Understanding trends in functional limitations among older Americans.
OBJECTIVE
This report documents trends in functional limitations among older Americans from 1984 to 1993 and investigates reasons for such trends.


METHODS
We applied logistic regression to data for noninstitutionalized Americans aged 50 years and older from the Survey of Income and Program Participation. We focused on 4 functional limitation measures unlikely to be affected by changes in role expectations and living environments: reported difficulty seeing words in a newspaper, lifting and carrying 10 pounds, climbing a flight of stairs, and walking a quarter of a mile.


RESULTS
We found large declines in the crude prevalence of functional limitations, especially for those 80 years and older. Generally, changes in population composition explained only a small portion of the downward trends. Once changes in population composition and mobility-related device use were considered for difficulty walking, significant improvements in functioning remained for the 65- to 79-year-old group.


CONCLUSIONS
Changes in population composition, device use, survey design, role expectations, and living environments do not appear to account completely for improvements in functioning. We infer that changes in under-lying physiological capability--whether real or perceived--likely underlie such trends.
Labor and Population Program, RAND, Washington, DC 20005, USA. vicki_freedman@rand.org
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D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D005006:Ethnicity / Q000706:statistics & numerical data; D005260:Female; D015577:Geriatric Assessment; D006306:Health Surveys; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D044469:Racial Groups; D012959:Socioeconomic Factors; D014481:United States