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.