of people 65 years of age and older with ADL and IADL impairments (the National Long-Term Care Survey), the stereotypical view of age-related monotonic decline in functional capacity was clearly contradicted (Manton, 1988). In the first two years of this continuing study (1982-1984), 81.6 percent of the older adults who in 1982 did not have disabling conditions remained free of them two years later. Of the persons who had chronic disabling conditions in 1982, notable proportions were significantly improved two years later. For example, 22.2 percent of the persons who were most limited (5 to 6 ADL impairments) and 23.7 percent of those who were moderately limited (3 to 4 ADL impairments) showed an improvement in functional status two years later.
Research evidence is accumulating that a broad range of interventions have demonstrable beneficial effects in reducing the risk of disability associated with aging. Riley and Riley (1989) provide an excellent collection of relevant articles that review the research documenting the modifiability of some aging processes. Some cognitive loss, for example, typically described as an inevitable concomitant of aging, is known to be reversible under a variety of conditions. Conceptions of self can be improved, as can an individual's sense of empowerment to take interest in, and some responsibility for, self-care, even in very old institutionalized individuals with severe limitations. In addition, the capacity of older adults to benefit physically from systematic exercise has been repeatedly demonstrated (Fries, 1988). Older adults constitute, in sum, an interesting case of the modifiability of disablement from chronic diseases and impairment over the entire life course through risk factor reduction. A related question to be pursued in future research is the effect of not sustaining previously developed healthy lifestyles in later years. Without further evidence, old age cannot be assumed to provide immunity from the risks of unhealthy lifestyles.
Some of the beneficial interventions to prevent or reduce disability are self-initiated, such as adopting and maintaining healthy lifestyles. Research indicates that healthy lifestyles are as characteristic of older adults as they are of adults generally (Berkman and Breslow, 1983; Kaplan and Haan, 1989). Health professionals, however, can and do play an important complementary role in limiting or reversing the consequences of potentially disabling disease or impairment. Timely access to geriatric assessment with appropriate follow-up services has, in randomized controlled trials, proved to be beneficial in improving both functional capacity and more effective use of health resources among older patients (Chernoff and Lipschitz, 1988). The ultimate supporting evidence of improving functional status through systematic intervention is found in geriatric rehabilitation. Even difficult problems in later life, such as those related to incontinence and osteoporosis, have in many instances proven to be amendable to skilled rehabilitative intervention. Beneficial outcomes are known to be more likely in geriatric rehabilitation