described in terms of incidence and/or prevalence and are important components of population morbidity. Population health is often measured by mortality, so researchers will frequently evaluate not only rates, but also whether a population has premature and/or excessive mortality for specific conditions. Using a general index that reflects population health—such as a global burden of disease measured by disability‐adjusted life years (DALYS) or premature years of life lost—can provide insights into understanding mortality patterns in areas where populations vary [12].
For clinicians, rates of risk factors such as level of blood pressure, health‐related behaviors such as cigarette smoking, and biomarkers linked to disease outcomes such as glycosylated hemoglobin for diabetes are important components of population morbidity directly in the causal pathway of disease incidence. For clinicians and social scientists, the assessment of how patients or people feel and function using standardized measures provides important data and outcomes to consider. Such outcomes could include psychometrically tested symptom scores for specific conditions, quality of life measures, and activities of daily living. The interdisciplinary nature of minority health and health disparities science will benefit from concurrence on standardized terminology and measures.
1.4 The NIMHD Research Framework: Health Determinants in Action
There is no single identifiable mechanism or etiologic pathway for observed health or healthcare disparities. The robust association of SES with overall mortality underlies all other factors studied. If SES could be made equal across society, would health disparities be eliminated? If access to care were similar for all groups in terms of accessibility, cost and quality, would healthcare outcomes differ by SES or race/ethnicity? Opportunity in education and employment and access to quality healthcare will go a long way to addressing health and healthcare disparities, but other factors will continue to affect outcomes. Understanding complex interactions that may lead to health disparities, such as biological processes and genetics, cultural influences on individual behaviors and lifestyle, effects of the physical and social environment, and access to and interaction with the healthcare system all may play significant roles depending on the populations and conditions. To depict the wide array of determinants that promote or worsen minority health and/or cause, sustain, or reduce health and healthcare disparities, NIMHD scientific staff developed the NIMHD Research Framework (also referred to here as the Framework).4
The Framework reflects a hybrid of two models: the socioecological model [13] and the National Institute on Aging (NIA) Health Disparities Research Framework [14]. The socioecological model posits that health and human development are influenced by factors at multiple levels, from the individual to the macro or societal level. The NIA Framework organizes many of these factors into levels of analysis of health disparities relevant to aging research into several domains, including the biological, behavioral, sociocultural, and environmental.
The NIMHD Research Framework (Figure 1.3) has two axes, with the Y axis depicting domains of influence on health (biological, behavioral, physical/built environment, sociocultural environment, healthcare system) and the X axis depicting levels of influence on health (individual, interpersonal, community, societal). These 20 cells portray a set of determinants, any one of which may be relevant for a particular minority health outcome or health disparity. Examples of factors within each cell are provided in Figure 1.3; this list is not intended to be comprehensive.
Figure 1.3 The NIMHD Research Framework.
Source: National Institute on Minority Health and Health Disparities. NIMHD Research Framework. 2017. Public Domain Available at: https://www.nimhd.nih.gov/about/overview/research‐framework.html. Accessed March 2, 2018.
In addition to characterizing determinants of health disparities, the Framework describes how health outcomes span multiple levels (individual, family/organizational, community, and population). Health outcomes beyond the individual level reflect collective or aggregate outcomes. Also included in the Framework are designated health disparity populations, as well as demographic factors relevant to understanding the impact of the intersectionality of population group membership—such as sex/gender, disability status, and geographic region—on minority health and health disparities. Finally, the Framework identifies the importance of a life‐course perspective when examining determinants across domains of influence, including consideration of early adverse events, chronic and cumulative social and environmental exposures, transgenerational transmission of risk and resilience, and critical periods for developing risk or resilience.
The NIMHD Research Framework is intended to convey the complexity of minority health and health disparities and the reality that focusing research exclusively on one cell of the Framework may produce incomplete knowledge. Much of the early research on minority health and health disparities used a unidimensional approach, focusing, for example, on individual behaviors and lifestyle comparisons in an effort to understand observed epidemiological differences and develop tailored interventions; or to take another example, examining the roles of language fluency and culture to understand how immigrants interacted with the healthcare system.
The role of racism and discrimination has for decades been postulated as a major contributor to adverse health outcomes, and the volume of research on this topic has steadily increased [15]. However, racism and discrimination have not been routinely included in health studies that primarily emphasize other types of determinants or etiological factors. For any particular minority health or health disparity issue, multiple factors may be relevant, from lifestyle choices, cultural beliefs, and racism and discrimination to place‐based factors such as community violence exposure, availability of green space, public transportation, and access to healthy foods. Social factors, such as social support and size and cohesiveness of social networks and macro‐level factors, such as health and other policies, are all relevant as well. The Research Framework is intended to stimulate consideration and research about potential factors and determinants of health outcomes that transcend traditional disciplinary silos or service sector boundaries.
Another principle conveyed by the NIMHD Research Framework is the importance of the interaction between biological, sociocultural, and environmental processes. Early work in minority health and health disparities often focused primarily on biological or social‐behavioral factors. The explosion of information describing and understanding biological processes and genetics has provided several plausible models for observed differences in specific conditions. The genetic contribution to the higher prevalence, earlier onset, and higher morbidity of prostate cancer among African Americans is not fully understood and warrants exploration of the social and environmental factors that may play a role in these outcomes [16].
The fact that all racial/ethnic minority groups studied in the United States have a higher prevalence of diabetes would suggest a common pathway that triggers metabolic abnormalities based on chronic stress, nutritional habits, and/or environmental interactions with genetic susceptibility. Major differences in the numbers of suicides by race/ethnicity may be explained by the interactions of underlying neurological and psychological factors with cultural and social factors that have not been measured. Minority health and health disparities researchers, who typically are aware of the social determinants of health, need also to understand and follow developments in the research on biological mechanisms, such as genetic stability, cellular function, and physiological indicators. Such integrative research requires interdisciplinary collaborations and team science approaches.
Additionally,
