374 research outputs found
A Comparison Of New Calculations Of The Yearly 10Be Production In The Earths Polar Atmosphere By Cosmic Rays With Yearly 10Be Measurements In Multiple Greenland Ice Cores Between 1939 And 1994 - A Troubling Lack Of Concordance Paper #2
We have compared the yearly production rates of 10Be by cosmic rays in the
Earths polar atmosphere over the last 50-70 years with 10Be measurements from
two separate ice cores in Greenland. These ice cores provide measurements of
the annual 10Be concentration and 10Be flux levels during this time. The
scatter in the ice core yearly data vs. the production data is larger than the
average solar 11 year production variations that are being measured. The cross
correlation coefficients between the yearly 10Be production and the ice core
10Be measurements for this time period are <0.4 in all comparisons between ice
core data and 10Be production, including 10Be concentrations, 10Be fluxes and
in comparing the two separate ice core measurements. In fact, the cross
correlation between the two ice core measurements, which should be measuring
the same source, is the lowest of all, only ~0.2. These values for the
correlation coefficient are all indicative of a "poor" correlation. The
regression line slopes for the best fit lines between the 10Be production and
the 10Be measurements used in the cross correlation analysis are all in the
range 0.4-0.6. This is a particular problem for historical projections of solar
activity based on ice core measurements which assume a 1:1 correspondence. We
have made other tests of the correspondence between the 10Be predictions and
the ice core measurements which lead to the same conclusion, namely that other
influences on the ice core measurements, as large as or larger than the
production changes themselves, are occurring. These influences could be
climatic or instrumentally based. We suggest new ice core measurements that
might help in defining more clearly what these influences are and-if
possible-to correct for them.Comment: 24 pages, 6 figure
Determinants of the Mechanical Behavior of Human Lumbar Vertebrae After Simulated Mild Fracture
The ability of a vertebra to carry load after an initial deformation and the determinants of this postfracture load-bearing capacity are critical but poorly understood. This study aimed to determine the mechanical behavior of vertebrae after simulated mild fracture and to identify the determinants of this postfracture behavior. Twenty-one human L3 vertebrae were analyzed for bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) and for microarchitecture by microβcomputed tomography (Β΅CT). Mechanical testing was performed in two phases: initial compression of vertebra to 25% deformity, followed, after 30 minutes of relaxation, by a similar test to failure to determine postfracture behavior. We assessed (1) initial and postfracture mechanical parameters, (2) changes in mechanical parameters, (3) postfracture elastic behavior by recovery of vertebral height after relaxation, and (4) postfracture plastic behavior by residual strength and stiffness. Postfracture failure load and stiffness were 11% Β± 19% and 53% Β± 18% lower than initial values (p = .021 and p < .0001, respectively), with 29% to 69% of the variation in the postfracture mechanical behavior explained by the initial values. Both initial and postfracture mechanical behaviors were significantly correlated with bone mass and microarchitecture. Vertebral deformation recovery averaged 31% Β± 7% and was associated with trabecular and cortical thickness (r = 0.47 and r = 0.64; p = .03 and p = .002, respectively). Residual strength and stiffness were independent of bone mass and initial mechanical behavior but were related to trabecular and cortical microarchitecture (|r| = 0.50 to 0.58; p = .02 to .006). In summary, we found marked variation in the postfracture load-bearing capacity following simulated mild vertebral fractures. Bone microarchitecture, but not bone mass, was associated with postfracture mechanical behavior of vertebrae. Β© 2011 American Society for Bone and Mineral Research
Treatment with intravenous pamidronate is a good alternative in case of gastrointestinal side effects or contraindications for oral bisphosphonates
<p>Abstract</p> <p>Background</p> <p>In case of contraindications or intolerance during treatment with oral bisphosphonates (OB), administration of pamidronate intravenously is a widely used alternative.</p> <p>In this study we compared the effect on change in bone mineral density (BMD) of the spine and hip during long term treatment with pamidronate iv in comparison to OB.</p> <p>Methods</p> <p>We studied 61 patients receiving treatment for at least two years. In case of contraindications or intolerance (within 3 months) of an OB, pamidronate iv was started. BMD was measured on a Hologic 4500 and a Lunar DPX-IQ at the spine (L1-L4) and total hip.</p> <p>Results</p> <p>Thirty-one patients were enrolled in the OB group and 30 in the intravenous pamidronate group. Mean follow-up duration (SD) was 4.3 (1.3) years. We observed a significant increase (p < 0.001) in spinal BMD, both in the OB group (8.3%) as well as in the pamidronate iv group (6.1%), but no significant difference in BMD change between the OB and pamidronate iv groups. At the hips, we observed a tendency to increased BMD in both groups, 1.1% in the OB and 1.4% in the pamidronate iv group.</p> <p>Conclusion</p> <p>We conclude that intravenous pamidronate is a good alternative for oral bisphosphonates in the treatment of osteoporosis in patients with contraindications or intolerance during treatment with oral bisphosphonates.</p
Timing and risk factors for clinical fractures among postmenopausal women: a 5-year prospective study
BACKGROUND: Many risk factors for fractures have been documented, including low bone-mineral density (BMD) and a history of fractures. However, little is known about the short-term absolute risk (AR) of fractures and the timing of clinical fractures. Therefore, we assessed the risk and timing of incident clinical fractures, expressed as 5-year AR, in postmenopausal women. METHODS: In total, 10 general practice centres participated in this population-based prospective study. Five years after a baseline assessment, which included clinical risk factor evaluation and BMD measurement, 759 postmenopausal women aged between 50 and 80 years, were re-examined, including undergoing an evaluation of clinical fractures after menopause. Risk factors for incident fractures at baseline that were significant in univariate analyses were included in a multivariate Cox survival regression analysis. The significant determinants were used to construct algorithms. RESULTS: In the total group, 12.5% (95% confidence interval (CI) 10.1β14.9) of the women experienced a new clinical fracture. A previous clinical fracture after menopause and a low BMD (T-score <-1.0) were retained as significant predictors with significant interaction. Women with a recent previous fracture (during the past 5 years) had an AR of 50.1% (95% CI 42.0β58.1) versus 21.2% (95% CI 20.7β21.6) if the previous fracture had occurred earlier. In women without a fracture history, the AR was 13.8% (95% CI 10.9β16.6) if BMD was low and 7.0% (95% CI 5.5β8.5) if BMD was normal. CONCLUSION: In postmenopausal women, clinical fractures cluster in time. One in two women with a recent clinical fracture had a new clinical fracture within 5 years, regardless of BMD. The 5-year AR for a first clinical fracture was much lower and depended on BMD
Marking their own homework: The pragmatic and moral legitimacy of industry self-regulation
When is industry self-regulation (ISR) a legitimate form of governance? In principle, ISR can serve the interests of participating companies, regulators and other stakeholders. However, in practice, empirical evidence shows that ISR schemes often under-perform, leading to criticism that such schemes are tantamount to firms marking their own homework. In response, this paper explains how current management theory on ISR has failed to separate the pragmatic legitimacy of ISR based on self-interested calculations, from moral legitimacy based on normative approval. The paper traces three families of management theory on ISR and uses these to map the pragmatic and moral legitimacy of ISR schemes. It identifies tensions between the pragmatic and moral legitimacy of ISR schemes, which the current ISR literature does not address, and draws implications for the future theory and practice of ISR
Ethnic difference of clinical vertebral fracture risk
Vertebral fractures are the most common osteoporotic fractures. Data on the vertebral fracture risk in Asia remain sparse. This study observed that Hong Kong Chinese and Japanese populations have a less dramatic increase in hip fracture rates associated with age than Caucasians, but the vertebral fracture rates were higher, resulting in a high vertebral-to-hip fracture ratio. As a result, estimation of the absolute fracture risk for Asians may need to be readjusted for the higher clinical vertebral fracture rate. Introduction: Vertebral fractures are the most common osteoporotic fractures. Data on the vertebral fracture risk in Asia remain sparse. The aim of this study was to report the incidence of clinical vertebral fractures among the Chinese and to compare the vertebral-to-hip fracture risk to other ethnic groups. Methods: Four thousand, three hundred eighty-six community-dwelling Southern Chinese subjects (2,302 women and 1,810 men) aged 50 or above were recruited in the Hong Kong Osteoporosis Study since 1995. Baseline demographic characteristics and medical history were obtained. Subjects were followed annually for fracture outcomes with a structured questionnaire and verified by the computerized patient information system of the Hospital Authority of the Hong Kong Government. Only non-traumatic incident hip fractures and clinical vertebral fractures that received medical attention were included in the analysis. The incidence rates of clinical vertebral fractures and hip fractures were determined and compared to the published data of Swedish Caucasian and Japanese populations. Results: The mean age at baseline was 62 Β± 8.2 years for women and 68 Β± 10.3 years for men. The average duration of follow-up was 4.0 Β± 2.8 (range, 1 to 14) years for a total of 14,733 person-years for the whole cohort. The incidence rate for vertebral fracture was 194/100,000 person-years in men and 508/100,000 person-years in women, respectively. For subjects above the age of 65, the clinical vertebral fracture and hip fracture rates were 299/100,000 and 332/100,000 person-years, respectively, in men, and 594/100,000 and 379/100,000 person-years, respectively, in women. Hong Kong Chinese and Japanese populations have a less dramatic increase in hip fracture rates associated with age than Caucasians. At the age of 65 or above, the hip fracture rates for Asian (Hong Kong Chinese and Japanese) men and women were less than half of that in Caucasians, but the vertebral fracture rate was higher in Asians, resulting in a high vertebral-to-hip fracture ratio. Conclusions: The incidences of vertebral and hip fractures, as well as the vertebral-to-hip fracture ratios vary in Asians and Caucasians. Estimation of the absolute fracture risk for Asians may need to be readjusted for the higher clinical vertebral fracture rate. Β© 2011 The Author(s).published_or_final_versionSpringer Open Choice, 21 Feb 201
Bone turnover is adequately suppressed in osteoporotic patients treated with bisphosphonates in daily practice
<p>Abstract</p> <p>Background</p> <p>Monitoring osteoporosis therapy by measurement of bone turnover markers (BTMs) might detect non-compliance in an earlier stage of anti-osteoporosis treatment and improve persistence.</p> <p>Methods</p> <p>BTMs were measured in two groups. The first group consisted of patients newly diagnosed with osteoporosis and starting treatment. We observed which proportion of patients had a decrease of serum levels of procollagen type 1 N-terminal propeptide (P1NP) and C-terminal crosslinking telopeptide (CTX) greater than the least significant change (LSC) after 3 months of treatment. Secondly, we determined which proportion of patients who were treated with bisphosphonates for β₯ 3 months reached the biological goal of therapy, BTMs in the lower half of the normal premenopausal range. P1NP and CTX were also measured in a reference population of 34 healthy premenopausal women.</p> <p>Results</p> <p>In the first group 31 patients were included, in 25 patients (81%) levels of both markers decreased with β₯ LSC, in the other patients a possible explanation was found.</p> <p>In the second group 95 patients were included, in 95% the serum P1NP levels and CTX levels were in the lower half of the premenopausal range. In 6 of the 7 patients with a level above the premenopausal range a possible explanation was found.</p> <p>Conclusion</p> <p>A decrease in bone turnover β₯ LSC can be observed in the majority of newly treated patients. In chronically treated patients, 95% have a bone turnover in the premenopausal range. In most patients with inadequate suppression of BTMs during bisphosphonate treatment, an explanation was found. Monitoring treatment effect with BTMs in daily practice is feasible, and might be an additive tool in improving therapy compliance.</p
Reduction in Fracture Rate and Back Pain and Increased Quality of Life in Postmenopausal Women Treated with Teriparatide: 18-Month Data from the European Forsteo Observational Study (EFOS)
The European Forsteo Observational Study was designed to examine the effectiveness of teriparatide in postmenopausal women with osteoporosis treated for up to 18Β months in normal clinical practice in eight European countries. The incidence of clinical vertebral and nonvertebral fragility fractures, back pain, and health-related quality of life (HRQoL, EQ-5D) were assessed. Spontaneous reports of adverse events were collected. All 1,648 enrolled women were teriparatide treatment-naive, 91.0% of them had previously received other anti-osteoporosis drugs, and 72.8% completed the 18-month study. A total of 168 incident clinical fractures were sustained by 138 (8.8%) women (821 fractures/10,000 patient-years). A 47% decrease in the odds of fracture in the last 6-month period compared to the first 6-month period was observed (PΒ <Β 0.005). Mean back pain VAS was reduced by 25.8Β mm at end point (PΒ <Β 0.001). Mean change from baseline in EQ-VAS was 13Β mm by 18Β months. The largest improvements were reported in the EQ-5D subdomains of usual activities and pain/discomfort. There were 365 adverse events spontaneously reported, of which 48.0% were considered related to teriparatide; adverse events were the reason for discontinuation for 79 (5.8%) patients. In conclusion, postmenopausal women with severe osteoporosis who were prescribed teriparatide in standard clinical practice had a significant reduction in the incidence of fragility fractures and a reduction in back pain over an 18-month treatment period. This was associated with a clinically significant improvement in HRQoL. Safety was consistent with current prescribing information. These results should be interpreted in the context of the open-label, noncontrolled design of the study
Patient preference and acceptability of calcium plus vitamin D3 supplementation: a randomised, open, cross-over trial
Preference for a drug formulation is important in adherence to long-term medication for chronic illnesses such as osteoporosis. We investigated the preference for and acceptability of chewable tablet containing calcium and vitamin D (Calci Chew D3, Nycomed) compared to that of a sachet containing calcium and vitamin D3 (Cad, Will-Pharma). This open, randomised, cross-over trial was set up to compare the preference and acceptability of two calcium plus vitamin D3 formulations (both with 500Β mg calcium and 400/440Β IU vitamin D3), given twice a day in patients with osteoporosis. Preference and acceptability were assessed by means of questionnaires. Preference was determined by asking the question, which treatment the patient preferred, and acceptability was measured by scoring five variables, using rating scales. Of the 102 patients indicating a preference for a trial medication, 67% preferred the chewable tablet, 19% the sachet with calcium and vitamin D3, and 15% stated no preference. The significant preference for Calci Chew D3 (pβ<β0.0001) was associated with higher scores for all five acceptability variables. The two formulations were tolerated equally well. A significant greater number of patients considered the chewable tablet as preferable and acceptable to the sachet, containing calcium and vitamin D3. Trial registration: Current Controlled Trials ISRCTN18822358
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