Throughout its history, the 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 has also given high priority to programs that focus exclusively on minority health issues.
Since FY 1991, the Institute has had procedures in place to ensure full compliance with the NIH Policy on Inclusion of Women and Minorities as Subjects in Clinical Research. As a result, all NHLBI-supported research that involves human subjects includes minorities, with the exception of a very few projects for which a compelling justification for limited diversity in the study population exists. Thus, all segments of the population, minority and nonminority, women, and children, stand to benefit from the Institute's research programs.
It has long been a goal of the NHLBI to increase the number of individuals from underrepresented groups in biomedical and behavioral research. Selected FY 2010 activities addressing this goal include the following:
The Office of Research Training and Minority Health (ORTMH) within the Office of the Director provides oversight for, and coordinates, supports, and evaluates Institute programs related to minority health outcomes, including research, research training and career development, public outreach, and translation of research findings. The ORTMH also coordinates activities to foster greater participation of underrepresented minorities in NHLBI research and research training and career development programs. Selected FY 2010 activities include the following:
See Chapter 13 for additional NHLBI-supported research training and career development programs for individuals from diverse backgrounds.
The following text describes selected current projects that focus on minority populations and reflect the Institute's research portfolio related to minority health. Additional information can be found in in Chapters 9?11.
Long-term epidemiologic studies are critical to uncovering risk factors that lead to disease. The Institute has initiated several major studies of heart disease focused significantly or completely on minority populations:
The Institute supports components of the NHANES that track the prevalence of disease and risk factors for cardiovascular and lung diseases by race and ethnicity in the U.S. population and the National Longitudinal Mortality Study that analyzes socioeconomic, demographic, occupational, and racial differentials in mortality in the United States.
The NHLBI also supports a variety of investigator-initiated research activities across a range of racial and ethnic groups on risk factors, genetic contributors, and health disparities in heart, lung, and blood diseases and sleep disorders. Many of them are ancillary studies to NHLBI-initiated cohort studies.
Investigator-initiated studies on cardiovascular risk factors in ethnic and minority groups range in focus from biological to environmental, psychosocial, and cultural. Examples are studies to determine geographic and ethnic variations in the prevalence of CHD risk factors; investigate risk factors linked to atherosclerosis and disease progression in South Asians living in the United States; determine whether vascular injury is detectable at a young age in those with obesity and high blood pressure; compare the prevalence of vulnerable atherosclerotic plaque and differences in plaque vulnerability in blacks and whites; study the effects of arsenic exposure on diabetes and CVD in American Indians; and examine sociocultural risk factors for CVD in Hispanics/Latinos.
Areas of focus in genetic epidemiology include gene discovery through linkage studies in family-based samples and GWAS in population-based samples; effects of gene?environment interactions on risk factors and health; and genotypic characterization in relationship to intermediate phenotypes, such as biomarkers.
Genetic epidemiologic research is also beginning to transition to predicting and assessing genetic risk and reporting genetic results to participants of research studies. The activities offer unique insights into specific populations and general observations that are relevant to all populations. Examples are studies of genetics of hypertension in populations of West African origin; the role of stress in gene?environment interaction in a multi-ethnic population; the contribution of genetic variation to obstructive sleep apnea, impaired endothelial function, and central blood pressure in Mexican Americans; salt sensitivity and blood pressure in Chinese populations; genetics of high serum triglycerides and metabolic traits in Mexican Americans; genetic susceptibility to lipid disorders in blacks; and genetic variation that underlies obesity and obesity-related phenotypes among Samoan adults.
The NHLBI is committed to supporting and conducting research that will contribute to reducing health disparities among racial and ethnic minorities. Efforts related to reducing health disparities include:
The Institute supports ancillary studies to major Institute-initiated and investigator-initiated studies that characterize health disparities and their determinants in ethnic minorities. Projects integrating data from multiple sources include one that is developing a population-based surveillance system in a large U.S. metropolitan area to identify and track chronic disease disparities among several ethnic groups at the local level and another that is creating a state-wide network of information on health, health care quality, and public health resources to assess health disparities at the community level.
Other studies on determinants of health disparities include one that is investigating the impact of neighborhood socioeconomic status and psychosocial factors?such as discrimination, stress, and social support?on coronary heart disease risk in blacks in Mississippi; another that is studying the influences of cultural and environmental factors on ethnic disparities in obesity prevalence; a third that is examining black?white racial disparities in physician practice care for obesity and patient self-management of body weight; and a fourth that is determining the degree to which ethnic/racial bias among health care providers is associated with disparities in the management and control of hypertension in racial and ethnic minority populations.
The NHLBI, through DARD, translates research findings into practice by developing clinical practice guidelines, communicating research advances, and disseminating health information to physicians, health care professionals, patients, and the public on ways to prevent or treat diseases within the Institute's mandate. The Institute has initiated the following activities to improve cardiovascular health in racial and cultural/ethnic groups:
In addition to the activities mentioned above, the Institute has prepared publications on CVD prevention for minority populations. They include the following:
The educational materials listed throughout this chapter can be obtained from the NHLBI public Web site or through the NHLBI online catalog.
Arrhythmia is a disorder of the normal rhythms of the heart, whereby it beats too fast (tachycardia), too slow (bradycardia), or irregularly. The NHLBI is supporting basic and genetic research on the mechanisms that underlie cardiac arrhythmias to improve diagnosis, treatment, and prevention of arrhythmias in all racial and ethnic groups in the United States. One study is investigating the genetic basis and electrophysiological mechanisms of Ca2+ triggered arrhythmias in inherited diseases and syndromes?such as catecholaminergic polymorphic ventricular tachycardia, long QT syndrome, and hypertrophic cardiomyopathy?as a means to improve understanding of the pathogenesis of sudden cardiac arrest. Another study is evaluating variants of the gene NOS1AP that affect the QT interval in various racial and ethnic populations. A third study is evaluating the distributions of electrocardiographic predictors of atrial fibrillation in racial and ethnic groups to identify whether minority populations may have a higher risk for this arrhythmia than whites.
Scientists have identified an association between variations in certain receptors that are activated during sympathetic nervous system stimulation and an increased risk of sudden cardiac death, most often due to ventricular arrhythmia. Although significant differences in associated risk of sudden cardiac death were not found between blacks and whites, continued research is expected to advance understanding of differences in genetic predisposition for cardiac arrhythmias among racial and ethnic groups and ultimately lead to improved therapy.
Investigators identified two mutations in a gene encoding the major intracellular calcium release channel in two cases of SIDS. One mutation was identified in 1 of 50 black infants and the other in 1 of 83 white infants. Researchers reported a pathogenic mechanism for SIDS, whereby SIDS-linked mutant ion channels become "leaky" during stress and thus potentially trigger fatal cardiac arrhythmias. Importantly, researchers have found further evidence that cardiac arrhythmias of genetic origin contribute to SIDS, a concept that offers a chance to prevent some avoidable tragedies.
Heart failure (heart muscle dysfunction) affects about 5 million Americans of all ethnicities and is a growing public health concern. It is frequently the end result of other conditions, such as hypertension, diabetes, and prior heart attacks.
The NHLBI is supporting basic and clinical research associated with heart failure that will benefit Americans of all ethnicities. One Institute-initiated study is facilitating the translation of basic science discoveries into clinical applications:
Investigator-initiated research targeting minority populations includes an examination of the role that impaired ATP synthesis and delivery contribute to contractile dysfunction in heart failure?30 percent of the participants are from racial minority populations; an investigation of genetic variations (especially those common in blacks) that affect individual responses to the beta blocker drugs used to treat heart failure; a study of underlying genetic variations that result in familial dilated cardiomyopathy, an inherited form of heart dysfunction; and a study on angioedema?a severe allergic reaction and a life-threatening side effect of ACE-inhibitor drugs that is more common in blacks than in whites. Investigators are determining the mechanisms that cause this side effect and are studying the genetic profile of affected individuals and their families to determine who should avoid taking the drugs.
Individuals with heart failure typically have a poor prognosis and a diminished quality of life. Inadequate health literacy skills, depression, and emotional stress are common and often associated with poor health outcome. One study seeks to determine whether a literacy-sensitive intervention to improve heart failure self-management skills can improve health outcomes, especially in those with inadequate literacy; 60 percent of the participants are from racial and ethnic minority populations. Another study seeks to determine whether cognitive behavioral intervention is superior to supportive clinical management for depressed outpatients with heart failure; 30 percent of participants are expected to be black. A third study is examining the role of emotional stress on heart failure exacerbations; currently, two-thirds of the participants are black. A fourth study is investigating whether an exercise intervention, such as tai chi, can increase physical function, cardiac functional capacity, and quality of life in patients with heart failure; 40 percent of the participants are expected to come from minority populations.
An investigator-initiated, multicenter observational clinical study is being conducted to improve the ability of physicians to identify and treat appropriately patients who are at high risk for serious complications from heart failure. Participants will comprise individuals who visit the emergency department at one of three hospitals that treats racially and socioeconomically diverse patients.
High blood pressure is a serious health problem that is especially prevalent and severe among minorities. The NHLBI supports a number of investigator-initiated studies to identify genes linked to hypertension in blacks, Mexican Americans, and whites to determine if part of the disparity in prevalence can be attributed to genetic differences among the groups. Genes under investigation include those associated with the renin-angiotensin system, the autonomic nervous system, and sodium transport.
Other gene variants under investigation include those associated with adipokine regulatory genes. Based on evidence of a pro-inflammatory adipokine profile and markers of vascular injury in obese adolescents with high blood pressure but not in obese adolescents without high blood pressure, scientists are examining the contribution of genetic variants in adipokine regulatory genes to the development of vascular injury and high blood pressure in obese black adolescents.
The role of dietary factors, particularly macronutrients, in the etiology of high blood pressure is another area of investigation. Scientists are conducting epidemiologic studies among participants with diverse ethnicity, SES, and dietary habits in four countries to determine the effect of selected dietary components (proteins, lipids, carbohydrates, amino acids, calcium, magnesium, sodium, potassium, antioxidants, fiber, and caffeine) on blood pressure. Another study is seeking to identify the link between healthy diet, genetic factors, and their underlying biological mechanisms.
Treatment and Prevention
Identifying effective treatment strategies for various populations requires large-scale studies with representative populations in sufficient numbers.
An investigator-initiated ancillary study to ALLHAT, the largest hypertension clinical trial conducted by the NHLBI, is evaluating the pharmacogenetic response to antihypertensive treatment and long-term clinical complications in blacks, whites, and Hispanics. Scientists are seeking to determine whether pharmacogenetics is a feasible approach to personalized therapy for hypertension.
The Institute also supports a number of investigator-initiated studies to prevent hypertension and improve blood pressure control in racial and ethnic minorities. Interventions target both lay and medical communities. Strategies being tested include communication skill enhancement, organizational change, educational programs, lifestyle and nutritional counseling, use of technology, case management, pharmacy-based interventions, and provision of care by community health workers and other nontraditional providers.
Understanding racial differences in blood pressure control is an area of major interest for the Institute. Scientists are examining whether variations in genes of the renin-angiotensin-aldosterone system predict differences in blood pressure response to diuretic therapy among hypertensive blacks and whites. Research is also focusing on variations in the ACE gene between blacks and whites to explain racial differences in the antihypertensive responsiveness to ACE inhibitors.
The NHLBI has developed a number of outreach activities to inform minority populations of the importance of blood pressure control. Several publications and Web-based products have been developed for and introduced to health professionals, patients, and the public. Some examples are:
The Institute supports investigator-initiated studies to identify genes that influence the lipoprotein profile within racial and ethnic groups, including blacks, Hispanics, and American Indians. Research findings could offer an explanation for differences in susceptibility to CHD found among racial and ethnic groups. One project involving extended families of Mexican Americans in the San Antonio Family Heart Study has detected and mapped many quantitative trait loci (QTLs) for CVD risk factors, including some that influence HDL and LDL levels. Scientists seek to identify the genes for the QTLs related to lipoproteins. Another study is focused on the variation in hepatic lipase activity that leads to differences in plasma concentrations of HDL and LDL synthesis and catabolism. Researchers are investigating whether racial differences in hepatic lipase activity are responsible for the well-known differences in plasma HDL concentrations found in blacks and whites. Thirty-nine percent of participants are black.
The NHLBI is supporting an investigator-initiated study among minority preschool children to track the long-term effectiveness of nutrition interventions on diet and blood cholesterol levels. Additional potential risk factors?such as increased blood pressure, obesity, and intention to smoke?will also be monitored.
The Institute has prepared the following publications on blood cholesterol for minority audiences:
Obesity is a major health concern that affects children and adults. Minorities?including blacks, Mexican Americans, and American Indians?are especially at risk. Data from the 2003?2006 NHANES show that 33 percent of adults and 16 percent of children aged 2?19 years are obese. Understanding the causes of obesity could lead to effective strategies to combat it.
An investigator-initiated study seeks to elucidate interconnected biological and social pathways associated with adolescent obesity and risk for later development of type 2 diabetes and CVD in Latin American youth. The goal of the study is to identify modifiable conditions to prevent obesity and related diseases.
The NHLBI funds several studies that focus on genetic risk factors for obesity in one or more minority populations. Evidence for obesity genes has been identified on chromosomes 5 and 6 in blacks, on chromosome 9 in Mexican Americans, and on chromosome 4 in American Indians. In some cases, the results confirm those found in European Americans, and in other cases, they represent novel findings.
Researchers have found that black and Hispanic children are especially likely to develop sleep apnea. An investigator-initiated study will assess the role of obesity in the development of abnormalities that increase the likelihood of developing sleep apnea and whether the problem can be corrected with weight loss. Blacks comprise 55 percent of participants. Another study is determining whether obese children with sleep apnea are at greater risk of cognitive impairment and vascular disease. Forty-five percent of participants are black.
Many women experience weight gain during the transitional period from pre- to post-menopause. Using data and repository specimen resources of the Study of Women's Health Across the Nation, an epidemiologic study seeks to characterize the development and progression of CVD risk factors in relation to biochemical markers of obesity metabolism. The study will determine the interrelationships between biochemical markers of obesity metabolism, ovarian aging, and CVD risk in a multi-ethnic population of women aged 42?52 years at baseline.
Treatment and Prevention
The NHLBI has initiated programs to test approaches for treating or preventing obesity:
The Institute supports a number of investigator-initiated studies on the effectiveness of obesity prevention and control interventions among diverse populations. One study is testing the effectiveness of weight-control interventions (involving diet, physical activity, psychosocial and familial influences) administered during the critical transition period from prepuberty to puberty in black girls at high risk for obesity. Another study in preadolescent black girls is evaluating the efficacy of an after-school dance program and a family-based intervention involving reduced use of television, videotapes, and video games to reduce weight gain. A third study is testing an integrated school- and community-based intervention that involves physical activity and diet to reduce the prevalence of obesity among Asians, Hispanics, and whites.
Blacks at high risk of CVD often have limited success in weight loss and lifestyle change programs. A study was initiated to examine the role of social support, particularly from family members and friends, to facilitate weight loss and related dietary and physical activity changes in blacks.
Hispanics are also an important population targeted for intervention programs. One project is studying the effects of physical activity and dietary behaviors in a microenvironment (i.e., home environment) and in a macroenvironment (i.e., apartment complex, schools, grocery stores, parks, restaurants). Community health workers (promotoras) are working with the families and the community to increase awareness and promote environmental change. Another project with strong Hispanic participation is evaluating how well an intervention, Planned Care for Obesity and Risk Reduction, supports primary care treatment of obesity in adults with at least one other cardiovascular risk factor. The study is seeking to improve the way primary care providers offer services to their patients who are overweight and who also have other important medical conditions or health risks, such as hypertension, smoking, or high cholesterol.
Obesity is one of the major health challenges facing Native American children and has serious implications for the development of type 2 diabetes. A school-based intervention, augmented with a family intervention, is focusing on reducing excess weight gain by increasing physical activity and healthy dietary practices in kindergarten and first-grade Native American children.
The NHLBI has prepared health information on losing excess weight for minorities:
Despite substantial research about the positive impact of physical activity on CVD and its risk factors, physical inactivity is highly prevalent, especially among minority populations. Researchers have observed an age-related decline in physical activity or aerobic capacity in the biracial cohorts of Institute-initiated longitudinal cohort studies (National Growth and Health Study and CARDIA). Those results, when coupled with findings from MESA and HCHS, have helped to increase understanding of the interrelationships of cardiorespiratory fitness, body composition, and CVD-related risk factors and endpoints, and may provide the basis for more specific evidence-based recommendations on the role of fitness in cardiovascular health among minority children and adults.
Physical inactivity among children is often attributed to lack of open space, lack of recreational equipment, and fear by parents for the safety of children playing outdoors. A study is being conducted to determine if an intervention that changes these neighborhood features in a low-income, inner-city neighborhood will increase physical activity in children. Components of CARDIA, MESA, and HCHS are also examining the effects of the neighborhood environment on physical activity.
A longitudinal follow-up of the Trial of Activity for Adolescent Girls is examining the effects of a school?community joint intervention on physical activity among middle school girls.
A number of investigator-initiated studies are evaluating culturally appropriate interventions to increase physical activity. One study is using lay health advisors to increase moderate intensity physical activity among Mexican American women, a group with many countervailing family and community influences. Several studies are using faith-based approaches?including community-based participatory research approaches to engage church leaders and congregations?to increase activity levels in blacks. Other studies are testing culturally targeted interventions in schools or among pregnant women and mothers with young children.
Several projects are using mobile phone technology to increase physical activity and decrease sedentary behaviors. These studies capitalize on recent advances in communication technologies, such as "smart phones" that offer a potentially transformative platform to deliver convenient and sustainable adherence strategies.
The Institute has prepared the following publications for minorities on the importance of physical activity and ways to become more physically active:
The Institute also has developed a Web-based application on physical activity for lay health educators in English and Spanish, which can be found at http://hin.nhlbi.nih.gov/salud/pa/index.htm.
Smoking is a major risk factor for CHD, stroke, COPD, and other cardiovascular and respiratory conditions and is the leading cause of preventable death. Although considerable progress has been made in reducing smoking rates and providing effective prevention and cessation interventions, additional research is needed to extend these efforts and improve the maintenance of behavior change. The Institute has initiated a smoking intervention program in hospitalized patients.
Effectiveness Research on Smoking Cessation in Hospitalized Patients (see Chapter 11): To evaluate the translation of efficacious smoking cessation strategies initiated during hospitalization and continued post-discharge into effective programs that can be widely implemented in routine clinical practice and assess the cost-effectiveness of these interventions. One of the projects will have approximately 75 percent participation from Asian, Hispanic, and black populations.
The NHLBI supports a number of investigator-initiated studies of smoking cessation in underserved populations. One study among predominately black women who live in public housing neighborhoods is evaluating smoking cessation interventions that use a combination of strategies?including contact with community health workers, small-group behavioral counseling, and neighborhood support groups. Another study is assessing the efficacy of telemedicine as a way to provide smoking cessation counseling to primary care patients who live in rural areas, and a third study is testing ways to help people who have quit involuntarily to maintain their abstinence.
The Institute has prepared the following publications on smoking cessation for minorities:
A large and consistent body of evidence has demonstrated that psychosocial factors?such as depression, stress, and low social support?are associated with elevated risk for CVD and major adverse cardiac events in heart disease patients. Additionally, race and ethnicity, gender, and social class are important factors that can influence these associations in important ways.
The NHLBI is funding research to identify more precisely the nature of the relationship between depression and adverse cardiac outcomes and the conditions associated with successful treatment of depression. Research results will guide clinical care and inform future trials of depression treatment in heart patients and minority patient populations. Studies include defining the biologic pathways that link depression to physiological mechanisms in post-myocardial infarction and acute coronary syndrome patients?including inflammatory processes implicated in atherogenesis, autonomic nervous system dysfunction, and platelet aggregation and adhesion. Approximately 30 percent of participants are black.
The Institute is also supporting research among middle-aged black and white women to determine whether depression is associated with the adipocytokines adiponectin and leptin, which are bioactive molecules secreted by adipose tissue that play a critical role in atherogenesis and metabolic dysregulation. Research results will provide information on how depression affects risk for diabetes, metabolic syndrome, obesity, and CVD in women.
The Institute supports investigator-initiated research on the interactions of psychosocial factors with race and ethnicity, environmental factors, and low SES in the development of CHD. Scientists are investigating the contribution of biobehavioral factors (hostility, anxiety, and heightened cardiovascular reactivity to stress) in the etiology, pathogenesis, and course of CHD. Racial differences in stress-induced physiologic responses are also being examined.
The nature of the relationship between acute and chronic forms of stress and cardiac morbidity and mortality is particularly relevant to minority populations, because stress induced by environmental, social, and discriminatory influences can be significant. One study is investigating whether the effect of acute and chronic exposure to established risk factors (depressive symptoms, major life events, and lack of social support) for CVD over a 5-year period is related to a 2-year increase of subclinical CVD in a sample of women undergoing menopause. Fifty-four percent of participants will be black. Another study is examining whether racial disparity in AMI-recovery outcomes in older individuals is partially due to stress related to age and racial stigmas. Fifty percent of the population will be black. Other studies are seeking to clarify the physiologic pathways through which stress affects cardiovascular outcomes?including hemodynamic, sympathetic nervous system and neuroendocrine mechanisms, and inflammatory processes. The ultimate goal is to determine whether stress management interventions can alter these physiological indicators and improve cardiovascular outcomes.
Additional research supported by the Institute includes studies that are addressing the genetic basis of behavioral risk factors and the relationships between risk-promoting variables (psychosocial stress, smoking, poor diet, physical inactivity, lack of adherence to cardiac medications), presumed mediating variables (sympathetic nervous system activity and insulin metabolism), and CHD risk factors.
The Institute supports several investigator-initiated studies to develop and evaluate interventions that seek to improve cardiovascular outcomes. One study is seeking to determine the efficacy of a personalized health plan intervention that incorporates mind?body techniques targeted at reducing various risk factors for CVD?such as insulin resistance, inflammatory markers, and self-reported negative effect. Participants select their own goals on which to focus, and the intervention is tailored to their individual risk profile. Twenty-nine percent of participants will be from minority populations. Another study is evaluating the effectiveness of stress management training combined with exercise-based cardiac rehabilitation as a way to reduce stress in vulnerable cardiac patients. Approximately 25 percent of participants are black. A third study is developing and evaluating an intervention among racial minorities that reduces the impact of bias by reducing stereotypic perceptions that render patients and providers less able to communicate effectively and impair the effect of the visit to improve patient self-management behavior. Additional studies are investigating whether stress management in a high-risk population of blacks with hypertension can influence cardiovascular risk factors.
Diabetes mellitus is a strong risk factor for CVD. Individuals with type 2 diabetes are 2- to 4-times more likely to be at risk for CHD than the general population. Using GWASs, investigators have identified several genetic variants for CHD in the general population. An investigator-initiated study is seeking to identify new genetic variants for excessive risk of CHD in diabetic patients, assess the genetic effects on intermediate biochemical changes, and examine gene?environment interactions. One of the data sources will come from the Costa Rican Diabetes?CHD case-control study.
Two studies are determining the associations of fetuin-A with CVD mortality and diabetes. Fetuin-A is a protein that may simultaneously inhibit vascular calcification and promote insulin resistance and diabetes. One of the studies will use data from MESA.
Treatment and Prevention
The NHLBI supports clinical trials to determine the benefits of various strategies to reduce CVD among patients with diabetes or treat patients with coronary artery disease and diabetes:
The Institute has prepared the following publications on diabetes for minorities:
The NHLBI supports research on a number of lung diseases?such as asthma, COPD, sarcoidosis, TB, and HIV-related lung diseases?which disproportionately affect minorities. The following section provides examples of research to address health disparities in lung diseases; selected sleep disorders are also included.
Asthma is a chronic lung disease that inflames and narrows the airways. It affects people of all ages, but it most often starts in childhood. In the United States, more than 22 million people are known to have asthma, and more than 6 million of them are children. Prevalence rates are especially high in blacks and Puerto Ricans.
Etiology and Pathophysiology
The NHLBI has initiated several studies to determine the etiology and pathophysiology of asthma:
The Institute also supports investigator-initiated projects on the etiology and pathophysiology of asthma. One study will identify genetic, biologic, and immunologic characteristics and environmental exposures that interact in children who experience severe bronchiolitis caused by the respiratory syncytial virus early in life and determine their role in the subsequent development of asthma, airway hyperreactivity, and allergy. Forty percent of participants will be black. Another study will examine the relationship between selected genetic and environmental factors and asthma in Puerto Rican children. A third study will identify the genetic basis for differences between blacks and whites in asthma susceptibility and development (e.g., risk of exacerbations).
A new study is focused on the possible common genetic determinants for obesity and asthma. It will identify single nucleotide polymorphisms (SNPs) that are jointly associated with asthma and obesity, using data from the CAMP study, and subsequently validate the SNPs in three independent and ethnically diverse (Hispanic, black, and white) cohorts.
Environmental factors are known to trigger asthma symptoms. An investigator-initiated study is focusing on understanding the mechanisms by which occupational or environmental factors trigger the onset of asthma among low-income, urban blacks and Hispanics. Another study is examining multiple environmental stressors in a predominantly disadvantaged population to determine the effects of maternal stressors and environmental factors in the onset of asthma in early childhood. A third study is examining the reasons why children from lower SES groups suffer from worse asthma than children from higher SES groups. The goal is to develop models of how the social environment affects the onset and severity of childhood asthma and eventually build interventions to ameliorate these effects.
Treatment and Control
The Institute has initiated research to identify optimal drug strategies for treatment and management of asthma. Because the burden of asthma disproportionately affects minority children, it is important for them to be well represented in clinical trials.
The Institute is also supporting investigator-initiated studies focusing on finding effective treatment for various populations. One study in whites, blacks, and Hispanics is creating an asthma self-management skills training program for children and their parents. The program is being created for Web, CD?ROM, and DVD formats and focuses on improving understanding of asthma, preventing asthma attacks, and creating an asthma management plan. Another study will assess an asthma self-management intervention in Puerto Rican children; the intervention is delivered to families by Puerto Rican community health workers. The intervention will tailor a standard asthma core curriculum to family needs and cultural beliefs. A third study will seek to improve health among urban black adolescents with asthma. This study will use peer support?enhanced by a culturally sensitive, technology-based MP3 player platform?to increase adherence to daily controller medications. A fourth study will evaluate a Web-based intervention program that addresses asthma management and avoidance of tobacco use in rural, black adolescent boys.
Many individuals with asthma have poor disease management. A new study will determine whether a multifaceted prompting intervention, administered in urban primary care offices, reduces morbidity among urban children with asthma. Fifty percent of participants will be black. The intervention, designed to stimulate communication between caregivers and clinicians, includes information about the patient's asthma severity or level of control and individualized guideline-based recommendations for care. Another study to improve asthma management will use a highly tailored telephone counseling approach to foster a partnership between women and a clinician. Black women will be the target of this study. A third study will evaluate the efficacy of an evidence-based lifestyle weight loss intervention on asthma control among obese adults. Thirty-six percent of participants will be from minority populations.
The Institute is supporting several education activities. It has developed easy-to-read materials on asthma treatment and control directed to English and Spanish audiences with low literacy:
The Institute also disseminates clinical practice guidelines for the treatment and monitoring of asthma, patient education materials, and information on environmental control of allergens in the United States and throughout the world. It has developed several asthma education programs that are directed at controlling asthma in black and Hispanic children. For example, A Tailored Asthma Education Program for Urban Teens II is evaluating a school-based approach to motivate black students to change negative behaviors related to asthma management. The Institute supports projects that focus on innovative techniques to improve adherence to medical regimes among minorities and people living in poverty and address methods to improve physician adherence to clinical practice guidelines.
COPD?a disease in which the lungs are damaged, making breathing difficult?is the fourth leading cause of death in the United States. It is responsible for more than 500,000 hospitalizations and 100,000 deaths in the United States each year.
The NHLBI is supporting a large, investigator-initiated study of genetic factors that determine the risk of developing COPD or that influence the type and extent of damage done to the body by the disease. The COPDGene? study will enroll approximately 3,500 blacks with a substantial history of cigarette smoking, obtain extensive baseline clinical and phenotypic data regarding the individuals, and compare the severity and character of COPD in the subjects to analyses of their DNA. Genome-wide genetic assays will be performed on a substantial fraction of this cohort.
Although COPD is less common among blacks than among whites, it is nevertheless the seventh leading cause of death among blacks. Any disparity, whether higher or lower in the minority group, may reflect racial differences in the biology of the disease that would require use of different treatments or drugs for optimal disease management. If the genes found to be determinants of COPD risk differ in blacks and whites, this will provide clues to how the roles of specific pathogenetic pathways of COPD differ among races.
Treatment and Control
The Institute has established a research network to determine effective disease management approaches for individuals with moderate-to-severe COPD:
The NHLBI has developed a number of outreach activities associated with COPD. Several publications and Web-based products have been developed for and distributed to health professionals, patients, and the public. Some examples include:
Sarcoidosis is an inflammatory disease of unknown etiology characterized by persistent granulomas with damage to surrounding tissue. The Institute has initiated a program to determine the immunopathogenesis of granulomatous inflammation found in sarcoidosis, including the role of predisposing factors, the immune components involved in the formation of granulomas, and the defective regulatory immune response.
Sarcoidosis occurs more frequently and with more severity in blacks than in whites, suggesting the presence of genetic determinants to disease predisposition. To increase understanding of the disease, researchers are seeking to identify genes of African ancestry that play a significant role in the etiology and pathogenesis of sarcoidosis. Other possible causes of sarcoidosis are also being investigated. One study is examining the potential role of a mycobacterial etiology of sarcoidosis, and another study is seeking to elucidate mechanisms involved in the immunologic and inflammatory processes that ultimately lead to end-stage fibrosis in progressive pulmonary sarcoidosis. Most participants are black.
A mentored research project conducted within the Black Women's Health Study is investigating potential risk factors for sarcoidosis.
Sleep-disordered breathing (SDB), a condition characterized by repetitive interruption in breathing, is a common disorder that disproportionately affects blacks. It is associated with an increased risk of CVD, including hypertension and stroke, and is particularly prevalent in patients with heart failure. Ongoing programs are assessing the interrelationship between sleep disorders and heart failure and the mechanisms leading to cardiovascular stress when the two intersect.
The Institute also supports investigator-initiated projects to elucidate cardiovascular and other health consequences of SDB, sleep deprivation, and shift work in various community settings. Characterization of how SDB occurs within family groups is helping to identify potential genetic risk factors that may allow early identification and treatment of high-risk individuals. A community-based study of sleep in Hispanics is assessing the prevalence of sleep apnea.
Treatment and Control
The Institute initiated a clinical trial to determine whether adenotonsillectomy is an effective treatment for SDB in children:
Investigator-initiated research will assess treatment strategies in minorities. One study is seeking to develop in-home personalized sleep plans that can improve nightly sleep duration, neurocognitive function, and behavioral disorders in lower income minority children (ages 5 to 6 years). Another study is examining the effect of a sleep apnea treatment (positive airway pressure therapy) on biological markers of CVD risk, including inflammation and metabolism. More than 50 percent of study participants are from minority populations.
The NHLBI published Your Guide to Healthy Sleep, which provides the latest information about sleep apnea and other sleep disorders, including insomnia, restless legs syndrome, and narcolepsy.
HIV infection disproportionately affects minority populations in the United States and due to multidrug antiretroviral therapy, has become a chronic condition for many patients. Among them, HIV-associated lung complications are frequent causes of illness and death. But the long-term consequences of HIV infection and HIV-associated lung infections and complications are unknown. Little is known about drug-resistant pneumocystis, the prevalence and pathogenesis of HIV-associated COPD, HIV-associated pulmonary hypertension, and immune reconstitution syndromes. In developing countries where millions of people are HIV-infected, many have serious or fatal lung complications, including TB and bacterial pneumonias, that have never been well characterized.
In addition to supporting investigator-initiated research on the etiology and pathogenesis of HIV-associated lung diseases, the Institute has initiated research to understand their causes and impact and to identify potential therapeutic targets and preventive strategies:
TB is a common and often deadly infectious disease caused by the bacteria Mycobacterium tuberculosis. In the United States, an estimated 10 to 15 million people are infected with the TB bacteria. The rates among minorities and in the foreign-born remain high. In 2008, according to the CDC, more than 58 percent of all active TB cases in the United States were among the foreign-born. Racial disparity in TB rates was greatest for U.S.-born blacks, whose rate was 7-times higher than the rate for U.S.-born whites.
The immune response to TB infection is complex and involves the formation of granulomas in the lungs of infected individuals. In 2008, as part of the NHLBI Exploratory Program in Systems Biology, the Institute initiated a study that uses multiscale computational models and multisystem approaches to improve understanding of the role of granuloma formation in TB. In 2010, it began a systems biology approach to the mechanisms of TB latency and reactivation.
The Institute also supports investigator-initiated research that characterizes genes associated with TB susceptibility; investigates host lung defenses, including immune responses to infection; and examines the effect of TB on HIV disease. A new genetics study will fine-map chromosomal regions that have been linked to resistance to TB. Investigators will also analyze innate immune responses and model genetic predictors of resistance using data from a long-term household contact study conducted in Uganda.
Treatment and Control
The NHLBI supports a number of investigator-initiated studies focused on understanding the relationship between the immune system and TB. Most of the studies are being conducted among patients from minority populations. Included among them are studies to compare susceptibility to TB in populations in Mexico and Peru and examine the role of interferon-gamma in the pathogenesis of TB among Hispanics with and without HIV.
The NHLBI supports basic, translational, and clinical research on SCD and thalassemia (Cooley's anemia) with the goal of curing the disorders and improving patient care. The Institute also supports a deep vein thrombosis and venous disease program.
Basic and Translational Research
SCD, the most common inherited blood disorder in the United States, affects an estimated 70,000 to 100,000 Americans, most of whom are black. SCD occurs in about 1 in 500 blacks and 1 in 36,000 Hispanics. The disease is characterized by anemia, severe infections, acute and chronic pain, and organ damage. SCD, the first molecular disease described, was shown to be due to a single amino acid substitution on the beta chain of hemoglobin.
Since 1972, the NHLBI has supported an extensive research program to improve understanding of the pathophysiology of SCD, identify better approaches for its diagnosis and treatment, and prevent complications.
Basic and translational research currently focuses on genetic influences on disease manifestations, regulation of hemoglobin synthesis, discovery of drugs to increase fetal hemoglobin production, transplantation of blood-forming stem cells, gene therapy, pain research, and development of animal models for preclinical studies. Institute-initiated programs include:
Investigator-initiated studies include a project to examine the relationships between analgesia, biomarkers, and pain levels in adults with SCD. Researchers are seeking to understand the efficacy of analgesic treatment and determine whether novel serum biomarkers can be identified as useful tools for future studies in SCD pain crisis. Another project is investigating the mechanisms underlying pain in SCD to develop more effective pain therapies. Scientists are using a mouse model of SCD to examine peripheral and spinal mechanisms that contribute to pain related to SCD.
Gene therapy is another area of focus. One project is exploring lentiviral gene therapy for SCD, and another is studying the application of induced pluripotent stem cell technology to replace the defective sickle beta-globin gene with a normal gene in a SCD mouse model. Researchers are seeking to translate their results to human cells that will become the foundation for future clinical trials.
The NHLBI is committed to finding improved treatments and ultimately a cure for SCD and other hemoglobinopathies. Institute-initiated studies have begun to yield therapies that will alleviate the symptoms of sickle cell anemia and procedures that should ultimately provide a cure.
The NHLBI terminated two Institute-initiated studies early. The Sildenafil for Sickle Cell Disease-Associated Pulmonary Hypertension was stopped in July 2009, nearly 1 year early, based on recommendations from the Data and Safety Monitoring Board. After a review of interim data, the Board found that patients who received sildenafil were more likely to have serious medical problems compared with patients who received a placebo. The large multicenter cohort with a well-characterized cardiovascular phenotype continues to be a monitored as an off-study drug in an observational follow-up study that includes clinical monitoring, development and maintenance of a biorepository, and DNA analyses (with consent) for GWASs.
The SWiTCH study was stopped in June 2010, after the Data and Safety Monitoring Board reviewed interim results and raised safety concerns. The trial compared an experimental treatment of hydroxyurea and phlebotomy versus standard treatment of blood transfusions plus chelation in children with SCD who had both experienced a stroke and iron overload. The new approach was no better than the standard treatment and did not reduce the risk of recurrent stroke.
The NHLBI supports several transplant-related clinical studies that seek to reach minority populations:
The Institute is supporting two investigator-initiated treatment clinical trials for children with sickle cell anemia. One trial in children with abnormal transcranial Doppler (TCD) velocities is comparing standard therapy (transfusions) with alternative therapy (hydroxyurea) for maintenance of TCD velocities. The other trial is seeking to determine the effect of hydroxyurea treatment on the cumulative incidence of conversion from conditional to abnormal TCD velocities.
The NHLBI has developed a number of publications on SCD that target minorities:
Thalassemia is an inherited disorder of red blood cells whereby abnormal forms of hemoglobin are produced. The disorder, which results in excessive destruction of red blood cells and anemia, affects primarily people of African, Asiatic Indian, Chinese, Mediterranean, and Southeast Asian origin.
The Institute recently entered into an Interagency Agreement with the CDC to develop a registry of patients with hemoglobinopathies:
The NHLBI supports research efforts that include developing oral chelators to remove iron overload by repetitive transfusion therapy, testing drugs to enhance fetal hemoglobin production, and examining hematopoetic transplantation and gene therapy approaches to cure the disease.
In 2006, the Institute established the NHLBI Clinical Hematology Research Career Development Program to support career development of clinical researchers in nonmalignant clinical hematology, including Cooley's anemia.
Deep vein thrombosis (DVT) is a serious condition that can cause significant disability and death if not promptly diagnosed and effectively treated. Approximately 2 to 3 million individuals in the United States develop venous thromboembolism each year, and of them, 60,000 die primarily of pulmonary embolism. The Institute initiated a program to improve the understanding of DVT and venous disease.
Warfarin sodium, an anticoagulant drug, is prescribed to millions of patients each year to prevent thromboembolism. However, warfarin has an unusually narrow therapeutic range and is difficult to dose properly. To address this problem, the Institute is supporting several investigator-initiated studies to determine environmental and genetic factors that influence patient response to warfarin. Fifty to 60 percent of participants are from racial and ethnic minority populations.