The Science of Health Disparities Research. Группа авторов

for specificity and standardization in the field.

      1.3.2 Minority Health and Minority Health Research

      NIMHD defines minority health research as the study of all aspects of health and disease in one or more OMB‐defined racial/ethnic minority populations. Minority health research can include comparative research to examine and understand better or worse health outcomes in a racial/ethnic minority group relative to other groups. For example, greater prostate cancer mortality in African American men compared to White men, longer life expectancy in Asian and Hispanic/Latino populations compared to the general population, and higher rates of diabetes in all minority groups. Minority health research also encompasses within‐group variation in health, such as asthma prevalence and morbidity in Puerto Ricans compared to Mexican Americans, and variation in cancer rates among American Indians from different regions. Minority health research can also address health conditions or risk and resilience factors specific to or disproportionately found in specific racial/ethnic minority groups, such as pain management in African American sickle cell patients and the use of native or traditional medicines or health practices by American Indians/Alaska Natives and other population groups.

      An overarching common theme for all racial/ethnic minorities in the United States is to share a common experience of having been subject to some level of discrimination or social exclusion, which vary across groups and by socioeconomic status (SES) and need to be placed in historical and current contexts. The historical trauma experienced by American Indians as they were displaced from their lands and restricted to reservations, and the legacy of slavery for Black Americans carry a special burden. Moreover, societal discriminatory practices, like redlining to support residential segregation, have affected racial/ethnic minorities and are a fundamental cause that must be understood in order to reduce health disparities.

      1.3.3 Health Disparities and Health Disparities Research

NIMHD defines a health disparity as a health difference, based on one or more health outcomes, that adversely affects defined disadvantaged populations. According to the legislation that created NIMHD, a health disparity population is characterized by a pattern of poorer health outcomes, indicated by the overall rate of disease incidence, prevalence, morbidity, mortality, or survival in the population as compared to the health status of the general population. NIH‐designated health disparity populations were defined in this legislation and the authority to modify these designations was given to the director of NIMHD in consultation with the director of the Agency for Healthcare Research and Quality (AHRQ). Currently designated health disparity populations include the racial/ethnic minority groups mentioned above, populations of less privileged SES or poor persons from any race/ethnic group, under‐served rural populations, and sexual and gender minorities. Health disparities research is devoted to (i) understanding determinants that cause, sustain, or mitigate health disparities; and (ii) how this knowledge is translated into interventions to reduce disparities.

      NIMHD's definition of health disparities emphasizes an adverse difference in populations with a social disadvantage. From the NIMHD perspective, a defined difference in health outcomes between populations is not necessarily a disparity. We define disparity as a difference between a disadvantaged population and a more advantaged referent population or the general population.

By comparison, in Healthy People 2020, the contributions of social determinants to an individual's ability to achieve good health also include sex, age, and disability.³ Healthy People 2020 defines a health disparity as “a particular type of health difference that is closely linked with social, economic, and/or environmental disadvantage.” The NIMHD definition emphasizes the disadvantage of population groups, and thus all adverse health outcomes within the designated population groups are considered health disparities. The NIMHD definitions also emphasize the importance of the historical or current link to discrimination or exclusion in determining health and healthcare disparities. The contributions of biological mechanisms, healthcare access and quality, and interventions to ameliorate disparities also need to be considered.

      1.3.4 Is It Minority Health or Health Disparities?

There is substantial overlap in minority health research and health disparities research, in particular, research that focuses on worse health outcomes among particular racial/ethnic minority groups compared to Whites or other populations (Figure 1.1). For example, the fact that African American men have a higher prevalence and mortality for lung cancer is both a minority health and health disparities issue [4]. Blacks are a disparity population, smoke at a similar or lower rate than other racial/ethnic groups, and yet experience up to 50% more lung cancer for the same cigarette smoking intensity [4].

Figure 1.1 Overlapping but distinct constructs of Minority Health and Health Disparities Research.

      Another example is type 2 diabetes, which is more common and has more severe manifestations in all racial/ethnic minority groups studied in the United States compared to Whites [5]. However, within a staff model healthcare system, the rates of myocardial infarction or heart attacks in patients with diabetes were lower for all minority race/ethnic groups compared to Whites, while the rates of end‐stage renal disease were higher. Understanding the factors that lead to these substantial differences in outcomes by race/ethnicity in a well‐characterized disease such as diabetes are likely to advance knowledge about mechanisms of how the condition progresses [6].

      There are conditions where some racial/ethnic minority groups may have better health outcomes than the reference population, placing the study of these conditions within the domain of minority health research. Latinos or Hispanics have the longest life expectancy by gender of any other demographic group in the United States. This longer life expectancy is a consequence of lower overall rates of cardiovascular disease, cancer, and cerebrovascular disease [7]. Suicide and opioid overdoses are other examples of conditions with lower rates for African Americans, Latinos, and Asians, but higher rates among American Indians/Alaska Natives and lower SES and rural Whites [8]. Research related to the last two populations would fall squarely into the category of health disparities research.

      1.3.5 Standardized Measures of Minority Health‐ and Health Disparities‐Related Constructs

Evaluation of health disparities by SES requires a consistent and reliable approach. Household income is a powerful predictor of overall mortality in the United States, with those at the poverty level (defined as ≤ $25 000 household income per year) being three times more likely to die from any cause compared to the mortality rate among persons in a household with an income ≥ $115 000 per year (Figure 1.2) [9]. Although household income is a useful measure of SES, formal years of education may be simpler to obtain, more reliable and stable over the life course, and overall more efficient. Education may also be incorrectly reported, and years of schooling do not equate to quality of education. Thus, depending on the research question at hand, multiple indicators of SES may be the best strategy [10]. This relationship of SES measures and health outcomes is most robust for Whites and Blacks, but there is evident interaction between SES and race/ethnicity that needs to be inherent in most studies focused on minority health and health disparities.

Figure 1.2 Relative risk of all‐cause mortality by US annual household income