The association between low bone mass at the menopause and cardiovascular mortality

Effect of alendronate on vascular calcification in CKD stages 3 and 4: a pilot randomized controlled trial

BACKGROUND

Vascular calcification contributes to cardiovascular disease in patients with chronic kidney disease (CKD). Few studies have addressed interventions to decrease vascular calcification; however, experimental studies report benefits of bisphosphonates. Recent studies of hemodialysis patients also suggest benefits of bisphosphonates on vascular calcification; however, no study exists in nondialysis patients with CKD.

STUDY DESIGN

We conducted a randomized controlled trial to determine the effect of bisphosphonates on vascular calcification in patients with CKD.

SETTING & PARTICIPANTS

51 patients with CKD stages 3-4 were recruited from a hospital outpatient setting; 50 were treated with study medication.

INTERVENTIONS

Patients were randomly assigned to either alendronate, 70 mg (n = 25), or matching placebo (n = 25), administered weekly.

OUTCOMES

The primary outcome was change in aortic vascular calcification after 18 months. Secondary outcomes included superficial femoral artery vascular calcification, arterial compliance, bone mineral density (BMD), renal function, and serum markers of mineral metabolism.

MEASUREMENTS

At baseline and 12 and 18 months, computed tomography, pulse wave velocity using SphygmoCor (AtCor Medical, PWV Inc, www.atcormedical.com), and dual-energy x-ray absorptiometry were performed to measure vascular calcification, arterial compliance, and BMD, respectively. Analysis was by intention to treat, with a random-effect linear regression model to assess differences.

RESULTS

46 patients completed the study (24 alendronate, 22 placebo); baseline mean age was 63.1 +/- 1.8 years, estimated glomerular filtration rate was 34.5 +/- 1.4 mL/min/1.73 m(2), 59% had diabetes, and 65% were men. 91% had aortic vascular calcification at the start and 78% showed progression. At 18 months, there was no difference in vascular calcification progression with alendronate compared with placebo (adjusted difference, -24.2 Hounsfield units [95% CI, -77.0 to 28.6]; P = 0.4). There was an increase in lumbar spine BMD (T score difference, +0.3 [95% CI, 0.03-0.6]; P = 0.04) and a trend toward better pulse wave velocity (-1 m/s [95% CI, -2.1 to 0.1]; P = 0.07) with alendronate. Femoral BMD was similar between groups. There was a nonsignificant decrease in kidney function in patients on alendronate therapy compared with placebo (-1.2 mL/min/1.73 m(2) [95% CI, -4.0 to 1.7]).

LIMITATIONS

Small sample size and baseline differences, especially with aortic vascular calcification, may have diminished any potential difference between groups.

CONCLUSIONS

Unlike previous studies of hemodialysis patients, alendronate did not decrease the progression of vascular calcification compared with placebo in patients with CKD during 18 months.

Genetic determinants of osteoporosis: common bases to cardiovascular diseases?

Osteoporosis is the most common and serious age-related skeletal disorder, characterized by a low bone mass and bone microarchitectural deterioration, with a consequent increase in bone fragility and susceptibility to spontaneous fractures, and it represents a major worldwide health care problem with important implications for health care costs, morbidity and mortality. Today is well accepted that osteoporosis is a multifactorial disorder caused by the interaction between environment and genes that singularly exert modest effects on bone mass and other aspects of bone strength and fracture risk. The individuation of genetic factors responsible for osteoporosis predisposition and development is fundamental for the disease prevention and for the setting of novel therapies, before fracture occurrence. In the last decades the interest of the Scientific Community has been concentrated in the understanding the genetic bases of this disease but with controversial and/or inconclusive results. This review tries to summarize data on the most representative osteoporosis candidate genes. Moreover, since recently osteoporosis and cardiovascular diseases have shown to share common physiopathological mechanisms, this review also provides information on the current understanding of osteoporosis and cardiovascular diseases common genetic bases.

Bone mineral density and prediction of non-osteoporotic disease

It is widely recognized that bone mineral density (BMD) is one of the best predictors of osteoporotic fractures. Sex hormone status clearly affects bone either directly or indirectly and a longer estrogen exposure appears to be a major determinant of postmenopausal BMD. Accordingly, several studies have led to the hypothesis that BMD might represent a marker of the accumulated lifetime exposure of estrogen and therefore be used as a predictor factor of the risk of other postmenopausal conditions such as breast cancer or cardiovascular diseases (CVD). With regard to the risk of breast cancer, there is evidence that different surrogate markers of lifetime exposure to estrogen are associated with an increased risk for breast cancer. Most of these markers are the opposite of those for the risk of fracture. Furthermore, several studies have also reported that women with higher BMD have an increased risk of breast cancer compared to women with lower BMD. On the other hand, postmenopausal women with osteoporosis are at increased risk for acute cardiovascular events and mortality independently of age and cardiovascular risk factors. BMD has been shown to inversely correlate with surrogate markers of CVD including aortic calcifications and atherosclerosis. The underlying mechanisms of such a relationship are not fully understood. Several plausible molecular links are serum lipids, pro-inflammatory cytokines or the RANK/RANK ligand/osteoprotegerin system. Interestingly, all of these factors are modulated by estrogens. It could thus be hypothesized that the intensity of postmenopausal estrogen deficiency could be also the common pathogenic factor between atherosclerosis and osteoporosis.

Associations between vascular calcification, arterial stiffness and bone mineral density in chronic hemodialysis patients

AIM

The aim of our study was to examine the associations between vascular calcification, arterial stiffness and bone mineral density (BMD) in chronic hemodialysis (HD) patients.

METHODS

The study subjects were 83 (70 men and 13 women) HD patients. All patients had computed tomography (CT) to determine aortic calcification index (ACI), pulse wave velocity (PWV) using a volume-plethysmographic apparatus, and BMD estimated by digital image processing (DIP).

RESULTS

Patients, 84.3% male, 38.6% diabetic, had a mean age of 59.3 +/- 11.2 years. In univariate linear regression analysis, ACI correlated positively with age (r = 0.586, P < 0.0001), dialysis vintage (r = 0.47, P = 0.002), pulse pressure (r = 0.311, P = 0.004), C-reactive protein (CRP) (r = 0.226, P = 0.0397) and PWV (r = 0.422, P < 0.0001). There was no significant association between ACI and serum markers of mineral metabolism. There was also a positive association between PWV and systolic blood pressure (P = 0.0004) or pulse pressure (P < 0.0001), and a trend towards greater PWV with increasing age (r = 0.494). In multivariate regression analysis only increasing age, pulse pressure, serum levels of albumin and CRP were significantly associated with ACI and PWV. Mean BMD on DIP was 2.7 +/- 0.4 mmAL. ACI was inversely correlated with BMD (r = -0.234, P = 0.0331).

CONCLUSIONS

Vascular calcification is closely associated with arterial stiffness in HD patients. BMD is inversely correlated with ACI, suggesting that measurement of hand BMD by DIP is a useful tool for assessment of renal bone disease in these patients.

Fasudil hydrochloride induces osteoblastic differentiation of stromal cell lines, C3H10T1/2 and ST2, via bone morphogenetic protein-2 expression

Rho-kinase (ROK), downstream of the mevalonate pathway, is detrimental to vessels, and suppressing its activity is a target for the treatment of human disease such as coronary artery disease and pulmonary hypertension. Recent studies have shown that ROK has a crucial role in bone metabolism. However, the role of ROK in stromal cells is still unclear. The present study was undertaken to investigate the effect of a ROK inhibitor, fasudil hydrochloride, on stromal cell lines, C3H10T1/2 and ST2. In both cells, Fasudil significantly stimulated alkaline phosphatase activity and enhanced cell mineralization. Moreover, fasudil significantly increased the mRNA expression of collagen-I, osteocalcin, and bone morphogenetic protein-2 (BMP-2). Supplementation of noggin, a BMP-2 antagonist, significantly reversed the fasudil-induced collagen-I and osteocalcin mRNA expression in both cells. These findings suggest that fasudil induces the osteoblastic differentiation of stromal cells via enhancing BMP-2 expression, and that this drug might be beneficial for not only atherosclerosis but also osteoporosis by promoting bone formation.

Low bone mineral density at femoral neck is a predictor of increased mortality in elderly Japanese women

This study aimed to determine whether low bone mineral density (BMD) at the femoral neck independently predicts all-cause mortality in elderly Japanese women. A prospective cohort study of 271 women aged 67-89 years was conducted. A Cox proportional hazard model was used to examine independent associations between BMD and total mortality. During a 12-year follow-up period, the mortality risk (as measured by hazard ratio [HR]) was significantly increased in the three categories of baseline BMD (diagnostic criteria of osteoporosis, tertile of BMD, and quartile of BMD). After adjusting for major potential confounding variables for mortality, significantly increased mortality risks were found in subjects with osteoporosis (HR = 2.17, p = 0.032), in subjects in the lowest tertile (HR = 2.57, p = 0.007), and in subjects in the lowest quartile (HR = 3.13, p = 0.014], respectively. Our findings suggest that preventive strategies should be considered to increase and maintain high BMD at the femoral neck in the elderly women not only to prevent hip fractures but also probably to reduce mortality risk.

INTRODUCTION

Several longitudinal studies with Caucasian subjects have suggested that osteoporosis is associated with increased mortality. This study aimed to determine whether low bone mineral density (BMD) at the femoral neck independently predicts all-cause mortality in elderly Japanese community-dwelling women.

METHOD

A prospective cohort study of 271 women aged 67-89 years was conducted. A Cox proportional hazard model was used to examine independent associations between BMD at both the femoral neck and the trochanter and total mortality.

RESULTS

During a 12-year follow-up period, 81 of 271 women (29.9%) died. An independent and significant relationship was found between baseline BMD at the femoral neck and mortality risk. The mortality risk (as measured by HR) was increased by 2.80-fold (95% confidence interval [CI] 1.55-5.06; p < 0.01) in the subjects with osteoporosis or by 2.94-fold (95% CI 1.64-5.26; p < 0.001) in subjects in the lowest tertile or by 3.61-fold (95% CI 1.77-7.41; p < 0.001) in subjects in the lowest quartile of BMD, respectively. After adjusting for major potential confounding factors for mortality such as age, body mass index, blood pressure, blood variables, medical history, alcohol drinking, and smoking status, those in the subjects with osteoporosis (HR = 2.17 [95% CI 1.07-4.41], p = 0.032), in the lowest tertile (HR = 2.57 [95% CI 1.29-5.15], p = 0.007), or in the lowest quartile (HR = 3.13 [95% CI 1.26-7.73], p = 0.014] had a significantly increased risk of mortality. BMD measurement at the trochanter showed similar but weaker results.

CONCLUSIONS

Our findings suggest that preventive strategies should be considered to increase and maintain high BMD at the femoral neck in elderly subjects not only to prevent osteoporosis and its associated fractures but also probably to reduce mortality risk.

Bone mineral density, arterial stiffness, and coronary atherosclerosis in healthy postmenopausal women

OBJECTIVE

The aim of this study was to assess the correlation between bone mineral density (BMD), arterial stiffness, and coronary atherosclerosis in healthy postmenopausal women.

METHODS

We performed a retrospective review of 152 postmenopausal women who visited the health promotion center for a routine checkup, after excluding participants who had factors affecting BMD and coronary artery disease. BMD was evaluated by dual-energy x-ray absorptiometry in the lumbar spine and femur. Arterial stiffness was measured by brachial-ankle pulse wave velocity (baPWV), and coronary atherosclerosis was assessed by 64-row multidetector computed tomography.

RESULTS

Women with osteoporosis had a significantly higher baPWV than those in the osteopenia and normal BMD groups. Higher baPWV was also associated with the presence of atherosclerosis. The baPWV was significantly positively correlated with age, systolic blood pressure, diastolic blood pressure, and neutrophil to lymphocyte ratio and negatively correlated with femur BMD. The optimum predictive value of baPWV in coronary atherosclerosis was estimated using the receiver operating characteristic curve. A cutoff of 1,506 cm/second would give a sensitivity of 83.3% and specificity of 82.9%. A higher overall risk for coronary atherosclerosis emerges with higher baPWV levels (>1,500 cm/s) after controlling for age and cardiovascular risk factors.

CONCLUSIONS

Arterial stiffness by measuring baPWV can be a useful independent predictor for coronary atherosclerosis. In addition, our results suggest that postmenopausal women with osteoporosis should be considered for further evaluation of coronary atherosclerosis.

Association between low bone mass and aortic valve sclerosis in Koreans

BACKGROUND

Osteoporosis or low bone mass has been associated with cardiovascular disease and calcification in several clinical studies. However, few studies have assessed the relationship between bone mass and valvular calcification. The aim of this study was to evaluate the relationship between low bone mass and aortic valve sclerosis in Korean men and women.

METHODS

A total of 211 men and 117 women were included in this study. Each subject's bone mineral density (BMD) was measured with dual-energy X-ray absorptiometry, and aortic valve sclerosis was assessed using transthoracic echocardiography. Association between low bone mass and aortic valve sclerosis was assessed with multivariate logistic regression analysis in this cross-sectional study.

RESULTS

Of 328 total subjects enrolled in this study, 50 men (23.7%) and 18 women (15.4%) were found to have aortic valve sclerosis. The mean (+/-SD) BMD T-scores were -0.5 (+/-0.8) in men and -0.9 (+/-1.0) in women. After adjusting for covariates, only women with aortic valve sclerosis had significantly lower BMD T-scores than those without it. Multivariate logistic regression analysis showed that age, smoking and hypertension were independently associated with increased risk of aortic valve sclerosis in men. In women, however, logistic regression analysis showed that BMD T-score, as well as age, was an independent variable for aortic valve sclerosis. We also found that a T-score of less than -1.5 was significantly associated with increased risk of aortic valve sclerosis in women compared to normal T-scores.

CONCLUSION

Low bone mass might be independently associated with increased risk of aortic valve sclerosis in women, but not in men. Women with low bone mass should be further evaluated for the presence of aortic valve sclerosis and related cardiovascular diseases.

Lower bone mineral density is associated with higher coronary calcification and coronary plaque burdens by multidetector row coronary computed tomography in pre- and postmenopausal women

OBJECTIVES

There is growing evidence for the association between bone mineral density (BMD) and vascular calcification, which is related to cardiovascular disease. Coronary multidetector row computed tomography (MDCT) is a noninvasive tool developed to evaluate coronary status precisely. We used MDCT to evaluate this association.

DESIGN AND PATIENTS

Eight hundred and fifteen subjects received routine checkups. After excluding subjects with factors affecting bone metabolism and cardiovascular disease, 467 subjects were analysed.

MEASUREMENTS

Coronary calcification was measured with MDCT and BMD was measured with dual X-ray absorptiometry (DXA).

RESULTS

The BMD of the femur and the lumbar spine (L-spine) were negatively associated with the coronary calcium score (CCS) after adjusting for age in women but not in men. This inverse correlation was stronger in women with a longer time since menopause (r = -0.35 at femur, postmenopausal women vs. r = -0.10 at femur, premenopausal women, P < 0.05), and it was stronger at the femur than in the L-spine (r = -0.35 at femur vs. r = -0.16 at L-spine, P < 0.01). The relationship was also stronger in postmenopausal women with osteoporosis and osteopaenia than in women with normal BMD. The lower BMD was associated with higher coronary plaque burdens and multidiseased coronary vessels in both men and women (P < 0.01).

CONCLUSIONS

Increased CCS and subclinical atherosclerosis of plaque burdens as revealed by MDCT was associated with a low BMD in all women, independent of cardiovascular risk factors and age.

Low bone mineral density is related to atherosclerosis in postmenopausal Moroccan women

BACKGROUND

Some studies have implicated several possible metabolic linkages between osteoporosis and vascular calcification, including estrogen deficiency, vitamin D excess, vitamin K deficiency and lipid oxidation products. Nevertheless, it remains unclear whether osteoporosis and atherosclerosis are related to each other or are independent processes, both related to aging. The aim of this cross-sectional study was to evaluate the correlation between arterial thickening and bone status in a sample of apparently healthy Moroccan women.

METHODS

Seventy-two postmenopausal women were studied. All patients were without secondary causes that might affect bone density. Bone status was assessed by bone mineral density (BMD) in lumbar spine and all femoral sites. Arterial wall thickening was assessed by intima-media thickness (IMT) in carotid artery (CA) and femoral artery (FA). Prevalent plaques were categorized into four groups ranging from low echogenicity to high echogenicity.

RESULTS

The mean age was 59.2 +/- 8.3 years. 84.7% had at least one plaque. By Spearman Rank correlation, CA IMT was negatively correlated to Femoral total BMD (r = -0.33), Femoral neck BMD (r = -0.23), Ward triangle BMD (r = -0.30) and Trochanter BMD (r = -0.28) while there was no association with lumbar BMD. In multiple regression analysis, CA IMT emerged as an independent factor significantly associated with all femoral sites BMD after adjusting of confounding factors. FA IMT failed to be significantly associated with both Femoral and Lumbar BMD. No significant differences between echogenic, predominantly echogenic, predominantly echolucent and echolucent plaques groups were found concerning lumbar BMD and all femoral sites BMD CONCLUSION: Our results demonstrate a negative correlation between bone mineral density (BMD) qnd carotid intima-media thickness (IMT) in postmenopausal women, independently of confounding factors. We suggest that bone status should be evaluated in patients with vascular disease to assess whether preventive or therapeutic intervention is necessarry.

Postmenopausal women with osteoporosis may be associated with high endothelin-1

AIM

We aimed to find out if there was any difference of the endothelin-1 (ET-1) and asymmetric dimethylarginine (ADMA) levels between osteoporotic and non-osteoporotic healthy postmenopausal women and whether there were any associations between ET-1 and ADMA levels and bone mineral density (BMD).

METHODS

A total of 75 healthy postmenopausal women were enrolled in the study. BMD was measured at lumbar spine (LS) and femur neck (FN). Serum ET-1 and ADMA levels were measured by ELISA. In this population, 41 (54%) women had BMD t-scores > or = 2.5 at the LS and/or FN defined as osteoporosis and 34 (46%) of them had normal BMDs (non-osteoporotic group).

RESULTS

The mean value of ET-1 serum level in patients was 0.42 +/- 0.30, 0.28 +/- 0.12 fmol/ml in osteoporotic and non-osteoporotic groups, respectively (p = 0.018). In non-osteoporotic group, there was an only significant positive correlation was found between BMD (g/cm(2)) and total t-scores at the lumbar region and ET-1 level. In osteoporotic group, no correlation was found between BMD and total t-scores and ET-1 levels. Serum ADMA level was not significantly different between osteoporotic and non-osteoporotic postmenopausal women (p > 0.05).

CONCLUSIONS

ET-1 may be a physiologic regulator in non-osteoporotic healthy postmenopausal women. Osteoporotic postmenopausal women had higher ET-1 levels than non-osteoporotic postmenopausal women. ADMA seems not to have effect on bone in postmenopausal women.

Bone mineral density and atherosclerosis: the Multi-Ethnic Study of Atherosclerosis, Abdominal Aortic Calcium Study

CONTEXT

Molecular and cell biology studies have demonstrated an association between bone and arterial wall disease, but the significance of a population-level association is less clear and potentially confounded by inability to account for shared risk factors.

OBJECTIVE

To test population-level associations between atherosclerosis types and bone integrity.

MAIN OUTCOME MEASURES

Volumetric trabecular lumbar bone mineral density (vBMD), ankle-brachial index (ABI), intima-media thickness (IMT) of the common carotid (CCA-IMT) and internal carotid (ICA-IMT) arteries, and carotid plaque echogenicity.

DESIGN, SETTING AND PARTICIPANTS

A random subset of participants from the Multi-Ethnic Study of Atherosclerosis (MESA) assessed between 2002 and 2005.

RESULTS

904 post-menopausal female (62.4 years; 62% non-white; 12% ABI <1; 17% CCA-IMT >1mm; 33% ICA-IMT >1mm) and 929 male (61.4 years; 58% non-white; 6% ABI <1; 25% CCA-IMT >1mm; 40% ICA-IMT >1mm) were included. In serial, sex-specific regression models adjusting for age, ethnicity, body mass index, dyslipidemia, hypertension, smoking, alcohol consumption, diabetes, homocysteine, interleukin-6, sex hormones, and renal function, lower vBMD was associated with lower ABI in men (p for trend <0.01) and greater ICA-IMT in men (p for trend <0.02). CCA-IMT was not associated with vBMD in men or women. Carotid plaque echogenicity was independently associated with lower vBMD in both men (trend p=0.01) and women (trend p<0.04). In all models, adjustment did not materially affect results.

CONCLUSIONS

Lower vBMD is independently associated with structural and functional measures of atherosclerosis in men and with more advanced and calcified carotid atherosclerotic plaques in both sexes.

Oxidized lipids enhance RANKL production by T lymphocytes: implications for lipid-induced bone loss

Osteoporosis is a systemic disease that is associated with increased morbidity, mortality and health care costs. Whereas osteoclasts and osteoblasts are the main regulators of bone homeostasis, recent studies underscore a key role for the immune system, particularly via activation-induced T lymphocyte production of receptor activator of NFkappaB ligand (RANKL). Well-documented as a mediator of T lymphocyte/dendritic cell interactions, RANKL also stimulates the maturation and activation of bone-resorbing osteoclasts. Given that lipid oxidation products mediate inflammatory and metabolic disorders such as osteoporosis and atherosclerosis, and since oxidized lipids affect several T lymphocyte functions, we hypothesized that RANKL production might also be subject to modulation by oxidized lipids. Here, we show that short term exposure of both unstimulated and activated human T lymphocytes to minimally oxidized low density lipoprotein (LDL), but not native LDL, significantly enhances RANKL production and promotes expression of the lectin-like oxidized LDL receptor-1 (LOX-1). The effect, which is also observed with 8-iso-Prostaglandin E2, an inflammatory isoprostane produced by lipid peroxidation, is mediated via the NFkappaB pathway, and involves increased RANKL mRNA expression. The link between oxidized lipids and T lymphocytes is further reinforced by analysis of hyperlipidemic mice, in which bone loss is associated with increased RANKL mRNA in T lymphocytes and elevated RANKL serum levels. Our results suggest a novel pathway by which T lymphocytes contribute to bone changes, namely, via oxidized lipid enhancement of RANKL production. These findings may help elucidate clinical associations between cardiovascular disease and decreased bone mass, and may also lead to new immune-based approaches to osteoporosis.

Analysis of skeletal status by quantitative ultrasonometry in a cohort of postmenopausal women with high blood cholesterol without documented osteoporosis

Osteoporosis and atherosclerosis are leading causes of mortality and morbidity in the Western world. A link between osteoporosis and atherosclerosis was proposed by epidemiologic and laboratory data. In the present study, we investigated skeletal status in postmenopausal women with hypercholesterolemia using quantitative ultrasonometry (QUS). Six hundred healthy postmenopausal subjects were enrolled within a 2-mo period by primary care physicians. Information on lifestyle and calcium intake was collected for each enrolled subject. Subjects (n = 256) were divided into two groups according to lipid profile: normal (n = 180) with serum cholesterol <200 mg/dL and hypercholesterolemic (n = 76) with serum cholesterol >or=200 mg/dL. Hypercholesterolemic subjects were further stratified into two groups, one receiving dietary treatment (n = 34) and the other receiving statin treatment (n = 42). We found a statistically significant reduction in amplitude dependent speed of sound (AD-SoS) in hypercholesterolemic subjects compared with subjects with normal cholesterol (p = 0.006). Calcium intake behaved similarly to AD-SoS (p = 0.0001). No statistical significant difference in AD-SoS were observed between the group on diet treatment versus the group on statin (p = 0.52). Calcium intake was lower in patients on statins treatment compared with subjects on diet treatment only (p < 0.0001). Our data suggest that hypercholesterolemia per se is a risk factor for impaired skeletal status. Our data also call attention to the risk of a poor calcium intake in patient receiving diet to lower plasma cholesterol. Moreover, our data suggest that statins per se may exert a protective effect on bone independently from calcium intake.

Relation of bisphosphonate therapies and risk of developing atrial fibrillation

Bisphosphonates comprise the most common treatment for patients with osteoporosis and fracture risk. Large randomized trials have shown that these therapies may increase the risk of atrial fibrillation (AF). Controversy over the arrhythmia risk prompted the Federal Drug Administration to recently pursue an ongoing safety review to determine the cardiac risk across the entire drug class. Study patients came from 2 large prospective databases (ongoing registry of consecutive patients who underwent coronary angiography and the Intermountain Healthcare health plans database). Medical details regarding bisphosphonate use and cardiovascular risk factors were abstracted from the records. End points included AF, myocardial infarction, and death. In the angiographic database (n = 9,623), patients treated with bisphosphonates were older and more likely to have hypertension, a previous myocardial infarction, heart failure, and osteoporosis. Over 1,481 +/- 1,024 days we found no increased risk of AF in the drug-treated group (hazard ratio 0.90, 95% confidence interval 0.48 to 1.68, p = 0.74). In the Intermountain Healthcare health plans database (n = 37,485), patients treated with bisphosphonates were older and were more likely to have hyperlipidemia and osteoporosis. Over 1,667.5 +/- 557.0 days, there was no increased risk of AF (hazard ratio 0.82, 95% confidence interval 0.66 to 1.01, p = 0.63). In the 2 databases there was no statistical difference in long-term rates of myocardial infarction or mortality. In conclusion, in a long-term study of >47,000 patients, we were unable to find an association between bisphosphonate therapy and AF. However, patients who received bisphosphonates were older and had more cardiovascular disease that we suspect accounts for the increased arrhythmia risk reported in other trials.

Calcium plus vitamin D supplementation and mortality in postmenopausal women: the Women's Health Initiative calcium-vitamin D randomized controlled trial

BACKGROUND

Calcium and vitamin D (CaD) supplementation trials including the Women's Health Initiative (WHI) trial of CaD have shown nonsignificant reductions in total mortality. This report examines intervention effects on total and cause-specific mortality by age and adherence.

METHODS

The WHI CaD trial was a randomized, double-blind, placebo-controlled trial that enrolled 36,282 postmenopausal women aged 51-82 years from 40 U.S. clinical centers. Women were assigned to 1,000 mg of elemental calcium carbonate and 400 IU of vitamin D(3) daily or placebo with average follow-up of 7.0 years.

RESULTS

The hazard ratio (HR) for total mortality was 0.91 (95% confidence interval [CI], 0.83-1.01) with 744 deaths in women randomized to CaD versus 807 deaths in the placebo group. HRs were in the direction of reduced risk but nonsignificant for stroke and cancer mortality, but near unity for coronary heart disease and other causes of death. HRs for total mortality were 0.89 in the 29,942 women younger than 70 years (95% CI, 0.79-1.01) and 0.95 in the 6,340 women aged 70 and older (95% CI, 0.80-1.12; p value for age interaction = .10). No statistically significant interactions were observed for any baseline characteristics. Treatment effects did not vary significantly by season.

CONCLUSIONS

In the WHI CaD trial, supplementation did not have a statistically significant effect on mortality rates but the findings support the possibility that these supplements may reduce mortality rates in postmenopausal women. These data can neither support nor refute recommendations for higher dose vitamin D supplementation to reduce cancer or total mortality.

Oxidative stress, free radicals and bone remodeling

Reactive oxygen species (ROS) are widely considered to be a causal factor in aging and in a number of pathological conditions, such as atherosclerosis, carcinogenesis and infarction. Their role in bone metabolism is dual, considering their effects under physiological or pathological conditions. Under physiological conditions, the production of ROS by osteoclasts helps accelerate destruction of calcified tissue, thus assisting in bone remodeling. In pathological conditions, when a bone fractures, e.g., radical generation is remarkably high. However, though the increases in osteoclastic activity and ROS production are linked in many skeletal pathologies, it remains to be clarified whether increased ROS production overwhelms antioxidant defenses, leaving the individual open to hyperoxidant stress.

Association between serum cholesterol and bone mineral density

BACKGROUND

Hypercholesterolaemia has been associated with low bone mineral density (BMD) in some but not all studies.

OBJECTIVES

To examine the influence of age, menopausal status and hormone replacement therapy (HRT) on the relationship between serum cholesterol and BMD in women.

PATIENTS AND MEASUREMENTS

497 female participants (age range 20-81) comprising 224 premenopausal and 273 postmenopausal women (156 on HRT and 117 no HRT) underwent measurements of bone mineral density (BMD) and serum lipid profile.

RESULTS

Total serum cholesterol (TC) and low density lipoprotein (LDL) levels were higher and lumbar spine BMD was lower in postmenopausal women not taking HRT compared to those taking HRT. TC and LDL were negatively associated with BMD at all measured sites among postmenopausal women not taking HRT in univariate regression analysis (all p<0.05). High density lipoprotein (HDL) had inverse relationships with BMD at all sites in pre-menopausal women and those who were exposed to HRT (p<0.05). In fully adjusted regression models the relationships between TC and BMD remained significant at the lumbar spine and whole body (p<0.05) and between LDL and lumbar spine BMD only (p<0.05). For subjects in the other groups, no significant associations between TC or LDL and BMD were found. Significant interactions between total cholesterol and LDL levels with HRT were detected among post-menopausal women in the regression analyses (all p<0.05). No such interactions were found between HDL levels and HRT.

CONCLUSION

There is a modest inverse relationship between lumbar spine and whole body BMD and serum TC and LDL levels and in post-menopausal women and HDL in pre-menopausal women. HRT use appears to modify these relationships. The mechanisms of this relationship require further study.

Relationship between bone quantitative ultrasound and mortality: a prospective study

In a cohort of 5,201 women [72.3 +/- 5.3 years] from 58 primary care centers in Spain, followed for three years, no relationship between heel QUS parameters and overall mortality was found. However, a significant relationship between a low speed of sound (SOS) and vascular mortality was observed.

INTRODUCTION

An inverse relationship between mortality and bone mineral density measured by dual-energy absorption densitometry or quantitative bone ultrasound (QUS) has been described. The aim of the present study was to test this relationship in the ECOSAP cohort, a 3-year prospective study designed to assess the ability of heel QUS and clinical risk factors to predict non-vertebral fracture risk in women over 64.

METHODS

A cohort of 5,201 women [72.3 +/- 5.3 years] was studied. QUS was assessed with the Sahara(R) bone sonometer. Women attended follow-up visits every 6 months. Physicians recorded if the patient died and cause of death. Hazard rates (HR) of all-cause and vascular mortality per one standard deviation reduction in QUS parameters were determined.

RESULTS

One hundred (1.9%) women died during a median of 36.1 months follow-up, for a total of 14,999 patient-years, 42 because of vascular events (both cardiovascular and cerebrovascular). After adjusting for age, none of the QUS variables showed statistically significant differences between the patients who died and the survivors. In the final multivariate model, adjusted for age, current thyroxine and hypoglycaemic drug use, chronic obstructive pulmonary disease and decreased visual acuity, SOS was marginally non-significant: (HR: 1.19; 0.97-1.45). However, each 1 SD reduction in SOS was associated with a 39% increase in vascular mortality (HR: 1.39; 1.15-1.66).

CONCLUSIONS

In our cohort, SOS was related with vascular mortality, but not overall mortality.

Atherosclerosis and osteoporosis: age-dependent degenerative processes or related entities?

Osteoporosis and atherosclerosis, two multifactorial and degenerative entities, are major public health problems. These diseases accompany the aging process and share common risk factors. Furthermore, several common pathophysiological factors have been suggested. These include similar molecular pathways involving bone and vascular mineralization, estrogen deficiency, parathyroid hormone, homocysteine, lipid oxidation products, inflammatory process, as well as vitamin D and K. Moreover, the use of statins, biphosphonates, beta-blockers and experimental dual-purpose therapies based on the biological linkage of the above entities may simultaneously benefit bone loss and vascular disease. This review considers a potential link between osteoporosis and atherosclerosis beyond aging. These common factors may lead to appropriate treatment strategies.

Safety of bisphosphonates in the treatment of osteoporosis

In this review 4 experts consider the major safety concerns relating to bisphosphonate therapy for osteoporosis. Specific topics covered are skeletal safety (particularly with respect to atypical fractures and delayed healing), gastrointestinal intolerance, hypocalcemia, acute-phase (i.e., postdose) reactions, chronic musculoskeletal pain, renal safety, and cardiovascular safety (specifically, atrial fibrillation).

Can self-rated health identify US women and men with low bone mineral density? A cross-sectional population study

BACKGROUND

Despite its simplicity, self-rated health (SRH) is a significant dimension of health assessment, with demonstrated means to identify individuals at increased risk of morbidity and mortality.

OBJECTIVE

The aim of the present study was to assess whether SRH, age, and modifiable osteoporosis risk factors in a hypothetical screening situation could identify individuals with low bone mineral density (BMD).

METHODS

Data were analyzed from a multiethnic sample of 4905 women and men aged 50 to 79 years from the Third National Health and Nutrition Examination Survey. Low BMD was assessed according to the World Health Organization definition using gender- and race/ethnicity-specific young adult mean values to calculate T-scores. Multiple linear regression analysis was used to determine whether BMD was lower among those with poorer SRH; multiple logistic regression analysis was used to determine whether poor SRH was associated with low BMD.

RESULTS

The study population included 616 and 589 African American; 522 and 564 Mexican American; and 1312 and 1302 white women and men, respectively. The distributions of SRH responses differed for African American and Mexican American women and men compared with the distributions for same-gender whites, with significantly more white women and men reporting excellent or very good health (P < 0.05) and significantly greater proportions of African American and Mexican American women and men reporting poorer health (P < 0.05). Among women and nonwhite men, there was no evidence of an association between BMD and SRH. Linear trends of decreasing BMD with declining SRH were detected for all men with low or normal body mass index (P < 0.001) and overweight men (P < 0.001). When stratified by race/ethnicity, a linear trend of decreasing BMD with declining SRH was found for nonobese white men only (P-trend: <0.001). The likelihood of having low BMD among nonobese white men who reported excellent or very good health was two-thirds that of their male counterparts with poor SRH (P < 0.001).

CONCLUSIONS

Independent of age and modifiable osteoporosis risk factors, poor SRH may be a relevant risk factor for low BMD among older nonobese white men. Further research is needed to determine whether SRH may be a useful risk assessment tool for low BMD in this group of men.

Body mass index and risk of adverse cardiac events in elderly patients with hip fracture: a population-based study

OBJECTIVES

To determine whether obesity affects cardiac complications after hip fracture repair.

DESIGN

A population-based historical study using data from the Rochester Epidemiology Project.

SETTING

Olmsted County, Minnesota.

PARTICIPANTS

All urgent hip fracture repairs between 1988 and 2002.

MEASUREMENTS

Body mass index (BMI) was categorized as underweight (<18.5 kg/m(2)), normal-weight (18.5-24.9 kg/m(2)), overweight (25.0-29.9 kg/m(2)), and obese (>or=30 kg/m(2)). Postoperative cardiac complications were defined as myocardial infarction, angina pectoris, congestive heart failure, or new-onset arrhythmias within 1-year of surgery. Incidence rates were estimated for each outcome, and overall cardiac complications were assessed using Cox proportional hazards models adjusted for age, sex, year of surgery, use of beta-blockers, and the Revised Cardiac Risk Index.

RESULTS

Hip fracture repairs were performed in 184 (15.6%) underweight, 640 (54.2%) normal-weight, 251 (21.3%) overweight, and 105 (8.9%) obese subjects (mean age 84.2 +/- 7.5; 80% female). Baseline American Society of Anesthesiologists (ASA) status was similar in all groups (ASA I/II vs III-V, P=.14). Underweight patients had a significantly higher risk of developing myocardial infarction (odds ratio (OR) 1.44, 95% confidence interval (CI)=1.0-2.1; P=.05) and arrhythmias (OR=1.59, 95% CI=1.0-2.4; P=.04) than normal-weight patients. Multivariate analysis demonstrated that underweight patients had a higher risk of developing an adverse cardiac event of any type (OR=1.56, 95% CI=1.22-1.98; P<.001). Overweight and obese patients with hip fracture had no excess risk of any cardiac complication.

CONCLUSION

The obesity paradox and low functional reserve in underweight patients may influence the development of postoperative cardiac events in elderly people with hip fracture.

Activation of AMP kinase and inhibition of Rho kinase induce the mineralization of osteoblastic MC3T3-E1 cells through endothelial NOS and BMP-2 expression

AMP-activated protein kinase (AMPK) and Rho kinase (ROK) are known to modulate the mevalonate pathway. Activation of AMPK suppresses 3-hydroxy-3-methylglutaryl (HMG)-coenzyme A (CoA) reductase. ROK acts downstream of HMG-CoA reductase, and its inhibition exerts antiatherosclerosis effects. However, whether or not these enzymes are involved in bone metabolism is unclear. The present study was undertaken to investigate the effects of an AMPK activator, 5-aminoimidazole-4-carboxamide1-beta-d-ribonucleoside (AICAR), and a ROK inhibitor, fasudil hydrochrolide, on the mineralization of osteoblastic MC3T3-E1 cells. Real-time PCR and mineralization stainings revealed that both AICAR and fasudil significantly stimulated endothelial nitric oxide synthase (eNOS), bone morphogenetic protein-2 (BMP-2), and osteocalcin mRNA expression as well as mineralization in the cells. Supplementation of either mevalonate or geranyl-geranyl pyrophosphate, the downstream molecules of HMG-CoA reductase, or coincubation with either a nitric oxide synthase inhibitor, N(G)-nitro-l-arginine methyl ester, or a BMP-2 antagonist, noggin, significantly reversed these AICAR-induced reactions. Western blot analysis showed that AICAR activated protein kinase B and extracellular signal-regulated kinase (ERK). ERK inhibitor significantly reversed the AICAR-induced increase in eNOS and BMP-2 mRNA expression. Measurement of ROK activities by enzyme-linked immunosorbent assay revealed that both AICAR and fasudil significantly suppressed the phosphorylation of the myosin-binding subunit of myosin phosphate, a ROK substrate. These findings suggest that the AMPK activator and the ROK inhibitor are able to stimulate the mineralization of osteoblasts through modulating the mevalonate pathway. These agents could be candidate drugs that promote bone formation for the treatment of osteoporosis.

Serum osteocalcin level is associated with glucose metabolism and atherosclerosis parameters in type 2 diabetes mellitus

CONTEXT

Recent animal studies showed that osteocalcin action is related to not only bone metabolism but also glucose metabolism and fat mass. We investigated the relationship between two bone formation markers, serum osteocalcin and bone-specific alkaline phosphatase, and glucose metabolism, serum adiponectin, and the amount of fat mass as well as atherosclerosis parameters in men and postmenopausal women with type 2 diabetes.

METHODS

A total of 179 men and 149 postmenopausal women were recruited consecutively, and radiographic and biochemical characteristics were collected. Brachial-ankle pulse wave velocity (baPWV) and intima-media thickness (IMT) were evaluated as the parameters of atherosclerosis.

RESULTS

Multiple regression analysis adjusted for age, duration of diabetes, body mass index, and serum creatinine showed that osteocalcin negatively correlated with fasting plasma glucose and hemoglobin A(1c) in both men and postmenopausal women (P < 0.05) and with percent fat, baPWV, and IMT in men (P < 0.05). Osteocalcin positively correlated with total adiponectin in postmenopausal women (P < 0.001). After additional adjustments for systolic blood pressure, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, hemoglobin A(1c), and Brinkmann index, osteocalcin still significantly and negatively correlated with baPWV and IMT in men. In contrast, osteocalcin did not correlate with fasting C-peptide, and bone-specific alkaline phosphatase did not correlate with any variable in either men or postmenopausal women.

CONCLUSIONS

Serum osteocalcin is associated with glucose and total adiponectin levels, fat mass, and atherosclerosis parameters in patients with type 2 diabetes, suggesting that osteocalcin is important for not only bone metabolism but also glucose and fat metabolism.

Low bone mass is associated with carotid atherosclerosis in postmenopausal women: the Japanese Population-based Osteoporosis (JPOS) Cohort Study

We analyzed 609 women belonging to the JPOS study in a 10-year follow-up survey, to examine the association of osteoporosis with atherosclerosis. Osteoporosis or prevalent vertebral fracture at baseline was associated with increased intima-media thickness of the carotid bifurcation in postmenopausal women, adjusted for age, BMI, and other variables at baseline.

INTRODUCTION

Whether low bone mass predicts increased carotid atherosclerosis has not been fully investigated.

METHODS

In 2006, we conducted a 10-year follow-up survey of 1,040 women (follow-up rate: 68.6%). We analyzed 609 women > or =50 years old in 2006 without a history of cardiovascular or connective tissue diseases at baseline. BMD and evaluation of vertebral fracture at baseline were used. The intima-media thickness of carotid bifurcation (BIF-IMT) was measured by B-mode ultrasonography in 2006.

RESULTS

Adjusted BIF-IMT values of subjects with spine T-score > or =-1, between-2.5 and -1, and <-2.5 or prevalent vertebral fracture were 1.19 mm, 1.34 mm, 1.57 mm, respectively, in women with less than 10 years since menopause (YSM) (n = 159), 1.30 mm, 1.32 mm, 1.53 mm, in women with YSM > or =10 without a history of hypertension at baseline (n = 144) (both with p < 0.05 for linear trend). Those values among no versus prevalent vertebral fracture in women with YSM > or =10 were 1.40 mm, 1.66 mm with p < 0.05 (n = 202). Those associations were independent of age, BMI, total cholesterol, smoking and drinking habits, history of diabetes mellitus, and hypertension (for women with YSM < 10) at baseline.

CONCLUSION

Osteoporosis including prevalent vertebral fracture may be associated with carotid atherosclerosis in the first 10 years of postmenopausal women.

Bisphosphonates in chronic kidney disease; balancing potential benefits and adverse effects on bone and soft tissue

Cardiovascular disease is highly prevalent in chronic kidney disease (CKD) and is often associated with increased vascular stiffness and calcification. Recent studies have suggested a complex interaction between vascular calcification and abnormalities of bone and mineral metabolism, with an inverse relationship between arterial calcification and bone mineral density (BMD). Although osteoporosis is recognized and treated in CKD 1 to 3, the interpretation of BMD levels in the osteoporotic range is controversial in CKD 4, 5, and 5D when renal osteodystrophy is generally present. In addition, there is a paucity of data for patients with CKD mineral and bone disorder (MBD), because studies using bisphosphonates in postmenopausal and glucocorticoid-induced osteoporosis have generally excluded patients with significant CKD. For these patients, treatment of low BMD using standard therapies for osteoporosis is not without potential for harm due to the possibility of worsening low bone turnover, osteomalacia, mixed uraemic osteodystrophy, and of exacerbated hyperparathyroidism; and bisphosphonates should only be used selectively and with caution. Some experimental and clinical studies have also suggested that bisphosphonates may reduce progression of extra-osseous calcification and inhibit the development of atherosclerosis. The authors review the potential benefits and risks associated with bisphosphonate use for bone protection in CKD, and assess their effect on vascular calcification and atherosclerosis.

Determination and validation of aortic calcification measurement from lateral bone densitometry in dialysis patients

BACKGROUND AND OBJECTIVES

Vascular calcification (VC) contributes to increased cardiovascular (CV) disease in dialysis patients and is inversely correlated with bone mineral density (BMD). Screening for VC may determine patients at greater CV risk and bone densitometry may have dual role in assessing VC as well as BMD. The aim of this study was to determine measurement of VC using dual-energy x-ray absorptiometry (DXA) with correlation to gold standard computed tomography (CT).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Forty hemodialysis patients had abdominal aortic CT and lateral DXA of lumbar spine to determine aortic VC and BMD. Semiquantitative measurement of aortic VC from lateral DXA was determined using previously validated 24- and 8-point scales and correlated with aortic VC with CT. Anteroposterior (AP) and lateral DXA-reported BMD was compared with BMD from L2 through L4 with CT.

RESULTS

Patients, 70% men, 38% diabetic, had median age 58.5 yr. Aortic VC was present in 94% with CT and 68% on lateral DXA. For 24- and 8-point scores, intraclass correlation coefficients for intrarater agreement were 0.93 and 0.88, respectively. DXA-measured VC correlated with CT. Sensitivity and specificity for CT aortic VC > or = 500 HU was 50 and 86%, respectively, for DXA VC > or = 6 on a 24-point scale. Lateral DXA-reported BMD significantly correlated with BMD from CT, but AP DXA did not.

CONCLUSIONS

Lateral DXA may be useful because images may provide concurrent assessment of aortic calcification as well as more accurate lumbar spine BMD, avoiding some of the limitations of AP DXA.

Abdominal aortic calcification, BMD, and bone microstructure: a population-based study

To better define the relationship between vascular calcification and bone mass/structure, we assessed abdominal aortic calcification (AAC), BMD, and bone microstructure in an age-stratified, random sample of 693 Rochester, MN, residents. Participants underwent QCT of the spine and hip and high-resolution pQCT (HRpQCT) of the radius to define volumetric BMD (vBMD) and microstructural parameters. AAC was quantified with the Agatston scoring method. In men, AAC correlated with lower vertebral trabecular and femoral neck vBMD (p < 0.001), but not after age or multivariable (age, body mass index, smoking status) adjustment. Separation into <50 and >or=50 yr showed this pattern only in the older men. BV/TV and Tb.Th inversely correlated with AAC in all men (p < 0.001), and Tb.Th remained significantly correlated after age adjustment (p < 0.05). Tb.N positively correlated with AAC in younger men (p < 0.001) but negatively correlated in older men (p < 0.001). The opposite was true with Tb.Sp (p = 0.01 and p < 0.001, respectively). Lower Tb.N and higher Tb.Sp correlated with AAC in older men even after multivariable adjustment. Among all women and postmenopausal women, AAC correlated with lower vertebral and femoral neck vBMD (p < 0.001) but not after adjustment. Lower BV/TV and Tb.Th correlated with AAC (p = 0.03 and p = 0.04, respectively) in women, but not after adjustment. Our findings support an age-dependent association between AAC and vBMD. We also found that AAC correlates with specific bone microstructural parameters in older men, suggesting a possible common pathogenesis for vascular calcification and deterioration in bone structure. However, sex-specific differences exist.

Relationship between carotid atherosclerosis and lumbar spine bone mineral density in postmenopausal women

Osteoporosis and increased carotid intima-media thickness (IMT) have been associated with atherosclerosis. We investigated the correlation between carotid IMT and lumbar spine bone mineral density (BMD) in postmenopausal women. We studied the carotid IMT in 175 postmenopausal women, including 43 women (control) with normal spinal BMD, 73 women with osteopenia, and 59 women with osteoporosis. Carotid IMT was assessed by ultrasonography. BMD at the lumbar spine (lumbar 2 to 4 vertebrae) was measured by dual-energy X-ray absorptiometry. Age, years since menopause, and carotid IMT were significantly greater in the osteoporosis group than in the control (all p<0.01) and osteopenia groups (all p<0.01). Estradiol was significantly lower in the osteoporosis group than in the control group (p<0.05). BMD was significantly lower in the osteoporosis group than in the osteopenia or control group (both p<0.01) and in the osteopenia group than in the control group (p<0.01). After adjusting for age, years since menopause, and estradiol, women with osteoporosis had significantly greater carotid IMT than controls (p<0.05). The univariate linear regression analysis revealed that carotid IMT was significantly positively correlated with age, years since menopause, and low-density lipoprotein (LDL) cholesterol (all p<0.05) and was significantly negatively correlated with estradiol and BMD (all p<0.05), but showed no significant association with other clinical variables. In multivariate regression analysis, the carotid IMT was significantly positively correlated with LDL cholesterol (p<0.01) and negatively correlated with BMD (p<0.01), but not with other variables. Carotid atherosclerosis might be associated with lumbar spine bone mass in postmenopausal women, suggesting that postmenopausal women with osteoporosis may have more advanced carotid atherosclerosis than those with a normal bone mass.

Relationship of calcification of atherosclerotic plaque and arterial stiffness to bone mineral density and osteoprotegerin in postmenopausal women referred for osteoporosis screening

Arterial calcification leading to increased arterial stiffness, a powerful risk factor for cardiovascular disease, may underlie the association of osteoporosis with cardiovascular disease in postmenopausal women. Osteoprotegerin (OPG), an indirect inhibitor of osteoclastogenesis, may be involved in arterial calcification. We examined relationships between calcification of subclinical atherosclerotic plaque and arterial stiffness with bone mineral density (BMD) and OPG in a group of 54 postmenopausal women referred for routine osteoporosis screening by dual-energy X-ray absorptiometric scanning of the lumbar spine and hip. Presence of calcified and noncalcified plaque in carotid and femoral arteries was examined using ultrasonography. Pulse wave velocity (PWV), a measure of arterial stiffness, was determined by sequential tonometry over the carotid and femoral region. Fifty-nine percent of osteoporotic women had calcified (echogenic) plaque at one or more sites compared with 42% and 20% for women with osteopenia and normal BMD, respectively (P = 0.04). There was a significant negative correlation between PWV and hip BMD (r = -0.35, P = 0.01), which remained significant when age, mean arterial pressure, and serum lipids were taken into account (P = 0.05). No significant relationships were observed between serum concentrations of OPG and lumbar spine or total hip BMD or with the number of arterial sites with calcified or noncalcified plaque. However, there was a strong correlation between OPG and PWV (r = 0.44, P = 0.001), which remained significant when adjusted for age (P = 0.01). These findings suggest that decreased BMD is associated with arterial calcification and stiffening and raise the possibility that OPG is a marker of arterial stiffening, independent of any association with BMD.

Progression of vascular calcifications is associated with greater bone loss and increased bone fractures

In this prospective study, we found a positive relationship between the prevalence of aortic calcifications and age. Aortic calcifications at baseline were positively associated with osteoporotic fractures. In addition, progression of aortic calcifications was also positively associated with the rate of decline in BMD at lumbar spine.

INTRODUCTION

The aim of this study was to analyze the relationship between the progression of abdominal aortic calcification and osteoporosis in a Spanish cohort of men and women older than 50.

METHODS

Men and women (n=624) aged 50 and over underwent two lateral X-rays of thoracic and lumbar spine and a dual X-ray absorptiometry (DXA) study at lumbar spine and hip, and were followed during 4 years. Abdominal aortic calcifications were classified as absent, mild-moderate and severe.

RESULTS

There was a positive relationship between the prevalence of aortic calcifications and age. In both sexes, prevalent severe aortic calcifications were positively associated with prevalent osteoporotic fractures [odds ratio (OR)=1.93 (1.02-3.65)]. The association was stronger when only vertebral fracture was considered [OR=2.45 (1.23-4.87)]. In addition, progression of aortic calcifications showed a positive association with the rate of decline in bone mineral density (BMD) at lumbar spine.

CONCLUSIONS

Aortic calcifications at baseline were positively associated with osteoporotic fractures. The progression of aortic calcifications was also positively associated with the rate of decline in BMD at lumbar spine.

Compromised bone marrow perfusion in osteoporosis

A link between bone blood flow and osteoporosis may exist. Outside of the spine, the proximal femur is the most common site of osteoporotic fracture and is also an area prone to avascular necrosis and fracture nonunion. This study of the proximal femur investigates the relationship between BMD, bone marrow fat content, bone perfusion, and muscle perfusion. One hundred twenty healthy female subjects (mean age, 74 yr; age range, 67-89 yr) underwent DXA examination of the hip, proton MR spectroscopy, and dynamic contrast-enhanced MR imaging of the right proximal femur, acetabulum, and adductor thigh muscle. In all bone areas examined (femoral head, femoral neck, femoral shaft, acetabulum), perfusion indices (maximum enhancement, enhancement slope) were significantly reduced in subjects with osteoporosis compared with subjects with osteopenia or normal BMD. Adductor muscle perfusion was not affected by change in BMD. As marrow perfusion decreased in the proximal femur, marrow fat increased (r = 0.827). This increase in fat content seemed to account for the decrease in marrow perfusion more than a reduction in BMD. For normal BMD subjects, perfusion parameters in the femoral head were one third of those in the femoral neck or shaft and one fifth of those in the acetabulum. Perfusion throughout the proximal femur is reduced in osteoporotic subjects compared with osteopenic and normal subjects. This reduction in perfusion only affects bone and not those tissues outside of bone with the same blood supply. As bone perfusion decreased, there was a corresponding increase in marrow fat.

Echogenic carotid artery plaques are associated with vertebral fractures in postmenopausal women with low bone mass

Although low bone mass has been associated with atherosclerosis even after adjustment for age, little is known about the association between vertebral fractures and calcified atherosclerotic plaques. Our objective was to investigate whether osteoporotic vertebral fractures are independently related to the prevalence of atherosclerotic carotid plaques in postmenopausal women with low bone mass. We enrolled 195 postmenopausal women with osteopenia or osteoporosis. Bone mineral density and the presence of vertebral fractures were assessed. Intima media thickness and atherosclerotic plaques of the carotid artery were assessed using ultrasonography. Of the 195 subjects in the study, 84 had no plaques and 111 had at least one. The percentage of women with vertebral fractures was significantly higher in subjects with echogenic carotid plaques than in those without (27% vs. 11%, respectively; P < 0.05). However, there was no difference in the prevalence of vertebral fractures between women with echolucent plaques and those without (10.9% vs. 10.7%, respectively; P = nonsignificant). By logistic regression analysis with multivariate adjustment, age (P < 0.01), dyslipidemia (P < 0.05), and the presence of vertebral fracture (P < 0.05) were independent risk factors for echogenic carotid plaques. Osteoporotic vertebral fractures are associated with an increased risk of echogenic atherosclerotic plaques in postmenopausal women with low bone mass. It appears that the high association of echogenic atherosclerotic plaques and vertebral fractures could partially explain why osteoporotic vertebral fractures are linked to increased mortality.

Does osteoprotegerin or receptor activator of nuclear factor-kappaB ligand mediate the association between bone and coronary artery calcification?

CONTEXT

Accumulating evidence indicates that vascular and bone mineralization may be related, although the exact mechanism remains unknown.

OBJECTIVE

Our objective was to investigate whether an observed inverse association between bone mineral density (BMD) and coronary artery calcification (CAC) in postmenopausal women currently taking estrogen therapy is mediated by osteoprotegerin (OPG) or receptor activator of nuclear factor-kappaB ligand (RANKL).

DESIGN

Participants were 92 postmenopausal women (aged 58-81 yr) taking estrogen therapy who had hip and spine BMD assessed by dual-energy x-ray absorptiometry and CAC measured by electron-beam computed tomography in 1998-2002 and serum RANKL and OPG levels measured in samples collected in 1997-1999. Total CAC score was dichotomized as none/minimal (</=10) vs. some (>10).

RESULTS

OPG serum levels were higher in women who had some CAC compared with those who had none/minimal (126.8 +/- 1.08 vs. 102.9 +/- 1.07 pg/ml, respectively, P = 0.03); these differences became nonsignificant after adjustment for age and other risk factors (P = 0.51). A 1 sd increase in hip BMD was associated with significantly lower odds of having CAC > 10 (odds ratio = 0.52; 95% confidence interval = 0.29-0.93) independent of age, fat-free mass, high-density lipoprotein cholesterol, current smoking, and use of cholesterol-lowering medications. Other skeletal sites demonstrated a similar pattern. Addition of RANKL and/or OPG to the model had minimal effect on the magnitude or statistical significance of the BMD-CAC association. Additionally, a test of interaction indicated that RANKL and OPG are not significant effect modifiers.

CONCLUSIONS

Serum OPG and RANKL do not account for the observed association between bone and coronary artery calcification among postmenopausal women using hormone therapy.

Bone mineral density in end-stage renal disease patients: association with wasting, cardiovascular disease and mortality

BACKGROUND

Bone and mineral disorders may contribute to extraosseous ossifications and cardiovascular disease (CVD) in end-stage renal disease (ESRD) patients. We have investigated the relationship between bone mineral density (BMD) and inflammation, wasting, CVD and mortality in ESRD patients.

METHODS

BMD (dual energy X-ray absorptiometry) and biochemical, nutritional and inflammatory markers were assessed in 277 incident ESRD patients (GFR 7.1 +/- 0.2 ml/min) who were then followed prospectively for a mean of 27 (range 1-60) months. Carotid plaques were determined in 103 patients.

RESULTS

Patients with carotid plaques, clinical manifestation of CVD and wasting (assessed by subjective global assessment) had significantly lower BMD than their counterparts. Low BMD was associated with high all-cause and cardiovascular mortality. Even after adjustment for several confounders and risk factors, all-cause (HR = 2.1, CI: 1.1-3.9, p = 0.02) and cardiovascular (HR = 2.8, CI: 1.2-6.3, p = 0.02) mortality remained significantly associated with low BMD.

CONCLUSIONS

Low BMD is associated with wasting and CVD, and is an independent predictor of all-cause and cardiovascular mortality in ESRD patients.

Characterization of oxidized low-density lipoprotein-induced hormesis-like effects in osteoblastic cells

Epidemiological studies indicate that patients suffering from atherosclerosis are predisposed to develop osteoporosis. Atherogenic determinants such as oxidized low-density lipoprotein (oxLDL) particles have been shown both to stimulate the proliferation and promote apoptosis of bone-forming osteoblasts. Given such opposite responses, we characterized the oxLDL-induced hormesis-like effects in osteoblasts. Biphasic 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reductive activity responses were induced by oxLDL where low concentrations (10-50 microg/ml) increased and high concentrations (from 150 microg/ml) reduced the MTT activity. Cell proliferation stimulation by oxLDL partially accounted for the increased MTT activity. No alteration of mitochondria mass was noticed, whereas low concentrations of oxLDL induced mitochondria hyperpolarization and increased the cellular levels of reactive oxygen species (ROS). The oxLDL-induced MTT activity was not related to intracellular ROS levels. OxLDL increased NAD(P)H-associated cellular fluorescence and flavoenzyme inhibitor diphenyleneiodonium reduced basal and oxLDL-induced MTT activity, suggesting an enhancement of NAD(P)H-dependent cellular reduction potential. Low concentrations of oxLDL reduced cellular thiol content and increased metallothionein expression, suggesting the induction of compensatory mechanisms for the maintenance of cell redox state. These concentrations of oxLDL reduced osteoblast alkaline phosphatase activity and cell migration. Our results indicate that oxLDL particles cause hormesis-like response with the stimulation of both proliferation and cellular NAD(P)H-dependent reduction potential by low concentrations, whereas high concentrations lead to reduction of MTT activity associated with the cell death. Given the effects of low concentrations of oxLDL on osteoblast functions, oxLDL may contribute to the impairment of bone remodeling equilibrium.

Bone metabolism and vascular calcification

Osteoporosis and atherosclerosis are chronic degenerative diseases which have been considered to be independent and whose common characteristic is increasing incidence with age. At present, growing evidence indicates the existence of a correlation between cardiovascular disease and osteoporosis, irrespective of age. The morbidity and mortality of osteoporosis is mainly related to the occurrence of fractures. Atherosclerosis shows a high rate of morbidity and especially mortality because of its clinical repercussions such as angina pectoris, acute myocardial infarction, stroke, and peripheral vascular insufficiency. Atherosclerotic disease is characterized by the accumulation of lipid material in the arterial wall resulting from autoimmune and inflammatory mechanisms. More than 90% of these fatty plaques undergo calcification. The correlation between osteoporosis and atherosclerosis is being established by studies of the underlying physiopathological mechanisms, which seem to coincide in many biochemical pathways, and of the risk factors for vascular disease, which have also been associated with a higher incidence of low-bone mineral density. In addition, there is evidence indicating an action of antiresorptive drugs on the reduction of cardiovascular risks and the effect of statins, antihypertensives and insulin on bone mass increase. The mechanism of arterial calcification resembles the process of osteogenesis, involving various cells, proteins and cytokines that lead to tissue mineralization. The authors review the factors responsible for atherosclerotic disease that correlate with low-bone mineral density.

Increased augmentation index and central aortic blood pressure in osteoporotic postmenopausal women

Osteoporosis has been associated with cardiovascular disease. We found increased augmentation index, a measure of wave reflections and arterial stiffness, and central pressures in osteoporotic postmenopausal women. They also showed a higher estimated aortic pulse wave velocity, indicating a stiffer aorta. These changes may increase cardiovascular risk in postmenopausal osteoporosis.

INTRODUCTION

Evidence suggests a link between osteoporosis and cardiovascular disease. We investigated whether augmentation index (AIx), a measure of pulse wave reflections and arterial stiffness, is increased and related to the osteoprotegerin (OPG)/receptor activator of nuclear factor-kappa B ligand (RANKL) system in postmenopausal osteoporosis.

METHODS

AIx and central aortic haemodynamics were assessed using pulse wave analysis in 182 cardiovascular disease-free osteoporotic postmenopausal women and in 160 controls. Statistical analysis was performed by unpaired t test, Mann-Whitney test, Spearman's correlation coefficient, and multivariate linear regression analysis.

RESULTS

AIx (37.2 +/- 7.0 vs. 29.6 +/- 9.2 %, P < 0.0001) and central aortic systolic (117.5 +/- 12.1 vs. 111.4 +/- 12.2 mmHg, P < 0.0001) and pulse (40.5 +/- 10.3 vs. 36.4 +/- 8.1 mmHg, P = 0.0007) pressures were significantly higher in osteoporotic patients than in controls. The estimated aortic pulse wave velocity (PWV) was also significantly higher in the osteoporotic group. In multivariate analysis for osteoporotic patients, femoral neck and lumbar spine bone mineral density T scores were independent negative predictors of AIx (P < 0.0001). AIx was not correlated with serum levels of OPG and RANKL.

CONCLUSIONS

Osteoporotic postmenopausal women show increased AIx and central aortic pressures, and a higher estimated aortic PWV, indicating a stiffer aorta. Such alterations may increase cardiovascular risk in postmenopausal osteoporosis.

Reduced bone mineral density is associated with breast arterial calcification

BACKGROUND

Arterial calcification, a marker of atherosclerosis, results from a complex process of biomineralization resembling bone formation. Breast arterial calcification (BAC) has been associated with angiographic and clinical cardiovascular disease. The purpose of this study was to determine the association between reduced bone mineral density (BMD) and BAC, which may share a common pathophysiology.

METHODS

We conducted a retrospective study of 228 women (55% Hispanic, mean age 64 +/-10 yr) who had both mammography and BMD evaluation at Columbia University Medical Center from 2001-2003. Each mammogram was reviewed for the presence of BAC using standardized methods. BMD was measured using dual-energy x-ray absorptiometry and categorized as normal, low bone density (osteopenia), or osteoporosis as defined by the World Health Organization. Univariate and multivariate logistic regression analyses were performed to evaluate the association between reduced BMD and BAC.

RESULTS

The prevalence of BAC, low bone density (osteopenia), and osteoporosis was 39, 42, and 29%, respectively. Women with BAC were significantly more likely to be older, Hispanic, and postmenopausal and have osteoporosis as compared with women without BAC. In age-adjusted analyses, women with BAC were more likely to have reduced BMD (odds ratio 3.0, P < 0.01) as compared with women without BAC. Furthermore, osteoporosis was strongly associated with the presence of BAC (odds ratio 3.5, P < 0.01).

CONCLUSION

These data suggest that osteoporosis and arterial calcification are strongly and independently correlated. Reduced BMD may identify women at risk of vascular disease.

Vitamin D and cardiovascular disease risk

PURPOSE OF REVIEW

Despite our understanding of how to prevent and treat traditional cardiovascular risk factors, cardiovascular disease remains the leading cause of death of both men and women in the US. Thus, there is widespread interest in a number of emerging nontraditional risk factors for the detection of early cardiovascular disease in order to implement aggressive preventive therapies. 25-Hydroxyvitamin D deficiency has been identified as a potential novel cardiovascular disease risk factor. This review outlines what is known about the association of 25-hydroxyvitamin D levels and cardiovascular disease risk.

RECENT FINDINGS

Low 25-hydroxyvitamin D levels have been associated with the cardiovascular disease risk factors of hypertension, obesity, diabetes mellitus and the metabolic syndrome, as well as cardiovascular disease events including stroke and congestive heart failure. Studies suggest vitamin D deficiency may be a contributor to the development of cardiovascular disease potentially through associations with diabetes or hypertension.

SUMMARY

Vitamin D deficiency is easy to screen for and easy to treat with supplementation. Further larger observational studies and randomized clinical trials are, however, needed to determine whether vitamin D supplementation could have any potential benefit in reducing future cardiovascular disease events and mortality risk.

Effects of raloxifene on fracture risk in postmenopausal women: the Raloxifene Use for the Heart Trial

Using data from a randomized placebo-controlled trial of 10,101 postmenopausal women not selected on the basis of osteoporosis, we examined whether the effect of raloxifene treatment on fractures was consistent across categories of fracture risk. Treatment with raloxifene for 5 yr reduced the risk of clinical vertebral fractures, but not nonvertebral fractures, irrespective of the presence or absence of risk factors for fracture.

INTRODUCTION

In The Raloxifene Use for The Heart (RUTH) trial, women assigned to raloxifene had a lower risk of clinical vertebral fractures but not nonvertebral fractures. However, it is uncertain whether the effect of raloxifene on fractures in this population not selected for low BMD differs according to risk factors for fractures.

MATERIALS AND METHODS

We randomly assigned 10,101 postmenopausal women >or=55 yr of age with documented coronary heart disease or at high risk for coronary events to 60 mg raloxifene daily or placebo and followed them for a median of 5.6 yr. Fractures (nonvertebral and clinical vertebral) were prespecified secondary endpoints that were reported at semiannual visits. Fractures were adjudicated and confirmed using X-ray reports or medical records.

RESULTS

There was no difference between raloxifene and placebo groups in risk of nonvertebral fractures (428 versus 438 events; hazard ratio [HR], 0.96; 95% CI, 0.84-1.10), including hip/femur (89 versus 103 events; HR, 0.85; 95% CI, 0.64-1.13) and wrist (107 versus 111 events; HR, 0.95; 95% CI, 0.73-1.24) fractures. Women treated with raloxifene had a lower risk of clinical vertebral fractures (64 versus 97 events; HR, 0.65; 95% CI, 0.47-0.89). The effect of treatment with raloxifene on risk of nonvertebral and clinical vertebral fractures was consistent across fracture risk categories defined at baseline by age, smoking status, physical activity level, prior history of fracture, family history of hip fracture, diabetes mellitus, previous use of hormone therapy, thyroid hormone use, statin use, weight loss, body mass index, or fracture specific summary risk score.

CONCLUSIONS

In older women with or at high risk of coronary heart disease not selected on the basis of osteoporosis or increased fracture risk, treatment with raloxifene for 5 yr reduced the risk of clinical vertebral fractures, but not nonvertebral fractures, irrespective of presence or absence of risk factors for fracture.