Predictors of physical function among the oldest old: a comparison of three outcome variables in a 24-year follow-up.

This study has measured physical function in a nationally representative sample of persons aged 77 to 98 (N = 508) in 1992. Three measures of function are used: activities of daily living (ADL), an index of mobility, and performance tests. These are used as outcomes and analyzed in relation to variables gathered in a survey in 1968. Variables from 1968 include education, mobility, smoking, and an index of circulation problems. All four variables predict some limitations in physical function in old age. However, there are different patterns of predictors found for the three outcome measures. All three outcomes are associated with age, education, and previous circulation problems. ADL limitations are also associated with poor previous mobility and smoking; mobility limitations are also associated with sex and smoking; performance limitations are also associated with sex.