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，而且这种相关性似乎与研究人群、队列和使用的认知测试无关。 然而，认知能力在流行病学中传统上不被考虑，它们对预测死亡率的附加价值也不清楚。 另一方面，认知能力下降被认为是老龄化过程的多方面之一，但很少有研究在认知对死亡率的变化过程中具有相关特征。 对这些问题的研究在很大程度上受到方法上的困难的阻碍。 该项目将研究几种新的方法来调查认知（特别是情景记忆和言语能力）和死亡率的关系，使用美国70岁及以上成年人的全国样本的纵向数据。 这些方法将以渐进的顺序使用，包括潜在曲线模型、混合效应变点模型、联合增长和生存模型、传统生存分析和递归分割技术（生存树和随机森林）。该项目将研究最老人群的认知变化，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。 这个项目的实质性结果可能是特别翔实的政策制定者在考虑临终关怀计划。 在方法上，本计画将比较分析纵向和存活资料的替代方法，并将探索性资料探勘应用于存活分析。 该方法的发现可能在行为和健康科学的许多领域具有广泛的应用。 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.