Doctoral Dissertation Research: Dynamic Analyses of Cognition and Mortality in the Oldest Old

越来越多的证据表明，认知能力与死亡率呈负相关，这种关联似乎与研究人群、队列和使用的认知测试无关。然而，在流行病学中，认知能力传统上不被考虑，而且它们对预测死亡率的附加价值尚不清楚。另一方面，认知衰退被认为是衰老过程的一个多方面的方面，但很少有研究在认知到死亡的变化过程中有相关的特征。对这些问题的研究在很大程度上受到了方法上的困难的阻碍。本项目将研究几种新方法来研究认知（特别是情景记忆和语言能力）与死亡率之间的关系，使用美国70岁及以上成年人的全国样本的纵向数据。这些方法将按渐进顺序使用，包括潜在曲线模型、混合效应变化点模型、联合生长和生存模型、传统的生存分析和递归划分技术（生存树和随机森林）。该项目将检查最年长人群的认知变化，并将其与死亡率联系起来。这一群体在人口中所占比例的增加正在影响许多社会和经济问题。本计画的实质结果可能对决策者在考虑安宁疗护计划时提供特别的资讯。在方法上，该项目将比较分析纵向和生存数据的不同方法，并将在生存分析中使用探索性数据挖掘。方法上的发现可能在行为科学和健康科学的许多领域有广泛的应用。作为博士论文研究改进奖，提供支持，使有前途的学生建立一个强大的，独立的研究生涯。

Evidence is accumulating that cognitive abilities are inversely associated with mortality, and this association seems to be present irrespective of study population, cohort, and the cognitive tests used. Cognitive abilities are not traditionally considered in epidemiology, however, and their additional value to the prediction of mortality is not clear. On the other hand, cognitive decline is viewed as one of the multifaceted aspects of the aging process, but few studies have related characteristics in the changing process of cognition to mortality. The examination of these problems largely has been impeded by methodological difficulties. This project will examine several novel methods to investigate the relations of cognition (in particular, episodic memory and verbal ability) and mortality using longitudinal data in a national sample of U.S. adults aged 70 years and older. These methods will be employed in a progressive order and will include latent curve models, mixed-effects change point models, joint growth and survival models, traditional survival analysis, and recursive partitioning techniques (survival trees and random forests). The project will examine cognitive change in the oldest population cohort and relate it to mortality. The increasing proportion of this group in the population is impacting many social and economic issues. The substantive results from this project may be especially informative for policy makers in considering hospice care plans. Methodologically, this project will compare alternative approaches to analyzing longitudinal and survival data and will employ exploratory data mining in survival analysis. The methodological finding may have broad applications for many fields in the behavioral and health sciences. As a Doctoral Dissertation Research Improvement award, support is provided to enable a promising student to establish a strong, independent research career.