[show abstract][hide abstract] ABSTRACT: In several studies, investigators are interested in estimating the bivariate distribution of the onset ages of a generic disorder in successive generations. The empirical distribution is inappropriate for this purpose due to truncation: only parent–child pairs with onset ages prior to the ages at interview were included in the sample. In this paper, we propose a simple nonparametric estimator for the underlying bivariate distribution of the onset ages. Compared with the existing estimators, the proposed estimator has a closed form and smaller biases when estimating marginal distributions. A real example is used to illustrate this estimator.
Journal of Statistical Planning and Inference 01/2009; 139(6):2116-2116. · 0.71 Impact Factor
[show abstract][hide abstract] ABSTRACT: To determine whether cardiovascular (CV) risk is associated with subtle memory deficits in non-demented, healthy older women with a family history of Alzheimer disease (AD).
Baseline data of 375 participants from a randomized, double-blind placebo-controlled primary prevention trial to test the efficacy of hormone replacement therapy in delaying AD and cognitive decline were analyzed. All subjects were women over 65 with a family history of AD who had normal cognition and no active heart disease at baseline. A baseline memory composite score was calculated, consisting of immediate and delayed recall of verbal and nonverbal material. Multiple linear regression was performed to examine the association of relative CV risk with memory functioning; age, ethnicity and education level were included as covariates.
Mean baseline memory composite score was significantly higher in those with low relative CHD risk than those with high relative CHD risk.
These findings suggest that subtle elevation of CHD risk may negatively affect memory functioning even in otherwise healthy, non-demented older women without a history of heart disease.
Neurobiology of aging 10/2008; 31(7):1250-3. · 5.94 Impact Factor