Racial/Ethnic Differences in the Prevalence and Impact of Doctor-Diagnosed Arthritis --- United States, 2002
Arthritis is among the most prevalent chronic conditions in the United States, diagnosed in approximately 21% of adults (1). In addition, arthritis is the most common reported cause of disability (2) and the third leading cause of work limitation in the United States (3). Racial/ethnic differences have been documented in the prevalence of arthritis and in the prevalence of limitations caused by arthritis (4). To examine racial/ethnic differences in the prevalence and impact of arthritis, CDC analyzed data from the 2002 National Health Interview Survey (NHIS). This report summarizes the results of that analysis, which indicated that, when compared with whites, a higher proportion of blacks had arthritis-attributable activity limitations, work limitations, and severe joint pain, and a higher proportion of Hispanics had arthritis-attributable work limitations and severe joint pain. Examining racial/ethnic disparities in the prevalence and impact of arthritis is important to identify priority populations for public health interventions.
The 2002 NHIS sample adult questionnaire was administered by personal interview in English or Spanish to a nationally representative sample (n = 31,044) of the U.S. civilian, noninstitutionalized population aged >18 years; the survey response rate for this component was 74.3%. Respondents were asked about their health conditions and limitations and were considered to have self-reported, doctor-diagnosed arthritis if they answered "yes" to the question, "Have you ever been told by a doctor or other health professional that you have some form of arthritis, rheumatoid arthritis, gout, lupus, or fibromyalgia?" Those who answered "yes" were asked about limitation of usual activities caused by arthritis and if arthritis affected whether they worked or the type or amount of work they did. Responses to the work limitation question were analyzed only for the typical working age population (i.e., ages 18--64 years).
Respondents were also asked if they had joint pain (excluding the neck or back) during the preceding 30 days and to rate their average pain on a scale of 0 (no pain) to 10 (extreme pain). Severe joint pain was defined as a reported level of 7 or higher. Approximately 27.9% of those with doctor-diagnosed arthritis reported no joint pain, were therefore not asked the question about pain severity, and were classified as not having severe joint pain.
For this study, data are presented only for white, black, Hispanic, and other/multiple races combined because the sample sizes for other racial/ethnic populations, when analyzed separately, were too small for meaningful analysis. In this report, persons who are white, black, and other/multiple races are all non-Hispanic. Because different racial/ethnic populations have different age distributions, both crude and age-adjusted prevalence estimates were calculated. Data were adjusted for nonresponse and weighted to provide national estimates. Confidence intervals (CIs) were calculated by using statistical analysis software to account for the multistage probability sample. Estimates were age-adjusted to the standard 2000 U.S. population. All differences noted are statistically significant (p<0.05) with nonoverlapping 95% CIs.
In 2002, an estimated 20.8% (42.7 million) of adults aged >18 years had self-reported, doctor-diagnosed arthritis* (Table 1). Women had higher prevalence of arthritis than men, and prevalence among all respondents increased with age (Table 1). Of all adults reporting arthritis, approximately one in three (37.6%) reported activity limitations caused by arthritis or joint symptoms, which corresponds to 7.8% (16.0 million) of the total U.S. adult population (Table 2). Nearly one in four (24.6%) adults with arthritis reported severe joint pain during the preceding 30 days. Among persons aged 18--64 years with arthritis, 30.6% reported work limitations attributable to arthritis, which corresponds to 4.8% (8.2 million) of the total U.S. adult population aged 18--64 years.
Age-adjusted estimates indicated that blacks had a prevalence of arthritis similar to that of whites (Table 1), but a higher proportion had activity limitations attributable to arthritis (44.2% versus 34.1%) and thus a higher prevalence of arthritis-attributable activity limitations (10.1% versus 7.9%) (Table 2). Similarly, among respondents aged 18--64 years, blacks had a higher proportion with work limitations (39.5% versus 28.0%) and thus a higher prevalence of arthritis-attributable work limitation (6.6% versus 4.6%). Overall, blacks with doctor-diagnosed arthritis had a higher prevalence of severe pain attributable to arthritis, compared with whites (34.0% versus 22.6%).
Compared with whites, Hispanics had a lower prevalence of doctor-diagnosed arthritis (21.9% versus 15.8%) (Table 1) but a similar proportion with activity limitations attributed to arthritis (34.1% versus 39.7%), resulting in a lower prevalence of arthritis-attributable activity limitations (7.9% versus 6.5%) (Table 2). Among respondents aged 18--64 years, Hispanics had a higher proportion of work limitations than whites (38.8% versus 28.0%), resulting in a similar prevalence of arthritis-attributable work limitations (4.1% versus 4.6%). A higher proportion of Hispanics with doctor-diagnosed arthritis reported severe joint pain, compared with whites (32.5% versus 22.6%).
Reported by: J Bolen, PhD, J Sniezek, MD, K Theis, MPH, C Helmick, MD, J Hootman, PhD, T Brady, PhD, G Langmaid, Arthritis Program, Div of Adult and Community Health, National Center for Chronic Disease Prevention and Health Promotion, CDC.
The findings in this report indicate that, in 2002, approximately 21% of U.S. adults had self-reported, doctor-diagnosed arthritis, more than one third of those with arthritis had activity limitations attributable to arthritis, and nearly one third of working-age adults with arthritis also had arthritis-attributable work limitations. Compared with whites, blacks had a similar prevalence of doctor-diagnosed arthritis but a higher proportion of arthritis-attributable activity limitations, work limitations, and severe joint pain, and Hispanics had a lower prevalence of arthritis but a higher proportion with arthritis-attributable work limitations and severe joint pain.
The reasons for these racial/ethnic differences are not understood, but might be related to differences in health-care access, use of available health-care services, and language barriers (5). A higher prevalence of activity limitations attributable to arthritis among blacks could also be related to a higher prevalence of obesity, a condition known to be related to arthritis prevalence and poor physical functioning. The higher proportion of work limitations attributable to arthritis among blacks and Hispanics might also reflect certain racial/ethnic differences in the type of work activities the respondents perform. Those who engage in more physically demanding work (e.g., work that requires frequent knee-bending and lifting) might also experience limitations sooner because specific work tasks can exacerbate joint symptoms and because adapting certain job tasks to accommodate joint problems is difficult.
The findings in this report are subject to at least two limitations. First, data were from self-reports of survey participants; thus, the presence of doctor-diagnosed arthritis were not confirmed by a health-care provider. However, this case-finding question appears valid for surveillance purposes (6). Second, this analysis did not take into account other factors (e.g., socioeconomic status, body mass index, or comorbid conditions) that might be related to a person's risk for activity and work limitation and that might differ by race/ethnicity (7).
Arthritis is a common illness with a major impact on all racial/ethnic populations. However, the disabling effects of arthritis (e.g., arthritis-attributable activity limitations, work limitations, and severe pain) affect racial/ethnic minorities disproportionately. Evidence-based arthritis interventions should increase among all persons with arthritis, especially these high-need populations. For example, physical activity and weight reduction programs can reduce the disabling effects of arthritis; these interventions should be made more available and accessible to all persons with arthritis, especially to blacks and Hispanics. The Arthritis Self Help Course (ASHC) is a self-management education program that has been shown to reduce pain and physician visits among persons with arthritis (8). A Spanish version of ASHC, also shown to be effective (9), should be made available to all Spanish-speaking persons with arthritis. Because the number of persons with arthritis is expected to increase during the next 25 years as the population ages (10) and the number of persons limited by arthritis symptoms is likely to increase, expansion of these programs is key. Increased attention should be given to implementing and evaluating evidence-based interventions in different populations, as well as adapting the interventions as necessary. Additional research is also needed to clarify reasons for racial/ethnic disparities in the occurrence of arthritis and arthritis-attributable limitations.
* An additional 11.3% (23.2 million) of adults had possible arthritis (data not shown). Respondents with possible arthritis reported chronic joint pain but no doctor-diagnosed arthritis.
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