Disability among older Americans is declining dramatically—and at an accelerating pace. According to new analyses from the National Long Term Care Survey (NLTCS), the percentage of people age 65 and older with disabilities fell 1.6 percent per year from 1989 through 1994 and 2.6 percent annually from 1994 though 1999. The improvements in recent years are also noteworthy for a newly observed decline in disability among black Americans as well as a decrease of at least 200,000 in the number of people estimated to live in nursing homes.
The study, by Kenneth G. Manton, Ph.D., and XiLiang Gu, M.S., of the Center for Demographic Studies at Duke University, appears in the May 8, 2001, issue of the Proceedings of the National Academy of Sciences (PNAS). Earlier NLTCS reports from Manton and others detailed large reductions in disability rates among older Americans through 1996. The findings released today show that the decline in disability rates has accelerated in recent years and includes a more diverse group of Americans.
"This accelerating decline in disability is dramatic and important news," says Richard M. Suzman, Ph.D., Associate Director for Behavioral and Social Research at the National Institute on Aging (NIA), which supported the study. "It is a promising sign for the future as the older population grows significantly, offering further evidence that we may be able to influence how we age."
According to Suzman, the causes for the disability decline are not well understood and he noted that several factors have been advanced to explain the trend. It is hoped that by pinpointing the factors contributing to the decline, the trend can be maintained and even accelerated further. Scientists have suggested that the improvements so far may be related to public health measures over the last century, the progress in medicine and behavioral science that has resulted in improved health and function, and possibly social factors such as increases in education.
A further question is whether the disability decline will continue. "That's a critical point," says Duke's Manton. "Investing in the development and use of medical and technological innovations could possibly contribute to a continuation of the trend, but these and other factors still need to be looked at."
In the survey, the researchers assessed how many problems people had with basic "activities of daily living," such as eating, dressing, or bathing, and "instrumental activities of daily living," like shopping or using the telephone, for 3 months or more.
Overall, from 1982 through 1999, the prevalence of disability among older Americans declined from 26.2 percent to 19.7 percent, a reduction of 6.5 percent. A major feature of the decline was its acceleration from 1994 through 1999. In contrast, the U.S. population age 65 and older increased by more than 30 percent from 1982 through 1999.
In absolute numbers, the changes are remarkable as well. In 1982, the disabled older population totaled 7.1 million, growing to 7.5 million in 1994 as disability rates declined but the older population grew, according to the age-standardized analysis. By 1999, however, with the acceleration in the reduction in the rates of disability, the number of older people with disability was actually fewer—7 million—than it was 17 years ago. There has also been an absolute drop in the number of people residing in nursing homes between 1982 and 1999.
Among black Americans, although here the data are less precise, a sharp reduction in disability rates came during the 1990s, reversing earlier trends. From 1982 through 1989, disability rates for older black Americans had apparently increased. Then, the trend changed direction, with the prevalence of disability among blacks falling by 4.7 percent between 1989 and 1994 and the reduction in the rate of disability accelerating from 1994 through 1999, dropping by almost 6 percent.
A number of factors are thought to have influenced the decline in disability over the last decade or so. Among them might be: improvements in maternal nutrition and public health early in the last century; better control of the infectious diseases associated with childhood; significant increases in the education and finances of succeeding generations reaching old age; health-related behavioral changes such as smoking cessation; improved control and treatment of such diseases as hypertension and heart disease; development and use of new surgical interventions, and the impact of newly developed drugs.
As scientists sort out the relative contribution of these and other factors to the decline in disability, predicting and affecting disability trends in the future will be challenging, Suzman points out. Even if the reasons for the recent declines in disability are pinpointed with some confidence, circumstances may change; new factors could come into play or the role of factors contributing over the last decade could be reduced. For example, scientists are looking closely at the link between trends in levels of education and trends in disability. Education levels increased rapidly during the course of this study, paralleling the decrease in disability rates. Numerous studies have linked higher levels of education with better health and longevity, with education consistently appearing to be one of the more important influences on health. But the potential improvements associated with education may not continue to contribute to a decline in disability as the rapid increases in education levels among the older population plateau over the next 10-15 years. More research will be needed to identify the medical, social, and behavioral approaches that could continue to improve the rates of disability.
Researchers also are studying the broader implications of the decline in disability. For example, can continued reductions in disability, if maintained or accelerated, help control costs for Medicare, Medicaid, or other health care expenditures, for older people, such as costs of long-term care? Manton and Gu examine one aspect of this question in the PNAS report, looking at the reduction in nursing home residence as one possible area of cost savings. If a nursing home stay costs about $47,200 per year, they note, the reduction in nursing home stays may have avoided several billion dollars in nursing home costs from 1994–1999.
The 1999 NLTCS also measured the use of assisted living facilities, which had not been studied in earlier waves of the survey. These latest numbers from NLTCS indicate that some 800,000 people live in this relatively new type of facility.
Duke University is one of 10 Centers on the Demography of Aging, supported by the NIA to study the changes and dynamics of an aging U.S. and world. The centers are part of NIA's behavioral and social research program on aging, which, along with basic biological and clinical research, addresses issues affecting the health and well-being of older people and their families. More information on these programs, as well as consumer-oriented publications on aging, can be found on the NIA's web site www.nia.nih.gov or by calling toll free 1-800-222-2225. Specific information on memory and Alzheimer's disease is located on the NIA-sponsored website of the Alzheimer's Disease Education & Referral Center (ADEAR) at www.nia.nih.gov/alzheimers or by calling 1-800-438-4380.