Yashin Anatoli I, Arbeev Konstantin G, Kulminski Alexander, Akushevich Igor, Akushevich Lucy, Ukraintseva Svetlana V
Sociology Department, Duke University, Durham, North Carolina 27708, USA.
Rejuvenation Res. 2007 Mar;10(1):75-86. doi: 10.1089/rej.2006.0500.
The composite index constructed from longitudinal survey data as the level of deficits accumulated by an individual (frailty index) captures important systemic aspects of deterioration in a human organism, and is an attractive candidate for studying determinants of aging and longevity. The objective of this paper was to investigate the ability of this index to characterize human aging, mortality, and longevity. We use 32 variables from the National Long Term Care Survey data characterizing health and daily activities deficits to construct the cumulative frailty index. We use the Cox's proportional hazard model to describe its contribution to mortality. The risk of death considered as the function of the frailty index has asymmetric U-shaped form. The asymmetric U-function of the absolute risk is getting steeper (narrower) with age. The asymmetric U-function describing the relative risk exhibits the opposite tendency with age. The narrowing of the absolute risk functions with age reflects the age-related decline in stress resistance. The widening of the relative risk function with age indicates an increase in the relative contribution of other, unobserved, risk factors (including senescence) to the risk of death. This suggests increasing the role of senescence per se in the increasing risk of death with age compared to the role of specific pathology.
从纵向调查数据构建的综合指数作为个体累积的缺陷水平（衰弱指数），捕捉了人类机体衰退的重要系统方面，是研究衰老和长寿决定因素的一个有吸引力的候选指标。本文的目的是研究该指数刻画人类衰老、死亡率和长寿的能力。我们使用来自国家长期护理调查数据的32个表征健康和日常活动缺陷的变量来构建累积衰弱指数。我们使用Cox比例风险模型来描述其对死亡率的贡献。将死亡风险视为衰弱指数的函数呈不对称U形。绝对风险的不对称U函数随年龄增长变得更陡（更窄）。描述相对风险的不对称U函数随年龄呈现相反趋势。绝对风险函数随年龄变窄反映了与年龄相关的应激抵抗能力下降。相对风险函数随年龄变宽表明其他未观察到的风险因素（包括衰老）对死亡风险的相对贡献增加。这表明与特定病理的作用相比，衰老本身在随年龄增长的死亡风险增加中作用越来越大。
