Low bone density is not associated with aortic calcification

Bone mineral density and the risk of peripheral arterial disease in men and women: results from Mr. and Ms Os, Hong Kong

Previous population studies have demonstrated an association between peripheral vascular disease and bone mineral density in women, but not in men. In a large prospective cohort of 3,998 Chinese men and women aged 65 to 92 years of age in Hong Kong, the association between peripheral vascular disease and bone mineral density was explored. Demographic and lifestyle information was obtained from face to face interviews using a standardized questionnaire. This included demographic information, medical history and lifestyle factors. Physical examination measurements included anthropometry and tibial and brachial systolic blood pressures. The ratio of the posterior tibial and brachial systolic blood pressures, the ankle/arm index, was used as a measure of peripheral arteriosclerosis in the lower extremities. Bone mineral density (BMD) at the total hip and spine (L1-L4) was measured by Hologic QDR-4500 W densitometers (Hologic, Inc., Waltham, Mass.). In this cross-sectional analysis, the ankle brachial index (ABI) was positively correlated with hip BMD (correlation coefficient=0.27; P<0.001). However, after adjustment for confounders, the correlation became much weaker (correlation coefficient=0.03; P<0.05). This showed that much of the relationship between ABI and BMD could be explained by other confounders. In multiple regression analysis, an increase in ABI of 1 SD of ABI was associated with an increase of 0.5% (95% CI: 0.02%, 0.9%) in hip BMD after adjusting for age, sex, body weight, smoking status, history of diabetes, cardiovascular diseases, use of thiazide diuretics, grip strength and physical activity. Although our study shows that peripheral vascular disease in the lower extremities may be associated with decreased bone mineral density, the association is weak especially after adjustment was made for confounders. This indicates that other factors may be contributing to the association between peripheral vascular disease and osteoporosis.

Effects of lifestyle factors on stiffness index of calcaneus measured by quantitative ultrasound system among Japanese women aged 40 years and over: the Hizen-Oshima Study

To explore how the stiffness index of the calcaneus is related to lifestyle factors, we examined the associations of lifestyle factors, age, and years since menopause, with stiffness index of the calcaneus among 573 community-dwelling Japanese women aged 40-89 years. Stiffness index of the calcaneus was obtained from quantitative ultrasound measurement. Body height and weight were measured, from which body mass index (BMI) was calculated. Physical activity index was calculated using a validated questionnaire. Dietary calcium intake and amount of ingested alcohol were estimated by a semiquantitative food frequency questionnaire. Current smoking status was obtained by questionnaire. In univariate analysis, stiffness index was positively related to physical activity index and BMI, and inversely to age and years since menopause, but not to dietary calcium intake. Stiffness index of drinkers and current smokers was not significantly different from that of non-drinkers and non-smokers, respectively. Among the natural menopausal women, multiple regression analysis showed that advancing age and years since menopause were associated with lower stiffness index, while higher physical activity index and greater BMI were associated with higher stiffness index. In conclusion, higher physical activity, in combination with adequate nutrition for weight maintenance, should be emphasized as a part of a healthy lifestyle in order to maintain bone health among middle-aged and elderly Japanese women.

Low bone density and abnormal bone turnover in patients with atherosclerosis of peripheral vessels

Patients with vascular calcifications often have low bone mineral density (BMD), but it is still uncertain if osteoporosis and peripheral vascular disease (VD) are interrelated and linked by a common pathomechanism. Moreover, data on bone turnover in patients with advanced atherosclerosis are lacking. We measured BMD by dual-energy X-ray absorptiometry (DXA) and quantitative bone ultrasound (QUS), as well as the serum levels of osteocalcin (OC), bone-specific alkaline phosphatase (BAP), osteoprotegerin (OPG) and its ligand RANKL, and the urinary concentration of the C-terminal telopeptides of type I collagen (CrossLaps), in 36 patient (20 male and 16 female) with serious atherosclerotic involvement of the carotid and/or femoral artery to investigate the underlying mechanism of vascular and osseous disorders. Thirty age-matched and gender matched healthy individuals served as controls. After adjustment for age, BMD was significantly reduced at the lumbar spine in 23/36 (63%) patients (mean T score -1.71+/-1.42) and at the proximal femur in 34/36 (93%) patients (neck mean T score -2.5+/-0.88). Ten patients (27%) had abnormal QUS parameters. Gender and diabetes had no effect on the relationship between vascular calcification and bone density at any site measured. VD subjects had OC and BAP serum levels lower than controls (13.3+/-3.1 vs 27.7+/-3.3 ng/ml, P<0.01, and 8.4+/-2.3 vs 12.5+/-1.4 microg/l, P<0.01, respectively). Urinary CrossLaps excretion was not significantly different in patients with VD and in controls (257.9+/-138.9 vs 272.2+/-79.4 micro g/mmol Cr, respectively). Serum OPG and RANKL levels were similar in patients and in controls (3.5+/-1.07 vs 3.4+/-1.05 pmol/l, and 0.37+/-0.07 vs 0.36+/-0.06 pmol/l, respectively). We proved high occurrence of osteoporosis in VD, with evidence of age and gender independence. Negative bone remodelling balance would be a consequence of reduced bone formation, with no apparent increased activation of the OPG-RANKL system.

Are Cardiovascular Disease and Osteoporosis Directly Linked?

For years, osteoporosis and cardiovascular disease were thought to be two independent consequences of aging; however, mounting evidence supports an association between these diseases. Recently, a widespread class of cholesterol-lowering drugs known as statins have demonstrated (in rodents and cell cultures) the ability to induce bone formation. This finding is significant since current therapies are limited to the prevention or slowing down of bone loss rather than (enhancing/improving) bone formation. In humans, the ability of statins to generate new bone has not been consistent; however, several investigations have demonstrated a dramatic decrease in fracture risk. Although it has been proposed that statins induce new bone via increased bone morphogenetic protein-2, other conditions affected by statins such as dyslipidaemia, vascular calcification, endothelial dysfunction and impaired nitric oxide expression, may also contribute to the cardiovascular and bone health paradigm. Furthermore, the role of physical activity and its influence on cardiovascular and bone health, especially in postmenopausal women, may contribute to the discrepancy of findings in human data. In summary, it remains to be determined if statins contribute to bone health via improvements in vascular health or by pleiotropic properties unique to their pharmacology. This review provides information on our current understanding of the bone and cardiovascular association, as well as on novel areas of research to further our current understanding of these conditions.

Automated assessment of exclusion criteria for DXA lumbar spine scans

Modern bone densitometry systems using dual-energy X-ray absorptiometry (DXA) automatically analyze lumbar spine scans and provide clinically important information concerning spine bone mineral density (BMD) and fracture risk. Lumbar spine BMD accurately reflects skeletal health and fracture risk in most cases, but degenerative diseases associated with aging may lead to the formation of reactive bone (osteophytes) and other confounding conditions that elevate BMD without a concomitant increase in bone strength or decrease in fracture risk. Automated densitometry software known as computer-aided densitometry (CAD) (GE Medical Systems Lunar) assists the user in identifying scans with common acquisition and analysis irregularities known to influence BMD values. Visual examination of 231 female spine scans measured with DXA found abnormal conditions that could influence BMD results in 29% of scans. The sensitivity and specificity of several criteria for identifying scans with conditions that could influence BMD were determined. A good criterion for identifying scans with abnormal conditions was a T-score difference of greater than 0.9 or 1.0 between L1-L4 mean and individual vertebrae. Criteria for excluding affected vertebrae were determined. Exclusion of affected vertebrae resulted in a mean BMD decrease of nearly 0.6 SD (T-score) among affected scans.