The Conference on Socioeconomic Status (SES) and Cardiovascular Health and Disease, sponsored by the National Heart, Lung, and Blood Institute (NHLBI), was held in Bethesda, Md, November 6-7, 1995. This important meeting addressed a topic of great timeliness and interest to those of us who are concerned with public health in the United States.
Participants at the conference were given the following charge: (1) to review existing knowledge of biological, behavioral, and social factors related to SES variations in cardiovascular disease (CVD) morbidity and mortality and their trends, particularly with respect to minorities; (2) to identify scientific information that is ready for transfer to healthcare professionals and the public to improve the cardiovascular health of the country; and (3) to determine future opportunities and needs for research on SES factors and their relationships with cardiovascular health and disease.
A Chartbook of U.S. National Data on Socioeconomic Status and Cardiovascular Health and Disease served as background to the conference. The product of more than 2 years of work by a number of distinguished nonfederal scientists and representatives of the NHLBI, the National Center for Health Statistics, and the Health Care Financing Administration, the Chartbook is unique in its wealth of US national data about race-, sex-, and age-specific associations between SES and CVD.
The full text (no graphics) of the conference report is available on the NHLBI Gopher (gopher://gopher.nhlbi.nih.gov:70/1). A printed copy can be obtained from Judy Corbett, NHLBI, Bldg 31, Room 5A06, National Institutes of Health, 31 Center Dr, MSC 2482, Bethesda, MD 20892-2482.
As the report indicates, current knowledge and understanding of the behavioral, social, psychological, and biological pathways through which SES influences CVD remain limited. To clarify the association between SES and CVD, a number of approaches must be vigorously pursued to acquire new scientific information, validate therapeutic and preventive approaches, and transfer new knowledge into practice.
The summary that follows was prepared by the conference cochairs, Drs Jeremiah Stamler and Helen P. Hazuda. We are grateful to them and to the conference participants for their thoughtful contribution to our efforts. It is our hope that this report and its recommendations will receive close attention from the scientific community and serve as a starting point for identifying ways to reduce CVD among all segments of society.
Disease prevention is an essential part of the mission of the NHLBI. Over the years, the Institute has developed some remarkably effective preventive strategies based on research to identify the major risk factors for CVD. It is no surprise that the sharp declines in CVD mortality that occurred during the past 30 years coincided with our understanding that such factors as smoking, hypertension, high blood cholesterol, obesity, and diabetes increase the risk of a person's developing CVD.
Gratifying as this progress is, we still have far to go. Much evidence indicates that the beneficial trends in CVD mortality have not been felt equally across all segments of society. Rather, the most striking improvements in cardiovascular health have occurred among wealthier, better-educated Americans, whereas progress among groups with lower SES has lagged. The observation that the gap between high-SES and low-SES populations may be widening is particularly disturbing.
The Conference on Socioeconomic Status and Cardiovascular Health and Disease was convened to address these important public health issues. More than 120 people attended, representing such fields as cardiovascular and preventive medicine, epidemiology and biostatistics, behavioral and social sciences, and health policy research. The goals of the meeting were to assess the extent to which SES is related to CVD mortality, morbidity, and risk factors in men and women of various ages, races/ethnicities, and geographic locations; to assess time trends in the SES-CVD association; to explore possible biological, psychosocial, and lifestyle-related pathways by which SES may relate to CVD; to identify strategies for reducing SES-based disparities in cardiovascular health; and to recommend promising avenues for future research on this topic.
Several crosscutting themes emerged from the conference presentations and discussions. First is the need to improve our understanding of the concept of SES and the ways in which it reflects the conditions of everyday life for people of various strata. This task will involve development of more sophisticated and refined measures of SES. The importance of seeking input from other related fields (eg, sociology, demography, and economics) was emphasized.
The conference also highlighted the importance of rapidly transferring new scientific knowledge into practice and, most critical, of more effectively applying what we already know about risk-reduction strategies (eg, smoking cessation, blood pressure control, and diet), especially to population strata that have not yet been reached. In this regard, the superb national leadership taken by the NHLBI through its education programs was repeatedly acknowledged.
Irrefutable evidence that an SES gradient in CVD risk exists—that there is room for improvement at every SES level—speaks to the importance of a population-wide approach to reducing the burden of CVD. Sustained and focused efforts among all SES groups of various races/ethnicities are needed.
Session 1: Setting the Stage
The first session focused on US national data relating SES to CVD morbidity and mortality; to lifestyle, biomedical, and psychosocial risk factors; and to use of medical care. Presenters gave an overview of data in the Chartbook of U.S. National Data on Socioeconomic Status and Cardiovascular Health and Disease, which had been prepared as background to the conference.
The national data document that SES relates to CVD, to lifestyles, and to major lifestyle-related biomedical CVD risk factors (with variations by age, sex, ethnicity, and specific aspects of lifestyle, as well as with variations over time). The general finding is that more adverse patterns of these variables exist for lower-SES strata than for higher-SES strata in the US population. For instance, a wealth of information on smoking shows strong and consistent relationships with SES (ie, for all age groups, both sexes, and all racial/ethnic groups, the lower the SES, the higher the prevalence of smoking and the lower the quit rate during recent decades).
Strong and consistent inverse relationships also prevail—for adults of every age and both sexes, for blacks, non-Hispanic whites, Hispanics, Asian Americans, and Native Americans—between SES and high blood pressure and between SES and obesity. Lower-SES groups have higher rates of both hypertension and obesity than higher-SES groups. Upward trends in body weight and in prevalence of overweight during the last decades have been more marked in lower- than in higher-SES strata.
Other SES–risk factor relationships are less strong and consistent: for example, the relationship between SES and serum cholesterol. However, trend data from successive national population surveys indicate that declines in adult average serum cholesterol levels have been smaller in lower- than in higher-SES strata. National data about such relevant aspects of lifestyle as diet and physical activity and their time trends across SES strata are limited.
National data are also sparse with respect to psychosocial risk factors across SES strata. In particular, data are lacking on psychosocial variables for SES groups of various ethnic backgrounds. Furthermore, little information exists about such variables as job change, unemployment, job and income instability, work-related psychosocial variables, social support, and social isolation and how these variables influence relationships of SES to CVD, CVD risks, and their trends.
As the Chartbook documents and the presenters noted, national mortality data show clearly that for major ethnic groups in the US population, lower-SES strata have higher mortality rates than higher-SES strata for coronary heart disease (CHD), all CVD, and all causes. National morbidity surveys give generally concordant findings.
Discussants noted that SES is related to many aspects of daily life, experiences at work and in the community, stresses and strains, and access to and use of medical care, including preventive services and state-of-the-art diagnostic and therapeutic services. To understand better how SES influences CVD, an epidemiology of everyday life that encompasses these phenomena needs to be developed.
1. Promote measurement of SES in both observational and interventional research by use of established, valid, reproducible, acceptable indexes appropriate for a given study and its aims. Encourage data analysis approaches that include use of information on SES as both a control and a stratification variable.
2. Develop, validate, and incorporate more sophisticated measures of SES and SES-related aspects of everyday life into research with a major focus on SES and CVD. In studies of women, minorities, and rural residents, give explicit attention to special features that may condition the definition, meaning, and impact of SES.
3. Investigate the relationships between SES and CVD initiation, progression, prognosis, morbidity, disability, and death. Emphasize greater use of methods to measure preclinical disease (eg, echocardiography, electrocardiography, sonographic measurement of carotid artery intima-media wall thickness, and measurement of ankle-arm blood pressure ratio) to achieve earlier and more comprehensive assessments of the impact of SES-related exposures on CVD. Link such findings to data on nonfatal and fatal clinical CVD.
Session 2: Pathways Linking SES and CVD
Several presenters reviewed data on SES-CVD relationships and on possible pathways of these relationships in men and women from specific US population strata (ie, blacks, whites, Hispanics, Asians and Pacific Islanders, Native Americans, rural populations, and employed groups). Two other presenters discussed evidence from psychosocial studies and from research on stress, work, and social support. The last speaker addressed medical care access, use, and costs.
In agreement with national data, findings from studies of specific US population groups generally show an inverse relationship between SES and CVD (ie, higher CVD rates with lower SES). Two broad pathways were noted linking SES and CVD: (1) less favorable patterns of established major lifestyle and biomedical risk factors (smoking, adverse diet, sedentary lifestyle, high serum cholesterol, high blood pressure, obesity, and diabetes) in lower- than in higher-SES strata and (2) less favorable patterns of psychosocial factors (hostility, depression, low social support, social isolation, racism, job instability/insecurity/strain/powerlessness, unemployment) in lower- than in higher-SES strata. Data are sparse on possible SES-related biological mediators of relationships between psychosocial factors and CVD (eg, altered sympathetic and parasympathetic nervous system function, altered hypothalamic-pituitary-adrenal axis function, and altered cellular-molecular biology of key cells) and on social-environmental mechanisms whereby lower SES leads inordinately, from early childhood on, to development of more adverse behavioral and psychosocial patterns.
Men with low levels of all established biomedical risk factors (blood pressure, cholesterol, smoking, diabetes, and previous heart attack) have been found to experience lower CHD and CVD mortality rates than men without such a favorable profile. Such a favorable profile is found in <10% of the population. These findings indicate that controlling the established biomedical risk factors has the potential to achieve low CHD-CVD rates for all groups in the United States, including low-SES strata of various racial/ethnic backgrounds.
These observations underscore the importance of primary prevention and control of the established major biological risk factors for CHD-CVD. Improved understanding of the reasons why lower-SES groups have more adverse levels of the major risk factors, the pathways producing these patterns, and the contributory role of more adverse behavioral and psychosocial patterns is key to achieving this goal. Also important is improved understanding of the lifestyle, behavioral, psychosocial, cultural, metabolic, and genetic components of maintaining low-risk status into middle age. Such knowledge will lead to development and application of better approaches for the primary (including “primordial”) prevention and control of the major risk factors, with a focused emphasis on lower- as well as higher-SES strata of all racial/ethnic groups.
1. Investigate relationships between SES and development/evolution of lifestyles, behaviors, and risk factors, including both adverse and favorable patterns.
2. Analyze existing data and data currently being collected by trials and demonstration projects to document further the effectiveness of interventions in lower- and higher-SES groups of various races/ethnicities; report and disseminate such data and their implications for programs to control CVD in lower-SES groups.
3. Conduct research to enhance understanding of mechanisms underlying clustering of adverse lifestyles, behaviors, and risk factors in lower-SES groups of various races/ethnicities.
4. Study SES and precursors of adult lifestyles and behaviors from childhood on, including influences of the family, community, school, and workplace.
5. Elucidate the mechanisms whereby conditions of everyday life for lower-SES groups—exposures during prenatal life, infancy, childhood, and adulthood—contribute to the development of more adverse patterns of lifestyles, behaviors, risk factors, and psychosocial traits. Include studies of the roles of racism; sexism; deprivation; relative and absolute income levels and their trends; knowledge and attitudes; home, school, workplace, community, and mass-media exposures; peer pressures; housing conditions; relationships to organizations; early exposures to food, alcohol, and drugs; and barriers to adoption of heart-healthy behavior.
6. Investigate the interrelationships between psychosocial traits and lifestyles in lower-SES groups with the aim of clarifying environmental and biological mediators and pathways of these interrelationships (including neurological, endocrine, cellular, and molecular pathways) and thereby enhancing understanding of how psychosocial factors and acculturation influence CVD risk.
Session 3: Experience in Educational and Preventive Interventions Across SES Groups
This session focused on preventive strategies that, if applied more broadly, have potential to reduce the SES gradient in CVD health and disease. Speakers reviewed evidence from clinical trials and a broad range of intervention studies to determine whether observed reductions in CVD risk factors, morbidity, and mortality extended equally to low- and high-SES participants, including those from ethnic minorities. Findings clearly indicate that, although there is more to be learned, much is already known about how to reduce CVD in low-SES groups.
Interventions in several large NHLBI-supported primary prevention trials were efficacious in reducing CVD risk factors, morbidity, and mortality in multiple SES-race substrata, although only limited special efforts were made to tailor the interventions for lower-SES, nonwhite participants. Interventions consisted of antihypertensive drug treatment involving stepped care as well as multifactor behavioral interventions aimed at smoking cessation, reduction of total serum cholesterol, weight control, increased physical activity, and reduction of salt and alcohol intake. Lower SES was not a barrier to intervention success for either the drug treatment or the behavioral components. In one antihypertensive trial, the SES gradient in mortality was eliminated in the intervention group.
Studies in communities, worksites, and schools confirm that public health interventions can be designed to benefit all segments of society. Favorable changes in lifestyles and lifestyle-related biomedical risk factors have been achieved across all SES groups in community interventions that have used a broad, multimedia communication approach with special efforts to target and involve low-SES, culturally diverse groups. Worksite interventions incorporating on-site classes and payroll incentives have also achieved favorable results in both blue- and white-collar employees. The success of school-based programs in achieving similar magnitudes of risk factor reduction in both low- and high-SES students is particularly noteworthy, given the schools' potential for building lifelong heart-healthy habits and thereby contributing importantly to the key strategic goal of preventing the development of major risk factors.
Preliminary findings from programs specifically designed to address the need for nutrition education materials suitable for English-speaking adults with limited literacy skills indicate that the approaches developed result in increased use of intervention materials among ethnically diverse, low-SES individuals and can lead to gradual, sustained progress toward favorable risk factor change over time. Most programs use multimedia, client-centered instructional approaches that include interactive computer technology, videotapes, audiocassettes, compact disks, and printed materials.
Across all SES groups, self-help is the method of choice for smoking cessation by more than 90% of smokers. Programs that combine media presentations with telephone counseling hotlines or distribution of self-help materials have been particularly effective with lower-SES smokers. A community organization approach used in one study had the greatest effect in low-SES individuals. Counseling of smokers by physicians or dentists has also been shown to significantly increase their likelihood of quitting smoking.
Sedentary lifestyle is particularly prevalent among lower-SES persons and ethnic minorities. Experience from community-based heart-health programs suggests that interventions promoting moderate-intensity rather than vigorous-intensity activities are more likely to be successful and that exercise campaign events tied to preexisting community structures or traditional community events have the greatest participation levels. Worksite interventions have demonstrated that clinically significant increases in physical activity can be achieved in both low- and high-SES employees.
The National High Blood Pressure Education Program and the National Cholesterol Education Program have been prime movers in the substantial progress made in achieving the Healthy People 2000 blood pressure and cholesterol objectives. Their achievements underscore the effectiveness of science-based public health strategies that rely on broad-based cooperation between government and the private sector in overcoming the barriers to reducing CVD in all sectors of the population.
The overall conclusion is that more widespread application of interventions already known to work across multiple SES and ethnic groups can make a substantial contribution to eliminating the SES gradient and ending the CVD epidemic in all segments of society.
1. Incorporate nonsmoking messages into educational efforts targeting all SES-ethnic groups, with a particular focus on more habituated smokers and on do-it-yourself approaches to smoking cessation.
2. Evaluate existing obesity intervention programs; look for successes and develop approaches based on them, with the aim of achieving national goals for obesity prevention and control for all SES strata, including reversal of the decades-long rise in obesity rates among children, youth, and adults.
3. Intensify efforts to increase consumption of heart-healthy foods—reduced in total fat, saturated fat, cholesterol, salt, refined sugars, and calories—in lower-SES communities.
4. Enhance efforts to prevent and control high alcohol intake among lower-SES groups of various races/ethnicities.
5. Enhance efforts to achieve daily or near-daily physical activity by lower-SES groups from childhood on and to increase the proportion of people who regularly engage in moderate activity.
6. Emphasize the potential contribution of stress reduction to modifying risk factors and subsequent CVD morbidity and mortality.
7. Encourage assessment of literacy as a relevant aspect for improving ability to intervene effectively in lower-SES groups; use group-specific programs appropriate for literacy level and sensitive to group culture.
8. Develop effective strategies to promote favorable behavior changes in lower-SES groups.
9. Conduct demonstration research in communities, workplaces, and schools with persons from lower-SES groups of various ethnicities. Include participation of community outreach workers (including workers trained and supervised by nurses and dieticians) and community representatives in all aspects of such projects (ie, planning, intervention, and data evaluation) to enhance the potential for lasting accomplishments.
- Copyright © 1996 by American Heart Association