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

Abstract

Objectives: 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.

Method: 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.

Results: 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.

Discussion: 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.

Keywords: Age-period-cohort model; Black–white disparity; Disability; Older adults..

Figure 1.

Sociodemographic- and APC-adjusted age, period, and cohort trends of ADL and IADL disabilities: (A) general age trends of ADL and IADL disabilities: ages 70–84, (B) general period trends of ADL and IADL disabilities: years 1982–2009, and (C) general cohort trends of ADL and IADL disabilities: cohorts 1905–1940. ADL = activities of daily living; APC = age, period, and cohort; IADL = instrumental activities of daily living.

Figure 2.

Period-, cohort-, and sociodemographic-adjusted age trends of black–white disparity in ADL and IADL disabilities among men and women: for U.S. adults aged 70–84, 1982–2009. ADL = activities of daily living; IADL = instrumental activities of daily living.

Figure 3.

Age-, cohort-, and sociodemographic-adjusted period trends of black–white disparity in ADL and IADL disabilities among men and women: for U.S. adults aged 70 and older, 1982–2009. ADL = activities of daily living; IADL = instrumental activities of daily living.

Figure 4.

Age-, period-, and sociodemographic-adjusted cohort trends of black–white disparity in ADL and IADL disabilities among men and women: for U.S. adults aged 70 and older, 1982–2009. ADL = activities of daily living; IADL = instrumental activities of daily living.

Figure 5.

Sociodemographic contributions to the cohort-based ADL and IADL disparity trends among men and women: (A) contributions to black–white disparity in ADL disability: men, (B) contributions to black–white disparity in ADL disability: women, (C) contributions to black–white disparity in IADL disability: men, and (D) contributions to black–white disparity in IADL disability: women. ADL = activities of daily living; IADL = instrumental activities of daily living. *The actual percent contributions of education and region for ADL disparity among men in 1935 cohort do not match with what were shown in the figure. The percent contribution for education (283.6%) and region (−163.1%) for cohort 1935 among men were very large, thus, the contributions for these two covariates were re-scaled in cohort 1935 to improve the readability of Figure 5A.