BACKGROUND: Declines in functional dependence among older adults were observed before the 1990s, but there is uncertainty about subsequent trends. Our study aimed to verify the temporal trends in disability during 1991-2010 in an older Swedish population and to estimate the associated changes in survival.

METHODS: Functional status in octogenarians and nonagenarians was assessed at seven occasions with intervals of 2-3 years. Sample size varied at each assessment with an average of 646 (range 212-1096). Disability was defined as difficulty in one or more of personal activities of daily living. We compared prevalence and incidence, as well as mortality, and survival associated with disability over the 20-year period.

RESULTS: Sex-standardized prevalence of disability remained steady over time with a tendency toward a gradual decline, and a statistically significant decrease was present among nonagenarians. Sex-standardized cumulative incidence also remained steady. The proportion of people with prevalent disability who died <3 years remained stable, as did the survival time of people with incident disability. In contrast, among nondisabled persons, 3-year mortality decreased significantly, and for octogenarians median survival time was 1.3 years longer at the more recent assessment than a decade earlier.

CONCLUSIONS: Both prevalence and incidence of disability remained stable over the last two decades in this urban Swedish population, with a trend toward a slow decline. Mortality remained steady among disabled persons but decreased among persons without disability, suggesting that increased life expectancy during the last two decades may be essentially driven by longer lives of functionally independent people.