Search results for "regression dilution"
showing 4 items of 4 documents
Lipoprotein(a) is not associated with venous thromboembolism risk.
2020
Objectives. Evidence from case-control studies as well as meta-analyses of these study designs suggest elevated lipoprotein(a) [Lp(a)] to be associated with an increased risk of venous thromboembolism (VTE). Prospective evidence on the association is limited, uncertain, and could be attributed to regression dilution bias. We aimed to assess the prospective association of Lp(a) with risk of VTE and correct for regression dilution. Design. We related plasma Lp(a) concentrations to the incidence of VTE in 2,180 men of the Kuopio Ischemic Heart Disease cohort study. Hazard ratios (HRs) (95% confidence intervals [CI]) were assessed and repeat measurements of Lp(a) at 4 and 11 years from baseline…
Physical activity may not be associated with long-term risk of dementia and Alzheimer's disease.
2020
Background: While it is well established that physical activity is associated with reduced risk of vascular and non-vascular outcomes as well as mortality, evidence on the association between physical activity and dementia is inconsistent. We aimed to assess the associations of physical activity with the risk of dementia and Alzheimer’s disease (AD).Material and methods: We analysed data on 2,394 apparently healthy men with good baseline cognitive function from the prospective population-based Kuopio Ischaemic Heart Disease study. We assessed habits of physical activity at baseline using a 12-month leisure-time physical activity (LTPA) questionnaire. Using Cox regression, we calculated haza…
On the ambiguous consequences of omitting variables
2015
This paper studies what happens when we move from a short regression to a long regression (or vice versa), when the long regression is shorter than the data-generation process. In the special case where the long regression equals the data-generation process, the least-squares estimators have smaller bias (in fact zero bias) but larger variances in the long regression than in the short regression. But if the long regression is also misspecified, the bias may not be smaller. We provide bias and mean squared error comparisons and study the dependence of the differences on the misspecification parameter.
Cardiorespiratory Fitness and the Risk of Serious Ventricular Arrhythmias: A Prospective Cohort Study.
2019
Cardiorespiratory fitness (CRF) is an established risk factor for cardiovascular disease outcomes. However, the relationship of CRF with risk of ventricular arrhythmias (VAs) is unknown. We aimed to assess the prospective association of CRF with the risk of serious VAs. Cardiorespiratory fitness, as measured by maximal oxygen uptake, was assessed using a respiratory gas exchange analyzer in 2299 middle-aged men in the Kuopio Ischemic Heart Disease prospective cohort. We corrected for within-person variability in CRF levels using data from repeated measurements 11 years apart. During median follow-up of 25.3 years (interquartile range, 18.7-27.2 years), 73 serious VAs were recorded. The age-…