Volumetric BMD and vascular calcification in middle-aged women: the Study of Women's Health Across the Nation

Pros and cons of fatty acids in bone biology

Despite the growing interest in deciphering the causes and consequences of obesity-related disorders, the mechanisms linking fat intake to bone behaviour remain unclear. Since bone fractures are widely associated with increased morbidity and mortality, most notably in elderly and obese people, bone health has become a major social and economic issue. Consistently, public health system guidelines have encouraged low-fat diets in order to reduce associated complications. However, from a bone point of view, mechanisms linking fat intake to bone alteration remain quite controversial. Thus, after more than a decade of dedicated studies, this timely review offers a comprehensive overview of the relationships between bone and fatty acids. Using clinical evidences as a starting-point to more complex molecular elucidation, this work highlights the complexity of the system and reveals that bone alteration that cannot be solved simply by taking ω-3 pills. Fatty acid effects on bone metabolism can be both direct and indirect and require integrated investigations. Furthermore, even at the level of a single cell, one fatty acid is able to trigger several different independent pathways (receptors, metabolites…) which may all have a say in the final cellular metabolic response.

Decreased bone mineral density is associated with coronary atherosclerosis in healthy postmenopausal women

Objective

This study aimed to assess the association between bone mineral density (BMD) and coronary atherosclerosis in healthy postmenopausal women.

Methods

We performed a retrospective review of 252 postmenopausal women who had visited a health promotion center for a routine checkup. BMD of the lumbar spine (L1-L4) and femoral neck was evaluated using dual-energy X-ray absorptiometry, and coronary atherosclerosis was assessed using 64-row multidetector computed tomography. Participants were divided into normal BMD and osteopenia-osteoporosis groups, according to the T-scores of their lumbar spine or femoral neck.

Results

Participants with osteopenia-osteoporosis had a significantly higher proportion of coronary atherosclerosis than did those with normal BMD at the lumbar spine (P=0.003) and femoral neck (P=0.004). Osteopenia-osteoporosis at the lumbar spine (odds ratio [OR], 2.86; 95% confidence interval [CI], 1.12 to 7.27) or femoral neck (OR, 3.35; 95% CI, 1.07 to 10.57) was associated with coronary atherosclerosis, after controlling for age and cardiovascular risk factors.

Conclusion

Decreased BMD is associated with coronary atherosclerosis in healthy postmenopausal women, independent of age and cardiovascular risk factors. Postmenopausal women with decreased BMD may have a higher risk of developing coronary atherosclerosis.

Influence of chronic stroke impairments on bone strength index of the tibial distal epiphysis and diaphysis

SUMMARY

The influence of various stroke impairments on bone health is poorly understood. This study showed that muscle function and small artery compliance were more strongly associated with the bone strength index at the tibial diaphyseal and epiphyseal regions, respectively. These impairments should be targeted in promoting bone health post-stroke.

INTRODUCTION

This study examined the bone structural properties of the tibial distal epiphysis and diaphysis after chronic stroke and identified the clinical correlates of the bone strength index measured at these sites.

METHODS

The tibial distal epiphysis (4% site) and diaphysis (66% site) were scanned on both sides in 66 chronic stroke patients and 23 control participants using peripheral quantitative computed tomography. Dynamic knee muscle strength, balance function, spasticity, arterial compliance, and endurance were also measured in the stroke group.

RESULTS

At the 4% site, multivariate analysis showed a significant side×group interaction effect (Wilk's lambda=3.977, p<0.001), with significant side-to-side differences in total volumetric bone mineral density (vBMD), trabecular vBMD, and bone strength index in the stroke group, but not in the control group. A significant side×group interaction was also found at the 66% site (Wilk's lambda=4.464, p<0.001), with significant side-to-side differences in cortical vBMD, cortical area, cortical thickness, and bone strength index in the stroke group only. Balance and endurance were independently associated with bone strength index at both tibial sites in the paretic leg (p<0.05) after adjusting for relevant factors in multivariate regression analysis. Small artery compliance and muscle strength were significantly associated with the bone strength index at the 4% site and 66% site, respectively.

CONCLUSIONS

The influence of various stroke impairments on bone was region-specific. While muscle function was more strongly associated with the bone strength index in the diaphyseal region, the effect of vascular health was more apparent in the tibial epiphysis in the paretic leg.

Increased low-density lipoprotein cholesterol level is associated with non-vertebral fractures in postmenopausal women

Although a high serum low-density lipoprotein cholesterol (LDL-C) level is an established risk factor for atherosclerosis, it is unclear whether it is associated with osteoporosis. In this study, the associations between the serum LDL-C level and bone mineral density (BMD), bone metabolic markers, and the presence of prevalent vertebral or non-vertebral fractures were examined. A total of 211 healthy postmenopausal women (age range, 46-80 years) who visited a community health center were recruited consecutively. Their radiographic and biochemical characteristics were collected. Prevalent vertebral and non-vertebral fractures were found in 49 (23.2%) and 36 (17.1%) subjects, respectively. Simple regression analyses showed that the serum LDL-C level was not significantly correlated with lumbar or femoral BMD or serum levels of total amino-terminal propeptide of type I collagen (PINP) or carboxy-terminal telopeptide of type I collagen (CTX). Logistic regression analyses adjusted for age and BMI showed that the increased serum LDL-C level was selected as an index affecting the presence of prevalent non-vertebral fractures, but not vertebral fractures. This result was still significant after additional adjustments for years since menopause, physical activity, previous cardiovascular events, bone markers, BMD, serum Ca, P, Cr, 25(OH)D, grip strength, tandem gait test, and use of drugs for hyperlipidemia [odds ratio 1.76 (1.13-2.73), p=0.012]. These findings suggest that a high serum LDL-C level may be a risk factor for prevalent non-vertebral fragility fractures independent of bone turnover, bone mass, vitamin D insufficiency, or frail status in postmenopausal women, and that it may be detrimental to bone, as well as blood vessels.

Association of lumbar fractures, abdominal aortic calcification, and osteopenia

PURPOSE

The purpose was to assess if abdominal aortic calcification (AAC) and low bone mineral density (BMD) are associated with fractures on lumbar spine radiographs in trauma patients.

METHODS

Retrospectively, 303 consecutive lumbar radiographs were independently reviewed by two radiologists for AAC, low BMD, and traumatic findings.

RESULTS

Thirty-one percent of patients had low BMD, 34% had AAC, and 24% had both. Eleven percent of radiographs showed traumatic findings. Seventy-six percent of positive cases had low BMD (P<.001), and 64% had AAC (P<.001).

CONCLUSION

A higher index of suspicion for fractures is warranted when AAC and low BMD are present.

Axial QCT: clinical applications and new developments

Quantitative computed tomography (QCT) is currently undergoing a renaissance, with an increasing number of studies being published and the definition of both QCT-specific osteoporosis thresholds and treatment criteria. Compared with dual-energy X-ray absorptiometry, the current standard bone mineral density technique, QCT has a number of pertinent advantages, including volumetric measurements, less susceptibility to degenerative spine changes, and higher sensitivity to changes in bone mass. Disadvantages include the higher radiation doses and less experience with fracture prediction and therapy monitoring. Over the last 10 yr, a number of novel applications have been described allowing assessment of bone mineral density and bone quality in larger patient populations, developments that may substantially improve patient care.

Inverse association between bone microarchitecture assessed by HR-pQCT and coronary artery calcification in patients with end-stage renal disease

It is a matter of debate whether vascular calcification and bone loss are simultaneously occurring but largely independent processes or whether poor bone health predisposes to vascular calcification, especially in patients with kidney disease. Here we investigated the association between the changes of microarchitecture in weight bearing bone and the extent of coronary artery calcification in patients with chronic renal failure. The bone microarchitecture of the tibia using high-resolution peripheral quantitative computed tomography (HR-pQCT), bone mineral density using dual X-ray absorptiometry (DXA) of the lumbar spine, femoral neck and distal radius as well as coronary artery calcification using multi-slice CT and reported as Agatston score were measured in 66 patients with end-stage renal disease on chronic hemodialysis. Markers of bone turnover, vitamin D status and intact parathyroid hormone (iPTH) were assessed. CAC score was found to be <100 in 39% and ≥100 in 61% of patients. The median [95% CI] total CAC score was 282 [315-2587]. By univariate analysis, significant correlations between CAC and age (R=0.52, p<0.001), weight (R=0.3, p<0.01) and serum cross laps (CTX, R=-0.39, p<0.01) were found, and parameters of bone microarchitecture were numerically but not significantly lower in patients with CAC scores ≥100. In multivariate analysis stratifying for gender and correcting for age, tibial density (Dtot) and bone volume/total volume (BV/TV) were significantly lower in patients with CAC scores ≥100 (p<0.05 for both). Low trabecular bone volume and decreased cortical bone density are associated with coronary artery calcification in dialysis patients.

Role of bone mineral density in the inverse relationship between body size and aortic calcification: results from the Baltimore Longitudinal Study of Aging

OBJECTIVE

There is a J-shaped relationship between body mass index (BMI) and cardiovascular outcomes in elderly patients (obesity paradox). Whether low BMI correlates with aortic calcification (AC) and whether this association is accounted for by bone demineralization is uncertain.

METHODS

Presence of AC was evaluated in 687 community-dwelling individuals (49% male, mean age 67 ± 13 years) using CT images of the thoracic, upper and lower abdominal aorta, and scored from 0 to 3 according to number of sites that showed any calcification. Whole-body bone mineral density (BMD) was evaluated by dual-energy X-ray absorptiometry. Predictors of AC were assessed by logistic regression, and the role of BMD using mediation analysis.

RESULTS

Age and cardiovascular risk factors were positively associated while both BMI (r = -0.11, p < 0.01) and BMD (r = -0.17, p < 0.0001) were negatively associated with AC severity. In multivariate models, lower BMI (OR 0.96, 95%CI 0.92-0.99, p = 0.01), older age, higher systolic blood pressure, use of lipid-lowering drugs and smoking were independent predictors of AC. A nonlinear relationship between BMI and AC was noticed (p = 0.03), with decreased AC severity among overweight participants. After adjusting for BMD, the coefficient relating BMI to AC was reduced by 14% and was no longer significant, whereas BMD remained negatively associated with AC (OR 0.82, 95%CI 0.069-0.96, p = 0.01), with a trend for a stronger relationship in older participants.

CONCLUSION

Low BMI is associated with increased AC, possibly through calcium mobilization from bone, resulting in low BMD. Prevention of weight loss and bone demineralization with aging may help reducing AC.

Prevalence and determinants of osteoporosis in patients with type 1 and type 2 diabetes mellitus

BACKGROUND

Increased risk of osteoporosis and its clinical significance in patients with diabetes is controversial. We analyze osteoporosis prevalence and determinants of bone mineral density (BMD) in patients with type 1 and 2 diabetes.

METHODS

Three hundred and ninety-eight consecutive diabetic patients from a single outpatient clinic received a standardized questionnaire on osteoporosis risk factors, and were evaluated for diabetes-related complications, HbA1c levels, and lumbar spine (LS) and femoral neck (FN) BMD. Of these, 139 (71 men, 68 women) type 1 and 243 (115 men, 128 women) type 2 diabetes patients were included in the study. BMD (T-scores and values adjusted for age, BMI and duration of disease) was compared between patient groups and between patients with type 2 diabetes and population-based controls (255 men, 249 women).

RESULTS

For both genders, adjusted BMD was not different between the type 1 and type 2 diabetes groups but was higher in the type 2 group compared with controls (p < 0.0001). Osteoporosis prevalence (BMD T-score < -2.5 SD) at FN and LS was equivalent in the type 1 and type 2 diabetes groups, but lower in type 2 patients compared with controls (FN: 13.0% vs 21.2%, LS: 6.1% vs 14.9% men; FN: 21.9% vs 32.1%, LS: 9.4% vs 26.9% women). Osteoporosis prevalence was higher at FN-BMD than at LS-BMD. BMD was positively correlated with BMI and negatively correlated with age, but not correlated with diabetes-specific parameters (therapy, HbBA1c, micro- and macrovascular complications) in all subgroups. Fragility fracture prevalence was low (5.2%) and not different between diabetes groups. Fracture patients had lower BMDs compared with those without fractures; however, BMD T-score was above -2.5 SD in most patients.

CONCLUSIONS

Diabetes-specific parameters did not predict BMD. Fracture occurrence was similar in both diabetes groups and related to lower BMD, but seems unrelated to the threshold T-score, <-2.5 SD. These results suggest that osteoporosis, and related fractures, is a clinically significant and commonly underestimated problem in diabetes patients.

Inflammatory, metabolic, and genetic mechanisms of vascular calcification

This review centers on updating the active research area of vascular calcification. This pathology underlies substantial cardiovascular morbidity and mortality, through adverse mechanical effects on vascular compliance, vasomotion, and, most likely, plaque stability. Biomineralization is a complex, regulated process occurring widely throughout nature. Decades ago, its presence in the vasculature was considered a mere curiosity and an unregulated, dystrophic process that does not involve biological mechanisms. Although it remains controversial whether the process has any adaptive value or past evolutionary advantage, substantial advances have been made in understanding the biological mechanisms driving the process. Different types of calcific vasculopathy, such as inflammatory versus metabolic, have parallel mechanisms in skeletal bone calcification, such as intramembranous and endochondral ossification. Recent work has identified important regulatory roles for inflammation, oxidized lipids, elastin, alkaline phosphatase, osteoprogenitor cells, matrix γ-carboxyglutamic acid protein, transglutaminase, osteoclastic regulatory factors, phosphate regulatory hormones and receptors, apoptosis, prelamin A, autophagy, and microvesicles or microparticles similar to the matrix vesicles of skeletal bone. Recent work has uncovered fascinating interactions between matrix γ-carboxyglutamic acid protein, vitamin K, warfarin, and transport proteins. And, lastly, recent breakthroughs in inherited forms of calcific vasculopathy have identified the genes responsible as well as an unexpected overlap of phenotypes. Until recently, vascular calcification was considered a purely degenerative, unregulated process. Since then, investigative groups around the world have identified a wide range of causative mechanisms and regulatory pathways, and some of the recent developments are highlighted in this review.

High hip fracture risk in men with severe aortic calcification: MrOS study

A significant link between cardiovascular disease and osteoporosis is established in postmenopausal women, but data for men are scarce. We tested the hypothesis that greater severity of abdominal aortic calcification (AAC) was associated with an increased risk of nonspine fracture in 5994 men aged ≥ 65 years. AAC was assessed on 5400 baseline lateral thoracolumbar radiographs using a validated visual semiquantitative score. Total hip bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry. Incident nonspine fractures were centrally adjudicated. After adjustment for age, body mass index (BMI), total hip BMD, fall history, prior fracture, smoking status, comorbidities, race, and clinical center, the risk of nonspine fracture (n=805) was increased among men with higher AAC (hazard ratio [HR] quartile 4 [Q4] [AAC score ≥ 9] versus quartile 1 [Q1] [0-1], 1.36; 96% confidence interval [CI], 1.10-1.68). This association was due to an increased risk of hip fracture (n=178) among men with higher AAC (HR Q4 versus Q1, 2.33; 95% CI, 1.41-3.87). By contrast, the association between AAC and the risk of nonspine, nonhip fracture was weaker and not significant (HR Q4 versus Q1, 1.22; 95% CI, 0.96-1.55). The findings regarding higher AAC and increased risk of fracture were not altered in additional analyses accounting for degree of trauma, estimated glomerular filtration rate, presence of lumbar vertebral fractures (which may bias AAC assessment), preexisting cardiovascular disease, ankle brachial index, or competing risk of death. Thus, in this large cohort of elderly men, greater AAC was independently associated with an increased risk of hip fracture, but not with other nonspine fractures. These findings suggest that AAC assessment may be a useful method for identification of older men at high risk of hip fracture.

Association of volumetric bone mineral density with abdominal aortic calcification in African ancestry men

SUMMARY

We tested for association between cortical and trabecular volumetric bone mineral density (vBMD) with abdominal aortic calcification (AAC) prevalence in 278 Afro-Caribbean men. AAC was present in 68.3 % of the men. Greater cortical, but not trabecular, vBMD was associated with significantly decreased odds of AAC independent of traditional risk factors.

INTRODUCTION

The aim of this study is to assess the prevalence and correlates of AAC in a sample of 278 Afro-Caribbean men (mean age 56) and to test for a largely unexplored association between cortical and trabecular vBMD with AAC prevalence.

METHODS

Men were recruited consecutively as part of an ongoing prospective cohort study of body composition in men aged 40+. For this analysis, AAC was assessed by computed tomography of the abdomen from L3 to S1. Aortic calcium was scored using the Agatston method, and prevalence was defined as a score ≥10 to rule out false positives. Men also had BMD assessed using peripheral quantitative computed tomography at 4 % (trabecular vBMD) and 33 % (cortical vBMD) of the radius and tibia.

RESULTS

Abdominal aortic calcification was present in 68.3 % of the men. Significant independent predictors of AAC prevalence were increased age, increased BMI, hypertension, and current smoking. Age was the strongest predictor, with each SD (7.8 year) increase in age conferring 2.7 times increased odds of having AAC (P < 0.0001). A one SD greater cortical, but not trabecular, vBMD was associated with a significant decreased odds of AAC prevalence independent of other traditional risk factors (OR 0.65; 95 % CI 0.45-0.92).

CONCLUSIONS

Cortical vBMD is inversely associated with AAC presence. This finding suggests that there may be shared physiology between cortical bone compartment remodeling and vascular calcification.

Alendronate as an effective treatment for bone loss and vascular calcification in kidney transplant recipients

Kidney transplant recipients develop secondary osteoporosis induced by immunosuppressive medication, with a high risk of fracture, and abdominal aortic calcification (AC) is a known predictor of cardiovascular mortality. In this study of 12 stable kidney recipients, we estimated the preventive effect of bisphosphonate treatment on bone loss and progression of AC. We randomly divided the subjects into a treatment group with alendronate (group A: 5 subjects) and a control group (group C: 7 subjects). Group A patients received 35 mg/week of alendronate over 24 months, while group C patients were not administered with any bisphosphonates. Two major endpoints were established: (1) the time-dependent change in bone mineral density (BMD) estimated with DEXA and (2) progression of abdominal AC, calculated twice as an index (ACI) using computed tomography data. Over the 2-year study period, group A patients showed significantly increased BMD of 1.86 ± 0.85% (P = 0.015 versus baseline), and almost complete inhibition of ACI progression (38.2 ± 24.2% to 39.6 ± 24.3%), but group C patients showed a decrease in BMD decline with bone loss and progression of ACI (32.8 ± 25.0% to 37.8 ± 29.2%, P = 0.061). In conclusion, alendronate therapy was an effective treatment in kidney transplant recipients for secondary osteoporosis and vascular calcification as ectopic calcification. This clinical trial is registered with number JMA-IIA00155 of JMACCT CTR.

RANKL inhibition with denosumab does not influence 3-year progression of aortic calcification or incidence of adverse cardiovascular events in postmenopausal women with osteoporosis and high cardiovascular risk

Atherosclerosis and osteoporosis are chronic diseases that progress with age, and studies suggest aortic calcification, an indicator of atherosclerosis, is inversely associated with bone mineral density (BMD). The osteoprotegerin (OPG)/receptor activator of NF-κB (RANK)/RANK ligand (RANKL) system has been proposed as a shared regulatory system for bone and vasculature. Denosumab (DMAb), a monoclonal antibody against RANKL, improved BMD and reduced fracture risk in the Fracture Reduction Evaluation of Denosumab in Osteoporosis Every 6 Months (FREEDOM) trial. We evaluated whether or not treatment with DMAb influenced progression of aortic calcification (AC) and incidence of cardiovascular (CV) adverse events. We included 2363 postmenopausal women with osteoporosis (1142 placebo, 1221 DMAb), selected from 7808 participants in the FREEDOM trial (3906 placebo, 3902 DMAb), at high risk of CV events according to modified Raloxifene Use for the Heart (RUTH) criteria. CV adverse events were reported by participants. AC scores were assessed using a semiquantitative method from lateral spine X-rays. Change in AC score from baseline to 12 (n = 1377), 24 (n = 1231), and 36 months (n = 1045) was calculated as AC score at follow-up minus AC score at baseline. AC progression was defined as change in AC score >0. Baseline characteristics, CV risk factors, and AC scores were similar between treatment groups. Mean age of participants was 74 years (range, 60-90), 88% were white, and 77% had AC score >0 at baseline. Frequency of AC progression over 3 years did not differ between women in placebo (22%) and DMAb (22%) groups (p = 0.98). AC progression did not differ between treatment groups when analyzed by baseline estimated glomerular filtration rate or by baseline AC scores. Frequency of CV adverse events did not differ between placebo (40%) and DMAb (38%) groups (p = 0.26). In conclusion, DMAb treatment had no effect on progression of AC or incidence of CV adverse events compared to placebo.

Bone mineral density, vertebral fractures and body mass index in postmenopausal women with abdominal aortic calcification

BACKGROUND

Evidence suggest that there are connections between osteoporosis and cardiovascular diseases.

OBJECTIVES

The aim of the study was to analyze the relationship between radiological measurements of abdominal aorta calcifications (AAC) and bone mineral density (BMD) in postmenopausal women.

METHODS

In this cross-sectional study were included 125 postmenopausal women 50-84 years of age. BMD of the spine and hip was measured by dual energy X-ray absorptiometry (DXA). AAC were assessed by lateral radiographs of lumbar spine (L1-L4), using the antero-posterior severity score (0-24). Vertebral fractures were evaluated from T4 to L4 using Genant's semiquantitative method.

RESULTS

Forty-one (32.8%) patients had osteoporosis and 61 (48.8%) had AAC with a mean score of 3.1. Postmenopausal women with AAC were older and had significantly lower femoral neck and trochanteric BMD than subjects without AAC (all p < 0.01). There were no significant differences in the frequency of fractures between subjects with AAC and those without AAC (p > 0.05). In univariate analysis, age, height, weight, femoral and trochanter BMD were significantly associated with the severity of AAC score. In multiple regression analysis, femoral neck BMD, but not lumbar spine, trochanter BMD or age, was an independent predictor of AAC.

CONCLUSIONS

Reduced femoral neck BMD is negatively associated with the presence of AAC in postmenopausal women. The association between BMD and AAC seems to be age-independent, which suggests a common pathogenesis for bone loss and vascular calcifications.

Vascular elasticity and grip strength are associated with bone health of the hemiparetic radius in people with chronic stroke: implications for rehabilitation

BACKGROUND

People with stroke often have increased bone loss and fracture rate. Increasing evidence has demonstrated a link between cardiovascular health and bone loss in other patient populations.

OBJECTIVE

The study objectives were: (1) to compare the bone density and geometry of the radius diaphysis on the left and right sides in people with chronic stroke and people who were matched for age (control participants) and (2) to examine the relationship between the bone strength index at the hemiparetic radius diaphysis and vascular health in people with chronic stroke.

DESIGN

This was a case-control study.

METHODS

The radius diaphysis on both sides was scanned with peripheral quantitative computed tomography in 65 participants with chronic stroke and 34 control participants. Large-artery and small-artery elasticity indexes were evaluated with a cardiovascular profiling system.

RESULTS

The paretic radius diaphysis had significantly lower values for cortical bone mineral density, cortical thickness, cortical area, and the bone strength index but a larger marrow cavity area than the nonparetic radius diaphysis in participants with chronic stroke, whereas no bone measurement showed a significant side-to-side difference in control participants. Multiple regression analyses showed that the large-artery elasticity index and grip strength remained significantly associated with the bone strength index at the hemiparetic radius diaphysis after controlling for age, sex, time since stroke diagnosis, body mass index, and physical activity (R(2)=.790).

LIMITATIONS

This study was cross-sectional and could not establish causality. The radius diaphysis is not the most common site of fracture after stroke.

CONCLUSIONS

Both the integrity of the vasculature and muscle strength were significantly associated with the bone strength index at the hemiparetic radius diaphysis in participants with chronic stroke. The results may be useful in guiding rehabilitative programs for enhancing bone health in the paretic arm after stroke.

The relevance of mouse models for investigating age-related bone loss in humans

Mice are increasingly used for investigation of the pathophysiology of osteoporosis because their genome is easily manipulated, and their skeleton is similar to that of humans. Unlike the human skeleton, however, the murine skeleton continues to grow slowly after puberty and lacks osteonal remodeling of cortical bone. Yet, like humans, mice exhibit loss of cancellous bone, thinning of cortical bone, and increased cortical porosity with advancing age. Histologic evidence in mice and humans alike indicates that inadequate osteoblast-mediated refilling of resorption cavities created during bone remodeling is responsible. Mouse models of progeria also show bone loss and skeletal defects associated with senescence of early osteoblast progenitors. Additionally, mouse models of atherosclerosis, which often occurs in osteoporotic participants, also suffer bone loss, suggesting that common diseases of aging share pathophysiological pathways. Knowledge of the causes of skeletal fragility in mice should therefore be applicable to humans if inherent limitations are recognized.

Association between circulating osteoblast progenitor cells and aortic calcifications in women with postmenopausal osteoporosis

BACKGROUND AND AIMS

Ectopic artery calcification has been documented in women with postmenopausal osteoporosis, in whom an imbalance in the number of circulating osteoprogenitor cells (OPCs) has been identified. Circulating OPCs form calcified nodules in vitro; however, it remains unknown whether an association exists between the number of circulating OPCs and aortic calcifications. We investigated the relationship between OPCs and aortic calcifications in women with postmenopausal osteoporosis.

METHODS AND RESULTS

The number of circulating OPCs was quantified by FACS analysis in 50 osteoporotic postmenopausal women. OPCs were defined as CD15-/alkaline-phosphatase(AP)+ cells coexpressing or not CD34. Participants underwent measurement of markers of bone metabolism, bone mineral density and abdominal aortic calcium (AAC) by 64-slice computed tomography. Patients with AAC were older, had lower 25(OH)vitamin D levels and higher circulating CD15-/AP+/CD34- cells than those without AAC. Significant correlates of AAC included age (rho = 0.38 p = 0.006), calcium (rho = 0.35 p = 0.01), 25(OH)vitamin D (rho = -0.31, p = 0.03) and the number of CD15-/AP+/CD34- cells (rho = 0.55 p < 0.001). In regression analyses, the log-transformed number of CD15-/AP+/CD34- cells was associated with the presence (OR = 6.45, 95% CI 1.03-40.1, p = 0.04) and severity (β = 0.43, p < 0.001) of AAC, independent of age, 25(OH)vitamin D, calcium and other potential confounders. Patients with low 25(OH)vitamin D and high CD15-/AP+/CD34- cells had higher median AAC than other patients (1927/μL, 862-2714/μL vs 147/μL, 0-1665/μL, p = 0.003).

CONCLUSION

In women with postmenopausal osteoporosis, the number of circulating CD15-/AP+/CD34- cells is significantly associated with increased aortic calcifications, that appear to be correlated also with reduced 25(OH)vitamin D levels.

Severity of aortic calcification is positively associated with vertebral fracture in older men--a densitometry study in the STRAMBO cohort

In older men, severe abdominal aortic calcification and vertebral fracture (both assessed using dual-energy X-ray absorptiometry) were positively associated after adjustment for confounders including bone mineral density.

INTRODUCTION

Abdominal aortic calcification (AAC) is associated with higher fracture risk, independently of low bone mineral density (BMD). Dual-energy X-ray absorptiometry (DXA) can be used to assess both vertebral fracture and AAC and requires less time, cost, and radiation exposure.

METHODS

We conducted a cross-sectional study of the association between AAC and prevalent vertebral fractures in 901 men≥50 years old. We used DXA (vertebral fracture assessment) to evaluate BMD, vertebral fracture, and AAC.

RESULTS

Prevalence of vertebral fracture was 11%. Median AAC score was 1 and 12% of men had AAC score>6. After adjustment for age, weight, femoral neck BMD, smoking, ischemic heart disease, diabetes, and hypertension, AAC score>6 (vs ≤6) was associated with 2.5 (95% CI, 1.4-4.5) higher odds of vertebral fracture. Odds of vertebral fracture for AAC score>6 increased with vertebral fracture severity (grade 1, OR=1.8; grade 2, OR=2.4; grade 3, OR=4.4; trend p<0.01) and with the number of vertebral fractures (1 fracture, OR=2.0, >1 fracture, OR=3.5). Prevalence of vertebral fracture was twice as high in men having both a T-score<-2.0 and an AAC score>6 compared with men having only one of these characteristics.

CONCLUSIONS

Men with greater severity AAC had greater severity and greater number of vertebral fractures, independently of BMD and co-morbidities. DXA can be used to assess vertebral fracture and AAC. It can provide a rapid, safe, and less expensive alternative to radiography. DXA may be an important clinical tool to identify men at high risk of adverse outcomes from osteoporosis and cardiovascular disease.

Calcium intake is not associated with increased coronary artery calcification: the Framingham Study

BACKGROUND

Adequate calcium intake is known to protect the skeleton. However, studies that have reported adverse effects of calcium supplementation on vascular events have raised widespread concern.

OBJECTIVE

We assessed the association between calcium intake (from diet and supplements) and coronary artery calcification, which is a measure of atherosclerosis that predicts risk of ischemic heart disease independent of other risk factors.

DESIGN

This was an observational, prospective cohort study. Participants included 690 women and 588 men in the Framingham Offspring Study (mean age: 60 y; range: 36-83 y) who attended clinic visits and completed food-frequency questionnaires in 1998-2001 and underwent computed tomography scans 4 y later in 2002-2005.

RESULTS

The mean age-adjusted coronary artery-calcification Agatston score decreased with increasing total calcium intake, and the trend was not significant after adjustment for age, BMI, smoking, alcohol consumption, vitamin D-supplement use, energy intake, and, for women, menopause status and estrogen use. Multivariable-adjusted mean Agatston scores were 2.36, 2.52, 2.16, and 2.39 (P-trend = 0.74) with an increasing quartile of total calcium intake in women and 4.32, 4.39, 4.19, and 4.37 (P-trend = 0.94) in men, respectively. Results were similar for dietary calcium and calcium supplement use.

CONCLUSIONS

Our study does not support the hypothesis that high calcium intake increases coronary artery calcification, which is an important measure of atherosclerosis burden. The evidence is not sufficient to modify current recommendations for calcium intake to protect skeletal health with respect to vascular calcification risk.

Bone Mineral Density as a Predictor of Atherosclerosis and Arterial Wall Stiffness in Obese African-American Women

Bone demineralization is associated with higher cardiovascular event rates, possibly due to vascular calcification and accelerated atherosclerosis. African-Americans have less bone loss and less calcium content within atherosclerotic plaques. However, whether loss of bone mass is related to atherosclerosis has not been examined in African-Americans. The objective of this study was to evaluate possible associations between bone mineral density (BMD), carotid intimal-medial thickness (CIMT), and arterial stiffness. We studied 100 obese African-American women (BMI: 26.6 ± 6.2; age: 63 ± 14 years) referred for BMD estimation by dual-energy X-ray absorptiometry scan. BMD (g/cm(2)) was obtained at the lumbar spine (L1-L4), femoral neck, and total hip. Arterial stiffness was evaluated by the heart rate-corrected augmentation index (AI@75) and pulse wave velocity (PWV) using applanation tonometry. CIMT was measured by vascular ultrasound. Mean CIMT, AI@75, and PWV were 0.72 ± 0.14 mm, 28.8 ± 9.0%, and 8.9 ± 1.6 m/s, respectively. Mean BMD values at the lumbar spine, femoral neck, and hip were 0.96 ± 0.19, 0.80 ± 0.16, and 0.91 ± 0.17 g/cm(2). Older subjects had higher CIMT (r = 0.61, p < 0.001) and AI@75 (r = 0.42, p < 0.001). There was a significant correlation between AI@75 and CIMT (r = 0.45, p < 0.001). BMD was negatively correlated with AI@75 (lumbar: r = -0.22, p = 0.03; femoral neck: r = -0.24, p = 0.01; hip: r = -0.21, p = 0.03). BMD was unrelated to CIMT (lumbar: r = -0.09, p = 0.42; femoral neck: r = -0.15, p = 0.17; hip: r = -0.13, p = 0.23). On multivariate analysis, age (p < 0.001), hypertension (p = 0.02), and lumbar BMD (p = 0.01, R(2) = 0.30) were independent predictors of increased AI@75 after adjusting for age, height, and cardiovascular risk factors. These findings were unchanged upon substitution of femoral neck BMD (p = 0.05, R(2) = 0.28) into the model. There was a trend with hip BMD (p = 0.06, R(2) = 0.28) in the regression model. Age-matched comparison between normal BMD (n = 25) and osteoporotic patients (n = 34) demonstrated a significant difference in AI@75 (26.6 ± 8.9 vs. 31.6 ± 9.1%, p = 0.04). In summary, women with lower BMD had increased arterial stiffness. There was no relationship between BMD and atherosclerosis. In conclusion, age, hypertension, and BMD are independent predictors of higher arterial stiffness. Vascular changes are related to bone mineral loss, suggesting lower BMD may increase cardiovascular risk in African-Americans.

Relative impact of neuromuscular and cardiovascular factors on bone strength index of the hemiparetic distal radius epiphysis among individuals with chronic stroke

The objective of this study was to examine the associations of neuromuscular and cardiovascular impairments with the bone strength index of the hemiparetic distal radius epiphysis in chronic stroke survivors. The results showed that grip strength is the most predominant predictor of the bone strength index.

INTRODUCTION

The purpose of the study was to examine the associations of neuromuscular and cardiovascular impairments with the bone strength index of the hemiparetic distal radius epiphysis in chronic stroke survivors.

METHODS

Sixty-five chronic stroke survivors and 34 healthy control subjects underwent scanning of the distal radius epiphyseal site on both sides using peripheral quantitative computed tomography to measure trabecular volumetric bone mineral density (vBMD) (mg/cm(3)), total vBMD (mg/cm(3)), total area (mm(2)), and compressive bone strength index (cBSI) (g(2)/cm(4)). Various indicators of neuromuscular (grip strength, spasticity) and cardiovascular function (vascular elasticity, oxygen consumption during 6-min walk test) were evaluated.

RESULTS

Analysis of variance revealed a significant main effect of side (p < 0.001) and group × side interaction (p < 0.05) for total BMC, total vBMD, trabecular vBMD, and cBSI (p < 0.05), with the stroke group showing greater side-to-side difference in these variables. However, no significant side-to-side difference in total area was detected in either group (p > 0.05). Sex-specific analysis yielded similar results. Multiple regression analyses revealed that the cBSI of the hemiparetic distal radius epiphysis had a stronger association with neuromuscular factors than cardiovascular factors. Overall, grip strength was the strongest determinant of the cBSI of the hemiparetic distal radius epiphysis (p < 0.01).

CONCLUSIONS

Muscle weakness is the most predominant determinant of cBSI in the hemiparetic distal radius epiphysis among chronic stroke patients. Future studies should investigate the efficacy of different muscle-strengthening strategies in enhancing bone strength of this skeletal site in the chronic stroke population.

Association between cardiovascular diseases and osteoporosis-reappraisal

Positive association between cardiovascular diseases and osteoporosis is important because it concerns two major public health problems. Men and women with cardiovascular diseases (including severe abdominal aortic calcification (AAC) and peripheral arterial disease) tend to have lower areal and volumetric bone mineral density (BMD) as well as faster bone loss, although findings vary according to skeletal site. On one hand, severe forms of cardiovascular diseases (heart failure, myocardial infarction, hypertension, severe AAC) are associated with higher risk of osteoporotic fracture, especially hip fracture. This link was found in the studies based on healthcare databases and the cohort studies. On the other hand, low BMD, history of fragility fracture, vitamin D deficit and increased bone resorption are associated with higher risk of major cardiovascular events (myocardial infraction, stroke, cardiovascular mortality). Moreover, osteocalcin secreted by osteoblasts may be involved in the regulation of energetic and cardiovascular metabolism. The association between both pathologies depends partially on the shared risk factors, and also on the mechanisms that are involved in the regulation of bone and cardiovascular metabolism. Interpretation of the data should take into account methodological limitations: representativeness of the cohorts, quality of the registers and the information obtained from questionnaires, severity of diseases, number of events (statistical power) and their temporal closeness, availability of the information on potential confounders. It seems that patients with severe form of osteoporosis would benefit from assessment of the cardiovascular status and vice versa. However, official guidelines for the clinical practice are still lacking.

Osteoporosis imaging: state of the art and advanced imaging

Osteoporosis is becoming an increasingly important public health issue, and effective treatments to prevent fragility fractures are available. Osteoporosis imaging is of critical importance in identifying individuals at risk for fractures who would require pharmacotherapy to reduce fracture risk and also in monitoring response to treatment. Dual x-ray absorptiometry is currently the state-of-the-art technique to measure bone mineral density and to diagnose osteoporosis according to the World Health Organization guidelines. Motivated by a 2000 National Institutes of Health consensus conference, substantial research efforts have focused on assessing bone quality by using advanced imaging techniques. Among these techniques aimed at better characterizing fracture risk and treatment effects, high-resolution peripheral quantitative computed tomography (CT) currently plays a central role, and a large number of recent studies have used this technique to study trabecular and cortical bone architecture. Other techniques to analyze bone quality include multidetector CT, magnetic resonance imaging, and quantitative ultrasonography. In addition to quantitative imaging techniques measuring bone density and quality, imaging needs to be used to diagnose prevalent osteoporotic fractures, such as spine fractures on chest radiographs and sagittal multidetector CT reconstructions. Radiologists need to be sensitized to the fact that the presence of fragility fractures will alter patient care, and these fractures need to be described in the report. This review article covers state-of-the-art imaging techniques to measure bone mineral density, describes novel techniques to study bone quality, and focuses on how standard imaging techniques should be used to diagnose prevalent osteoporotic fractures.

Osteoporosis imaging: state of the art and advanced imaging

Osteoporosis is becoming an increasingly important public health issue, and effective treatments to prevent fragility fractures are available. Osteoporosis imaging is of critical importance in identifying individuals at risk for fractures who would require pharmacotherapy to reduce fracture risk and also in monitoring response to treatment. Dual x-ray absorptiometry is currently the state-of-the-art technique to measure bone mineral density and to diagnose osteoporosis according to the World Health Organization guidelines. Motivated by a 2000 National Institutes of Health consensus conference, substantial research efforts have focused on assessing bone quality by using advanced imaging techniques. Among these techniques aimed at better characterizing fracture risk and treatment effects, high-resolution peripheral quantitative computed tomography (CT) currently plays a central role, and a large number of recent studies have used this technique to study trabecular and cortical bone architecture. Other techniques to analyze bone quality include multidetector CT, magnetic resonance imaging, and quantitative ultrasonography. In addition to quantitative imaging techniques measuring bone density and quality, imaging needs to be used to diagnose prevalent osteoporotic fractures, such as spine fractures on chest radiographs and sagittal multidetector CT reconstructions. Radiologists need to be sensitized to the fact that the presence of fragility fractures will alter patient care, and these fractures need to be described in the report. This review article covers state-of-the-art imaging techniques to measure bone mineral density, describes novel techniques to study bone quality, and focuses on how standard imaging techniques should be used to diagnose prevalent osteoporotic fractures.

C-reactive protein is associated with aortic stiffness in a cohort of African American and white women transitioning through menopause

OBJECTIVE

Arterial stiffness is a marker of cardiovascular health. Arterial stiffness and C-reactive protein (CRP) are linked to cardiovascular outcomes. Increases in both inflammation and arterial stiffness are known to occur with menopause. The association between CRP and arterial stiffness is well accepted; however, no study has determined whether there are differences in this association by menopause status and race, independent of age.

METHODS

The cross-sectional association between CRP and aortic pulse wave velocity (PWV), a validated measure of central arterial stiffening, was evaluated in 307 African American and white women enrolled in an ancillary study to the Study of Women's Health Across the Nation. Women were categorized into premenopausal or early perimenopausal (n = 185) and late perimenopausal or postmenopausal (n = 122).

RESULTS

Natural log-transformed CRP was not associated with PWV in a linear regression model adjusted for age and cardiovascular risk factors (β = 15.9, P = 0.11). Moreover, models stratified by menopause status showed a linear relationship between CRP and PWV among late perimenopausal or postmenopausal women (β = 36.2, P = 0.049) but not for premenopausal or early perimenopausal women (β = 5.9, P = 0.61). The menopause status × log-transformed CRP and menopause status × race interactions were significant in their respective models adjusted for age and risk factors (P = 0.03 for both); however, when combined into one model, the two interactions were slightly attenuated (P = 0.063 and 0.052, respectively).

CONCLUSIONS

Menopause is strengthening the association between CRP and PWV, independent of age, and this effect seems to be stronger among African American women. This study provides a potential mechanism for the increased risk of cardiovascular disease among postmenopausal women.

Dual-energy X-ray absorptiometry in the evaluation of abdominal aortic calcifications

The objective of this study was to evaluate the diagnostic performance of the new dual-energy X-ray absorptiometry equipment vs digital radiography (DR) in the detection and scoring of abdominal aortic calcifications (AACs). Seventy-five patients with indication for morphometric evaluation of the spine underwent vertebral fracture assessment (VFA) and spinal DR (gold standard). The radiographic and VFA images were analyzed to detect AAC using a previously validated 24-point scale (AAC-24) and a simplified 8-point scale (AAC-8). The evaluation was conducted by 2 expert radiologists and repeated by the more experienced of the 2 after 7d to verify the results. Patients with a score of 5 or more in AAC-24 and 3 or more in AAC-8 were considered at risk for cardiovascular diseases (CVDs). The aorta was not completely visible in 11 VFA and 1 DR images. DR detected AAC in 42 of the 63 patients (66.7%), whereas 15 patients (23.8%) were considered at risk for CVD. The VFA showed sensitivity, specificity, and accuracy in the detection of AAC with values of 78.6%, 85.7%, and 81.0%, respectively, with both AAC-24 and AAC-8; in the identification of patients at risk for CVD, VFA demonstrated sensitivity, specificity, and accuracy, respectively, with values of 86.7%, 100%, and 96.8% using AAC-24 and 86.7%, 93.8%, and 92.1% using AAC-8. In the detection of AAC, intraobserver agreement was superimposable using both the techniques (κ=1.00), whereas in the identification of patients at risk for CVD, kappa values were 0.96 and 0.95 using AAC-24 and 1.00 and 0.96 using AAC-8 for DR and VFA, respectively. Interobserver agreement in the evaluation of the presence/absence of AAC showed a kappa value of 0.76 for DR and 0.71 for VFA, whereas kappa values of 0.91 and 0.87 for DR and 0.85 and 0.83 for VFA were achieved for CVD risk using AAC-24 and AAC-8, respectively. AAC can be easily and accurately diagnosed by VFA with satisfactory accuracy, reproducibility, and repeatability. VFA may be used in the assessment and monitoring of AAC.

Association between vascular calcification and osteoporosis in men with type 2 diabetes

Atherosclerotic vascular disease is common in diabetes, and some data support a link with bone loss. This study evaluates the association between osteoporosis and clinical and metabolic factors and chronic complications of diabetes. We studied 59 diabetic men aged 50-80 yr who were assessed with bone densitometry (dual-energy X-ray absorptiometry). Of them, 10.2% of the patients were found to have osteoporosis in the lumbar spine and 45.8% osteopenia, whereas in the femoral neck, 11.8% had osteoporosis and 49% had osteopenia. There was a significant association of osteoporosis in the lumbar spine L1-L4 (p=0.004) and in the femoral neck (p=0.036) with iliac artery calcification. In addition, there was no association with any other metabolic factors, clinical factors, or chronic complications of diabetes evaluated, except for an association between a previous personal history of fractures (p=0.016) and low bone mineral density in the femoral neck. In conclusion, we found a positive association between the iliac artery calcification and osteoporosis in type 2 diabetic male patients.

Lipids, menopause, and early atherosclerosis in Study of Women's Health Across the Nation Heart women

OBJECTIVE

The risk of cardiovascular disease increases after menopause. Recent evidence suggests that it is possible for high-density lipoprotein (HDL) to become proatherogenic or dysfunctional in certain situations. Our objective was to evaluate whether the relationship of HDL cholesterol (HDL-C) to subclinical cardiovascular disease differed across the menopausal transition, which would provide insight for this increased risk.

METHODS

Aortic calcification (AC), coronary artery calcification (CAC), carotid plaque, and intima media thickness (IMT) were measured in an ancillary study of the Study of Women's Health Across the Nation. Women not using hormone therapy were stratified into premenopausal or early perimenopausal (Pre/EP, n=316) and late perimenopausal or postmenopausal (LP/Post, n=224).

RESULTS

The inverse relationship of HDL-C to subclinical atherosclerosis measures among Pre/EP women was weaker or reversed among LP/Post women, adjusted for age, site, race, systolic blood pressure, glucose, body mass index, smoking, menopause status, and low-density lipoprotein cholesterol. Specifically, multivariable modeling demonstrated an inverse association between HDL-C level and AC and IMT among Pre/EP women; however, the protective effect of HDL-C for AC, left main CAC, carotid plaque, and IMT was not seen in LP/Post women. In a small subset (n=53), LP/Post women had more total and small HDL particles, higher triglyceride levels, and more total low-density lipoprotein particles compared with Pre/EP women (P<0.05).

CONCLUSIONS

These results suggest that the protective effect of HDL may be diminished as women transition in menopause. Future studies should examine whether this may be due to changes in HDL size, functionality, or related changes in other lipids or lipoproteins.

Molecular imaging insights into early inflammatory stages of arterial and aortic valve calcification

Traditional imaging modalities such as computed tomography, although perfectly adept at identifying and quantifying advanced calcification, cannot detect the early stages of this disorder and offer limited insight into the mechanisms of mineral dysregulation. This review presents optical molecular imaging as a promising tool that simultaneously detects pathobiological processes associated with inflammation and early stages of calcification in vivo at the (sub)cellular levels. Research into treatment of cardiovascular calcification is lacking, as shown by clinical trials that have failed to demonstrate the reduction of calcific aortic stenosis. Hence, the need to elucidate the pathways that contribute to cardiovascular calcification and to develop new therapeutic strategies to prevent or reverse calcification has driven investigations into the use of molecular imaging. This review discusses studies that have used molecular imaging methods to advance knowledge of cardiovascular calcification, focusing in particular on the inflammation-dependent mechanisms of arterial and aortic valve calcification.

Molecular imaging insights into early inflammatory stages of arterial and aortic valve calcification

Traditional imaging modalities such as computed tomography, although perfectly adept at identifying and quantifying advanced calcification, cannot detect the early stages of this disorder and offer limited insight into the mechanisms of mineral dysregulation. This review presents optical molecular imaging as a promising tool that simultaneously detects pathobiological processes associated with inflammation and early stages of calcification in vivo at the (sub)cellular levels. Research into treatment of cardiovascular calcification is lacking, as shown by clinical trials that have failed to demonstrate the reduction of calcific aortic stenosis. Hence, the need to elucidate the pathways that contribute to cardiovascular calcification and to develop new therapeutic strategies to prevent or reverse calcification has driven investigations into the use of molecular imaging. This review discusses studies that have used molecular imaging methods to advance knowledge of cardiovascular calcification, focusing in particular on the inflammation-dependent mechanisms of arterial and aortic valve calcification.

Is reduced bone mineral density independently associated with coronary artery calcification in subjects older than 50 years?

It has not been clearly defined whether reduced bone mineral density (BMD) is a direct risk factor of vascular calcification. A total of 2,160 subjects who were older than 50 years and underwent routine health examination at the Seoul National University Hospital Healthcare System Gangnam Center were included in this study. Coronary artery calcium scores (CACS) were calculated to quantify the extent of coronary artery calcification (CAC) using computed tomography. Bone dual-energy X-ray absorptiometry was also performed in all the subjects. BMD was classified as normal, osteopenia, or osteoporosis according to the lowest T score in the lumbar spine, femoral neck, or total hip. The mean value of CACS was 66.1 ± 234.0, and 1,372 subjects (63.5%) showed no coronary artery calcium deposits. A gender difference in the association between BMD and CACS was observed; a significant relationship was identified only in women. Unadjusted odds ratio for the presence of CAC in female subjects with reduced BMD was 1.925 (95% CI 1.383-2.679, p < 0.001). However, after adjusting for age and other risk factors, the association was no longer significant. Age, hypertension, glucose, and male gender were independent factors determining CAC in multiple regression analysis. Although reduced BMD and CAC were common findings among the elderly, the close association between them diminished after considering other factors affecting CAC.

The relationship between coronary artery calcification and bone mineral density in patients according to their metabolic syndrome status

Background and Objectives

The extent of coronary artery calcification (CAC) is closely related to total atherosclerotic plaque burden. However, the pathogenesis of CAC is still unclear. Conditions such as diabetes mellitus, renal failure, smoking, and chronic inflammation have been suggested to link vascular calcification and bone loss. In the present study, we hypothesized that bone loss can contribute to the pathogenesis of CAC in patients with the chronic inflammatory condition that accompanies metabolic syndrome (MetS). The objective of this study was to investigate the relationship between CAC and bone mineral density (BMD) in patients with MetS and in patients without MetS, by using coronary multidetector-row computed tomography (MDCT).

Subjects and Methods

Data from 395 consecutive patients was analyzed retrospectively. From the MDCT database, only those patients who underwent both coronary MDCT and dual-energy X-ray absorptiometry within an interval of one month, were selected. The presence of MetS was determined by the updated criteria as defined by the Third Adult Treatment Panel Report of the National Cholesterol Education Program.

Results

In patients with MetS, a significant correlation was found between CAC and age {odds ratio (OR)=1.139, 95% confidence interval (CI) 1.080 to 1.201, p<0.001}, CAC and male sex (OR=3.762, 95% CI 1.339 to 10.569, p=0.012), and CAC and T-score of L-spine (OR=0.740, 95% CI 0.550 to 0.996, p=0.047) using a forward multiple logistic regression analysis model including clinical variables of gender, age, lipid profile, body mass index, diabetes mellitus, hypertension, smoking, and BMD. But in patients without MetS, BMD by itself was not found to contribute to CAC.

Conclusion

BMD was inversely correlated with CAC only in patients with MetS. This finding suggests that low BMD accompanied by MetS, may have significant clinical implications.

Association between coronary artery calcification using low-dose MDCT coronary angiography and bone mineral density in middle-aged men and women

Six hundred sixty-one participants who had at least one cardiac risk factor but were without known coronary heart disease underwent low-dose multidetector computed tomography coronary angiography (MDCT-CA) and dual-energy X-ray absorptiometry. The association between presence of subclinical coronary calcified plaque and low bone mineral density for the middle-aged individual was not significant after multivariate adjustment.

INTRODUCTION

Results of previous clinical studies assessing the relationship between osteoporosis and coronary calcification are inconsistent. This study aimed to evaluate the association between subclinical coronary calcification and osteoporosis in middle-aged men, premenopausal women, and postmenopausal women by using low-dose MDCT-CA and bone mineral density (BMD).

METHODS

This study enrolled 661 participants with at least one cardiac risk factor but without known coronary artery disease (CAD). All subjects underwent low-dose MDCT-CA and dual-energy X-ray absorptiometry on the same day.

RESULTS

The mean age was 52.2 years for men, 44.8 years for premenopausal women, and 59.1 years for postmenopausal women. The prevalence of calcified plaques between men with normal BMD and low BMD at lumbar spine were significantly different (P=0.042). The prevalence of mixed plaque and calcified plaque between pre- and postmenopausal women with normal BMD and low BMD at lumbar spine and femoral neck were not significantly different (P>0.05). Possible association between lumbar spine, femoral neck, and total proximal femur BMD and the presence of CAP was evaluated for men, premenopausal women, and postmenopausal women using multivariate logistic regression analysis: results were not significant (P>0.05).

CONCLUSION

Our study demonstrates that the association between the presence of subclinical coronary calcification and low BMD among middle-aged men and women was not significant after controlling for age and other risk factors for CAD and osteoporosis.

Coronary arterial calcification and thoracic spine mineral density in early menopause

OBJECTIVES

Cardiovascular disease and osteoporosis increase in women after menopause. While aortic calcification is associated with bone loss in women, a similar relationship for coronary arterial calcification (CAC), a risk factor for coronary artery disease in women, is less clear. This study was designed to examine the relationship between CAC and volumetric bone mineral density (vBMD) in women (n=137) who were within a median of 18 months past their last menses at screening for the Kronos Early Estrogen Prevention Study (KEEPS).

METHODS

CAC was measured using 64-slice computed tomography; vBMD was measured from these images using the Spine Cancer Assessment program. Concentrations of osteocalcin, bone alkaline phosphatase, tartrate-resident acid phosphatase-5b and osteopontin as bone matrix protein in serum and plasma were evaluated by ELISA.

RESULTS

CAC scores ranged from 0 to 327.6 Agatston Units (AU); 113 women had a score of 0 AU, 20 had a CAC score between 0 and 50 AU, and four had a CAC score>50 AU. Although not statistically significant, there was a trend toward decreasing central density of thoracic T9 with increasing CAC. On average, levels of markers of bone turnover were within the normal range but did not correlate with age or with months past menopause.

CONCLUSIONS

Clinically significant CAC and spine vBMD are quantifiable from the same scans within the first 3 years of menopause. Additional work is needed to determine how these measurements change with increasing age or with estrogenic treatments.

(Sub)clinical cardiovascular disease is associated with increased bone loss and fracture risk; a systematic review of the association between cardiovascular disease and osteoporosis

Introduction

Both cardiovascular disease and osteoporosis are important causes of morbidity and mortality in the elderly. The co-occurrence of cardiovascular disease and osteoporosis prompted us to review the evidence of an association between cardiovascular (CV) disease and osteoporosis and potential shared common pathophysiological mechanisms.

Methods

A systematic literature search (Medline, Pubmed and Embase) was conducted to identify all clinical studies that investigated the association between cardiovascular disease and osteoporosis. Relevant studies were screened for quality according to guidelines as proposed by the Dutch Cochrane Centre and evidence was summarized.

Results

Seventy studies were included in this review. Due to a large heterogeneity in study population, design and outcome measures a formal meta-analysis was not possible. Six of the highest ranked studies (mean n = 2,000) showed that individuals with prevalent subclinical CV disease had higher risk for increased bone loss and fractures during follow-up compared to persons without CV disease (range of reported risk: hazard ratio (HR) 1.5; odds ratio (OR) 2.3 to 3.0). The largest study (n = 31,936) reported a more than four times higher risk in women and more than six times higher risk in men. There is moderate evidence that individuals with low bone mass had higher CV mortality rates and incident CV events than subjects with normal bone mass (risk rates 1.2 to 1.4). Although the shared common pathophysiological mechanisms are not fully elucidated, the most important factors that might explain this association appear to be, besides age, estrogen deficiency and inflammation.

Conclusions

The current evidence indicates that individuals with prevalent subclinical CV disease are at increased risk for bone loss and subsequent fractures. Presently no firm conclusions can be drawn as to what extent low bone mineral density might be associated with increased cardiovascular risk.

The Founder's Lecture 2009: advances in imaging of osteoporosis and osteoarthritis

The objective of this review article is to provide an update on new developments in imaging of osteoporosis and osteoarthritis over the past three decades. A literature review is presented that summarizes the highlights in the development of bone mineral density measurements, bone structure imaging, and vertebral fracture assessment in osteoporosis as well as MR-based semiquantitative assessment of osteoarthritis and quantitative cartilage matrix imaging. This review focuses on techniques that have impacted patient management and therapeutic decision making or that potentially will affect patient care in the near future. Results of pertinent studies are presented and used for illustration. In summary, novel developments have significantly impacted imaging of osteoporosis and osteoarthritis over the past three decades.

Arterial and aortic valve calcification inversely correlates with osteoporotic bone remodelling: a role for inflammation

AIMS

Westernized countries face a growing burden of cardiovascular calcification and osteoporosis. Despite its vast clinical significance, the precise nature of this reciprocal relationship remains obscure. We hypothesize that cardiovascular calcification progresses with inflammation and inversely correlates with bone tissue mineral density (TMD).

METHODS AND RESULTS

Arterial, valvular, and bone metabolism were visualized using near-infrared fluorescence (NIRF) molecular imaging agents, targeting macrophages and osteogenesis. We detected significant arterial and aortic valve calcification in apoE(-/-) mice with or without chronic renal disease (CRD, 30 weeks old; n = 28), correlating with the severity of atherosclerosis. We demonstrated decreases in osteogenic activity in the femurs of apoE(-/-) mice when compared with WT mice, which was further reduced with CRD. Three-dimensional micro-computed tomography imaging of the cortical and cancellous regions of femurs quantified structural remodelling and reductions in TMD in apoE(-/-) and CRD apoE(-/-) mice. We established significant correlations between arterial and valvular calcification and loss of TMD (R(2) = 0.67 and 0.71, respectively). Finally, we performed macrophage-targeted molecular imaging to explore a link between inflammation and osteoporosis in vivo. Although macrophage burden, visualized as uptake of NIRF-conjugated iron nanoparticles, was directly related to the degree of arterial and valvular inflammation and calcification, the same method inversely correlated inflammation with TMD (R(2) = 0.73; 0.83; 0.75, respectively).

CONCLUSION

This study provides direct in vivo evidence that in arteries and aortic valves, macrophage burden and calcification associate with each other, whereas inflammation inversely correlates with bone mineralization. Thus, understanding inflammatory signalling mechanisms may offer insight into selective abrogation of divergent calcific phenomena.

Chronic kidney disease bone and mineral disorder (CKD-MBD) in apolipoprotein E-deficient mice with chronic renal failure

BACKGROUND

Chronic kidney disease (CKD) is associated with disorders of mineral and bone metabolism (MBD) which include renal osteodystrophy and vascular calcifications. This is of clinical concern because the high risk of cardiovascular (CVD) complications observed in uremic patients may be linked with bone disease. In this context, our aim was to characterize the bone lesions in CKD-apolipoprotein E-deficient mice (apoE(-/-)) and analyze their relationships with the vascular calcifications which these animals develop rapidly in this model. With ApoE being also involved in bone metabolism, we compared the effects of CRF on the bone of apoE(-/-) mice to those observed in wild type mice (WT) of the same genetic background, C57/BL6.

METHODS

After CRF creation or sham surgery, 10 week-old female apoE(-/-) and WT mice were randomized to 4 groups (n=10-14/group) and fed with standard diet. Eight weeks later, animals were euthanized. Serum, aorta and femur were sampled. Femurs were imaged with 3-dimensional microtomography (microCT) and processed for bone histomorphometry (BHM). Additional quantitative histology was performed on atherosclerotic and calcified lesions in the aortas of apoE(-/-) mice.

RESULTS

First, apoE(-/-) mice exhibited higher cortical (10%) and trabecular (31%) bone mass than WT. CRF led to a further increase in trabecular BV/TV in WT and in apoE(-/-) mice (10.2% and 77.2%, respectively). We observed a similar increase in osteoid surface and osteoblastic parameters in CRF mice of both genotypes while resorption parameters were less augmented by CRF in apoE(-/-) mice. Finally, based on either BHM or microCT we found positive correlations between the extent of atherosclerotic lesions and bone volume parameters, and between the size of plaque calcification and osteoclast parameters in apoE(-/-) mice.

CONCLUSION

ApoE deficiency is associated with an increase in bone mass and volumetric mineral density in 20 week-old female mice. Bone mass is further increased, whereas bone mineral density is decreased, in response to CRF in association with histological features of osteitis fibrosa. Finally, our findings of correlations between changes in bone and aortic lesions in apoE(-/-) mice, are compatible with the hypothesis of a link between bone and vascular disease and require further study.

From estrogen-centric to aging and oxidative stress: a revised perspective of the pathogenesis of osteoporosis

Estrogen deficiency has been considered the seminal mechanism of osteoporosis in both women and men, but epidemiological evidence in humans and recent mechanistic studies in rodents indicate that aging and the associated increase in reactive oxygen species (ROS) are the proximal culprits. ROS greatly influence the generation and survival of osteoclasts, osteoblasts, and osteocytes. Moreover, oxidative defense by the FoxO transcription factors is indispensable for skeletal homeostasis at any age. Loss of estrogens or androgens decreases defense against oxidative stress in bone, and this accounts for the increased bone resorption associated with the acute loss of these hormones. ROS-activated FoxOs in early mesenchymal progenitors also divert ss-catenin away from Wnt signaling, leading to decreased osteoblastogenesis. This latter mechanism may be implicated in the pathogenesis of type 1 and 2 diabetes and ROS-mediated adverse effects of diabetes on bone formation. Attenuation of Wnt signaling by the activation of peroxisome proliferator-activated receptor gamma by ligands generated from lipid oxidation also contributes to the age-dependent decrease in bone formation, suggesting a mechanistic explanation for the link between atherosclerosis and osteoporosis. Additionally, increased glucocorticoid production and sensitivity with advancing age decrease skeletal hydration and thereby increase skeletal fragility by attenuating the volume of the bone vasculature and interstitial fluid. This emerging evidence provides a paradigm shift from the "estrogen-centric" account of the pathogenesis of involutional osteoporosis to one in which age-related mechanisms intrinsic to bone and oxidative stress are protagonists and age-related changes in other organs and tissues, such as ovaries, accentuate them.