Abstract Bone turnover markers (BTM) predict bone loss and fragility fracture. Although cortical porosity and cortical thinning are important determinants of bone strength, the relationship between ...BTM and cortical porosity has, however, remained elusive. We therefore wanted to examine the relationship of BTM with cortical porosity and risk of non-vertebral fracture. In 211 postmenopausal women aged 54–94 years with non-vertebral fractures and 232 age-matched fracture-free controls from the Tromsø Study, Norway, we quantified femoral neck areal bone mineral density (FN aBMD), femoral subtrochanteric bone architecture, and assessed serum levels of procollagen type I N-terminal propeptide (PINP) and C-terminal cross-linking telopeptide of type I collagen (CTX). Fracture cases exhibited higher PINP and CTX levels, lower FN aBMD, larger total and medullary cross-sectional area (CSA), thinner cortices, and higher cortical porosity of the femoral subtrochanter than controls ( p ≤ 0.01). Each SD increment in PINP and CTX was associated with 0.21–0.26 SD lower total volumetric BMD, 0.10–0.14 SD larger total CSA, 0.14–0.18 SD larger medullary CSA, 0.13–0.18 SD thinner cortices, and 0.27–0.33 SD higher porosity of the total cortex, compact cortex, and transitional zone (all p ≤ 0.01). Moreover, each SD of higher PINP and CTX was associated with increased odds for fracture after adjustment for age, height, and weight (ORs 1.49; 95% CI, 1.20–1.85 and OR 1.22; 95% CI, 1.00–1.49, both p < 0.05). PINP, but not CTX, remained associated with fracture after accounting for FN aBMD, cortical porosity or cortical thickness (OR ranging from 1.31 to 1.39, p ranging from 0.005 to 0.028). In summary, increased BTM levels are associated with higher cortical porosity, thinner cortices, larger bone size and higher odds for fracture. We infer that this is produced by increased periosteal apposition, intracortical and endocortical remodeling; and that these changes in bone architecture are predisposing to fracture.
Aim of this study is to estimate the gender- and age-specific 10-year and lifetime absolute risks of non-vertebral and osteoporotic (included hip, distal forearm and proximal humerus) fractures in a ...large cohort of men and women. This is a population-based 10 years follow-up study of 26,891 subjects aged 25 years and older in Tromsø, Norway. All non-vertebral fractures were registered from 1995 throughout 2004 by computerized search in radiographic archives. Absolute risks were estimated by life-table method taking into account the competing risk of death. The absolute fracture risk at each year of age was estimated for the next 10 years (10-year risk) or up to the age of 90 years (lifetime risk). The estimated 10-year absolute risk of all non-vertebral fracture was higher in men than women before but not after the age of 45 years. The 10-year absolute risk for non-vertebral and osteoporotic fractures was over 10%, respectively, in men over 65 and 70 years and in women over 45 and 50 years of age. The 10-year absolute risks of hip fractures at the age of 65 and 80 years were 4.2 and 18.6% in men, and 9.0 and 24.0% in women, respectively. The risk estimates for distal forearm and proximal humerus fractures were under 5% in men and 13% in women. The estimated lifetime risks for all fracture locations were higher in women than men at all ages. At the age of 50 years, the risks were 38.1 and 24.8% in men and 67.4 and 55.0% in women for all non-vertebral and osteoporotic fractures, respectively. The estimated gender- and age-specific 10-year and lifetime absolute fracture risk were higher in Tromsø than in other populations. The high lifetime fracture risk reflects the increased burden of fractures in this cohort.
A synoptic overview of scientific methods applied in bone and associated research fields across species has yet to be published. Experts from the EU Cost Action GEMSTONE ("GEnomics of MusculoSkeletal ...Traits translational Network") Working Group 2 present an overview of the routine techniques as well as clinical and research approaches employed to characterize bone phenotypes in humans and selected animal models (mice and zebrafish) of health and disease. The goal is consolidation of knowledge and a map for future research. This expert paper provides a comprehensive overview of state-of-the-art technologies to investigate bone properties in humans and animals - including their strengths and weaknesses. New research methodologies are outlined and future strategies are discussed to combine phenotypic with rapidly developing -omics data in order to advance musculoskeletal research and move towards "personalised medicine".
Our aim was to examine associations between leisure time physical activity and risk of non-vertebral fractures in men and women aged ≥55 years, with focus on the anatomical fracture location. ...Self-reported physical activity was registered in 3,450 men and 4,072 women aged 55-97 years at baseline in the Tromso Study, Norway, in 1994-1995. Non-vertebral fractures were registered through December 31, 2009. During 75,546 person-years at risk, 1,693 non-vertebral fractures were identified. Risk of any non-vertebral fracture decreased with increasing physical activity level in men (P ^sub trend^ = 0.006) and non-significantly in women (P ^sub trend^ = 0.15), after adjustment for age, body mass index, height, smoking, and previous fracture. The reduced fracture risk was due to a reduced risk in the weight-bearing skeleton, particular at the hip, whereas risk of fracture in the non-weight-bearing skeleton was not related to physical activity. At weight-bearing sites, an inverse relationship between physical activity and fracture risk was present in both sexes (P ^sub trend^ ≤ 0.013). Compared with sedentary subjects, the most active men and women had respectively 37% (HR = 0.63, 95% CI: 0.45, 0.88) and 23% (HR = 0.77, 95% CI: 0.62, 0.95) reduced fracture risk in the weight-bearing skeleton. Physical activity is associated with reduced fracture risk at weight-bearing sites, with no associations at non-weight-bearing sites, in both sexes. Habitual physical activity is an important amendable approach to prevent hip fracture.PUBLICATION ABSTRACT
This paper presents the results of a study to investigate the effect of computer monitor height on the neck muscle activity, user comfort and user acceptability for office based tasks in the seated ...posture. Ten subjects with intermediate level of computer-skill participated in the study. Three computer monitor height settings- high, medium and low representing respectively angles of sight of 15 degrees, 30 degrees and 45 degrees below the horizontal at eye level were considered. Electromyography recordings from the right and left upper trapezius muscles were obtained for each monitor placement. The ratings of user comfort and acceptability were also obtained for each of the monitor settings. Statistical analysis of muscular activity data showed that there was no statistically significant difference between the mean RMS values for the three monitor settings. Results of the study indicate that the overall comfort was significantly more for high monitor setting than for the medium and low settings. It was also found that the comfort ratings for the neck and the low back regions were significantly higher for the high monitor setting compared to the low setting. Data analysis of user acceptability ratings for different monitor positions showed that the high monitor setting was significantly more acceptable than the medium and the low settings.
Highly Oscillatory Problems Engquist, Bjorn; Fokas, Athanasios; Hairer, Ernst ...
07/2009, Letnik:
v.Series Number 366
eBook, Book
The first book to approach high oscillation as a subject of its own, Highly Oscillatory Problems begins a new dialogue and lays the groundwork for future research. It ensues from the six-month ...programme held at the Newton Institute of Mathematical Sciences, which was the first time that different specialists in highly oscillatory research, from diverse areas of mathematics and applications, had been brought together for a single intellectual agenda. This ground-breaking volume consists of eight review papers by leading experts in subject areas of active research, with an emphasis on computation: numerical Hamiltonian problems, highly oscillatory quadrature, rapid approximation of functions, high frequency wave propagation, numerical homogenization, discretization of the wave equation, high frequency scattering and the solution of elliptic boundary value problems.
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