Disentangling the Life Course Process of Disability in Later Life : The Role of Socioeconomic Status

Over the past few decades, disability has become one of the most salient and researched outcomes for older adults in the United States. It is predominantly conceptualized as a life course process and is increasingly measured over time using transitions or trajectories. In this paper, I extend this research by using methods unutilized in aging research to measure disability as both a transition and trajectory, therefore better capturing it as a life course process. Previous theory and research on SES and health suggests that education and financial resources work differently on disability over time. I revisit these arguments, finding that the independent effects of education are mainly protective for onset, where financial resources also impact level of disability given onset. I discuss these findings in terms of past and future research, focusing on what may be gained by conceptualizing and measuring disability in later life as a life course process. * Correspondence should be directed to Miles Taylor, Carolina Population Center, University of North Carolina at Chapel Hill, CB# 8120, University Square, 123 West Franklin Street Chapel Hill, NC 27516-2524 Phone: (919) 843-4757 Fax: (919) 966-6638 Email: mtaylor@unc.edu. The first author was supported by National Institute on Aging (grant no. T32AG00139& F32AG026926). DRAFT: PLEASE DO NOT QUOTE OR CITE WITHOUT PERMISSION FROM THE AUTHOR 2 Among the most notable global demographic trends of the 21 century is population aging, where the mortality and fertility declines seen almost universally across the globe have meant an increasing percentage of the population at older ages (Gavrilov & Heuveline, 2003). Of particular importance to population projections and resources is the measure of active life expectancy. Even with the observed increases in active life (see Freedman, Martin, & Scheoni, 2004; Crimmins, 2004), there will still be an increasing number of elderly in need of services and policy that reflect a valid picture of their disablement processes (Spillman, 2004; Uhlenberg, 1992). Disability, the measure commonly underlying active life expectancy calculations, has therefore become one of the most salient and researched outcomes for older adults. As a variable, it predicts mortality, institutionalization, depression, and other key outcomes for individuals at high levels of significance. By the accepted standards of conceptualization and measurement, disability is nested in the social context of an individual’s biography, arguably even more than self-reports of health status. It is partially defined as the inability of any individual to function in his/her respective roles in society. Therefore, it is both extremely powerful as a predictor and inherently sociological as an indicator of health. Disability is primarily conceptualized as a life course process (see Verbrugge & Jette, 1994). Accepted theory of disablement fits neatly into a life course framework, with its emphasis on transitions that fit into trajectories in a human life. Increasingly, measurement of disability and analytic strategies used to study it have encompassed the dynamic nature of disability over time (Manton, 1988; Taylor & Lynch, 2004). Mapping disability experience longitudinally fits accepted theory on the disablement process and the life course framework.