3,449 research outputs found
Conditional Choice Modelling of Time Allocation Among Spouses in Transport Settings
As part of a wider rule-based model of activity behaviour, this paper explores the possibility to build a suite of linked conditional choice models to predict the amount of time spouses in a household spend on a set of activities together and alone. First, a choice model is used to predict the probability and hence the amount of time the spouses spend together and alone. Conditional on the outcome of this choice model, a second model predicts the amount of time that is spent by each spouse separately on a set of activities, as a function of sociodemographics, car availability and work status. The model is estimated using a small sample in Hendrik-Ido-Ambacht and Zwijndrecht in the Netherlands. The results indicate the model to have face validity. Rho-square values are also high
Higher Education Is Associated with a Lower Risk of Dementia after a Stroke or TIA. The Rotterdam Study
Background: Higher education is associated with a lower risk of dementia, possibly because of a higher tolerance to subclinical neurodegenerative pathology. Whether higher education also protects against dementia after clinical stroke or transient ischemic attack (TIA) remains unknown. Methods: Within the population-based Rotterdam Study, 12,561 participants free of stroke, TIA and dementia were followed for occurrence of stroke, TIA and dementia. Across the levels of education, associations of incident stroke or TIA with subsequent development of dementia and differences in cognitive decline following stroke or TIA were investigated. Results: During 124,862 person-years, 1,463 persons suffered a stroke or TIA, 1,158 persons developed dementia, of whom 186 developed dementia after stroke or TIA. Risk of dementia after a stroke or TIA, compared to no stroke or TIA, was highest in the low education category (hazards ratio [HR] 1.46, 95% CI 1.18-1.81) followed by intermediate education category (HR 1.36, 95% CI 1.03-1.81). No significant association was observed in the high education category (HR 0.62, 95% CI 0.25-1.54). In gender stratified analyses, decrease in risk of dementia with increasing education was significant only in men. Conclusion: Higher education is associated with a lower risk of dementia after stroke or TIA, particularly in men, which might be explained by a higher cognitive reserve. (C) 2016 S. Karger AG, Base
Higher Education Is Associated with a Lower Risk of Dementia after a Stroke or TIA. The Rotterdam Study
Background: Higher education is associated with a lower risk of dementia, possibly because of a higher tolerance to subclinical neurodegenerative pathology. Whether higher education also protects against dementia after clinical stroke or transient ischemic attack (TIA) remains unknown. Methods: Within the population-based Rotterdam Study, 12,561 participants free of stroke, TIA and dementia were followed for occurrence of stroke, TIA and dementia. Across the levels of education, associations of incident stroke or TIA with subsequent development of dementia and differences in cognitive decline following stroke or TIA were investigated. Results: During 124,862 person-years, 1,463 persons suffered a stroke or TIA, 1,158 persons developed dementia, of whom 186 developed dementia after stroke or TIA. Risk of dementia after a stroke or TIA, compared to no stroke or TIA, was highest in the low education category (hazards ratio [HR] 1.46, 95% CI 1.18-1.81) followed by intermediate education category (HR 1.36, 95% CI 1.03-1.81). No significant association was observed in the high education category (HR 0.62, 95% CI 0.25-1.54). In gender stratified analyses, decrease in risk of dementia with increasing education was significant only in men. Conclusion: Higher education is associated with a lower risk of dementia after stroke or TIA, particularly in men, which might be explained by a higher cognitive reserve. (C) 2016 S. Karger AG, Base
Orthostatic Hypotension and the Long-Term Risk of Dementia: A Population-Based Study
Background: Orthostatic hypotension (OH) is a common cause of transient cerebral hypoperfusion in the population. Cerebral hypoperfusion is widely implicated in cognitive impairment, but whether OH contributes to cognitive decline and dementia is uncertain. We aimed to determine the association between OH and the risk of developing dementia in the general population. Methods and Findings: Between 4 October 1989 and 17 June 1993, we assessed OH in non-demented, stroke-free participants of the population-based Rotterdam Study. OH was defined as a ≥20 mm Hg drop in systolic blood pressure (SBP) or ≥10 mm Hg drop in diastolic blood pressure (DBP) within 3 min from postural change. We furthermore calculated within participant variability in SBP related to postural change, expressed as coefficient of variation. Follow-up for dementia was conducted until 1 January 2014. We determined the risk of dementia in relation to OH and SBP variability, using a Cox regression model, adjusted for age; sex; smoking status; alcohol intake; SBP; DBP; cholesterol:high-density lipoprotein ratio; diabetes; body mass index; use of antihypertensive, lipid-lowering, or anticholinergic medication; and apolipoprotein E genotype. Finally, we explored whether associations varied according to compensatory increase in heart rate. Among 6,204 participants (mean ± standard deviation [SD] age 68.5 ± 8.6 y, 59.7% female) with a median follow-up of 15.3 y, 1,176 developed dementia, of whom 935 (79.5%) had Alzheimer disease and 95 (8.1%) had vascular dementia. OH was associated with an increased risk of dementia (adjusted hazard ratio [aHR] 1.15, 95% CI 1.00–1.34, p = 0.05), which was similar for Alzheimer disease and vascular dementia. Similarly, greater SBP variability with postural change was associated with an increased risk of dementia (aHR per SD increase 1.08, 95% CI 1.01–1.16, p = 0.02), which was similar when excluding those who fulfilled the formal criteria for OH (aHR 1.08, 95% CI 1.00–1.17, p = 0.06). The risk of dementia was particularly increased in those with OH who lacked a compensatory increase in heart rate (within lowest quartile of heart rate response: aHR 1.39, 95% CI 1.04–1.85, p-interaction = 0.05). Limitations of this study include potential residual confounding despite rigorous adjustments, and potentially limited generalisability to populations not of European descent. Conclusions: In this population predominantly of European descent, OH was associated with an increase in long-term risk of dementia
Forgotten electrical accidents and the birth of shockproof X-ray systems
OBJECTIVES: To commemorate victims of electrical accidents that occurred in the first decades of radiology and relate these accidents to the evolution of the X-ray apparatus. METHODS: Digitised newspapers, scientific journals, books and reports of legal procedures were searched for electrical accidents involving X-ray systems. Information on the historical systems was retrieved from the scientific literature and brochures from manufacturers. RESULTS: We found 51 fatal and 62 non-fatal but serious electrical accidents. Most of them occurred between 1920 and 1940 and involved transformers that provided output currents well above the threshold for the induction of ventricular fibrillation. The accidents led to recommendations and regulations to improve safety for operators and patients, and spurred manufacturers to technical developments that culminated in fully electrically shockproof systems by 1935. CONCLUSIONS: Although largely forgotten, the development of the shockproof X-ray systems we take for granted today lasted about 4 decades and was associated with considerable human suffering. The complete solution of the problem is a success story of engineering realised by contributions from all parties involved. MAIN MESSAGES: • The development of electrically shockproof X-ray systems took about 4 decades (1895-1935). • Between 1896 and 1920 electrical shocks from X-ray systems were common, but their consequences limited. • After 1920, transformers killed by delivering currents above the ventricular fibrillation threshold. • Inductors, static generators and high-frequency coils were generally low-current systems and safe. • We found 51 fatal and 62 serious non-fatal electrical accidents, most occurring from 1920 to 1940
Low levels of endogenous androgens increase the risk of atherosclerosis in elderly men: the Rotterdam study
In both men and women, circulating androgen levels decline with advancing
age. Until now, results of several small studies on the relationship
between endogenous androgen levels and atherosclerosis have been
inconsistent. In the population-based Rotterdam Study, we investigated the
association of levels of dehydroepiandrosterone sulfate (DHEAS) and total
and bioavailable testosterone with aortic atherosclerosis among 1,032
nonsmoking men and women aged 55 yr and over. Aortic atherosclerosis was
assessed by radiographic detection of calcified deposits in the abdominal
aorta, which have been shown to reflect intimal atherosclerosis. Relative
to men with levels of total and bioavailable testosterone in the lowest
tertile, men with levels of these hormones in the highest tertile had
age-adjusted relative risks of 0.4 [95% confidence interval (CI), 0.2-0.9]
and 0.2 (CI, 0.1-0.7), respectively, for the presence of severe aortic
atherosclerosis. The corresponding relative risks for women were 3.7 (CI,
1.2-11.6) and 2.3 (CI, 0.7-7.8). Additional adjustment for cardiovascular
disease risk factors did not materially affect the results in men, whereas
in women the associations diluted. Men with levels of total and
bioavailable testosterone in subsequent tertiles were also protected
against progression of aortic atherosclerosis measured after 6.5 yr (SD
+/- 0.5 yr) of follow-up (P for trend = 0.02). No clear association
between levels of DHEAS and presence of severe aortic atherosclerosis was
found, either in men or in women. In men, a protective effect of higher
levels of DHEAS against progression of aortic atherosclerosis was
suggested, but the corresponding test for trend did not reach statistical
significance. In conclusion, we found an independent inverse association
between levels of testosterone and aortic atherosclerosis in men. In
women, positive associations between levels of testosterone and aortic
atherosclerosis were largely due to adverse cardiovascular disease risk
factors
Higher education is associated with a lower risk of dementia after a stroke or TIA
__Background:__ Higher education is associated with a lower risk of dementia, possibly because of a higher tolerance to subclinical neurodegenerative pathology. Whether higher education also protects against dementia after clinical stroke or transient ischemic attack (TIA) remains unknown.
__Methods:__ Within the population-based Rotterdam Study, 12,561 participants free of stroke, TIA and dementia were followed for occurrence of stroke, TIA and dementia. Across the levels of education, associations of incident stroke or TIA with subsequent development of dementia and differences in cognitive decline following stroke or TIA were investigated.
__Results:__ During 124,862 person-years, 1,463 persons suffered a stroke or TIA, 1,158 persons developed dementia, of whom 186 developed dementia after stroke or TIA. Risk of dementia after a stroke or TIA, compared to no stroke or TIA, was highest in the low education category (hazards ratio [HR] 1.46, 95% CI 1.18-1.81) followed by intermediate education category (HR 1.36, 95% CI 1.03-1.81). No significant association was observed in the high education category (HR 0.62, 95% CI 0.25-1.54). In gender stratified analyses, decrease in risk of dementia with increasing education was significant only in men.
__Conclusion:__ Higher education is associated with a lower risk of dementia after stroke or TIA, particularly in men, which might be explained by a higher cognitive reserve
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