Changes in functional status among older adults in Japan: successful and usual aging.

This research aimed to chart the trajectories of functional status in old age in Japan and to assess how self-rated health and cognitive functioning differentiate these trajectories and account for interpersonal differences. Data came from a 5-wave panel study of a national sample of 2,200 Japanese older adults between 1987 and 1999. The sample as a whole showed an accelerated increase in functional limitations with age. approximated by a quadratic function. More important, 3 major trajectories of functional change were identified: (a) minimal functional decrement, (b) early onset of functional impairment. and (c) late onset of functional impairment. These findings may serve as useful benchmarks for observations derived from other developed nations.