Psychosocial influences in onset and progression of late life disability.

OBJECTIVES: Disability in older age has been related to several psychosocial characteristics, including social networks, social engagement, and depression. However, the exact role of these characteristics in the disablement process remains uncertain.
METHOD: Data come from a population-based study of black and white adults aged ≥65 years (N = 5,306), with up to 9 yearly data on the primary outcome measure, activities of daily living (ADL) disability. We use a two-part regression model to simultaneously test the association between each psychosocial characteristic and both onset and progression of ADL disability, while controlling for demographic variables, education, and mode of interview in the first model and health status variables in the second model.
RESULTS: Social networks were negatively associated with onset of ADL disability but not associated with progression. The association became non-significant after adjustment for health status. Social engagement was negatively associated with both onset and progression of disability, even after adjustment for health status. Depression was significantly associated with onset of disability after adjustment for health status but not with progression of disability. DISCUSSION: The results suggest a differential role for psychosocial characteristics in the disablement process, with generally stronger associations for transitions to onset of ADL disability than progression of ADL disability.