A Model of Disability in Late Life
As we saw earlier in this chapter, one defining characteristic of a chronic condition is that it lasts a long time. This means that for most adults, the time between the onset of a chronic condition and death is long, measured in years and even decades. Chronic diseases typically involve some level of discomfort, and physical limitations are common, everyday issues for most people, as they are for Brian. Over the course of the disease, these
problems usually increase, resulting in more efforts by patients and health care workers to try to slow the progress of the disease. In many cases, these efforts allow people to resume such activities as daily walks and shopping and to feel optimistic about the future (Verbrugge, 1994). This is especially true for the oldest old (Fauth, Zarit, & Malmberg, 2008).
In the context of chronic conditions, disability is the effects of chronic conditions on people’s ability to engage in activities that are necessary, expected, and personally desired in their society (Verbrugge, 1994). When people are disabled as a result of a chronic condition, they have difficulty doing daily tasks, such as household chores, personal care, job duties, active recreation, socializing with friends and family, and errands. One of the most important research efforts related to health and aging is seeking to understand how disability results from chronic conditions and what might be done to help prevent it. It is important to understand the changing context of disability in the United States. As Fries (2003) points out, considerable data document an overall declining rate of disability since the early 1980s of roughly 2% per year. When compared to the overall decline in mortality of 1% per year over the same period, these changes create what is called the compression of morbidity.
Compression of morbidity refers to the situation in which the average age when one becomes disabled for the first time is postponed, causing the time between the onset of disability and death to be compressed into a shorter period of time. This implies that older adults in the United States are becoming disabled later in life, but are disabled a shorter time before dying than in past generations.
Verbrugge and Jette (1994) proposed an excellent and comprehensive model of disability resulting from chronic conditions that has greatly influenced research, which is shown in Figure 4.9. The model consists of four main parts. The main pathway is an adaptation of frameworks proposed by the World Health Organization (1980) and the U. S. Academy of Science’s Institute of Medicine (Pope & Tarlov, 1991), both of which were based on work by sociologist Saad Nagi (1965, 1991). This pathway emphasizes the relations between
pathology (the chronic conditions a person has), impairments of organ systems (such as muscular degeneration), functional limitations in the ability to perform activities (such as restrictions in one’s mobility), and disability.
The model also includes risk factors and two types of intervention strategies: environmental and health care (extraindividual factors) and behavioral and personality (intraindividual factors). Risk factors are long-standing behaviors or conditions that increase one’s chances of functional limitation or disability. Examples of risk factors include low socioeconomic status, chronic health conditions, and health-related behaviors such as smoking. Extraindividual factors include interventions such as surgery, medication, social support services (e. g., Meals on Wheels), and physical environmental supports (e. g., wheelchair ramps). The presence of these factors often helps people maintain their independence and may make the difference between living at home and living in a long-term care facility. Intraindividual factors include such things as beginning an exercise program, keeping a positive outlook, and taking advantage of transportation programs to increase mobility.
Femia, Zarit, and Johansson (2001) and Fauth and colleagues (2008) validated Verbrugge and Jette’s
(1994) model in research on older adults over age 79 in Sweden. Among the most important results were the mediating role of psychosocial factors such as mastery, depression, and loneliness on risk factors for disability; for example, higher feelings of mastery resulted in lower levels of disability.
Both extraindividual and intraindividual interventions are aimed at reducing the restrictions and difficulties resulting from chronic conditions. Unfortunately, sometimes they do not work as intended and may even create problems of their own. For example, a prescribed medication may produce negative side effects that, instead of alleviating the condition, create a new problem. Or social service agencies may have inflexible policies about when a particular program is available, which may make it difficult for a person who needs the program to participate in it. Such situations are called exacerbators, because they make the situation worse than it was
originally. Although they may be unintended, the results of exacerbators can be serious and necessitate additional forms of intervention.
One of the most important aspects of Verbrugge and Jette’s (1994) model is the emphasis on the fit between the person and the environment. When
a person’s needs are met by the environment, the person’s quality of life and adaptation are optimal. We take a close look at this principle in Chapter 5 when we examine theoretical models of person-environment fit in detail. In addition to person-environment theories, Putnam (2002)
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points out that disability models can be understood within other social theories of aging frameworks. Research not only focuses on rehabilitation, but also on the role of the workplace, community, social networks, and cultural attitudes and beliefs in shaping the life experiences of people with disabilities (Fougeyrollas & Beauregard, 2001).