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Persons using assistive technology might not be able to fully access information in this file. For assistance, please send e-mail to: mmwrq@cdc.gov. Type 508 Accommodation and the title of the report in the subject line of e-mail. Prevalence and Impact of Arthritis By Race and Ethnicity -- United States, 1989-1991Arthritis and other rheumatic conditions are among the most prevalent chronic conditions in the United States, affecting an estimated 40 million persons in 1995 and a projected 60 million by 2020 (1). Previous reports have documented marked differences in the prevalence rates of arthritis and related activity limitations by race and ethnicity (1,2), suggesting the relative importance of arthritis might vary among these groups. In addition, race and ethnicity are associated with important differences in health characteristics and must be addressed in efforts to reduce health disparities as specified by the national health objectives for the year 2000 (3). To examine the relative importance of arthritis among these groups, data from the 1989-1991 National Health Interview Survey (NHIS) were used to estimate the prevalence of self-reported arthritis and related activity limitation by race and ethnicity, compare these estimates to those for other chronic conditions, and estimate these prevalences for 2020. Prevalences of Arthritis and Activity Limitation The NHIS is an annual national probability sample of the civilian, noninstitutionalized population of the United States (4). Estimates of the prevalence of arthritis were based on a one-sixth random sample of 1989-1991 respondents (n=59,289) who answered questions about the presence of any musculoskeletal condition during the preceding 12 months and provided details about these conditions. Each condition was assigned a code from the International Classification of Diseases, Ninth Revision (ICD-9). This analysis used the definition of arthritis, which included arthritis and other rheumatic conditions, developed by the National Arthritis Data Workgroup (1). * Data were weighted to estimate the average annual number of cases and prevalence rates. Because age and sex are strongly associated with arthritis prevalence rates, adjusted rates were estimated using eight age categories (0-24, 25- 34, 35-44, 45-54, 55-64, 65-74, 75-84, and greater than or equal to 85 years) and by sex. Race (white, black, American Indian/Alaskan Native, and Asian/Pacific Islander) and ethnicity (Hispanic, non-Hispanic white, and non-Hispanic black) were determined by the respondent's description of his or her background. Activity limitation caused by arthritis was estimated by using all respondents in the 1989-1991 NHIS (n=356,592). Respondents were asked if they were unable to perform, or were limited in, their major activity (play or school for children and adolescents; working or keeping house for persons aged 18-69 years; independent living for those aged greater than or equal to 70 years) as a result of health condition(s), and if so, to specify the condition(s) they considered to be responsible for their limitations. Data from those attributing activity limitation to arthritis were weighted to estimate the average annual number of affected persons, prevalence rate, and age- and sex-adjusted rates. Unadjusted race-specific prevalence rates for arthritis varied from 5.6% (Asians/Pacific Islanders) to 16.0% (whites) (Table_1). Age- and sex-adjusted rates were significantly lower for Asians/Pacific Islanders (7.2% {95% confidence interval (CI)= plus or minus 1.6%}) than for other races (15.2% {95% CI= plus or minus 0.3%} for whites, 15.3% {95% CI= plus or minus 0.8%} for blacks, and 16.5% {95% CI= plus or minus 3.3%} for American Indians/Alaskan Natives). The unadjusted population prevalence rates for activity limitation attributable to arthritis varied from 0.7% (Asians/Pacific Islanders) to 3.0% (blacks and American Indians/Alaskan Natives). Age- and sex-adjusted rates were significantly higher for American Indians/Alaskan Natives (4.2% {95% CI= plus or minus 1.0%}) and blacks (4.0% {95% CI= plus or minus 0.2%}) and significantly lower for Asians/Pacific Islanders (1.1% {95% CI= plus or minus 0.3%}) than for whites (2.7% {95% CI= plus or minus 0.1%}). The proportion of persons with arthritis who had activity limitation attributable to arthritis was lower among whites (17.6%) and Asians/Pacific Islanders (13.0%) than among blacks (24.5%) and American Indians/Alaskan Natives (22.6%). Unadjusted prevalence rates for arthritis by ethnicity were 6.5% for Hispanics, 12.4% for non-Hispanic blacks, and 16.9% for non-Hispanic whites (Table_1). Age- and sex-adjusted rates were significantly lower for Hispanics (11.2% {95% CI= plus or minus 1.0%}) than for non-Hispanic whites and non-Hispanic blacks (15.5% {95% CI= plus or minus 0.3%} and 15.4% {95% CI= plus or minus 0.8%}, respectively). Unadjusted population prevalence rates for activity limitation were 1.4% for Hispanics and 3.0% for non-Hispanic whites and non-Hispanic blacks. Age- and sex-adjusted rates for activity limitation were similar for Hispanics and non-Hispanic whites (2.7%), and for both groups were significantly lower than for non-Hispanic blacks (3.9% {95% CI= plus or minus 0.2%}). The proportions of persons with arthritis who had activity limitation attributable to arthritis were similar for Hispanics (22.2%) and non-Hispanic blacks (24.3%) and were higher than that for non-Hispanic whites (17.5%). Comparison with Other Chronic Conditions Average annual prevalence estimates of chronic conditions other than arthritis were based on a one-sixth random sample of NHIS respondents in 1989-1991 who answered questions (on six separate condition lists) regarding the presence of these conditions. Analyses included the 21 most common conditions in the NHIS that were defined as chronic (i.e., a condition lasting greater than 3 months or assumed to be chronic {e.g., diabetes}). These data were weighted to estimate average annual numbers of persons affected. Average annual numbers of persons with activity limitation caused by these chronic conditions were estimated as they were for arthritis. Arthritis was the most common self-reported chronic condition among whites, the second most common among American Indians/Alaskan Natives and Hispanics, the third most common condition among blacks, and the fourth most common condition among Asians/Pacific Islanders (Table_2). For all groups, arthritis prevalence was higher than self-reported hearing impairment, heart disease, chronic bronchitis, asthma, and diabetes. Among the conditions reported to account for activity limitations, arthritis ranked first among blacks and second among the other groups. Projections for 2020 Arthritis prevalence was projected for 2020 by applying the average annual arthritis prevalence rate for 1989-1991, stratified by age and sex, to the relevant U.S. population projected by the Bureau of the Census (5). Based on these projections, in 2020, self-reported arthritis will affect an estimated 49.7 million whites, 7.0 million blacks, 442,000 American Indians/Alaskan Natives, 1.6 million Asians/Pacific Islanders, and 5.1 million Hispanics. In 2020, activity limitation attributable to arthritis will affect an estimated 9.3 million whites, 1.8 million blacks, 115,000 American Indians/Alaskan Natives, 264,000 Asians/Pacific Islanders, and 1.2 million Hispanics. Reported by: National Arthritis Data Workgroup. Div of Adult and Community Health, National Center for Chronic Disease Prevention and Health Promotion, CDC. Editorial NoteEditorial Note: The findings in this report indicate that during 1989-1991, arthritis was the first or among the top four self-reported chronic conditions among all racial/ethnic groups in the United States. As a cause of activity limitation, arthritis ranked either first or second within each group. For these racial groups and for Hispanics, both the large numbers and percentages of persons affected in 1989-1991 probably will increase markedly by 2020, reflecting projected increases in the average age of these populations. Potential explanations for group-specific differences may include variations in cultural thresholds for reporting arthritis (6) and group-specific differences in factors associated with the prevalence of arthritis (e.g., overweight, low socioeconomic status, and occupations involving knee-bending) (7,8). In addition, major histocompatibility genes -- especially molecularly defined alleles -- vary among ethnic groups and are associated with diseases such as rheumatoid arthritis (9). Although NHIS self-reported data enable more accurate estimates of activity limitation attributable to arthritis than do other sources (e.g., physician-based data) (10), neither the self-reported data nor the assigned ICD-9 codes were validated by a health-care provider. To improve understanding of arthritis and reduce its occurrence and activity limitation attributable to it, public health research and intervention efforts must focus on groups at greatest risk, better define the reasons for these differences among groups, better characterize the epidemiology and natural history of the different types of arthritis, more accurately estimate their economic and societal burden, and evaluate the effectiveness of interventions among these groups. In 1996, six state health departments have initiated use of an optional Behavioral Risk Factor Surveillance System arthritis module to obtain state-level information about arthritis, including data by race and ethnicity. Primary-care providers and state programs can decrease the impact of arthritis among affected groups by 1) promoting primary prevention of arthritis through weight reduction and prevention of sports- or occupational-associated joint injury and 2) encouraging early detection and appropriate education and exercise interventions. References
Table_1 Note: To print large tables and graphs users may have to change their printer settings to landscape and use a small font size. TABLE 1. Estimated average annual numbers and prevalence rates * of persons with self-reported arthritis + and related activity limitation in the total population, by race and ethnicity & -- National Health Interview Survey, United States, 1989-1991 ======================================================================================================================================================== Race Ethnicity -------------------------------------------------------------------- --------------------------------------------------- American Asian/ Non- Non- Indian/ Pacific Hispanic Hispanic Characteristic White Black Alaskan Native Islander Hispanic white black ------------------------------------------------------------------------------------------------------------------------------------------------------ Self-reported arthritis No. (thousands) 31,864 3,672 270 401 1,412 30,662 3,533 Rate (95% CI @) Unadjusted 16.0% (+/-0.5%) 12.3% (+/-0.7%) 13.4% (+/-3.5%) 5.6% (+/-1.4%) 6.5% (+/-0.8%) 16.9% (+/-0.4%) 12.4% (+/-0.7%) Age- and sex-adjusted 15.2% (+/-0.3%) 15.3% (+/-0.8%) 16.5% (+/-3.3%) 7.2% (+/-1.6%) 11.2% (+/-1.0%) 15.5% (+/-0.3%) 15.4% (+/-0.8%) Self-reported activity limitation attributable to arthritis No. (thousands) 5,620 899 61 52 314 5,364 858 Rate (95% CI) Unadjusted 2.8% (+/-0.1%) 3.0% (+/-0.2%) 3.0% (+/-0.8%) 0.7% (+/-0.2%) 1.4% (+/-0.2%) 3.0% (+/-0.1%) 3.0% (+/-0.2%) Age- and sex-adjusted 2.7% (+/-0.1%) 4.0% (+/-0.2%) 4.2% (+/-1.0%) 1.1% (+/-0.3%) 2.7% (+/-0.3%) 2.7% (+/-0.1%) 3.9% (+/-0.2%) Proportion of persons with arthritis who have activity limitation attributable to arthritis 17.6% 24.5% 22.6% 13.0% 22.2% 17.5% 24.3% ------------------------------------------------------------------------------------------------------------------------------------------------------ * Unadjusted rates are estimated for the 1989-1991 National Health Interview Survey (NHIS) civilian, noninstitutionalized population (CNI), using the appropriate weights. Age- and sex-adjusted rates use eight age categories (0-24, 25-34, 35-44, 45-54, 55-64, 65-74, 75-84, and >=85 years) to adjust to the 1989-1991 CNI population. To generate national numbers, unadjusted NHIS rates were applied to the total population. + Arthritis is defined by using the National Arthritis Data Workgroup's definition, which is based on the International Classification of Diseases, Ninth Revision, Clinical Modification, codes 95.6, 95.7, 98.5, 99.3, 136.1, 274, 277.2, 287.0, 344.6, 353.0, 354.0, 355.5, 357.1, 390, 391, 437.4, 443.0, 446, 447.6, 696.0, 710-716, 719.0, 719.2-719.9, 720-721, 725-727, 728.0-728.3, 728.6-728.9, 729.0-729.1, and 729.4. & Race and ethnicity are self-reported by the respondent. @ Confidence interval. CIs were calculated using SUDAAN. ======================================================================================================================================================== Return to top. Table_2 Note: To print large tables and graphs users may have to change their printer settings to landscape and use a small font size. TABLE 2. Estimated average annual numbers * of persons with self-reported chronic conditions + and related activity limitations in the civilian, noninstitutionalized population, by race, ethnicity &, and condition -- National Health Interview Survey, United States, 1989-1991 ==================================================================================================== No.(thousands), by race/ethnicity ------------------------------------------------------ American Indian/ Asian/ Alaskan Pacific Condition White Black Native Islander Hispanic ------------------------------------------------------------------------------------ Top five and selected self-reported conditions Arthritis @ 31,612 3,678 275 335 1,492 Chronic sinusitis 28,089 3,745 212 260 1,439 Deformity or orthopedic impairment 24,786 2,556 279 429 1,857 High blood pressure (hypertension) 22,516 4,185 188 338 1,315 Hearing impairment 19,780 1,486 156 329 979 Hay fever or allergic rhinitis without asthma 19,572 1,823 187 556 1,447 Heart disease 13,919 1,712 84 154 648 Chronic bronchitis 10,862 1,093 100 117 731 Asthma 9,064 1,578 140 205 926 Diabetes 5,163 1,082 91 109 491 Top five and selected self-reported conditions as a cause of activity limitation Deformity or orthopedic impairment 6,272 785 96 108 544 Arthritis 5,646 908 64 47 327 Heart disease 4,107 564 40 39 225 High blood pressure (hypertension) 1,972 797 32 36 205 Intervertebral disk disorders 1,831 170 20 14 115 Diabetes 1,733 497 31 26 216 Asthma 1,661 423 23 33 257 Visual impairment 1,027 151 21 18 87 Hearing impairment 954 79 11 14 66 Cerebrovascular disease 841 166 9 6 42 ------------------------------------------------------------------------------------ * The average annual number of persons affected in the civilian, noninstitutionalized population was estimated by using the appropriate weights in the 1989-1991 National Health Interview Survey (NHIS). Data in this table reflect the internal weights of the 1989-1991 NHIS, which are based on civilian, noninstitutionalized population estimates that differ slightly from those of the 1990 census total population estimates. Using the internal weights of the 1989-1991 NHIS allows easier comparison among the different chronic conditions. + A condition lasting >3 months or that is assumed to be chronic (e.g., diabetes). & Race and Hispanic ethnicity are self-reported by the respondent. @ Arthritis is defined by using the National Arthritis Data Workgroup's definition, which is based on the International Classification of Diseases, Ninth Revision, Clinical Modification; other chronic conditions are defined by using NHIS chronic condition recode C. Impairments are coded according to a special classification system for the NHIS. ==================================================================================================== Return to top. 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