Racial Disparities in Nationally Notifiable Diseases --- United States, 2002
Infectious diseases are a major cause of morbidity, mortality, and disability in the United States and often affect racial/ethnic populations disproportionately (1,2). Eliminating racial disparities is a goal of many of the national health objectives for 2010 (3). To estimate racial disparities in the incidence of nationally notifiable infectious diseases by race/ethnicity, CDC reviewed 2002 data from the Nationally Notifiable Diseases Surveillance System (NNDSS), collected through the National Electronic Telecommunications System for Surveillance (NETSS). This report summarizes the results of that analysis, which indicated that incidence rates were at least two times greater for blacks than whites for eight of 42 nationally notifiable diseases; however, substantial gaps exist in the reporting of racial/ethnic data for the 42 diseases, which accounted for approximately 1.3 million of the cases reported by NNDSS. Public health practitioners and policy makers might use these results to address disparities in disease rates among blacks and other racial/ethnic populations, but they also should work to close gaps in data reporting to accurately measure progress toward achieving the national health objectives.
NNDSS is a public health surveillance system that collects data on cases of notifiable diseases. The system is maintained by CDC, in collaboration with the Council of State and Territorial Epidemiologists (CSTE), which determines nationally notifiable conditions and standard case definitions. The decision to make a disease nationally notifiable is based on its public health importance (e.g., number of cases or severity of the disease) and its preventability. Since 1990, case data have been reported to NNDSS by the 50 states, District of Columbia, New York City, and U.S. territories. For this analysis, notifiable diseases were reviewed for completeness of racial data where 25 or more cases were reported; incidence rates were reported by race where five or more cases were reported. For this report, racial classifications might include both persons who are Hispanic and non-Hispanic. Hispanic ethnicity was only considered in determining the percentage of cases for which ethnicity data were not provided; no incidence rates were calculated for Hispanics. The number of cases, rate per 100,000 population by racial population, and black/white rate ratio were determined for 42 nationally notifiable diseases. Data for primary and secondary syphilis were combined. Data were analyzed for cases reported directly through NETSS; data from U.S. territories were excluded. Population data from states in which diseases were not notifiable or disease data were not available were excluded from rate calculations.
For 42 nationally notifiable infectious diseases in 2002, a total of 1,362,628 cases were reported (Table). Racial data were provided for 70% of cases; Hispanic ethnicity data were provided for 65% of cases. Missing data on race ranged from six (5%) cases of streptococcal toxic shock syndrome to 3,527 (71%) cases of coccidioidomycosis; missing data on Hispanic ethnicity ranged from zero for syphilis to 66% for coccidiodomycosis. By state, missing data on race ranged from 1% to 63% of cases, with an interquartile range of 13%--35%; missing data on Hispanic ethnicity ranged from zero to 98% of cases, with an interquartile range of 16%--45%. Nineteen diseases had >30% cases with missing race information.
At least 20,000 cases were reported by each of six infectious diseases: chlamydia (834,555 cases), gonorrhea (351,852), salmonellosis (44,264), Lyme disease (23,763), shigellosis (23,541), and giardiasis (21,206). For three of those six diseases, and eight of the 42 nationally notifiable diseases, the incidence rate for blacks was at least twice as high as the rate for whites in 1992. For gonorrhea, the incidence rate for blacks was 24 times greater, at 570.4 per 100,000 population, compared with 23.6 for whites. For malaria, the rates were 1.8 for blacks and 0.2 for whites; for chlamydia, 805.9 for blacks and 90.2 for whites; for syphilis, 9.4 for blacks and 1.1 for whites; for shigellosis, 16.8 for blacks and 4.0 for whites; for typhoid fever, 0.1 for blacks and 0.02 for whites; for hepatitis B, 3.9 for blacks and 1.5 for whites; and for Streptococcus pneumoniae (i.e., invasive, drug resistant), 1.5 for blacks and 0.7 for whites.
In other findings, the incidence rate for Lyme disease among whites (7.8 per 100,000 population) was approximately 11 times greater than that for blacks (0.7), and the incidence rate for giardiasis was approximately two times greater for whites (5.4) than for blacks (2.5). Among racial populations, the highest incidence rates of salmonellosis (17.4 per 100,000 population) and shigellosis (19.7) were among American Indians/Alaska Natives (AI/AN).
Reported by: N Adekoya, DrPH, RS Hopkins, MD, Div of Public Health Surveillance and Informatics, Epidemiology Program Office, CDC.
The findings in this report indicate substantial disparities between racial populations in notifiable infectious diseases, including three of the six diseases with more than 20,000 cases per year. Public health efforts should attempt to reduce these disparities in diseases, including gonorrhea, chlamydia, and shigellosis among blacks, salmonellosis and shigellosis among AI/AN, and giardiasis and Lyme disease among whites. However, efforts to reduce these disparities require more accurate and complete racial/ethnic data for nationally notifiable diseases. The amounts of missing racial/ethnic data from NETSS described in this report are similar to those reported previously (4).
The findings in this report are subject to at least four limitations. First, surveillance practices vary among states/areas, and definitions can be misapplied. Second, availability of resources can influence the detail of reporting (e.g., racial/ethnic data) by states/areas. Third, underreporting of certain diseases might reflect lack of awareness of a disease or its low priority with state and local officials; conversely, concerted efforts to reduce syphilis might explain the high percentage of syphilis cases reported with racial/ethnic data. Finally, the substantial gaps in collection of racial/ethnic data might be attributable to various factors and could result in underreporting of certain racial populations.
Although NETSS data have been useful at national and state levels (3), implementing the National Electronic Disease Surveillance System (NEDSS)*, including the NEDSS Base System, might lead to improvement in the reporting of racial/ethnic data, especially if the data are contained in electronic clinical records that are moved directly into NEDSS components. Implementing NEDSS might also improve the compatibility of racial/ethnic data reporting across states and across programs; data are collected in the same format and coding system as those used for the decennial census.
Infectious diseases continue to place a considerable burden on the nation, and better prevention and more effective control measures are needed (5--7). To plan programs and evaluate the success of efforts to control infectious diseases of public health importance, improvements are necessary in the data-collection methods of surveillance systems to enable targeting of populations at greatest risk and to reduce health disparities among racial/ethnic populations.
* NEDSS is designed as a major component of the Public Health Information Network to promote the use of data and information system standards to advance the development of efficient, integrated, and interoperable surveillance systems at federal, state, and local levels. The NEDSS Base System can be used by health departments for the surveillance and analysis of notifiable diseases. With NEDSS, providers can transfer clinical and laboratory-based data electronically to health departments, thereby lessening the burden of reporting, reducing missing data, and improving timeliness. Additional information is available at http://www.cdc.gov/nedss.
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