The ability to perform the instrumental activities of daily living (IADLs) is an important focus for the promotion of independent living in old age. If strategies to enable older people to remain in their own homes are to be developed, advances must be made in understanding the demands associated with IADLs. This paper reports on a study of how activity demands - the body postures, actions and hand functions involved in cooking, housework, laundering and shopping - relate to the capabilities of a sample of older people in Great Britain. Task data were analysed for 4,886 community-dwelling 55-93-year-olds who were enrolled in a follow-up survey to the 1996/97 Family Resources Survey. Logistic regression models were used to calculate adjusted odds ratios for associations between functional limitations and IADL difficulty. Attributable fraction estimates were also used to assess the population impact of the functional limitations. Comparable effect sizes were observed across activities for limitations in body postures (standing, reaching and bending/stooping), actions (lifting/lowering and holding/carrying) and hand functions. Most of the difficulties were attributable to limitations in body postures, primarily bending/stooping, whereas actions and hand functions accounted for much less difficulty. We present a matrix of the potential impact that design changes to alleviate each limitation would have on the ability to perform the activities studied. This can help to prioritise interventions aimed at supporting continued independent living.@en

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.

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The objective of this study was to understand patterns of capability loss among elderly users of products and services. Data from a longitudinal, population-based study were obtained for analysis, which recruited a representative sample of 13,004 people aged 65 years and over from five sites in Great Britain. Participants underwent a baseline interview during 1990-1994 and follow-ups at one, two, three, six, eight, and ten years. Those with full vision, hearing, thinking, locomotion, reaching, and dexterity ability at baseline were included in a survival analysis. Locomotion was the first ability to be lost, followed by reaching, thinking, hearing, vision, and dexterity. Women were consistently younger at capability loss than men except in terms of hearing. These findings suggest that capabilities required for product and service interaction follow a hierarchical pattern of loss, which has practical implications for design. Although improvements to reduce design exclusion are likely to require changes that address more than one demand, capabilities lost early in old age should take precedence over those lost later.@en