Associations between bone mineral density and subclinical atherosclerosis: a cross-sectional study of a Chinese population.

CONTEXT: The significance of associations between bone mineral density (BMD) and atherosclerosis in the Asian population is less clear. OBJECTIVE: The aim of this study was to explore the population-level associations between BMD and subclinical atherosclerosis. DESIGN AND SETTING: This was a community-based cross-sectional study conducted in Shenyang, China. PARTICIPANTS: A total of 385 Chinese women and men aged 37-87 years were studied. MAIN OUTCOME MEASURES: The BMD was measured at the total hip and lumbar spine using dual-energy x-ray absorptiometry. The ankle-brachial index (ABI), pulse wave velocity (PWV), and carotid intima-media thickness (CIMT) were measured to assess atherosclerosis. Multiple regression analysis was applied to study the associations. Multicolinearity was examined using the variance inflation factor, condition index, and variance proportions. Factor analysis and principal component regression were used to remove the problem of multicolinearity. RESULTS: The differences of ABI, PWV, and CIMT among the normal BMD, osteopenia, and osteoporosis groups were not found. Total hip BMD was correlated with ABI in women after adjustment for age (r = 0.156). Sex-specific regression models included adjustment for age, body mass index, cigarette smoking, alcohol consumption, menopausal status (women), systolic blood pressure, diastolic blood pressure, triglycerides, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, fasting blood glucose, serum uric acid, estimated glomerular filtration rate, high-sensitivity C-reactive protein, and fibrinogen. Total hip BMD was associated with ABI in women after adjustment for age (per SD decrease in ABI: -0.130 g/cm(2), P = .022), but the association was borderline significant after full adjustment (P = .045). Total hip BMD and lumbar spine BMD were not associated with ABI, PWV, and CIMT after full adjustment in participants without a fracture history. The risk of osteoporosis was not associated with ABI, PWV, and CIMT. CONCLUSIONS: Low BMD is not associated with subclinical atherosclerosis as assessed by ABI, PWV, and CIMT.

Analysis of the transient expansion behavior and design optimization of coronary stents by finite element method.

The percutaneous transluminal coronary angioplasty (PTCA) assisted with stenting technique has become a primary therapy to coronary heart disease. In practice, the structure conditions of both ends of stent/balloon system influence a stent's instantaneous expansion behavior. The transitory nonuniform expansion, the so-called dogboning, of stent/balloon system is one of the main reasons to induce the acute vascular injury at the two edges of a stent. This kind of vascular injury has a close relationship with the in-stent restenosis. In the present paper, the finite element method (FEM) was applied to simulate the transient expansion process of stent/balloon system with different stent structure and balloon length under the internal pressure. And two types of stent and six collocations of stent and balloon were modeled. Modeling results showed that the dogboning phenomenon can be eliminated by improving geometry of a stent or/and varying the length of balloon over stent. The above modeled results were further confirmed by following in situ observation.

[The influence of the screw thread and the height of constraints on the stress distribution around dental implants by using three-dimensional finite element analysis].

OBJECTIVE: To study the influence of the screw thread and the height of constraints on the stress distribution of the implants. METHODS: The three-dimensional emulational models of the implants with different screw-pitch were constructed by a CAD/CAM package. The Von Mises stress of the models was analyzed by three-dimensional finite element method. RESULTS: The constraints of the long implant were high. When the constraint height reduced, the change of the stress value of the implants without screw thread was much less than that of the implants with screw thread. The difference of screw-pitch had little influence on the stress value and the stress concentration of the implants. CONCLUSION: The strength requirement of screw implant was high. Stress distribution of the long dental implants was more reasonable than the other, which will contribute to the success of dental implants.