Because disability data of this type for the general population are lacking, the method has only been applied to data on older adults.
To make their estimates, Rogers and colleagues used data on ADLs reported by individuals interviewed in both the 1984 Supplement on Aging of the NHIS and the 1986 Longitudinal Study of Aging (LSOA), and they defined "dependence" as requiring assistance with seven ADLs. The researchers found that individuals who were independent at age 70 could expect to live 13.4 years on average and had a life expectancy of 3.4 years in a dependent state (25 percent of their life expectancy). Individuals who were dependent at age 70 had a total life expectancy of 12.5 years and a dependent life expectancy of 6.1 years (49 percent). Rogers and his colleagues also found differences in the active life expectancies of men and women. Among those independent at age 70, men had a lower life expectancy than women (11.3 vs. 15.4 years) but a proportionally shorter dependent life expectancy (18 percent vs. 29 percent of total life expectancy). The same pattern held among people who were dependent at age 70. Men had a 9.9-year life expectancy, 40 percent of which was in a dependent state, and women had a 14.5-year life expectancy, 53 percent of which was in a dependent state (Rogers, R.G., et al., 1989).
Disability imposes an enormous economic cost on society. It is costly to the nation in terms of the medical resources used for care, treatment, and rehabilitation; in reduced or lost productivity; and in premature death. For example, persons with disabilities use more medical care services than those without them. In 1979, 15 percent of the noninstitutionalized population that was limited in activity due to chronic conditions made 29 percent of the visits to physicians and accounted for 40 percent of the hospitalizations. Persons with activity limitations made 9.5 physician visits per person, compared with about 3.9 visits for persons with no activity limitation (National Center for Health Statistics, 1981a). Those unable to carry on their major activities made 11.9 visits per person per year. The hospitalization rate for those with activity limitations is almost four times that for people with no activity limitations: 38.3 discharges per 100 persons compared with 9.8 per 100, respectively.
Not surprisingly, older persons with chronic and disabling conditions are high utilizers of medical resources. The elderly with activity limitation had 8.7 visits to physicians per year, in contrast with 4.3 visits for persons with no activity limitation. They had 41.2 hospitalizations per 100 elderly persons per year, in contrast with 14.8 hospitalizations per 100 people with no limitation of activity. The 46 percent of elderly people who were limited in activity because of a chronic condition accounted for 63 percent of physician