DURHAM, N.C. -- Chronic disability among older people in the United States continues to decline, which could have major policy implications for the federal government's health programs, according to three Duke University researchers.
The chronic disability findings by Kenneth G. Manton, Larry Corder and Eric Stallard of Duke's Center for Demographic Studies are based on National Long Term Care Surveys from 1982, 1984, 1989 and 1994. The longitudinal surveys of the nation's elderly population were sponsored by the National Institute on Aging (NIA).
The three demographers found that from 1982 to 1994, the chronic disability rates for people 65 and older in the United States decreased almost 15 percent, with the largest rate of decline occurring from 1989 to 1994. The most significant declines from 1989 to 1994 occurred for the oldest-old and the most disabled people.
Chronic disability was defined as either being in a long-term care facility or as a person's inability to perform at least one activity of daily living (ADL), such as bathing or dressing oneself, or one or more instrumental activities of daily living (IADL), such as washing clothes or shopping for groceries, for a period of three months or more.
Chronic disability, and associated limitations of physical activity, are "primary risk factors for diseases such as stroke, coronary heart disease, peripheral vascular disease, diabetes and cancer," the demographers noted in their article, published in the March 18 issue of Proceedings of the National Academy of Sciences.
Manton said in an interview that if the rates had held steady from 1982 to 1994, there would be 1.2 million more older people with chronic disabilities in the United States than there actually are. There were about 7.1 million chronically disabled people in the nation in 1994.
"This is consistent with declines in U.S. mortality observed at ages 80 and above, and with the proposition that higher United States expenditures on long-term care better meet the needs of the very elderly than the lower long-term care expenditures, and less complete long-term care service availability, in Japan," the Duke researchers wrote in their article.
Richard M. Suzman, director of NIA's Office of the Demography of Aging, said this latest research shows "this trend is no flash in the pan or statistical aberration, but is real and appears to be accelerating. The finding gives us hope that we may be able to handle the revolution occurring in longevity better than we might have expected."
Manton said he believes the decline in chronic disability from 1989 to 1994 is increasingly due to medical and technological advances, "especially as new biomedical interventions are more generally adopted. For example, doctors were performing things like hip replacements, treatments for osteoporosis, and various other types of orthopedic surgical procedures in the early 1980s, but they have generally become more prevalent, more successful and more cost-effective as time has gone on."
The Duke study showed a large decline in the percentage of older Americans who are institutional residents.
Disability declines of this size "may have important implications for national health care costs," the three demographers wrote. "For example, the 1994 United States institutional population was estimated to be 1.7 million persons. The 1982 rates, after age standardization, implied 2.1 million persons would be institutionalized in 1994. The difference of 400,000 implies, assuming an annual per capita nursing home cost in 1994 of $43,300, savings of $17.3 billion in nursing home expenses in 1994."
The researchers concluded that declines in the prevalence of chronic disability "may have important implications in forecasting the future trajectory of changes in health expenditures in the United States elderly population."
For example, these findings could be significant for entitlement programs such as Social Security, Medicare and Medicaid, and on retirement ages, Manton said in the interview.
The study results also could affect the design of future housing for the elderly "in terms of providing facilities that are less restrictive and less intensive than, say, a nursing home," Manton added. "You might have an apartment complex that is built for people with mobility limitations. It might have wider doors, elevators. There's a lot you can do to make the housing more elderly friendly and friendly to people with moderate levels of disability."
To come up with their findings, the researchers used data on more than 35,000 people from the National Long Term Care Surveys, which followed for 12 years the health status and disability of a national sampling of people. Disability calculations were adjusted to account for the growth in the older population and the increasing age of the elderly during that period. Manton said another survey is being planned for 1999 to determine if these trends are continuing.
Note to editors: Kenneth Manton can be reached for further comment most afternoons after 3 at (919) 684-6126. For a copy of the article, contact Becky Habel in the National Academy of Sciences' news office, (202) 334-2138.