Bone
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To increase knowledge about recent trends in the number and incidence of various low-trauma injuries among elderly people, we selected, from the National Hospital Discharge Register, all patients > or =60 years of age who were admitted to hospitals in Finland (5 million population) for primary treatment of a first low-trauma ankle fracture during 1970-2000. In each year of the study, the age-adjusted and age-specific incidence of fracture was expressed as the number of patients per 100,000 persons. The predicted numbers and incidence rates of fractures until the year 2030 were calculated using a regression model. ⋯ The age-adjusted incidence of these fractures also rose in both women (from 66 in 1970 to 174 in 2000, a 164% increase) and men (from 38 in 1970 to 114 in 2000, a 200% increase). The regression model indicates that, if this trend continues, there will be about three times more low-trauma ankle fractures in Finland in the year 2030 than there was in 2000. In conclusion, the number of low-trauma ankle fractures in elderly Finns is rising rapidly at a rate that cannot be explained simply by demographic changes and, therefore, potentially effective preventive measures, such as prevention of slippings, trippings, and falls in elderly people, and use of ankle supports, should be urgently studied.
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Parathyroid hormone (PTH) stimulates receptor activator of nuclear factor-kappaB ligand (RANKL) mRNA and inhibits osteoprotegerin (OPG) mRNA expression in murine bone marrow cultures. To understand the mechanisms influencing these responses, we investigated the role of the protein kinase A (PKA) and protein kinase C (PKC) pathways in the regulation of RANKL and OPG mRNA expression in murine bone marrow cultures. Murine bone marrow cells were stimulated with bovine PTH(1-34) and (1-34) amide, which activate both pathways; PTH(3-34), which more selectively activates the PKC and calcium pathways; and human PTH (1-31), which stimulates adenylyl cyclase, but not protein kinase C. ⋯ Neither PGHS inhibitor altered PMA-induced effects on RANKL and OPG mRNA expression. These results demonstrate that the PKA pathway is predominantly involved in the effects of PTH on RANKL mRNA expression in murine bone marrow cultures, but there is also a PKC-mediated response, which is not sustained. Inhibition of OPG by PTH appears to be a selective PKA response.
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The objective of this study was to compare the ability of clinically available densitometric measurement techniques for evaluating vertebral strength in elderly individuals. Measurements were related to experimentally determined failure strength in the thoracic and lumbar spine. In 127 specimens (82 women and 45 men, age 80 +/- 10 years), dual-energy X-ray absorptiometry (DXA) was performed at the lumbar spine, femur, radius, and total body, and peripheral-quantitative computed tomography (pQCT) at the distal radius, tibia, and femur under in situ conditions with intact soft tissues. ⋯ However, this was not the case in the thoracic spine, for which lumbar cortical density (QCT) and DXA provided significantly better estimates than trabecular density (QCT). pQCT was significantly less correlated with the strength of lumbar and thoracic vertebrae (r(2) = 40%), but was equivalent to femoral or radial DXA. pQCT measurements in the lower limb showed no advantage over those at the distal radius. Ultrasound explained approximately 25% of the variability of vertebral failure strength and added independent information to spinal QCT, but not to spinal DXA. These experimental results advocate site-specific assessment of vertebral strength by either spinal DXA or QCT.
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Physical activity during the first three decades of life may increase peak bone mass and reduce future osteoporosis risk. The aim of this study was to determine the extent to which different components of physical activity may influence bone mineral status within a representative population sample of young men and women. Bone mineral density (BMD) and content (BMC) were determined at the lumbar spine and femoral neck in 242 men and 212 women, aged 20-25 years, by dual-energy X-ray absorptiometry. ⋯ These results demonstrate the importance of sports activities, especially those involving high peak strain, in determining peak bone status in young men. Failure to observe this association in women reflects their lower participation in such activities, but they may have the same capacity to benefit from these activities as men. Intervention studies are warranted to determine whether peak bone density in women can be improved by participating, during childhood and adolescence, in sports activities involving high peak strain.
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Subclinical vitamin D deficiency may be common in certain subgroups in the U. S., but to date vitamin D data from other groups in the population have not been available. We used serum 25-hydroxyvitamin D (25-OHD) data from 18,875 individuals examined in the Third National Health and Nutrition Examination Survey (NHANES III 1988-1994) to assess the vitamin D status of selected groups of the noninstitutionalized U. ⋯ Of particular interest is that insufficiency occurred fairly frequently in younger individuals, especially in the winter/lower latitude subsample. Our findings support continued monitoring of this vitamin in the U. S. population.