Research in Diseases, Disorders, and Health Conditions
Minority Health and Health Disparities
Scientific and technological discoveries throughout the 20th century have improved the overall health of the nation and generated hope for happier, healthier, and longer lives for all. However, some segments of the U.S. population continue to experience elevated morbidity and mortality, disproportionate incidence of disease and disability, and adverse outcomes in cancer, cardiovascular disease, diabetes, HIV/AIDS, infant mortality, and certain other conditions. These disparities in health are most visible in racial/ethnic minority groups, individuals from socioeconomically disadvantaged backgrounds, and people living in medically underserved areas, including some rural communities.
NIH has devoted considerable resources to understanding the root causes of health disparities. As a result of these efforts, a complex web of interconnected and overlapping factors (i.e., biological, behavioral, environmental, and societal) have begun to be identified. For example, poverty and lack of education correlate with poor health and lower life expectancy; moreover, discrimination based on racial, ethnic, and linguistic differences in the U.S. not only triggers biological stress, but also creates a barrier to accessing high-quality health care. In addition, some groups are genetically susceptible to certain diseases, and when this inherited biological vulnerability combines with adverse social and/or environmental factors (e.g., poor diet, pollution, economic stress), these groups exhibit poorer health outcomes. Confronting the interrelated factors that contribute to the existence of health disparities is at the heart of the vigorous efforts NIH is undertaking to make advances in science that will translate into effective prevention and treatment interventions.
Health disparities affecting racial/ethnic minorities and other medically underserved populations are seen across a broad spectrum of diseases and conditions. They represent one of the most persistent public health challenges in the U.S. Research findings consistently have shown that many health disparity populations also are less likely than most of the majority population to receive needed health care services, including clinically necessary procedures. Health disparities frequently are associated with differences in socioeconomic status (SES) and tend to diminish significantly and, in a few cases, disappear when SES factors are controlled. Nevertheless, some racial/ethnic disparities remain even after adjusting for SES differences and other factors related to health care access.
In keeping with its role as the nation’s primary steward of biomedical and behavioral research, NIH is firmly committed to eliminating health disparities in the U.S. Since the issuance of the Black and Minority Health Report in 1985, NIH has incorporated the goals of improved health for all Americans and the elimination of health disparities in its support of biomedical and behavioral research, research training, research capacity-building, outreach, and research and health information dissemination. Many of these activities are multidisciplinary collaborations involving several NIH ICs or NIH and non-federal organizations. These efforts not only have advanced health disparities research, but also have facilitated communications among stakeholders and moved the field forward exponentially during the last 25 years.
Throughout its history, NHLBI has been a leader in conducting and supporting research to eliminate health disparities that exist between various segments of the U.S. population. The Institute has not only initiated research projects with significant minority participation to compare health status between various populations, but also has given high priority to programs that focus exclusively on minority health issues. NHLBI epidemiology programs, for example, include several major studies of heart disease in minority populations, support for components of the NHANES that track prevalence and risk factors of cardiovascular and lung diseases by race and ethnicity, and the National Longitudinal Mortality Study that analyzes socioeconomic, demographic, occupational, and racial differentials in U.S. mortality. Genetic epidemiologic research includes studies of the genetics of hypertension in populations of West Africa origin, salt sensitivity in people of Chinese ethnicity, and metabolic traits in Mexican Americans. Understanding racial differences in blood pressure control is an area of major interest for NHLBI and clinical trials of therapies have consistently included strong representation of minority participants. Understanding the relationships between heart disease and stress induced by environmental, social, or discriminatory influences is another focus of research efforts. In the area of lung diseases, considerable effort has been directed toward understanding the disproportionate burden of asthma among urban black and Hispanic children and identifying culturally appropriate strategies to help them achieve good symptom control. The NHLBI research program in blood diseases has, since 1972, supported an extensive array of studies to understand the pathophysiology of sickle cell disease, identify better approaches to its diagnosis and treatment, and prevent complications.
Research on aging continues to document the existence of persistent health differentials among older racial and ethnic groups in the United States, both before and after age 65. NIA remains committed to addressing health disparities and inequities with initiatives supported in partnership with the NIMHD as well as with other Institutes and Centers. One of the Institute’s most visible and focused efforts to build the national research infrastructure for reducing and eliminating health disparities is the Resource Centers for Minority Aging Research (RCMAR) program, the mission of which includes establishing a research mentoring mechanism in minority health and health disparities, enhancing professional diversity in minority health research, evaluating/developing measurement tools tailored to minority and marginalized population groups, and developing strategies for recruiting and retaining research participants from diverse racial and ethnic backgrounds.311 Another program, The Healthy Aging in Neighborhoods of Diversity across the Life Span study, is an interdisciplinary, community-based, prospective longitudinal epidemiologic study examining the influences of race and SES on the development of age-related health disparities among socioeconomically diverse African Americans and whites in Baltimore. This study began in 2004 and is ongoing.312
Many diseases and disorders within the NIDDK mission area disproportionately affect minority populations. Therefore, the Institute supports a robust research portfolio to reduce health disparities and improve the health of all people. For example, related to type 2 diabetes, the HEALTHY313 study tested a middle school-based intervention for reducing risk factors for type 2 diabetes in youth; the TODAY314 clinical trial is testing different treatment strategies in youth diagnosed with type 2 diabetes; and the Diabetes Prevention Program Outcomes Study is following DPP participants to determine the durability of the interventions in preventing or delaying type 2 diabetes, and how the interventions affect the development of CVD and other complications of diabetes. Approximately 30-90 percent of participants in these studies are from minority groups disproportionately burdened by type 2 diabetes. Additionally, the NIDDK supports the Type 2 Diabetes Genes Consortium to identify type 2 diabetes risk genes in minority populations.
311 For more information, see https://www.rcmar.ucla.edu/index.php .
312 For more information, see https://handls.nih.gov.
313 Middle-School Based Primary Prevention Trial of Type 2 Diabetes (HEALTHY). For more information, see https://clinicaltrials.gov/show/NCT00458029 .
314 Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY). For more information, see https://clinicaltrials.gov/show/NCT00081328.
Toward the goal of building and sustaining a biomedical, behavioral, clinical, and social science research pipeline focused on NIDDK mission areas, the NIDDK supports the Short-Term Education Program for Underrepresented Persons (STEP-UP). STEP-UP provides research education grants to institutions to coordinate high school and undergraduate programs that provide eligible students with 10-12 weeks of summer research experience and training opportunities. STEP-UP seeks to increase the participation of students from backgrounds underrepresented in biomedical research, including individuals from disadvantaged backgrounds, individuals from underrepresented racial and ethnic groups, and individuals with disabilities. Additionally, the NIDDK has established a Network of Minority Research Investigators (NMRI) to increase the number of minority researchers and to increase research on health disparities. The goal of the NMRI is to foster a communication network of current and potential biomedical research investigators and technical personnel from traditionally under-served communities. This Network is led by the NIDDK’s Office of Minority Health Research Coordination, and currently has approximately 200 members.
The investigator-initiated research project, Racial/Ethnic Disparities in Early Life Risk Factors for Childhood Obesity, was designed to identify obesity risk factors during pregnancy, infancy, and early childhood. It found that Black and Hispanic children have a higher prevalence than white children of a range of risk factors for obesity by pre-school age, including maternal depression, early initiation of solid food consumption, and intake of sugar-sweetened beverages. The results suggest that there is a need for interventions in very early life to reduce disparities in childhood and adult obesity. The article reporting these findings was named as one of the Robert Wood Johnson Foundation’s Most Influential Research Articles of 2010.
The NIDDK-led Look AHEAD clinical trial is determining whether a lifestyle intervention designed to promote weight loss can improve health outcomes, including prevention of heart disease, in overweight or obese people with type 2 diabetes. For the first 4 years of the study, participants in the lifestyle intervention group lost significantly more weight and better maintained their lost weight than those in the control group; they also had improved fitness, glucose control, blood pressure, and HDL cholesterol with less use of medication. The trial is planned to continue for up to 13.5 years, and longer-term results will determine whether these effects will lead to reduced rates of cardiovascular disease and death.
NIDDK-supported researchers have found that African Americans with two copies of certain variants in the APOL1 gene are at increased risk of developing kidney disease, particularly focal segmental glomerulosclerosis (FSGS) and kidney disease related to infection with the HIV. These findings explain nearly all of the excess risk of non-diabetic kidney failure in African Americans, and have important implications for understanding the differences in kidney disease risk across populations. NIMHD is collaborating with NIDDK regarding future research directions in FSGS and the APOL1 gene.
The NIMHD Centers of Excellence (COE) program has created a research platform to advance scientific knowledge and develop interventions that address diseases affecting health disparity populations. They also provide a focal point for establishing partnerships with other institutions or federal agencies interested in health disparities research. For example, NIMHD and the Environmental Protection Agency (EPA) have launched the "Environmental Health Disparities Initiative," which examines the complex relationship between health disparities and the natural, built, social, and policy environments. The principal objective of this collaborative research effort is to generate innovative approaches to alleviate environmentally driven health disparities and improve access to healthy environments for vulnerable populations.
In a recent study, the NIMHD COE at Arizona State University explored when it is most efficacious to expose Mexican heritage youth to drug abuse prevention programs. Implementing the Keepin' it REAL drug prevention program in middle school (but not elementary school) decreased the use of alcohol, cigarettes, marijuana, and inhalants by Mexican heritage youth.
A diabetes epidemic is facing the U.S. Virgin Islands, yet little is known regarding the cultural context relevant to self-management of the disease in this U.S. territory. COE researchers in the Virgin Islands conducted in-home interviews of the local population, supplemented by a self-administered questionnaire and hemoglobin A1c testing, to characterize self-management knowledge, attitudes, and behaviors among patients living with diabetes. Several recurrent themes emerged from this study: 1) cultural nuances shaped perspectives on self-management, 2) culturally-specific challenges were barriers to effective self-management, 3) medical homes were rarely viewed as the primary source of education and support, and 4) fear of largely motivated or stalled self-management practices. This study highlights the need for culturally-tailored measures and interventions to address the specific needs within this population.
Stroke affects certain ethnic and minority populations at a disproportionately higher rate than non-Hispanic whites. African Americans are at a higher risk of stroke than whites, and while incidence is decreasing in whites, the same downward trend is not occurring in blacks. Stroke incidence is also higher in Mexican Americans compared with whites. Socioeconomic status only accounts for a portion of these disparities, suggesting that biological, cultural or geographic factors also may play a role. In certain areas of the southeastern U.S., stroke mortality is significantly higher than in the rest of the population. The "stroke belt" has a 40 percent higher rate, while the "stroke buckle" has a 20 percent higher rate. NINDS supports research aimed at better defining stroke risk, incidence and outcomes in the U.S. and among different sub-populations. Collection of population-based data helps identify and explain health disparities in stroke, and inform the development of preventive interventions that target high risk populations. For example, in the Reasons for Geographic and Racial Differences in Stroke study, investigators are exploring the geographical and racial influences on stroke risk in a cohort of about 30,000 individuals, about half of whom live in the “stroke belt” region of the southeastern US. This study has produced nearly 100 publications that have led to better understanding disparities in stroke in the US. Data generated from this study continue to help researchers pinpoint reasons that the stroke rate is higher in this region, and among African Americans, and to develop targeted strategies for intervention.
NINR supports a range of activities related to eliminating health disparities and promoting health equity in underrepresented populations, and to training new investigators underrepresented in the research community. NINR has recently sponsored research initiatives to reduce health disparities in minority and underserved children, and to promote health in racial and ethnic minority males. Recent studies have explored such topics as: risk factors for preterm labor and birth in African-American women and improving breast feeding in urban low-income mothers. In 2011, NINR released a Spanish-language version of its palliative care brochure to increase awareness of this comprehensive treatment for pain and other symptoms of serious illness in the Hispanic community.
The NCRR Research Centers in Minority Institutions Translational Research Network conducts multi-site clinical and translational research on diseases that disproportionately affect minority populations, such as cancer, diabetes, renal disease, infant mortality, HIV/AIDS, and cardiovascular diseases.315
ORWH supports trans-NIH efforts to promote research on health disparities and minority women’s health. The objectives of the NIH strategic plan on women’s health and sex differences research, Moving into the Future with New Dimensions and Strategies: A Vision for 2020 for Women’s Health Research, encompass a broad vision of disease-specific research in women’s health. The goal is to better understand the role of sex and gender differences in disease risk, vulnerability, progression, and outcomes for diverse populations throughout life.
Women from low SES backgrounds, especially from African American populations, are particularly susceptible to adverse pregnancy-related outcomes because of a high prevalence rate of obesity. The Weight Management in Obese Pregnant Underserved African American Women project, which is sponsored by ORWH, is testing a novel lifestyle intervention to help obese socioeconomically disadvantaged African American women achieve healthy weight control during and after pregnancy.
Epidemiology research funded by NEI, such as the Los Angeles Latino Eye Study, the Multi-ethnic Pediatric Eye Disease Study, and the Chinese American Eye Study, has pinpointed areas of health disparity in eye disease, especially glaucoma, which is the leading cause of irreversible blindness among Hispanic and African Americans, and diabetic eye disease. A genetics study comparing glaucoma in West African and American populations is pioneering new genetics techniques that require fewer patients for each analysis. Not only is the prevalence of glaucoma four times higher in African Americans than Caucasians, the risk of blindness is up to 10 times higher. The African Descent and Glaucoma Evaluation Study explores racial variations in optic nerve structure and biomechanics among glaucoma patients of African descent who are at increased risk for glaucoma relative to Caucasians with similar intraocular pressures. The Diabetic Retinopathy Clinical Research Network conducts trials in community clinics that serve a diverse complement of patients with diabetic retinopathy.
Oral health in the U.S. has improved considerably, but not for all Americans. Chronic dental and oral conditions remain among the most common health problems that afflict disadvantaged and underserved communities. Among those with lower levels of access to dental care are the poor, members of minority groups, the elderly, the very young, and people living in sparsely populated rural areas where dentists are few.
The NIDCR Health Disparities Research Program supports a full spectrum of research studies that identify practical, sustainable approaches so that more disadvantaged Americans may experience good oral health. The Centers of Research to Reduce Oral Health Disparities are conducting several clinical trials aimed at reducing early childhood caries, improving the oral health of disadvantaged pregnant women, and increasing early detection of oral cancer. Data from the National Health and Nutrition Examination Survey (NHANES),316 1999–2004, indicate that the prevalence of decayed or filled teeth is more prevalent in U.S. children (ages 2–4 and 6–8) who are Mexican American or Black compared with their non-Hispanic white counterparts. Nearly 70 percent of Mexican American children aged 6–8 have or have had decay compared with nearly 50 percent of non-Hispanic white children. Disparities in the prevalence of untreated tooth decay persist into adulthood, with the prevalence of tooth decay being nearly twice as great for racial/ethnic minorities compared to non-Hispanic whites.
The NIEHS Partnerships for Environmental Public Health (PEPH) program focuses on research into the risk of increased health burden in populations with inequities in environmental exposure and disease.
NIMHD and NIBIB created a joint program, the Development and Translation of Medical Technologies that Reduce Health Disparities Initiative, which supports the development and translation of medical technologies aimed at reducing disparities in healthcare access and health outcomes. Technologies targeted by this initiative are remote diagnosis and monitoring; sensors for point-of-care diagnosis; devices for in-home monitoring; portable diagnostic and therapeutic systems; devices that integrate diagnosis and treatment; diagnostics or treatments that do not require special training; devices that can operate in low-resource environments; non-invasive technologies for diagnosis and treatment; and an integrated, automated system to assess or monitor a specific condition.
NIMH has launched an administrative supplement program to support advanced research experiences for outstanding early career physicians and medical students from diverse backgrounds. As outlined in the 2008 National Advisory Mental Health Council Workgroup on Research Training,317 NIMH encourages the recruitment, training, and retention of outstanding physician-scientists from diverse backgrounds. The purpose of this program is to improve the diversity of the mental health research workforce by supporting and recruiting early stage investigators from groups that have been shown to be underrepresented in scientific disciplines relevant to mental health research on a national basis.
NIH outreach initiatives encompass a wide range of endeavors, including communications and education programs, partnerships and collaborations with public and private organizations, and enhancement and expansion of access to information and services among disadvantaged populations. Outreach initiatives span many forms of activity, from creation of a new slogan to promote early stroke awareness, to efforts to disseminate science-based oral health information to specific populations, to health information outreach initiatives targeting high school students, to efforts to disseminate science-based information on obesity and diabetes, and to a new, decade-long program devoted to environmental public health. They also address diverse stakeholder audiences, including students, patients, health care providers, public health educators and officials, policymakers, professional and patient advocacy organizations, and community-based groups. Information and interventions may target specific diseases and conditions such as HIV/AIDS, obesity, diabetes, digestive diseases, kidney disease, and Sudden Infant Death Syndrome (SIDS), or they may be oriented toward a particular health disparities population subgroup, or both. These include a variety of NIH health information Web sites, several of which are available in Spanish.318
NIH outreach also is tailored to meet the needs of specific groups or those who provide treatment or services to a group. Science-based oral health information disseminated by two NIH programs illustrates this point. A Spanish-language Web site increases access to science-based oral health information among Hispanics. The site was tested in two cities to ensure that it is understandable, credible, and attractive to the intended audience of Spanish-dominant and bilingual Hispanics from different countries of origin and with varying levels of education. Dentists, dental hygienists, and caregivers have learned how to better serve the oral health needs of people with developmental disabilities through an online continuing education (CE) program called Practical Oral Care for People with Developmental Disabilities. The modules have proven so popular that NIH extended the CE credit through 2011.
The National Diabetes Education Program (NDEP [https://ndep.nih.gov/]) and the National Kidney Disease Education Program (NKDEP [https://nkdep.nih.gov/]) disseminate evidence-based educational materials on diabetes and kidney disease, respectively. For example, the NDEP encourages people to take “small steps” to prevent type 2 diabetes. The NKDEP encourages African American families to discuss kidney disease at family reunions, and also provides tools and resources for health care providers to help coordinate care and improve patient outcomes for kidney disease. Both programs tailor materials for minority groups at high risk. The Weight-control Information Network (WIN [https://win.niddk.nih.gov/]) provides up-to-date, science-based information on weight control, obesity, physical activity, and related nutritional issues. WIN provides tailored information to high-risk groups, such as through the Sisters Together Program Guide: Move More, Eat Better, which is tailored for African American women.
315 On December 23, 2011, President Barack Obama signed the Consolidated Appropriations Act, 2012 (P.L. 112-74). As part of this legislation, the National Center for Research Resources (NCRR) is dissolved and the National Center for Advancing Translational Sciences (NCATS) is established. Science Education Partnership Awards (SEPA) is now part of the NIH Office of the Director, Division of Program Coordination, Planning and Strategic Initiatives, Office of Research Infrastructure Programs.
316 Center for Disease Control and Prevention, National Health and Nutrition Examination Survey, Atlanta, Georgia, 1999–2004. Available at https://www.cdc.gov/nchs/nhanes.htm.
317 For more information, see https://www.nimh.nih.gov/about/advisory-boards-and-groups/namhc/reports/investing-in-the-future.pdf.
318 For more information, see https://www.cancer.gov/espanol, https://medlineplus.gov/spanish/, https://aidsinfo.nih.gov/infoSIDA/, https://ndep.nih.gov/, https://win.niddk.nih.gov/, and www.nia.nih.gov/espanol.
In the spring of 2011, the NIH Associate Director of Research on Women’s Health was the spokesperson for nation-wide radio media tour entitled, “Understanding Family Health History/Preventing type 2 Diabetes in Women with a History of Gestational Diabetes.” The goal of the tour was to raise awareness of risks and prevention strategies for gestational diabetes mellitus (GDM). It reached over one million listeners and pieces were aired on over 200 stations and network affiliates. The tour focused on radio stations and geographic areas with large minority populations, including statewide stations in North Carolina and Tennessee, and the top-rated stations in northern California; St. Louis, Missouri; Dallas-Ft. Worth, Texas; and Denver, Colorado.