Frailty Index as a Major Indicator of Aging Processes and Mortality in Elderly: Results From Analyses of the National Long Term Care Survey Data


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.







Kenneth C. Land

John Franklin Crowell Distinguished Professor Emeritus of Sociology

I received my Ph.D. in sociology and mathematics from the University of Texas at Austin in 1969. After a year of postdoctoral study in mathematical statistics at Columbia University in New York City, I taught there and was a member of the staff of the Russell Sage Foundation for three years. I then was successively a member of the faculties of the University of Illinois at Urbana Champaign and the University of Texas at Austin before joining the Duke Sociology Department as Chairman in 1986. I served as Chair of Sociology from January 1986 to August 1997. My main research interests are contemporary social trends and quality-of-life measurement, social problems, demography, criminology, organizations, and mathematical and statistical models and methods for the study of social and demographic processes. I have done extensive research in each of these areas and have been elected a Fellow of the American Statistical Association (1978), the Sociological Research Association (1981), the American Association for the Advancement of Science (1992), the International Society for Quality-of-Life Studies (1997), and the American Society of Criminology (2004). I teach Contemporary Social Problems (SOCIOL 111), Advanced Methods of Demographic Analysis, and the Demography of Aging Proseminar (SOCIOL 750S). My other interests include tennis, jogging (10 kilometers), and music.


Konstantin Arbeev

Associate Research Professor in the Social Science Research Institute

Konstantin G. Arbeev received the M.S. degree in Applied Mathematics from Moscow State University (branch in Ulyanovsk, Russia) in 1995 and the Ph.D. degree in Mathematics and Physics (specialization in Theoretical Foundations of Mathematical Modeling, Numerical Methods and Programming) from Ulyanovsk State University (Russia) in 1999. He was a post-doctoral fellow in Max Planck Institute for Demographic Research in Rostock (Germany) before moving to Duke University in 2004 to work as a Research Scientist and a Senior Research Scientist in the Department of Sociology and the Social Science Research Institute (SSRI).  He is currently an Associate Research Professor in SSRI. Dr. Arbeev's major research interests are related to three interconnected fields of biodemography, biostatistics and genetic epidemiology as pertains to research on aging. The focus of his research is on discovering genetic and non-genetic factors that can affect the process of aging and determine longevity and healthy lifespan. He is interested in both methodological advances in this research area as well as their practical applications to analyses of large-scale longitudinal studies with phenotypic, genetic and, recently, genomic information. Dr. Arbeev authored and co-authored more than 150 peer-reviewed publications in these areas.

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