Use of calcium supplements and the risk of coronary heart disease in 52-62-year-old women: The Kuopio Osteoporosis Risk Factor and Prevention Study
ABSTRACT To analyse prospectively the effect of calcium or calcium+D supplementation on coronary heart disease (CHD) in 52-62-year-old women.
10,555 52-62-year-old women from the population-based Kuopio Osteoporosis Risk Factor and Prevention Study (OSTPRE) who did not have CHD at baseline were followed for nearly 7 years in 1994-2001. Information about use of calcium supplements and health events was obtained from two repeated questionnaires in 1989 and 1994. Information about causes of death during the follow-up was obtained from the Statistics Finland. Information about CHD and other disease morbidity before and during the follow-up was obtained from the Registry of Specially Refunded Drugs of the Finnish Social Insurance Institution (SII). Cox's proportional-hazards models were used to estimate the risk of CHD morbidity related to the use of calcium supplements. At baseline, 2723 women reported current use of calcium or calcium+D supplementation. During the follow-up, CHD was diagnosed in 513 women. Compared to non-users of calcium/calcium+D supplements, the multivariate adjusted hazard ratio (HR) of CHD was 1.24 (95% CI 1.02-1.52) in women who used these supplements. The multivariate adjusted HR for CHD morbidity in postmenopausal women who used calcium/calcium+D supplements was 1.26 (95% CI 1.01-1.57).
Calcium or calcium+D supplementation appears to increase the risk of CHD among women before old age.
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ABSTRACT: The effect of the interprocessor communication (IPC) mechanism on system performance in a multiple-instruction-stream-multiple-data-stream (MIMD) parallel-processor system is investigated. The architecture and a high-level implementation are specified for a parallel-processor system which uses multiple horizontal and vertical buses to interconnect processing elements. A software simulator is developed to support evaluation of systems based on the architecture, and experiments are conducted with the simulator to evaluate system performance. As a basis for comparison simulations are also conducted for the architecture and implementation of a single-bus parallel-processor system derived from the horizontal/vertical-bus system. The experiments deal with the parallel solution of a five-body problem; system performance is measured as processor speed, and IPC mechanism speeds are varied independently over a wide range. The results demonstrate the significant effects on performance of both the problem partition and the relative speeds of the processors and the IPC mechanism; they also demonstrate the extent to which the multiple-bus architecture provides higher performance than the single-bus architecture in this applicationComputers and Communications, 1989. Conference Proceedings., Eighth Annual International Phoenix Conference on; 04/1989
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ABSTRACT: Calcium supplementation is widely used for the prevention of osteoporosis in postmenopausal women and in men. While there has been ongoing debate regarding its effectiveness in fracture prevention, the underlying assumption has been that, even if it was not particularly effective, at least it was safe. The recent finding of the Auckland Calcium Study that myocardial infarctions were more common in women randomised to calcium calls this assumption into question, and consideration of vascular event data from other calcium trials does not refute the Auckland findings. Meta-analyses of these data will be necessary to settle this matter. It is already accepted that calcium supplements increase vascular risk in patients with renal compromise, even in those not yet requiring dialysis. Also, there is substantial epidemiological evidence that serum calcium levels in the upper part of the normal range are a risk factor for vascular disease, and that calcium supplements acutely elevate serum calcium - a combination of findings that lends plausibility to supplementation increasing vascular risk. As there are reasonable grounds for doubting the safety of calcium supplements, and as the evidence for their efficacy in fracture prevention remains marginal, we suggest that there should be a reappraisal of their role in the management of osteoporosis, with a greater emphasis on agents known to prevent fractures.Clinical Endocrinology 02/2010; 73(6):689-95. DOI:10.1111/j.1365-2265.2010.03792.x · 3.35 Impact Factor