U.S. residents want a society in which all persons live long, healthy lives (1); however, that vision is yet to be realized fully. As two of its primary goals, CDC aims to reduce preventable morbidity and mortality and to eliminate disparities in health between segments of the U.S. population. The first of its kind, this 2011 CDC Health Disparities and Inequalities Report (2011 CHDIR) represents a milestone in CDC's long history of working to eliminate disparities.
Health disparities are differences in health outcomes and their determinants between segments of the population, as defined by social, demographic, environmental, and geographic attributes (7). Health inequalities, which is sometimes used interchangeably with the term health disparities, is more often used in the scientific and economic literature to refer to summary measures of population health associated with individual- or group-specific attributes (e.g., income, education, or race/ethnicity) (8). Health inequities are a subset of health inequalities that are modifiable, associated with social disadvantage, and considered ethically unfair (9). Health disparities, inequalities, and inequities are important indicators of community health and provide information for decision making and intervention implementation to reduce preventable morbidity and mortality. Except in the next section of this report that describes selected health inequalities, this report uses the term health disparities as it is defined in U.S. federal laws (10,11) and commonly used in the U.S. public health literature to refer to gaps in health between segments of the population.
Public Health Importance of Health Disparities
Increasingly, the research, policy, and public health practice literature report substantial disparities in life expectancy, morbidity, risk factors, and quality of life, as well as persistence of these disparities among segments of the population (12 -- 16). In 2007, the Healthy People 2010 Midcourse Review revealed progress on certain objectives but less than adequate progress toward eliminating health disparities for the majority of objectives among segments of the U.S. population, defined by race/ethnicity, sex, education, income, geographic location, and disability status (17).
During 1980 -- 2000, the U.S. population became older and more ethnically diverse (18), and during 1992 -- 2005, household income inequality increased (19). Although the combined effects of changes in the age structure, racial/ethnic diversity, and income inequality on health disparities are difficult to assess, the nation is likely to continue experiencing substantial racial/ethnic and socioeconomic health disparities, even though overall health outcomes measured by Healthy People 2010 objectives are improving for the nation. Because vulnerable populations are more likely than others to be affected adversely by economic recession, the recent downturn in the global economy might worsen health disparities throughout the United States if the coverage and effectiveness of safety-net and targeted programs do not keep pace with needs (20).
About This Report
CHDIR 2011 consolidates the most recent national data available on disparities in mortality, morbidity, behavioral risk factors, health-care access, preventive health services, and social determinants of critical health problems in the United States by using selected indicators. Data presented throughout CHDIR 2011 provide a compelling argument for action. The data pertaining to inequalities in income, morbidity, mortality, and self-reported healthy days highlight the considerable and persistent gaps between the healthiest persons and states and the least healthy. However, awareness of the problem is insufficient for making changes. In the analytic essays that follow, certain specific actions, in the form of universally applied and targeted interventions, are recommended. A common theme among the different indicators presented in CHDIR 2011 is that universally applied interventions will seldom be sufficient to address the problems effectively. However, success stories among the indicators (i.e., the virtual elimination of disparities in certain vaccination rates among children) can be used to identify strategies for addressing remaining disparities.
CDC's role in addressing disparities will continue to include surveillance, analysis, and reporting through periodic CHDIRs. In addition, CDC has a key role in encouraging use of evidence-based strategies, supporting public health partners, and convening expert and public stakeholders to secure their commitment to take action.
The primary target audiences for CHDIR 2011 include practitioners in public health, academia and clinical medicine, the media, general public, policymakers, program managers, and researchers. CHDIR 2011 complements but does not duplicate the contents of the annual National Healthcare Disparities Report (12) and the periodic reports related to Healthy People 2010 (17).
CHDIR 2011 contains a limited collection of topics, each exploring selected indicators of critical U.S. health problems. Topics included in CHDIR 2011 were selected on the basis of one or more of the following criteria: 1) leading causes of premature death among segments of the U.S. population as defined by sex, racial/ethnicity, income or education, geography, and disability status; 2) social, demographic, and other disparities in health outcomes; 3) health outcomes for which effective and feasible interventions exist; and 4) availability of high-quality national-level data. For each of the topics and indicators, subject-matter experts used the most recent national data available to describe disparity measures (absolute or relative) by sex, race/ethnicity, family income (percentage of federal poverty level), educational attainment, disability status, and sexual orientation. Because of limits on data availability and optimal size of the report, certain topics of potential interest in the health disparities literature have been excluded. For example, disparities by country of birth and primary language spoken are not included in this report. Residential segregation, a social determinant of health, will be included in a future report when census tract level data from the 2010 U.S. Census become available in 2011. In each topic-specific analytic essay, the contributors describe disparities in social and health determinants among population groups. Each narrative and its tabular and graphic elements reveal the findings, their meaning, and implications for action if known.
The National Partnership for Action (NPA) to end health disparities is a national plan for eliminating health disparities affecting U.S. racial/ethnic minorities sponsored by the U.S. Department of Health and Human Services (DHHS) Office of Minority Health. One of NPA's five objectives is to ensure the availability of health data for all racial/ethnic minority populations. CHDIR 2011 will contribute to the achievement of that objective.
Measures of Health Inequality
Disparities are most often presented as a series of pair-wise comparisons: strata of a particular variable compared with a referent group. An index of disparity summarizes pair-wise comparisons into a single measure of disparity among a population (21). Health inequality - measured by using methods that originated in economics - provides summary measures that capture inequality in the overall distribution of health among persons or groups within a population.
A measure of health inequality can summarize in one number, instead of multiple pair-wise comparisons, the difference between individual persons or segments of a population with regard to a health outcome or related attribute by using all information available about the whole population instead of only the extremes of the distribution (22). Consistent estimates of health inequality at national, state, tribal, or local levels enable useful comparisons across indicators of health status and across time for each indicator; reveal targets for reducing inequality at multiple levels of geography; and compare inequality in the need for services with availability of services for different population segments. Thus, health indicators with lower inequality among the overall U.S. population but with higher inequality within certain groups require further exploration by focusing specifically on the determinants and potential remedies for the higher inequalities within population groups. If the data were available, the indicators in this report could be compared and ranked in terms of the degree of inequality among the U.S. population overall and within specific segments. To illustrate what might be possible with adequate data in future reports, three indicators of inequality are presented and compared by using the Gini index of inequality (23): 1) inequalities in income; 2) years of potential life lost (YPLL) before age 75 years; and 3) the Health and Activities Limitation Index (HALex), a measure of health-related quality-of-life (HRQL).
The Gini index, the most commonly used measure of income inequality, measures the extent to which the income distribution among a population deviates from theoretical income distribution in which each proportion of the population earns the same proportion of total income. The index varies from 0 to 1, with higher values indicating greater inequality (i.e., 0 indicates complete equality, and 1 indicates perfect inequality). The Gini index has been adapted to measure health inequality across populations by providing estimates that capture the distribution of health, or health risk, among the entire population or within specific groups. Researchers and policymakers recognize the importance of both individual- and group-level approaches in measuring health inequality because they capture different dimensions of health inequality that can complement one another to strengthen the overall assessment of population health (13,24,25).
Individual-Level Measures of Inequality
Income inequality. Income inequality in the United States (Gini index of 0.46 in 2007) is the highest among advanced industrialized economies (e.g., the combined Gini index for countries in the European Union and Russia is 0.31, ranging from the lowest score of 0.23 in Sweden to the highest for Russia at 0.41)…