]) and C-terminal cross-linked telopeptide (CTX) (-0.14 ng/ml [-0.22, -0.05]) were significantly lower among diabetes patients than non-diabetes patients, however other markers did not differ. All markers displayed very high heterogeneity by I2 statistics. In the methodological study, the addition of glucose did not significantly change the bone markers neither by level of glucose nor with increasing incubation time.

CONCLUSION

The dissociative pattern of biochemical bone markers of bone formation and bone resorption present in diabetes patients is thus not caused by glucose per se but may be modulated by unknown factors associated with diabetes mellitus.

Insulin resistance and bone strength: findings from the study of midlife in the United States

Although several studies have noted increased fracture risk in individuals with type 2 diabetes mellitus (T2DM), the pathophysiologic mechanisms underlying this association are not known. We hypothesize that insulin resistance (the key pathology in T2DM) negatively influences bone remodeling and leads to reduced bone strength. Data for this study came from 717 participants in the Biomarker Project of the Midlife in the United States Study (MIDUS II). The homeostasis model assessment of insulin resistance (HOMA-IR) was calculated from fasting morning blood glucose and insulin levels. Projected 2D (areal) bone mineral density (BMD) was measured in the lumbar spine and left hip using dual-energy X-ray absorptiometry (DXA). Femoral neck axis length and width were measured from the hip DXA scans, and combined with BMD and body weight and height to create composite indices of femoral neck strength relative to load in three different failure modes: compression, bending, and impact. We used multiple linear regressions to examine the relationship between HOMA-IR and bone strength, adjusted for age, gender, race/ethnicity, menopausal transition stage (in women), and study site. Greater HOMA-IR was associated with lower values of all three composite indices of femoral neck strength relative to load, but was not associated with BMD in the femoral neck. Every doubling of HOMA-IR was associated with a 0.34 to 0.40 SD decrement in the strength indices (p<0.001). On their own, higher levels of fasting insulin (but not of glucose) were independently associated with lower bone strength. Our study confirms that greater insulin resistance is related to lower femoral neck strength relative to load. Further, we note that hyperinsulinemia, rather than hyperglycemia, underlies this relationship. Although cross-sectional associations do not prove causality, our findings do suggest that insulin resistance and in particular, hyperinsulinemia, may negatively affect bone strength relative to load.

A lower value for quantitative ultrasound at radius is an additional indicator of metabolic syndrome and cardiovascular disease risk

BACKGROUND

The relationships between quantitative ultrasound (QUS) values, metabolic syndrome (MetS) and cardiovascular disease (CVD) risk are unclear. Objective The objective was to determine the relationships between QUS and MetS as well as CVD risk.

DESIGN

This was a cross-sectional study conducted in Shanghai, China.

PATIENTS

One-thousand four hundred and thirty-nine Chinese women and men with or without MetS were studied.

MEASUREMENTS

Speed of sound (SOS) at radius, phalanx and tibia and their relationships with MetS and Framingham's 10-year cardiovascular disease risk scores were investigated.

RESULTS

Premenopausal women with MetS had significant lower SOS at radius than those without MetS after adjusting for age, BMI and fat mass percentage (P = 0·02). The radius SOS was negatively associated with waist circumference (r = -0·109, P = 0·025), waist-to-hip ratio (r = -0·124, P = 0·01) and 2 h postprandial glucose level (r = -0·125, P = 0·012) in premenopausal women. Waist circumference, waist-to-hip ratio and 2 h postprandial glucose level increased with the decreasing tertiles of radius SOS after adjustment of age (P = 0·003, 0·002 and 0·008, respectively). The CVD risk increased with decreasing tertiles of radius SOS in postmenopausal women even after the adjustment of age, years since menopause, MetS components, smoking and alcohol habits (P < 0·001), but not in premenopausal women and men.

CONCLUSIONS

Lower radius SOS is associated with greater risks of MetS and CVD in premenopausal and postmenopausal women, respectively. The QUS value derived from non-weight-bearing site, such as radius, may represent an additional indicator of MetS and CVD risk in women.

Changes in trabecular bone microarchitecture in postmenopausal women with and without type 2 diabetes: a two year longitudinal study

BACKGROUND

The risk of experiencing an osteoporotic fracture is greater for adults with type 2 diabetes despite higher than normal bone mineral density (BMD). In addition to BMD, trabecular bone microarchitecture contributes to bone strength, but is not assessed using conventional BMD measurement by dual x-ray absorptiometry (DXA). The aim of this study was to compare two year changes in trabecular bone microarchitecture in women with and without type 2 diabetes.

METHODS

We used a 1 Tesla magnetic resonance imaging (MRI) scanner to acquire axial images (resolution 195 μm × 195 μm × 1000 μm) of the distal radius. We report the change in the number and size of trabecular bone holes, bone volume fraction (BVTV), trabecular thickness (Tb.Th), number (Tb.N) and separation (Tb.Sp), endosteal area, nodal and branch density for each group. Lumbar spine and proximal femur BMD were measured with DXA (Hologic, Discovery QDR4500A) at baseline and follow-up. Using a multivariable linear regression model, we evaluated whether the percent change in the trabecular bone microarchitecture variables differed between women with and without type 2 diabetes.

RESULTS

Of the 54 participants at baseline with valid MRI image sets, 37 participants (baseline mean [SD] age, 70.8 [4.4] years) returned for follow-up assessment after 25.4 [1.9] months. Lumbar spine BMD was greater for women with diabetes compared to without diabetes at both baseline and follow-up. After adjustment for ethnicity, women with diabetes had a higher percent increase in number of trabecular bone holes compared to controls (10[1] % versus -7 [2]%, p=0.010), however results were no longer significant after adjustment for multiple comparisons (p=0.090). There were no differences in the change in other trabecular bone microarchitecture variables between groups.

CONCLUSION

There were no differences in percent change in trabecular bone microarchitecture variables over two years in women with type 2 diabetes compared to women without diabetes. This study provides feasibility data, which will inform future trials assessing change in trabecular bone microarchitecture in women with type 2 diabetes. Larger studies using higher resolution imaging modalities that can assess change in trabecular and cortical bone compartments in women with type 2 diabetes are needed.

Prediction of hip osteoporotic fractures from composite indices of femoral neck strength

OBJECTIVE

To clarify whether composite hip strength indices improve predictive ability for hip osteoporotic fractures independent of conventional bone mineral density (BMD).

SUBJECTS AND METHODS

Three hundred and eighty-two health controls and 43 women with hip fractures (aged 28.2-87.7 years, mean age 59.5 ± 9.2 years) were measured by dual energy X-ray absorptiometry for femoral neck bone mineral density (FN_BMD) and proximal femur geometry parameters of hip, and composite hip strength indices (Compression strength index, Bending strength index, and Impact strength index). The association between the studied parameters and the fractures was modelled using multiple logistic regression, including age, height, weight, and menopausal status. Fracture-predicted probability was calculated for each predictor tested. ROC curve areas (AUCs) were calculated for the fracture status, having the calculated fracture-predicted probability as a test variable. AUCs were compared by the Hanley-McNeil test.

RESULTS

Women with hip fractures had lower FN_BMD, composite hip strength indices, and longer hip axis length than controls, and no significant difference in femoral neck width. Logistic regression showed composite hip strength indices could predict hip fractures risk. To the same extent as FN BMD, Compression Strength Index (CSI) best predicted the risk for each fracture (AUC = 0.787 ± 0.028). When CSI was added to FN_BMD, there was a small but not statistically significant increase in AUC to 0.796 ± 0.027 (P = 0.9018).

CONCLUSION

Composite indices of femoral neck strength may be valuable in the assessment of the biomechanics of bone fragility; however, they do not appear to add diagnostic value to the simple measurement of BMD.

Diabetes and change in bone mineral density at the hip, calcaneus, spine, and radius in older women

Older women with type 2 diabetes mellitus (DM) have higher bone mineral density (BMD) but also have higher rates of fracture compared to those without DM. Limited evidence suggests that DM may also be associated with more rapid bone loss. To determine if bone loss rates differ by DM status in older women, we analyzed BMD data in the Study of Osteoporotic Fractures (SOF) between 1986 and 1998. SOF participants were women ≥65 years at baseline who were recruited from four regions in the U.S. DM was ascertained by self-report. BMD was measured with dual-energy x-ray absorptiometry (DXA) at baseline and at least one follow-up visit at the hip (N = 6624) and calcaneus (N = 6700) and, on a subset of women, at the spine (N = 396) and distal radius (N = 306). Annualized percent change in BMD was compared by DM status, using random effects models. Of 6,867 women with at least one follow-up DXA scan, 409 had DM at baseline. Mean age was 70.8 (SD 4.7) years. Baseline BMD was higher in women with DM at all measured sites. In models adjusted for age and clinic, women with prevalent DM lost bone more rapidly than those without DM at the femoral neck (-0.96 vs. -0.59%/year, p < 0.001), total hip (-0.98 vs. -0.70%/year, p < 0.001), calcaneus (-1.64 vs. -1.40%/year, p = 0.005), and spine (-0.33 vs. +0.33%/year, p = 0.033), but not at the distal radius (-0.97 vs. -0.90%/year, p = 0.91). These findings suggest that despite higher baseline BMD, older women with DM experience more rapid bone loss than those without DM at the hip, spine, and calcaneus, but not the radius. Higher rates of bone loss may partially explain higher fracture rates in older women with DM.

Reduced serum osteocalcin concentrations are associated with type 2 diabetes mellitus and the metabolic syndrome components in postmenopausal women: the crosstalk between bone and energy metabolism

Although it has been shown that osteocalcin functions as a hormone in the regulation of glucose metabolism and fat mass, no population-based study to date has addressed serum osteocalcin levels in relation to energy metabolism concurrent with bone metabolism in postmenopausal women. In a population-based study, cardiovascular risk factors, high-sensitivity C-reactive protein (hs-CRP), osteoprotegerin, receptor activator of nuclear factor-κB ligand, osteocalcin, CrossLaps, alkaline phosphatase, and bone mineral density (BMD) at the lumbar spine (L2-L4) and the proximal femur were measured in 382 Iranian postmenopausal women. In multiple logistic regression analysis, lower osteocalcin and CrossLaps levels were associated with a higher odds ratio (OR) of having type 2 diabetes mellitus when adjustments were made for age, hs-CRP, cardiovascular risk factors, BMD, and markers of bone metabolism [OR 5.17, CI (2.66-10.04), p < 0.0001 and OR 2.51, CI (1.37-4.61), p = 0.003, respectively]. However, lower alkaline phosphatase levels were associated with a lower OR of having type 2 diabetes mellitus [OR 0.28, CI (0.15-0.52), p < 0.0001] in regression analysis. No significant difference was found between serum osteocalcin levels of those with and without metabolic syndrome. Among the metabolic syndrome components, low osteocalcin levels had significant associations with elevated blood glucose [OR 1.89, CI (1.16-3.07), p = 0.010] and elevated waist circumference [OR 2.53, CI (1.13-5.67), p = 0.024] in multivariate analyses. In conclusion, serum osteocalcin was independently associated with glucose intolerance and abdominal obesity as the components of metabolic syndrome and type 2 diabetes mellitus in postmenopausal women. Since CrossLaps and alkaline phosphatase levels were independently associated with the presence of type 2 diabetes mellitus, the unique contribution of osteocalcin in glucose metabolism could not be concluded.

Fracture risk assessment without race/ethnicity information

CONTEXT

Dual-energy x-ray absorptiometry-derived bone mineral density (BMD) does not explain interracial differences in fracture risk; thus, BMD-based fracture risk assessment requires patient race/ethnicity information and ethnicity-specific BMD reference databases.

OBJECTIVE

The objective of the study was to investigate whether composite femoral neck strength indices, which integrate dual-energy x-ray absorptiometry-derived femoral neck size, femoral neck BMD, and body size, will allow fracture risk assessment without requiring race/ethnicity information.

DESIGN

This was a prospective cohort study.

SETTING AND PARTICIPANTS

A total of 1940 community-dwelling women aged 42-53 yr from four race/ethnicity groups (968 Caucasian, 512 African-American, 239 Japanese, and 221 Chinese) were followed up for 9 yr.

OUTCOME MEASUREMENTS

Self-reported, nondigital, noncraniofacial fractures were measured.

RESULTS

Two hundred and two women (10.4%) sustained fractures and 82 (4.3%) had minimum-trauma fractures. Each sd increment in any of the strength indices was associated with a 34-41% reduction in fracture hazard over 9 yr (each P<0.001). Race/ethnicity predicted fracture hazard independent of BMD (P=0.02) but did not predict fracture hazard independent of any of the composite indices (P=0.11-0.22). Addition of race/ethnicity did not improve risk discrimination ability of the strength indices, but did significantly improve the discrimination ability of BMD. The discrimination ability of BMD with race/ethnicity was not statistically different from that of any of the strength indices without race/ethnicity.

CONCLUSIONS

Composite strength indices of the femoral neck can predict fracture risk without race/ethnicity information as accurately as bone mineral density does in combination with race/ethnicity information and therefore would allow risk prediction in people of mixed race/ethnicity and in groups without a BMD reference database.

Diabetic polyneuropathy relates to bone metabolism and markers of bone turnover in elderly patients with type 2 diabetes: greater effects in male patients

BACKGROUND

There is evidence that diabetic polyneuropathy (PNP) is associated with reduced bone mineral density (BMD) in type 1 diabetes but little is known about the impact of diabetic PNP on bone metabolism in type 2 diabetes.

OBJECTIVES

The aim of this study was to evaluate differences in bone metabolism by measuring markers of bone turnover and BMD in men and postmenopausal women with type 2 diabetes and diabetic PNP compared with those without PNP. Gender differences were analyzed for both groups of patients.

METHODS

One hundred twenty patients with type 2 diabetes, 68 without PNP (43 men, 25 women, mean age 62 [8] years) and 52 with PNP (28 men, 24 women, mean age 64 [8] years) were studied. Clinical parameters with bone turnover biomarkers such as osteocalcin, bone alkaline phosphatase, procollagen type 1 amino-terminal propeptide, and carboxy-terminal telopeptide of type 1 collagen were measured in all patients. Dual energy x-ray absorptiometry to evaluate BMD was performed in a subgroup of patients.

RESULTS

After controlling for age, body mass index, duration of diabetes, smoking, glycosylated hemoglobin, homeostasis model assessment index for insulin resistance, serum C-reactive protein, creatinine, calcium, gamma-glutamyltransferase, parathyroid and sex hormones levels, presence of micro/macrovascular complications, statin- as well as diabetes-related therapies, levels of carboxy-terminal telopeptide of type 1 collagen and procollagen type 1 amino-terminal propeptide were significantly higher among patients with PNP when compared with patients without PNP (P = 0.01 and P = 0.03, respectively). Differences in bone biomarkers were more pronounced among men with diabetes. BMD did not differ significantly between patients with and without PNP, independent of gender.

CONCLUSIONS

Male patients with PNP exhibit a higher rate of bone turnover than men without PNP. High rate of bone turnover increases the susceptibility for developing osteoporosis. Prevention of diabetic PNP might also reduce the incidence of osteoporosis and fractures in patients with type 2 diabetes.

Bone and the perimenopause

Loss of ovarian function has a profound impact on female skeletal health. Bone mineral density findings from the Study of Women's Health Across the Nation demonstrate an accelerated rate of bone loss during the menopausal transition. The greatest reduction occurs in the year before the final menstrual period and the first 2 years thereafter. Clinical management includes maintenance of adequate dietary calcium and vitamin D intake, attention to modifiable risk factors, and osteoporosis screening. Indications, benefits, and risks of pharmacologic osteoporosis therapy should be assessed individually; there are currently no established guidelines addressing the treatment and prevention of osteoporosis in perimenopausal women.

FRAX underestimates fracture risk in patients with diabetes

The study objective was to determine whether diabetes is a risk factor for incident hip or major osteoporotic fractures independent of the WHO fracture risk assessment tool (FRAX). Men and women with diabetes (n = 3518) and nondiabetics (n = 36,085) aged ≥50 years at the time of bone mineral density (BMD) testing (1990 to 2007) were identified in a large clinical database from Manitoba, Canada. FRAX probabilities were calculated, and fracture outcomes to 2008 were established via linkage with a population-based data repository. Multivariable Cox proportional hazards models were used to determine if diabetes was associated with incident hip fractures or major osteoporotic fractures after controlling for FRAX risk factors. Mean 10-year probabilities of fracture were similar between groups for major fractures (diabetic 11.1 ± 7.2 versus nondiabetic 10.9 ± 7.3, p = 0.116) and hip fractures (diabetic 2.9 ± 4.4 versus nondiabetic 2.8 ± 4.4, p = 0.400). Diabetes was a significant predictor of subsequent major osteoporotic fracture (hazard ratio [HR] = 1.61, 95% confidence interval [CI] 1.42-1.83) after controlling for age, sex, medication use, and FRAX risk factors including BMD. Similar results were seen after adjusting for FRAX probability directly (HR = 1.59, 95% CI 1.40-1.79). Diabetes was also associated with significantly higher risk for hip fractures (p < 0.001). Higher mortality from diabetes attenuated but did not eliminate the excess fracture risk. FRAX underestimated observed major osteoporotic and hip fracture risk in diabetics (adjusted for competing mortality) but demonstrated good concordance with observed fractures for nondiabetics. We conclude that diabetes confers an increased risk of fracture that is independent of FRAX derived with BMD. This suggests that diabetes might be considered for inclusion in future iterations of FRAX.

Diabetes and femoral neck strength: findings from the Hip Strength Across the Menopausal Transition Study

CONTEXT

Diabetes mellitus is associated with increased hip fracture risk, despite being associated with higher bone mineral density in the femoral neck.

OBJECTIVE

The objective of the study was to test the hypothesis that composite indices of femoral neck strength, which integrate dual-energy x-ray absorptiometry derived femoral neck size, femoral neck areal bone mineral density, and body size and are inversely associated with hip fracture risk, would be lower in diabetics than in nondiabetics and be inversely related to insulin resistance, the primary pathology in type 2 diabetes.

DESIGN

This was a cross-sectional analysis.

SETTING AND PARTICIPANTS

The study consisted of a multisite, multiethnic, community-dwelling sample of 1887 women in pre- or early perimenopause.

OUTCOME MEASUREMENTS

Composite indices for femoral neck strength in different failure modes (axial compression, bending, and impact) were measured.

RESULTS

Adjusted for age, race/ethnicity, menopausal stage, body mass index, smoking, physical activity, calcium and vitamin D supplementation, and study site, diabetic women had higher femoral neck areal bone mineral density [+0.25 sd, 95% confidence interval (CI) (+0.06, +0.44) sd] but lower composite strength indices [-0.20 sd, 95% CI (-0.38, -0.03) sd for compression, -0.19 sd, 95% CI (-0.38, -0.003) sd for bending, -0.19 sd, 95% CI (-0.37, -0.02) sd for impact] than nondiabetic women. There were graded inverse relationships between homeostasis model-assessed insulin resistance and all three strength indices, adjusted for the same covariates.

CONCLUSIONS

Despite having higher bone density, diabetic women have lower indices of femoral neck strength relative to load, consistent with their documented higher fracture risk. Insulin resistance appears to play an important role in bone strength reduction in diabetes.