Hierarchy of higher-level physical functions: a longitudinal investigation on a nationally representative population of community-dwelling middle-aged and elderly persons.
OBJECTIVE
Understanding the hierarchy of higher-level physical functions to infer disability level (mild, moderate or severe) is essential for the precise targeting of preventive interventions and has been examined previously in a cross-sectional study. Based on longitudinal data, this study evaluated the hierarchy of higher-level physical functions.


METHODS
Data from a cohort of 2729 community-dwelling persons aged over 50 with no initial disability were drawn from the "Survey of Health and Living Status of the Elderly in Taiwan" from 1996 through 2007. The three-level hierarchy of eight chosen activities was examined by the median ages to disability onset with survival analyses and by Cox regressions, which examined the effects of sex and age on the development of this hierarchy.


RESULTS
The progression of incident disability was as follows: mild level-running, carrying weight, and squatting; moderate level-climbing stairs, walking, and standing; and severe level-grasping and raising arms up. Women and older persons were at greater risk of developing more severe levels of disability. Another Cox regression with one index activity from each hierarchical level revealed similar results.


CONCLUSIONS
The three-level hierarchy of higher-level physical functions has been validated longitudinally, suggesting rich research and clinical implications.
Center for Education and Research on Geriatrics and Gerontology and Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan.
Chih-Jung
CJ
Yeh
Ching-Yi
CY
Wang
Pei-Fang
PF
Tang
Meng-Chih
MC
Lee
Hui-Sheng
HS
Lin
Hui-Ya
HY
Chen
D000203:Activities of Daily Living; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D006233:Persons with Disabilities / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010809:Physical Fitness; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012720:Severity of Illness Index; D012737:Sex Factors; D012931:Social Environment; D012959:Socioeconomic Factors; D016019:Survival Analysis; D013624:Taiwan