Objective: Patterns of capability loss and disability onset among older people were investigated prospectively.
Background: With aging, the gap between personal capability and environmental demand becomes wider, resulting in higher levels of disability in daily activities.
Methods: Data from a longitudinal, population-based study were obtained for analysis, which recruited a representative sample of 13,004 people aged 65 years and older from five sites in Great Britain. Participants completed a baseline interview during 1990 to 1994 and follow-up interviews after 1, 2, 3, 6, 8, and 10 years. Those who reported full vision, hearing, thinking, locomotion, reaching, and dexterity ability as well as no disability in cooking, housework, shopping, and transportation at baseline were included in a survival analysis.
Results: Locomotion was the first ability to be lost, followed by reaching, thinking, hearing, vision, and dexterity. Age at onset of disability was earliest for shopping, then housework, transportation, and cooking. Women were consistently younger at capability loss and disability onset than men except in terms of hearing and cooking.
Conclusion: These findings suggest that capabilities required for product and service interaction follow a hierarchical pattern of loss, which has practical implications for design. Although interventions to reduce disability in the older population are likely to require changes that address more than one demand, capabilities lost early in old age should take precedence over those lost later.
Application: A potential application of this research is in the development of an overall design strategy to enhance older people's ability to live independently.