3
Disability Trends

Disability is an ambiguous demographic, but one that is unambiguously increasing.

Glenn T. Fujiura (2001)


As described in Chapter 1, demographic trends—notably, the aging of the American population—promise to increase substantially the numbers of people at risk for disability. Whether such trends will translate in the future into increasing numbers of people with limits on their activities and participation in community life is less clear. Avoiding such increases will depend in part on the nation’s will to promote equalization of opportunity for all Americans, irrespective of age or ability.

The good news is that for many people the chances of experiencing activity limitations or participation restrictions can be reduced through a variety of means. These include making effective assistive technologies and accessible general-use technologies more widely available (see Chapter 7) and promoting broader acceptance and stronger enforcement of policies to remove environmental barriers to access and participation in areas such as health care, employment, transportation, and telecommunications (see Chapter 6 and Appendixes D, E, F, and G). In addition, public health and clinical interventions can help prevent the onset of illness or injury and associated physical or mental impairments, as well as minimize the devel-



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The Future of Disability in America 3 Disability Trends Disability is an ambiguous demographic, but one that is unambiguously increasing. Glenn T. Fujiura (2001) As described in Chapter 1, demographic trends—notably, the aging of the American population—promise to increase substantially the numbers of people at risk for disability. Whether such trends will translate in the future into increasing numbers of people with limits on their activities and participation in community life is less clear. Avoiding such increases will depend in part on the nation’s will to promote equalization of opportunity for all Americans, irrespective of age or ability. The good news is that for many people the chances of experiencing activity limitations or participation restrictions can be reduced through a variety of means. These include making effective assistive technologies and accessible general-use technologies more widely available (see Chapter 7) and promoting broader acceptance and stronger enforcement of policies to remove environmental barriers to access and participation in areas such as health care, employment, transportation, and telecommunications (see Chapter 6 and Appendixes D, E, F, and G). In addition, public health and clinical interventions can help prevent the onset of illness or injury and associated physical or mental impairments, as well as minimize the devel-

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The Future of Disability in America opment of secondary health conditions and limit the effects of atypical or premature aging among young adults with disabilities (see Chapter 5). To provide insight into the future of disability, this chapter reviews recent trends in the amount, type, and health-related causes of disability—primarily in the form of activity limitations—for people in early, middle, and late life. It considers projections of future levels of disability. The analysis here should be read in the context of the review in Chapter 2 of the inadequacies in the nation’s current disability surveillance system. As in 1991, when the Institute of Medicine (IOM) report Disability in America was published, data sources that can be used to guide the future of disability in America, particularly efforts to identify and remove environmental barriers to participation for people with disabilities, are inadequate. Current statistics, discussed further below, indicate that the number of people with disability (broadly defined as impairments, activity limitations, or participation restrictions) now exceeds 40 million—and that number could be more than 50 million. Data on trends in disability during early, middle, and late life present a mixed picture of the changes that have taken place during the last two decades and more. Among children, evidence points to increases in some health conditions—including asthma, prematurity, autism, and obesity—that contribute to disability. These increases have been accompanied by increases in certain activity limitations that are not entirely explained by increased health and educational screening of children. The percentage of adults under the age of 65 who had activity limitations, including work limitations, grew during the 1990s, although this increase appears to have leveled off recently. In contrast, among older adults, declines in the prevalence of personal care and domestic activity limitations have been reported, although not all groups appear to have benefited equally, and the reasons for these declines remain unclear. As described in Chapter 2, data on participation restrictions, in particular, remain relatively limited. Thus a full portrait of trends in disability is not possible. Moreover, although the equalization of opportunities for people with disabilities is an increasing focus of researchers, they cannot yet track the broad range of environmental factors that contribute to activity limitations and participation restrictions. This chapter focuses on trends during the past two decades in a relatively narrow set of activity limitations, the health conditions that contribute to those limitations, and, where relevant, possible explanations for these trends. CURRENT ESTIMATES OF DISABILITY AND RELATED CONDITIONS As discussed in Chapter 2, the omission of key groups from national population surveys has important implications for the development of basic

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The Future of Disability in America BOX 3-1 Selected Recent Chartbooks and Other Profiles of Statistical Data on Disability Federal Resources Centers for Disease Control and Prevention Disability and Health State Chartbook 2006: Profiles of Health for Adults with Disabilities U.S. Census Bureau Americans with Disabilities, 2002 (Steinmetz, 2006) Disability and American Families, 2000 (Wang, 2005) Health Resources and Services Administration, Maternal and Child Health Bureau. National Survey of Children with Special Health Care Needs Chartbook, 2001 (HRSA, 2004) National Institute on Disability and Rehabilitation Research Chartbook on Mental Health and Disability in the United States (Jans et al., 2004) Other Resources Cornell Center on Disability Demographics and Statistics 2004 Disability Status Reports: United States Summary (Houtenville, 2005) Disability Statistics Center, University of California at San Francisco Improved Employment Opportunities for People with Disabilities (Kaye, 2003) Population Reference Bureau Disability in America (Freedman et al., 2004b) estimates of the population with disabilities. Such estimates must be pieced together from various sources, and the figures vary depending on the choice of survey and definition. Box 3-1 lists several chartbooks and other profiles of disability data in the United States. The U.S. Census Bureau and most other agencies supply public use data sets so that researchers and others can obtain data more recent than those available in such profiles, and a few agency resources also allow some online analysis of the data.1 One challenge in using information from different surveys is that different surveys rely upon different conceptual notions of disability, which in 1 As indicated in the source citations for most of the figures in this chapter, the committee contracted with H. Stephen Kaye of the University of California at San Francisco to supply information from the public use data sets for the National Health Interview Survey.

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The Future of Disability in America turn lead to different population estimates. For example, Stein and Silver (2002) found estimates of the rates of disability among children to be in the range of 14 to 17 percent, depending on whether children were identified through chronic conditions, special health care needs, or reports of disability. Moreover, even seemingly minor differences in the phrasing of questions or response options or in the ways of summarizing the data may yield different or even inconsistent pictures of a particular aspect of disability. For example, for older adults, some surveys ask whether they “have difficulty” with an activity, whereas others ask if they “need help” and others ask if they “get help or use special equipment” to perform the activity. Such differences can lead to different estimates of disability levels and trends. Hence, the use of these measures outside of a coherent conceptual framework and the lack of sufficient attention by users to the implications of differences in measures contribute to inconsistency and confusion. Recognizing these caveats, the committee reviewed recent disability statistics and concluded that the total number of people in the United States with disabilities (defined to include individuals with impairments in body structure or function, activity limitations, or participation restrictions) currently exceeds 40 million. Depending on the survey from which statistics are drawn, the figure could exceed 50 million. No single data source yields estimates for all age groups living in the community and in institutional settings, so the estimate of the population with disabilities must be drawn from several different surveys. The committee began with data from the U.S. Census Bureau’s 2004 American Community Survey. As summarized in Table 3-1, an estimated 38 million people (4.1 million people between the ages of 5 and 20, 20.2 million people between the ages of 21 and 64, and 13.5 million people ages 65 and older) who live in the community report a disability.2 This estimate does not include people living in nursing homes and other institutional settings or children under age 5. The Medicare Current Beneficiary Survey estimates that approximately 2.2 million Medicare beneficiaries live in long-term care facilities and that about 350,000 of this population are adults under age 65 (CMS, 2005a). In addition, other surveys suggest that approximately 16,000 children with intellectual or developmental disabilities are living in out-of-home residential settings, about half which have four or more residents (Prouty et al., 2005). Data from the 2004 National Health Interview Survey indicate that perhaps 700,000 children under age 5 have a limitation in one or more activities because of a chronic condition, which 2 In the American Community Survey, “disability” is defined as a long-lasting sensory, physical, mental, or emotional condition that can make it difficult for a person to walk, climb stairs, dress, bathe, learn, remember, go outside the home alone, or work at a job or business. The term also covers vision or hearing impairments.

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The Future of Disability in America TABLE 3-1 Disability Rates by Sex and Age (Excluding Ages 0 to 4), Civilian Population (Excluding Residents of Nursing Homes, Dormitories, and Other Group Housing), 2004 Population With a Disability By Type of Disability (number, in millions)a Number (millions) Percent Sensory Physical Activityb Cognitivec Self-Care Go Outside Home Employment 5 years and over                 Male 17.8 13.8 5.0 10.2 6.8 2.8 NR NR Female 20.1 14.8 4.6 13.6 6.9 4.2 NR NR Both 37.9 14.3 9.5 23.8 13.8 7.1 NR NR 5 to 15 years                 Male 1.8 8.0 0.3 0.3 1.5 0.2 NA NA Female 1.0 4.5 0.2 0.2 0.8 0.1 NA NA Both 2.8 6.3 0.5 0.5 2.3 0.4 NA NA 16 to 20 years                 Male 0.7 7.8 0.1 0.1 0.5 0.1 0.1 0.2 Female 0.5 5.9 0.1 0.1 0.3 0.1 0.1 0.2 Both 1.3 6.9 0.3 0.3 0.9 0.1 0.3 0.4 21 to 64 years                 Male 9.8 11.9 2.6 5.8 3.4 1.6 2.1 5.6 Female 10.4 12.2 2.0 6.8 3.6 1.9 2.9 6.2 Both 20.2 12.1 4.7 12.7 7.0 3.3 5.0 11.7 65 years and over                 Male 5.4 37.1 2.5 3.9 1.5 1.1 1.7 NA Female 8.1 41.4 2.9 6.4 2.3 2.1 3.8 NA Both 13.5 39.6 5.5 10.3 3.7 3.2 5.6 NA aOne person may have more than one type of disability, so the overall figure may be smaller than the sum of the types. NA = not asked; NR = not reported. bThe U.S. Census Bureau refers to “physical” rather than “physical activity” disabilities or limitations. cThe U.S. Census Bureau uses the term “mental” rather than “cognitive” to refer to difficulties remembering, learning, or concentrating. SOURCE: U.S. Census Bureau (2005a, Tables S1801and B18002 to B18008).

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The Future of Disability in America brings the total of children ages 0 to 17 with disabilities to approximately 4.8 million. With these additional groups added to the American Community Survey estimate, the total estimate of people with disabilities exceeds 40 million. Surveys that use a broader conception of disability than that adopted by this committee yield higher estimates. For example, based on the 2002 Survey of Income and Program Participation, which includes numerous questions to identify individuals of all ages with disabilities living in the community, the U.S. Census Bureau estimated that 51 million people have disabilities, including 32 million who have a severe disability (Steinmetz, 2006).3 The Behavioral Risk Factor Surveillance System, which includes two broad items to identify the adult community-based population with disabilities, also places the figure for all states close to 50 million (CDC, 2006a).4 Based on its review, the committee concluded that the number of people in the United States with disabilities exceeds 40 million and may exceed 50 million. Although these figures are not directly comparable to the 35 million estimate from the 1991 IOM report (because the survey questions differ), the number of people with disabilities has almost certainly increased since 1988, when most of the data used in that report were collected. Table 3-2 lists the most common health conditions reported by respondents in the National Health Interview Survey as “causing” or contributing to limitations among people of different ages residing in the community. The survey questions reflect a largely medical model of disability. The committee could identify no national data on the extent to which features of the physical and social environments contribute to disability (see also Chapter 6). For children, the primary health conditions contributing to a limitation are cognitive, emotional, or developmental problems, although speech prob- 3 For adults, questions in the Survey of Income and Program Participation ask about mobility-related assistive technology use; activity limitations; learning disabilities; the presence of a mental or emotional condition, or both; mental retardation; developmental disabilities; Alzheimer’s disease; and conditions limiting employment or work around the house. For children, the questions involve specified conditions (autism, cerebral palsy, mental retardation, developmental disabilities); activity limitations (seeing, hearing, speaking, walking, running, taking part in sports); developmental delays; difficulty walking, running, or playing; or difficulty moving the arms or legs (Steinmetz, 2006). Not all the questions in the survey involve disability as defined in this report. 4 Widely cited estimates from the 2000 decennial census also put the estimate of the civilian, noninstitutional population with disabilities near 50 million. However, U.S. Census Bureau analysts attributed this estimate to a formatting problem with the census questionnaire that may have incorrectly increased positive responses to questions about disabilities with going-outside-the-home and work limitations (Stern and Brault, 2005). Subsequent estimates from the American Community Survey of the U.S. Census Bureau put the figure closer to 40 million.

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The Future of Disability in America TABLE 3-2 Leading Chronic Health Conditions Reported as Causing Limitations of Activities, by Age, Civilian, Noninstitutional Population, 2002 and 2003 Chronic Condition Number of People with Activity Limitations Caused by Selected Chronic Health Conditions per 1,000 Population   Under 5 years 5–11 years 12–17 years Speech problem 10.7 18.5 4.6 Asthma or breathing problem 8.2 8.4 8.3 Mental retardation or other development problem 7.0 10.2 9.6 Other mental, emotional, or behavioral problem 2.7 12.0 14.2 Attention deficit or hyperactivity disorder 2.1 17.6 21.8 Learning disability 2.9 23.3 33.9   18–44 years 45–54 years 55–64 years Mental illness 12.9 23.1 24.1 Fractures or joint injury 7.0 15.5 20.6 Lung 5.0 12.6 25.6 Diabetes 2.5 13.4 33.4 Heart or other circulatory 5.9 28.4 74.3 Arthritis or other musculoskeletal 22.2 61.9 100.7   65–74 years 75–84 years 85 years or over Senility (dementia) 6.8 30.5 96.1 Lung 34.7 41.4 44.4 Diabetes 41.1 49.4 38.4 Vision 18.2 44.3 96.6 Hearing 10.0 27.8 84.9 Heart or other circulatory 101.9 162.6 223.5 Arthritis or other musculoskeletal 125.8 171.0 267.6 NOTE: The table shows the numbers per 1,000 population. The respondents could mention more than one condition. SOURCE: NCHS (2005a, spreadsheet data for Figures 18, 19, and 20, based on the 2002 and 2003 National Health Interview Surveys). lems figure prominently for children under the age of 12 and asthma contributes to activity limitations among children in all age groups. For the 0.7 percent of children who had limitations so severe that they could not attend school, Msall and colleagues (2003), using data from the 1994–1995 disability supplement to the National Health Interview Survey, found that the most common reported reasons for nonattendance were life-threatening or

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The Future of Disability in America other physical disorders, neurodevelopmental disorders, learning-behavior disorders, and asthma. Among adults under age 65, musculoskeletal problems (including arthritis) and heart problems become increasingly important as people grow older. Mental illness is the second leading chronic condition mentioned as a cause of activity limitation for individuals ages 18 to 44 and is the fifth most frequently mentioned cause for individuals ages 55 to 64. For some people in this age group who are aging with disabilities, their primary health condition (e.g., cerebral palsy or spinal cord injury) is a risk factor for the development of secondary health conditions that have the potential to contribute to additional impairments, activity limitations, or participation restrictions. In general, survey questions have limited ability to distinguish such secondary disabling conditions from primary disabling conditions. (See Chapter 5 for further discussion.) For people ages 65 and over, musculoskeletal and heart problems continue to be leading contributors to limitations. Among people age 75 and over, senility (the term used by the National Center for Health Statistics but now more commonly referred to as dementia) is a major contributor to limitations. MONITORING TRENDS IN DISABILITY Monitoring trends in disability is important for several reasons. First, trend data provide a barometer of the nation’s achievements in terms of disability prevention. Second, when such data include measures of social, medical, and environmental risk factors, they can point policy makers to effective strategies for future interventions that will prevent or limit disabilities. Third, by including individuals of all ages, trend data can provide important insights into the future and serve as a basis for making assumptions that can be incorporated into projections. Studies that track and attempt to explain changes over time in the population require a high degree of consistency in survey design. Changes in the wording of questions, the type and coverage of the sample frame, the use of proxy respondents, and the frequency and timing of interviews, among other factors, can all influence the conclusions drawn from such studies (Freedman et al., 2002). Unfortunately, despite the growing number of data sources and the repetition of certain major surveys, the available data—on the whole—permit few direct comparisons with data from the 1980s and earlier. Notably, although several surveys that focused on older adults have allowed analysis of late-life trends since the 1980s, discontinuities in the surveys make comparisons of present survey data with data from previous surveys difficult for those in early and middle life. This difficulty will be particularly evident in discussions of data from the National Health Interview Survey before and after the major revisions made to that survey in

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The Future of Disability in America 1997 (see Chapter 2 for further discussion of the revisions). The 1991 IOM report used data from the 1988 National Health Interview Survey. With these limitations noted, the next three sections of this chapter review trends in disability in early, middle, and late life. These divisions of the human life span are necessarily artificial to some degree. They are based on a mix of social conventions, statistical convenience, and public policy considerations; but they reflect important distinctions. Thus age 18, when people become legal adults in nearly all states, is used as the endpoint for early life (childhood and adolescence), even though important physical and psychological development continues past that age and well into the third decade of life (see the discussion of the transition into adult life in Chapter 4). Midlife, ages 18 to 64, encompasses a particularly broad period of life, almost five decades. As discussed in Chapter 5, many people in this group have conditions that in years past commonly led to early death, and many are experiencing premature or atypical aging that neither they nor their physicians have anticipated. The late-life period is defined as beginning at age 65, although some studies focus on an older group (age 70 and older or age 85 and older) that is at a considerably higher risk of disability than younger groups within the older population. TRENDS IN EARLY LIFE In a background paper prepared for an IOM workshop held in August 2005, Stein observed that “over a 40-year period, the proportion of children reported to have major limitations in their activities related to play and school has gone from less than 2 percent to close to 7 percent” (Stein, 2006, p. 146). The reasons for this trend are complex and varied. In part, the trend reflects changes in the epidemiology of childhood illness and functioning. For example, data show disturbing increases in recent years in the number of children who are reported to have potentially disabling chronic conditions, such as asthma and autism, as well as increases in the prevalence of preterm births (Stein, 2006). In addition, longer-term trends likely reflect increases in the recognition and treatment of learning-related disabilities and other conditions. The next section reviews these trends in more detail, and the subsequent section describes two public health successes: declines in the rates of spina bifida and lead poisoning. Activity Limitations Examining disability trends among children presents special challenges. Especially in the first few years of life, children’s developmental changes make it difficult or inappropriate to identify certain kinds of behaviors as impairments or activity limitations. Furthermore, “the functioning of

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The Future of Disability in America children is always a moving target, as children mature at different rates, live in different cultures with different expectations of independence and self-sufficiency, and grow up in environments that vary markedly in the demands that they place on the performance of activities by children” (Stein, 2006, p. 145). Estimates of disability also vary depending on whether children are identified as having disabilities because of chronic conditions, special health care needs, or reports of activity limitations (Stein and Silver, 2002).5 In addition, as it is true for all age groups, revisions in national surveys complicate comparisons of disability trends for children. Despite these challenges and complexities, the data suggest increases in the proportion of children with activity limitations and conditions that put them at risk of disabilities. The earliest data from the National Health Interview Survey (Newacheck et al., 1984, 1986) reported activity limitations for only 1.8 percent of children under age 18 in 1960. The rate group increased to 3.8 percent for 1979 to 1981. For the period from 1984 to 1996, reports of the rates of activity limitations for this group increased from 5.1 to 6.1 percent (Table 3-3). More recent data, based on new National Health Interview Survey questions that asked about the receipt of special education services, the need for assistance with personal care, and limitations in walking and cognition, suggest that increases in the numbers of children with activity limitations also occurred between 1997 and 2004 (Table 3-4). In this more recent period, the increase in activity limitations was particularly affected by the increasing receipt of special education services, especially for boys. Boys are almost twice as likely as girls to be reported to be receiving such services. In addition, pooled data from the 2000 to 2002 National Health Interview Survey show that boys have higher rates of mental retardation, learning disabilities (including attention deficit or hyperactivity disorder), asthma, and vision or hearing problems (Xiang et al., 2005). Although special education services may be aimed, in particular, at children with conditions that primarily affect cognition (e.g., mental retardation), they also serve children with medical conditions that may secondarily affect the ability to learn. 5 As defined by the U.S. Maternal and Child Health Bureau, children with special health care needs are “those who have or are at increased risk for a chronic physical, developmental, behavioral, or emotional condition and who also require health and related services of a type or amount beyond that required by children generally” (McPherson et al., 1998, p. 137). This broad definition was developed to help in implementing amendments to the Social Security Act that provided for the development of community-based services for children with special health care needs and their families.

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The Future of Disability in America TABLE 3-3 Percentage of Children (Under Age 18) with Activity Limitations, by Type of Limitation and Age, 1984 to 1996 Activity Limitation 1984 1986 1988 1990 1992 1994 1996 Limited in activity (ages 0–17) 5.1 5.0 5.3 4.9 6.1 6.7 6.1 Limited in activity (ages 0–4) 2.5 2.5 2.2 2.2 2.8 3.1 2.6 Limited in activity (ages 5–17) 6.1 6.0 6.6 6.1 7.5 8.2 7.5 Needs ADL help (ages 5–17) 0.3 0.3 0.3 0.3 0.4 0.5 0.4 NOTE: Only limitations in activity caused by chronic conditions or impairments are included. Data for children residing in group settings are not included. Respondents are classified as having no activity limitation if they report a limitation due to a condition that is not known to be chronic. An activity limitation is defined as follows: children are classified in terms of the major activity usually associated with their particular age group. The major activities for the age groups are (1) ordinary play for children under 5 years of age and (2) attending school for those 5 to 17 years of age. A child is classified as having an activity limitation if he or she is (1) unable to perform the major activity, (2) able to perform the major activity but limited in the kind or amount of this activity, and (3) not limited in the major activity but limited in the kinds or amounts of other activities. ADL = activities of daily living. SOURCE: H. Stephen Kaye, Disability Statistics Center, University of California at San Francisco, unpublished tabulations from the National Health Interview Survey, as requested by the committee. (For the activity limitations and major activity limitations reported before 1997, boys also showed a higher prevalence of disability.)6 Potential Explanations of Trends As suggested above, the tripling of activity limitations among children over four decades likely reflects a confluence of forces. In part, there have been real changes in the epidemiology of illnesses and related disabilities among children. In addition, the trend may be capturing in part the increasing awareness by parents, health professionals, and other agencies 6 Other surveys besides the National Health Interview Survey suggest significant increases in the rates of certain potentially disabling chronic conditions among children and youth, especially in recent years. For example, the National Longitudinal Survey of Labor Market Experience, Youth Cohort, provides information on the health-related conditions of children born to women who were ages 14 to 21 in 1979. These data show an increase in the prevalence of chronic conditions from 11 percent in 1994 to 24 percent in 2000 among children who were ages 8 to14 in those years (unpublished tabulations from James Perrin, committee member).

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The Future of Disability in America same time, other data suggest that the rates of heart disease (Reynolds et al., 1999), stroke (Carandang et al., 2006), and arthritis (CDC, 1997) have been declining in this age group. The National Health Interview Survey also allows a glimpse into trends since 1997 in the rates of selected conditions identified by respondents as causing activity limitations. Again, note that the survey questions reflect a largely medical model of disability, without regard to the contribution of environmental factors. For the most common conditions that were listed earlier in this chapter (Table 3-2) as contributors to activity limitations, Table 3-5 suggests very recent declines in fractures and joint injuries, lung disease, heart or other circulatory diseases, and arthritis as “causes” of or contributors to activity limitations. Diabetes, in contrast, increased in importance in 2003 and 2004. Further analysis is needed to sort out whether these changes are statistically significant, whether they are maintained after controlling for demographic shifts during the period, and whether all groups have been equally affected. The Medicare Current Beneficiary Survey offers additional insights into the chronic conditions that exist among a subgroup of people between the ages of 18 and 65: those who have qualified for Medicare benefits not by age but by virtue of having qualified for SSDI. About 4 percent of Medicare beneficiaries are under age 45, and 11 percent are between the ages of 45 and 64. Perhaps the most striking trend revealed in Table 3-6 is the increase in the numbers of beneficiaries with a mental disorder, which is consistent with significant increases in SSDI awards because of mental disorders (Loftis and Salinsky, 2006). Finally, much has been written about the obesity epidemic in the United States (and elsewhere) and its implications. On the basis of data from the TABLE 3-5 Trends in Chronic Health Conditions Causing Limitations of Activity as Reported for Civilian, Noninstitutional Population, Ages 18 to 64, 1997 to 2004 Type of Chronic Health Condition Number of People with Activity Limitations Caused by Selected Chronic Health Conditions per 1,000 Population 1997 1998 1999 2000 2001 2002 2003 2004 Mental illness 14.2 13.2 13.2 13.1 15.3 17.3 16.0 14.5 Fractures and joint injuries 12.1 10.6 11.0 10.2 11.3 11.4 11.2 9.5 Lung 10.6 9.3 9.3 8.6 9.4 10.1 9.5 9.0 Diabetes 9.7 8.1 9.2 9.3 9.7 9.6 11.1 10.5 Heart, other circulatory 20.7 19.3 19.3 18.9 19.9 20.0 20.6 18.8 Arthritis, other musculoskeletal 42.5 38.9 37.7 33.8 37.5 38.0 37.7 35.5 SOURCE: Committee’s analysis of National Health Interview Survey data, 1997 to 2004.

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The Future of Disability in America TABLE 3-6 Trends in Self-Reported Health Conditions and Mobility Limitations, Community-Dwelling Medicare Beneficiaries Under Age 65, 1992 to 2002 Self-Reported Health Conditiona Percentage of Total Medicare Beneficiaries Under Age 65 1992 1994 1996 1998 2000 2002 Chronic conditionsb             None 20.9 16.8 17.8 18.1 17.4 15.3 Two or more 56.6 64.4 64.6 60.3 64.3 65.9 Disease or conditionb             Heart disease 33.2 32.9 33.0 32.0 33.3 35.7 Hypertension 42.9 47.5 47.8 45.6 48.3 52.1 Diabetes 17.3 18.2 19.5 18.8 20.3 22.0 Arthritis 46.6 49.6 49.3 49.1 50.3 52.7 Mental disorder 32.5 35.4 34.4 41.2 49.4 55.8 Mobility limitation             No limitation 36.9 38.0 38.1 35.9 33.7 31.4 aBeneficiaries who were administered a community-based interview answered health status and functioning questions themselves, unless they were unable to do so. A proxy, such as a nurse, always answered questions about the beneficiary’s health status and functioning for long-term care facility-based interviews. bIn 1997, the facility instrument was changed from a paper-and-pencil interview to a computer-assisted personal interview, and questions about certain diseases or conditions were asked differently. Consequently, there are significant fluctuations in the prevalence of certain diseases or conditions before and after 1997. SOURCE: Compiled from Medicare Current Beneficiary Survey, Health and Health Care Sourcebooks, 1992 to 2002. National Health and Nutrition Examination Surveys beginning in 1960, Figure 3-5 presents trend data on the rates of obesity among adults ages 20 to 39 and ages 40 to 59. The figure shows substantial increases in the rates of obesity among individuals in both age groups. In a paper prepared for the August 2005 IOM workshop on disability, Bhattacharya and colleagues (2006) linked these increases to increases in ADL and IADL limitations in middle life. Sturm and colleagues (2004) project increases in the prevalence of disability of 1 percent per year in the group ages 50 to 69, if current trends in obesity continue unabated. The link between obesity and disability needs further investigation because not only can obesity be a risk factor for disability but disability can likewise be a risk factor for obesity (see the discussion of secondary conditions in Chapter 5). TRENDS IN DISABILITY IN LATE LIFE Reflecting the high prevalence of disability in late life and concerns about the implications of an aging population on the economy, the health

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The Future of Disability in America FIGURE 3-5 Trends in the prevalence of obesity for men and women ages 20 to 39 and 40 to 59, civilian, noninstitutional population, 1960 to 2004. SOURCE: Compiled from the work of Flegal et al. (2002) and Ogden et al. (2006) on the basis of data from the National Health Examination Survey (1960 to 1962) and the National Health and Nutrition Examination Survey (other years). care system, and other areas of life, trends in disability have best been mapped and analyzed for older age groups. Generally, studies of disability trends in late life have focused on measures of activity limitations: ADLs and IADLs. Variations in the wording of questions across surveys, time periods, and other survey features have led to seemingly conflicting results in some cases. On balance, however, as first noted by Manton and colleagues (1993), trends in the prevalence of disability in late life are largely positive, with the evidence suggesting a substantial decline in the rates of IADL-related disabilities and smaller declines for ADL-related disabilities. This discussion relies primarily on data from the 1982 to 2004 National Health Interview Surveys. For older individuals, comparison of pre-1997 survey data with data from the revised survey suggested only minor discontinuities in the data on personal care and routine care limitations.11 Therefore, the data are presented without discontinuity by year. Personal Care and Routine Care Limitations Figure 3-6 shows the ADL and IADL trend data for 1982 through 2004. These data show a clear overall pattern of decline during the 1980s and 1990s in the percentage of the community-based population who need 11 This discussion draws on a background paper prepared for the August 2005 IOM workshop organized during the first phase of this study (Freedman, 2006).

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The Future of Disability in America FIGURE 3-6 Percentage of the civilian, noninstitutional population ages 70 years and older reporting need for help with personal care or help with routine care activities only, 1982 to 2003. ADL = needs help with personal care activities, such as eating, bathing, dressing, or getting around the home; IADL only = needs help only with routine needs, such as everyday household chores, doing necessary business, shopping, or getting around for other purposes. SOURCE: Analysis by Freedman (2006) of the 1982 to 2003 National Health Interview Survey data. assistance with limitations in routine care activities, such as shopping or preparing meals, but who do not need help with personal care. The decline has continued in the current decade but at a slower pace. Other data also point to declines in the percentage of the older people with limitations in routine care activities. For example, analyses based on data from the National Long-Term Care Survey suggested particularly large declines in three IADL measures from 1984 to 1999: doing laundry, managing money, and shopping for groceries (Spillman, 2004). A review of 16 relevant studies that used data from eight different surveys found substantial agreement that declines in IADL-related disabilities occurred through the 1980s and early 1990s (Freedman et al., 2002). A few more recent studies (Schoeni et al., 2005; Manton et al., 2006) suggest that such declines have continued into the current decade. Changes in trends for limitations with personal care activities, such as dressing or bathing, are not as large. As presented in Figure 3-6, data from the National Health Interview Survey showed a small decline in the prevalence of personal care limitations during the entire period, from 8.2 percent in 1982 to 7.8 percent in 2003. The Medicare Current Beneficiary

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The Future of Disability in America Survey also collects data on ADLs, although it asks about difficulty in performing an activity without help or special equipment. On the basis of data from that survey, Figure 3-7 shows decreases in limitations for community-dwelling beneficiaries in each category for the period from 1992 to 2003. A technical working group explored the inconsistencies in ADL trends across surveys and concluded that during the 1990s there were declines in difficulty with daily activities and the use of help with daily activities and increases in the percentage of individuals who used equipment to assist them with some activities (Freedman et al., 2004a). Despite the percent declines in IADL-related disabilities and the relative steady state of ADL-related disabilities, the total number of people with ADL or IADL limitations increased from approximately 4 million in 1982 to 4.2 million in 2003. (The numbers were calculated by using U.S. Census Bureau data on population by age group, available at http://www.census.gov/cgi-bin/ipc/idbagg.) FIGURE 3-7 Percentage of community-dwelling Medicare beneficiaries ages 65 and over who have difficulty in performing selected personal care activities without help or special equipment, 1992 to 2003. SOURCE: NCHS, 2007 (data from the Medicare Current Beneficiary survey obtained from tables compiled by CDC, available at http://209.217.72.34/aging/TableViewer/tableView.aspx?ReportId=362).

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The Future of Disability in America Without the declines in IADL limitations, the 2003 number would be much larger. The concern that not all groups may be benefiting equally from the declining rates of disability has led some researchers to investigate disparities in trends by race and socioeconomic status. Findings by race have been inconsistent thus far. On the one hand, data from the National Long-Term Care Survey suggest that racial disparities in chronic ADL- or IADL-related disabilities increased during the 1980s and decreased during the 1990s (Clark, 1997; Manton and Gu, 2001). On the other hand, three studies that used data from the National Health Interview Survey found no statistically significant changes in relative disparities in disabilities between racial minorities and whites, although the absolute size of the gaps may have narrowed (see, for example, the work of Schoeni et al. [2005]). A review of analyses of disparities in the rates of disabilities by level of education again found inconsistent results (Freedman et al., 2002). One study based on the National Long-Term Care Survey reported no clear pattern for the period from 1982 to 1999 (Manton and Gu, 2001). Another study that was also based on data from the National Health Interview Survey reported a decline in the prevalence of disabilities only among those with 13 or more years of education (Schoeni et al., 2001). More recently, using data from the National Health Interview Survey for the period 1982 through 2002, Schoeni and colleagues (2005) demonstrated widening gaps in the prevalence of disabilities by socioeconomic status. Disabilities Within Group Residential Care Settings Because of data limitations, many trend analyses have omitted data for the 2 million older individuals living in nursing homes and other group residential care settings. Data from the 1977 to 2004 National Nursing Home Surveys indicate that the proportion of older individuals living in nursing homes may have declined in recent years (Alecxih, 2006). Other analyses suggest that the short-stay population (those with stays of less than 3 months) has increased sharply, primarily as a result of Medicare’s adoption of hospital prospective payment, which gave hospitals strong incentives to discharge people more quickly, whether it was to home or to a post-acute care facility (Decker, 2005). Further insight into trends in disability among the population living in long-term care facilities is provided in Figure 3-8, which is based on data from the Medicare Current Beneficiary Survey. Figure 3-8 shows ADL-related data from 1992 to 2003 for beneficiaries age 65 and over living in long-term care facilities. (Note that the y-axis for Figure 3-6 extends from 0 to 16 percent, whereas it extends from 0 to 100 percent for Figure 3-8). Figure 3-8 shows increases in ADL disabilities for this group and, as ex-

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The Future of Disability in America FIGURE 3-8 Percentage of Medicare beneficiaries ages 65 and over living in nursing homes and other facilities who have any difficulty in performing selected personal care activities because of a health or physical problem, 1992 to 2003. SOURCE: NCHS, 2007 (data from Medicare Current Beneficiary Survey obtained from tables compiled by CDC, available at http://209.217.72.34/aging/TableViewer/tableView.aspx?ReportId=362). pected, very high levels of limitations. Data from the National Nursing Home Survey cited above show that the percentage of nursing home residents ages 85 and over increased from 35 to 47 percent between 1977 and 1999 (Decker, 2005). Other evidence also suggests that older adults living in nursing homes are frailer and have higher levels of disability now than older adults did a decade ago, perhaps because alternative care arrangements are more available for people with lesser but still significant levels of impairment (Spillman and Black, 2005b). For example, assisted living facilities, which offer supported living arrangements for those who need assistance but who do not require 24-hour skilled nursing care, grew from being almost nonexistent in the 1970s to serving about 750,000 older adults in 2000 (Spillman and Black, 2006).12 As described in Chapter 9, state Medicaid programs are paying for an increasing proportion of long-term care in home rather than institutional settings. 12 At a minimum, these facilities offer 24-hour supervision and assistance, as well as meals in a common dining area. Other services may include housekeeping and laundry services, medication reminders or help with medications, help with personal care activities, transportation, security, health monitoring, care management, and activities.

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The Future of Disability in America Health Conditions Associated with Disability in Late Life The extent to which some chronic conditions develop into disability may have been ameliorated in recent decades, in particular for arthritis (Freedman and Martin, 2000) and cardiovascular diseases (Cutler, 2003), even as the prevalence of many of the conditions in the older population has increased (Crimmins and Saito, 2000; Freedman and Martin, 2000; Crimmins, 2004). With respect to sensory functioning, the findings are mixed. Data from the Survey of Income and Program Participation suggest substantial declines in the percentage of older Americans with difficulty seeing from 1984 to 1993 (Freedman and Martin, 1998) and in the percentage with difficulty seeing or hearing from 1984 through 1999 (Cutler, 2001). Data from the Supplements on Aging to the National Health Interview Survey, however, show that the rates of blindness, deafness, and hearing impairment remained constant between 1984 and 1995 (Desai et al., 2001). Like the review for the nonelderly adult population, this summary of trends in health conditions and certain kinds of disabilities draws upon many data sources, data from different time periods, and different measures.13 The committee also reviewed trends in conditions that contribute to disability using data from the 1997 to 2004 National Health Interview Survey. The most common conditions linked to activity limitations among the population age 65 and older (Table 3-7) include arthritis and other musculoskeletal conditions, heart and other circulatory conditions, hearing and vision problems, diabetes, lung disease, and senility (dementia). The prevalence of these conditions as contributors to activity limitations declined for all conditions except diabetes and senility. Potential Explanations for Late-Life Trends Researchers are still trying to explain the declines in certain aspects of late-life disability and are debating whether past patterns are likely to continue (Cutler and Wise, in press). Several different factors have probably played roles in the recent declines. Increasing levels of education have likely played a role in decreasing disability; but the exact nature of this link remains unclear, and it appears that increases in educational attainment in the future will not match those of the past two decades (Freedman and Martin, 1999). Also, as noted previously, certain common chronic conditions appear to be less debilitating today than they were in the past (Crimmins and Saito, 2000; Cutler, 2003; Freedman and Martin, 2000). Moreover, as discussed in Chapters 1 and 7, assistive technologies may be replacing some kinds of personal caregiving (Spillman, 2004; Freedman 13 See IOM workshop paper prepared by Freedman (2006) for more details.

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The Future of Disability in America TABLE 3-7 Trends in Chronic Health Conditions Related to Activity Limitations, Civilian, Noninstitutional Population, Ages 65 and Over, 1997 to 2004 Type of Chronic Health Condition Number of People with Activity Limitations Caused by Selected Chronic Health Conditions per 1,000 Population 1997 1998 1999 2000 2001 2002 2003 2004 Senility (dementia) 22.8 22.9 23.8 25.3 24.5 24.6 27.5 25.6 Lung 39.5 39.8 39.4 38.6 38.0 38.0 38.7 35.0 Diabetes 44.2 44.0 41.8 46.4 50.6 45.3 49.4 49.2 Vision 49.3 41.1 42.9 42.9 45.7 42.0 35.7 34.9 Hearing 29.1 27.2 24.5 23.9 27.2 28.2 22.9 21.6 Heart, other circulatory 149.4 141.3 131.4 134.8 137.2 131.4 130.9 128.4 Arthritis, other musculoskeletal 161.9 146.1 146.6 139.5 143.4 139.2 149.1 145.5 SOURCE: Committee’s analysis of National Health Interview Surveys, 1997 to 2004. et al., 2006). This development could affect how people respond to questions about disability, particularly questions about the use of personal assistance (Wolf et al., 2005). Uncertainty remains, however, about the possible changes in people’s perceptions of disability at all stages of life and the relative contributions of changes in medical care, health behaviors, and living and working environments to declines in disability. PROJECTING THE FUTURE OF DISABILITY IN AMERICA The number of people with impairments in body structures or functions is likely to grow substantially in the coming years. Unless substantial progress is made in reducing the chances of such impairments developing into activity limitations and participation restrictions, particularly at older ages, the number of people in the United States facing barriers to work, health care, and independent living will no doubt escalate. The number of individuals needing personal assistance, whether it is from family members or from paid caregivers, will also increase. Designing and implementing strategies and policies to promote the health and well-being of people with existing disabilities and to prevent the development or progression of potentially disabling conditions should, therefore, be national priorities. In preparing this report, the committee reviewed the few existing studies that project the size of the population with disabilities. The review included, for example, projections related to the SSDI and SSI programs, the demand for long-term care services, and the rates of disability among the elderly population (see Bhattacharya et al. [2004] and Waidmann and Liu

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The Future of Disability in America [2000]).14 Although a comprehensive review of different methodologies is beyond the scope of this report, a few key issues can be cited. In projections of the future size of the older population, assumptions about life expectancy (that is, how long people can be expected to live) are key, whereas projections of the size of younger populations rely more heavily on assumptions about future birth rates. Also, projection methodologies generally make some assumptions about whether disability rates will increase, decline, or remain unchanged in the future. Some projection models have built elaborate assumptions about such rates (allowing variation, for example, in the timing of disease onset and progression), whereas others simply project forward the existing rates onto the numbers of people in each age group. Methods also vary in whether changes in other factors linked to disability (e.g., years of completed education) are incorporated into projections or are held constant. Finally, projections of program enrollment (in, e.g., the SSDI program) rather than disability per se may involve assumptions about additional variables, such as labor force participation rates. No source for projections of the number of children with disabilities could be identified. However, in the last half century and more, advances in biomedicine have saved many children who once would have died from conditions such as prematurity, traumatic injury, and a variety of genetic conditions or fetal developmental problems. Some of these children have gone onto experience slight to substantial physical or cognitive impairments. Other children have experienced impairments related to exposures to toxic substances. Furthermore, because disabling or potentially disabling conditions that are present at birth or that arise during childhood can have long-term consequences (Forrest and Riley, 2004; IOM, 2003a, 2005a, 2006a), the increases in the numbers of children with conditions such as childhood obesity and diabetes could eventually add to the numbers of adults and older adults with disabilities. The lack of projections based on these developments represents an important gap in present knowledge. The number of working-age adults eligible for SSDI (meaning that they have a qualifying disability and have worked long enough in Social Security-covered jobs to qualify for benefits) is projected to increase. For example, the Congressional Budget Office projects that caseloads will increase from 6.7 million in 2000 to 10.4 million in 2015 (CBO, 2005b). The number of beneficiaries per covered worker is also projected to increase, as described in Chapter 1. However, the consequences of premature aging or atypical aging for people with disabilities—including individuals with conditions that once were incompatible with long-term survival—have been 14 Projections of SSDI caseloads are available from CBO (2005b) and the work of Toder et al. (2002). Long-term care projections are available from CBO (1999). Social Security projections of SSI and SSDI are available from SSA (2006c).

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The Future of Disability in America little discussed with respect to their potential impact on the SSDI program. More generally, analysts have predicted that ADL disabilities and work limitations among adults will increase (irrespective of program eligibility), in part as a consequence of the growing prevalence of obesity and related disorders (Sturm et al., 2004). Focusing on older adults, if the rate of activity and other limitations for those ages 65 or over were to remain what it is today (roughly 40 percent from Table 3-1), the number of older people with impairments or limitations would increase from approximately 14 million today to more than 28 million in 2030. Using different definitions and a more complex methodology, Waidmann and Liu (2000) have projected that the numbers of older adults with activity limitations would grow from 22 million in 2005 to 38 million by 2030. They also projected that the number of people with limitations in ADLs or IADLs would increase from 12 million to 22 million over this period, if the rates of people with limitations in ADLs and IADLs remained constant but the numbers of people classified by age, sex, and education change according to U.S. Census Bureau projections. Importantly, Waidmann and Liu also project that if rates of activity limitations did not hold constant in the future but, instead, declined at the same rate observed during the 1990s, the number of people with such limitations would still grow to about 38 million by 2030. In contrast, the number of older people with limitations in ADLs or IADLs would stay steady at about 12 million. Another analysis, which assumes that disability rates remain constant, estimates that the number of Americans of all ages with limitations in ADLs only will increase from 5.2 million in 2000 to 9.3 million in 2030 (Friedland, 2004). Taken together, these projections suggest that the number of people with disabilities is likely to increase in the coming years, unless steps are taken to reduce the environmental barriers that contribute to avoidable activity limitations and participation restrictions. The good news is that the rates of limitations for some activities have already been declining for older individuals. As discussed earlier in this chapter, it is not completely clear why this is the case. As discussed in later chapters of this report and as recommended in Chapter 10, further research is needed to identify and disseminate practices and programs that minimize activity limitations and participation restrictions.