Browsing by Author "Ukraintseva, S"

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    Age-Associated Disorders As A Proxy Measure Of Biological Age: Findings From the NLTCS Data
    (2017-06-07) Kulminski, A; Yashin, A; Ukraintseva, S; Akushevich, I; Arbeev, K; Land, K; Manton, K
    Background: The relative contribution of different aging-associated processes to the age phenotype may differ among individuals, creating variability in aging manifestations among age-peers. Capturing this variability can significantly advance understanding the aging and mortality. An index of age-associated health disorders (deficits), called a "frailty index" (FI), appears to be a promising characteristic of such processes. In this study we address the connections of the FI with age focusing on disabled individuals who might be at excessive risk of frailty. Methods: The National Long Term Care Survey (NLTCS) assessed health and functioning of the U.S. elderly in 1982, 1984, 1989, 1994, and 1999. Detailed information for our sample was assessed from about 26,700 interviews. The individual FI is defined as a proportion of deficits for a given person. We perform cross-sectional empirical analysis of the FI age-patterns. Results: FI in the NLTCS exhibits accelerated (quadratic) increase with age. Deficits might accumulate faster among the elderly who, at younger ages, had a low mean FI ("healthy" group) than a high FI ("disabled" group). Age-patterns for "healthy" and "disabled" groups converge at advanced ages. The rate of deficit accumulation is sex-sensitive. Convergence of the (sex-specific) FI for "healthy" and "disabled" groups in later ages determines biological age limits, associated with given levels of health-maintenance in the society, which correspond to 109.4 years for females and 92.5 years for males. Conclusions: The FI can be employed as a measure of biological age and population heterogeneity for modeling aging processes and mortality in elderly individuals.
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    Frailty Index as a Major Indicator of Aging Processes and Mortality in Elderly: Results From Analyses of the National Long Term Care Survey Data
    (2017-06-07) Kulminski, A; Yashin, A; Akushevich, I; Ukraintseva, S; Land, K; Arbeev, K; Manton, K
    To better understand mortality change with age capturing the variability in individuals' rates of aging, we performed comprehensive analysis of statistical properties of a cumulative index of age-associated disorders (deficits), called a "frailty index" (FI). This index is calculated as the proportion of the health deficits in an individual. It is found, first, that frequency, time-to-death, mortality-rate, and relative-risk-of-death exhibit remarkably similar FI- and age- patterns. Second, the FI, on the one hand, and mortality rate and relative risk, on the other hand, also exhibit similar age patterns with accelerated increase up to oldest-old ages and with subsequent deceleration and even decline. Third, distribution of the FI with time-to-death is sharper than that of age with time-to-death. These and related findings support the conclusion that the FI can describe aging processes and population heterogeneity. We also discuss the ability of the FI to capture physiological processes underlying aging both on individual and population levels.
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    Joint analysis of health histories, physiological state, and survival
    (Mathematical Population Studies, 2011-12-01) Yashin, AI; Akushevich, I; Arbeev, KG; Kulminski, A; Ukraintseva, S
    Data on individual health histories, age trajectories of physiological or biological variables, and mortality allow for the study of the joint evolution of health and physiological states and their effects on mortality. Individual health and physiological trajectories are described using a stochastic process with two mutuallydependent continuous and jumping components. The parameters of this process and mortality rate are identified from the data in which the continuous component is measured in discrete times, and transitions of jumping process are observed. © Taylor & Francis Group, LLC.
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    PHYSIOLOGICAL DYSREGULATION AS PROMISING MEASURE OF ROBUSTNESS AND RESILIENCE IN AGING STUDIES
    (GERONTOLOGIST, 2016-11) Arbeev, K; Ukraintseva, S; Bagley, O; Duan, M; Arbeeva, L; Zhbannikov, I; Cohen, A; Yashin, AI