Patterns of Onset of Disability in Activities of Daily Living with Age

OBJECTIVES: To investigate the order in which activities of daily living (ADLs) are lost and whether the order is invariant between the sexes and age groups. DESIGN: Longitudinal data from the first five rounds of a routine health assessment by a nurse in participant's own home. SETTING: One large UK general practice with a list size of 32,500. PARTICIPANTS: Patients registered with the practice and age 75 and older. MEASUREMENTS: Disability was measured by self-report of performance in seven ADLs: mobility around the home, getting to and from the toilet, transfer from chair, transfer from bed, feeding, dressing, and bathing. Disability in each ADL was classified as being independent but having difficulty, using aids or help, or being unable to perform. Age at onset of disability in each ADL was calculated and analyzed using Kaplan-Meier plots and Cox regression models. Subjects who had died or remained independent by their last assessment were not included. RESULTS: The mean times between health assessments was approximately 20 months but with substantial variability both within and between individuals. A total of 1,344 people reported no difficulty in any ADL initially and 47.6% (640) subsequently reported disability. The order of activity restriction was bathing, mobility, toileting, dressing, transfers from bed and chair, and feeding. Women had a higher risk of disability in bathing (relative risk (RR) = 1.6, 95% confidence interval (CI) 1.3-1.9, P < .001) and toileting (RR = 1.7, 95% CI 1.2-2.5, P = .003), while for all ADLs there was a significant increase in the risk of disability with increasing age. The order of onset of disability for ADLs was invariant across sex and age groups. CONCLUSION: Lower-extremity strength (bathing, mobility, toileting) appears to be lost in older people before upper-extremity strength (dressing, feeding). Further work is now needed to develop prevention strategies to delay the onset of these disabilities.