Educational differences in the prevalence of mobility disability in old age: the dynamics of incidence, mortality, and recovery.

OBJECTIVES: Older people with less education have substantially higher prevalence rates of mobility disability. This study aimed to establish the relative contributions of incidence, recovery rates, and death to prevalence differences in mobility disability associated with educational status. METHODS: Data were from 3 sites of the Established Populations for Epidemiological Study of the Elderly, covering 8,871 people aged 65-84 years who were followed for up to 7 years. Participants were classified on years of education received and as disabled if they needed help or were unable to walk up or down stairs or walk half a mile. A Markov model computed relative risks, adjusting for the effects of repeated observations on the same individuals. RESULTS: Differences between education groups in person-years lived with disability were large. The relative risk of incident disability in men with 0-7 years of education (vs. those with 12 or more years) was 1.65 (95% CI = 1.37-1.97) and in women was 1.70 (95% CI = 1.15-2.53). Both recovery risks and risks of death in those with disability were not significantly different across education groups in either gender. DISCUSSION: Higher incidence of disability is the main contributor to the substantially higher prevalence of disability in older people of lower socioeconomic status. Efforts to reduce the disparity in disability rates by socioeconomic status in old age should focus mainly on preventing disability, because differences in the course of mobility disability after onset appear to play a limited role in the observed prevalence disparities.