In NHIS terminology, disability is defined as activity limitation. Activity limitation is defined at three levels: (1) inability to carry out a major activity, (2) limitation in the amount or kind of major activity that can be carried out, and (3) limitation in carrying out a nonmajor activity. Major activities considered usual for one's age group are defined as ordinary play for children under 5 years of age, attending school for children ages 5 to 17, working or keeping house for people ages 18 to 69, and capacity for independent living (ability to bathe, shop, eat, and care for oneself without the assistance of another person) for people ages 70 and older. Nonmajor activities include social, civic, or recreational pursuits. The 1994 NHIS estimate of the number of people limited in activity because of chronic conditions was 39 million, or 15 percent of the civilian noninstitutionalized population. Of these 39 million people, 18.2 million were male and 20.8 million were female; 32.4 million were white and 5.4 million were African American. Residents of the South (16.3 percent) and rural areas (17.6 percent) had a slightly higher prevalence of disability than did residents of other locations.
Table 2-1 presents disability rates by demographic characteristic for the 1992 NHIS. Table 2-2 indicates the prevalence of activity limitations, limitations in the self-reported ability to work among people 18 to 69 years, and limitation in activities of daily living (ADL) and instrumental activities of daily living (IADL) among people over age 5 years by the impairments and diseases or disorders causing the limitation. The data summarize information from LaPlante and Carlson (1996) and are derived from analyses of the 1992 National Health Interview Survey (NHIS) conducted by the Bureau of the Census for the National Center for Health Statistics. NHIS surveyed a stratified random sample of the noninstitutionalized population of the continental United States and had approximately 110,000 respondents. Sampling weights associated with each respondent allowed for the estimation of the total number of people in the continental United States with limitations associated with impairments and conditions.
Total Prevalence Table 2-2 presents data on the prevalence of activity limitations associated with major classifications of impairments and diseases or disorders, including the number of people with the particular classification and limitation and the proportion of all activity limitations attributed to the classification. Overall, in excess of 61 million impairments or diseases and disorders contributed to activity limitations in 1992; of these, 16.3 million were impairments (26.7 percent of the total) and the remaining 44.7 million were diseases or disorders (73.3 percent). Among