Accumulation of Deficits as a Proxy Measure of Aging
This paper develops a method for appraising health status in elderly people. A frailty index was defined as the proportion of accumulated deficits (symptoms, signs, functional impairments, and laboratory abnormalities). It serves as an individual state variable, reflecting severity of illness and pr...
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| Format: | Article |
| Language: | English |
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Wiley
2001-01-01
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| Series: | The Scientific World Journal |
| Online Access: | http://dx.doi.org/10.1100/tsw.2001.58 |
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| author | Arnold B. Mitnitski Alexander J. Mogilner Kenneth Rockwood |
| author_facet | Arnold B. Mitnitski Alexander J. Mogilner Kenneth Rockwood |
| author_sort | Arnold B. Mitnitski |
| collection | DOAJ |
| description | This paper develops a method for appraising health status in elderly people. A frailty index was defined as the proportion of accumulated deficits (symptoms, signs, functional impairments, and laboratory abnormalities). It serves as an individual state variable, reflecting severity of illness and proximity to death. In a representative database of elderly Canadians we found that deficits accumulated at 3% per year, and show a gamma distribution, typical for systems with redundant components that can be used in case of failure of a given subsystem. Of note, the slope of the index is insensitive to the individual nature of the deficits, and serves as an important prognostic factor for life expectancy. The formula for estimating an individual�s life span given the frailty index value is presented. For different patterns of cognitive impairments the average within-group index value increases with the severity of the cognitive impairment, and the relative variability of the index is significantly reduced. Finally, the statistical distribution of the frailty index sharply differs between well groups (gamma distribution) and morbid groups (normal distribution). This pattern reflects an increase in uncompensated deficits in impaired organisms, which would lead to illness of various etiologies, and ultimately to increased mortality. The accumulation of deficits is as an example of a macroscopic variable, i.e., one that reflects general properties of aging at the level of the whole organism rather than any given functional deficiency. In consequence, we propose that it may be used as a proxy measure of aging. |
| format | Article |
| id | doaj-art-7f029d9b2e1c414c892b7be79126bdb0 |
| institution | Kabale University |
| issn | 1537-744X |
| language | English |
| publishDate | 2001-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | The Scientific World Journal |
| spelling | doaj-art-7f029d9b2e1c414c892b7be79126bdb02025-02-03T06:12:06ZengWileyThe Scientific World Journal1537-744X2001-01-01132333610.1100/tsw.2001.58Accumulation of Deficits as a Proxy Measure of AgingArnold B. Mitnitski0Alexander J. Mogilner1Kenneth Rockwood2Department of Mechanical Engineering, Ecole Polytechnique, Montreal, Quebec, H3C 3A7, CanadaDepartment of Mechanical Engineering, Ecole Polytechnique, Montreal, Quebec, H3C 3A7, CanadaDepartment of Mechanical Engineering, Ecole Polytechnique, Montreal, Quebec, H3C 3A7, CanadaThis paper develops a method for appraising health status in elderly people. A frailty index was defined as the proportion of accumulated deficits (symptoms, signs, functional impairments, and laboratory abnormalities). It serves as an individual state variable, reflecting severity of illness and proximity to death. In a representative database of elderly Canadians we found that deficits accumulated at 3% per year, and show a gamma distribution, typical for systems with redundant components that can be used in case of failure of a given subsystem. Of note, the slope of the index is insensitive to the individual nature of the deficits, and serves as an important prognostic factor for life expectancy. The formula for estimating an individual�s life span given the frailty index value is presented. For different patterns of cognitive impairments the average within-group index value increases with the severity of the cognitive impairment, and the relative variability of the index is significantly reduced. Finally, the statistical distribution of the frailty index sharply differs between well groups (gamma distribution) and morbid groups (normal distribution). This pattern reflects an increase in uncompensated deficits in impaired organisms, which would lead to illness of various etiologies, and ultimately to increased mortality. The accumulation of deficits is as an example of a macroscopic variable, i.e., one that reflects general properties of aging at the level of the whole organism rather than any given functional deficiency. In consequence, we propose that it may be used as a proxy measure of aging.http://dx.doi.org/10.1100/tsw.2001.58 |
| spellingShingle | Arnold B. Mitnitski Alexander J. Mogilner Kenneth Rockwood Accumulation of Deficits as a Proxy Measure of Aging The Scientific World Journal |
| title | Accumulation of Deficits as a Proxy Measure of Aging |
| title_full | Accumulation of Deficits as a Proxy Measure of Aging |
| title_fullStr | Accumulation of Deficits as a Proxy Measure of Aging |
| title_full_unstemmed | Accumulation of Deficits as a Proxy Measure of Aging |
| title_short | Accumulation of Deficits as a Proxy Measure of Aging |
| title_sort | accumulation of deficits as a proxy measure of aging |
| url | http://dx.doi.org/10.1100/tsw.2001.58 |
| work_keys_str_mv | AT arnoldbmitnitski accumulationofdeficitsasaproxymeasureofaging AT alexanderjmogilner accumulationofdeficitsasaproxymeasureofaging AT kennethrockwood accumulationofdeficitsasaproxymeasureofaging |