[Changes in physical disability among Japanese elderly].

In order to investigate the natural course of physical disability among the elderly, the ability to perform activities of daily living (ADL) was examined on a probability sample (N = 3384) of residents aged 65 years and over in Sendai City, Japan, in 1988 and 1991. Information on ability to perform four ADL tasks-dressing, eating, using the toilet, and bathing-were collected by self-report. In 1988, 7.2% of the males and 7.9% of the females reported at least one ADL dependency. The prevalence of disability was the highest in bathing, followed by dressing, using the toilet, and the lowest in eating. The Cox proportional hazard models on three-year mortality indicated that those who were ADL dependent at baseline had 4.1 times the mortality risk of those who were ADL independent. Among those who were ADL independent in 1988 and who were alive in 1991, 5.0% of the males and 4.8% of the females became dependent in at least one ADL task in 1991. The incidence of disability was the highest in bathing, followed by dressing, using the toilet, and the lowest in eating. Among those who were ADL dependent in 1988 and who were alive in 1991, about one-third of them improved in ADL functioning. Improvement was more common among those who were younger in age. These results suggest that levels of ADL functioning is highly dynamic, and that physical disability is, to a certain extent, reversible among the elderly.