Black-white disparity in disability among U.S. older adults: age, period, and cohort trends.

Abstract

This study delineates activities of daily living (ADL) and instrumental activities of daily living (IADL) black-white disparity trends by age, period, and cohort (APC) and explores sociodemographic contributors of cohort-based disparity trends. We utilized multiple cross-sectional waves of National Health Interview Survey data (1982-2009) to describe APC trends of ADL and IADL disparities using a cross-classified random effect model. Further, we decomposed the cohort-based disparity trends using Fairlie's decomposition method for nonlinear outcomes. The crossover ADL and IADL disparities (whites > blacks) occurring at age 75 increased with age and reached a plateau at age of 80, whereas period-based ADL and IADL disparities remained constant for the past 3 decades. The cohort disparity trends for both disabilities showed a decline with each successive cohort except for ADL disparity among women. We examined the role of aging on racial disparity in disability and found support for the racial crossover effect. Further, the racial disparity in disability will disappear should the observed pattern of declining cohort-based ADL and IADL disparities persist. Although education, income, and marital status are important sociodemographic contributors to cohort disparity trends, future studies should investigate individual behavioral health determinants and cohort-specific characteristics that explain the cohort-based racial difference in ADL and IADL disabilities.