Improvement and decline in health status from late middle age: Modeling age-related changes in deficit accumulation

Arnold Mitnitski; Xiaowei Song; Kenneth Rockwood

doi:10.1016/j.exger.2007.08.002

Improvement and decline in health status from late middle age: Modeling age-related changes in deficit accumulation

Arnold Mitnitski, Xiaowei Song, Kenneth Rockwood

Medicine

Research output: Contribution to journal › Article › peer-review

53 Citations (Scopus)

Abstract

In a prospective multi-panel cohort study, we investigated how, from late middle age, individuals' health status improves or declines. In the Canadian National Population Health Survey, transition probabilities between different health states were estimated for 4330 people (58.8% women) aged 55+ at baseline over 2-year intervals from 1994 to 2000. Health status was defined by a deficit count, using 33 health-related variables combined in a frailty index. For each time interval, the chance of accumulating deficits increased linearly with the number of deficits. Older survivors (aged 70-85) showed a slightly lower chance of stability or improvement (52%; 95% confidence interval 50-54%) compared with those in late middle age (56%; 54-58%). Changes in health states can be described with high accuracy (R² = 0.92) by a modified Poisson distribution, using four parameters: the background odds of accumulating additional deficits, the chance of incurring more or fewer deficits, given the existing number, and the corresponding probabilities of dying. An age-invariant limit to deficit accumulation was observed at 22 deficits. From late middle age, transitions in health states occur with a regularity that is easily modeled. Improvements in health can occur at any age. At all ages, there is a limit to deficit accumulation.

Original language	English
Pages (from-to)	1109-1115
Number of pages	7
Journal	Experimental Gerontology
Volume	42
Issue number	11
DOIs	https://doi.org/10.1016/j.exger.2007.08.002
Publication status	Published - Nov 2007

Bibliographical note

Funding Information:
The study was funded by the Canadian Institutes of Health Research, through a grant to A.M. and K.R., MOP64169. The sponsor had no role in the study’s design or conduct. The data come from the longitudinal survey component of the National Population Health Survey (of Canada). The data are stored independently from us by Statistics Canada, but accessed through the Atlantic Regional Data Centre, in accordance with an established data access protocol, in which we become deemed employees of Statistics Canada. Statistics Canada reviewed the data to ensure that confidentiality is maintained, which was achieved by not releasing information in which fewer than five persons per cell are presented. This had the effect of truncating our estimates for data close to the limit of the distribution of the frailty index. Otherwise, Statistics Canada has no role in the conduct of the research.

ASJC Scopus Subject Areas

Biochemistry
Ageing
Molecular Biology
Genetics
Endocrinology
Cell Biology

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10.1016/j.exger.2007.08.002

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title = "Improvement and decline in health status from late middle age: Modeling age-related changes in deficit accumulation",

abstract = "In a prospective multi-panel cohort study, we investigated how, from late middle age, individuals' health status improves or declines. In the Canadian National Population Health Survey, transition probabilities between different health states were estimated for 4330 people (58.8% women) aged 55+ at baseline over 2-year intervals from 1994 to 2000. Health status was defined by a deficit count, using 33 health-related variables combined in a frailty index. For each time interval, the chance of accumulating deficits increased linearly with the number of deficits. Older survivors (aged 70-85) showed a slightly lower chance of stability or improvement (52%; 95% confidence interval 50-54%) compared with those in late middle age (56%; 54-58%). Changes in health states can be described with high accuracy (R2 = 0.92) by a modified Poisson distribution, using four parameters: the background odds of accumulating additional deficits, the chance of incurring more or fewer deficits, given the existing number, and the corresponding probabilities of dying. An age-invariant limit to deficit accumulation was observed at 22 deficits. From late middle age, transitions in health states occur with a regularity that is easily modeled. Improvements in health can occur at any age. At all ages, there is a limit to deficit accumulation.",

author = "Arnold Mitnitski and Xiaowei Song and Kenneth Rockwood",

note = "Funding Information: The study was funded by the Canadian Institutes of Health Research, through a grant to A.M. and K.R., MOP64169. The sponsor had no role in the study{\textquoteright}s design or conduct. The data come from the longitudinal survey component of the National Population Health Survey (of Canada). The data are stored independently from us by Statistics Canada, but accessed through the Atlantic Regional Data Centre, in accordance with an established data access protocol, in which we become deemed employees of Statistics Canada. Statistics Canada reviewed the data to ensure that confidentiality is maintained, which was achieved by not releasing information in which fewer than five persons per cell are presented. This had the effect of truncating our estimates for data close to the limit of the distribution of the frailty index. Otherwise, Statistics Canada has no role in the conduct of the research. ",

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Improvement and decline in health status from late middle age: Modeling age-related changes in deficit accumulation

Abstract

Bibliographical note

ASJC Scopus Subject Areas

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