MacArthur SES & Health Network


Reaching for a Healthier Life: Synopsis

There are substantial disparities in health and longevity among different sectors of the US population. Who suffers from poorer health and greater premature mortality? How do these differences come about? What can be done to eliminate these disparities?

Reaching for a Healthier Life answers these questions.

Reaching for a Healthier Life is the result of a decade of work by the MacArthur Foundation Research Network on SES & Health. This multidisciplinary group of scientists has examined the pathways by which socioeconomic status “gets into the body” to affect health and longevity. There is no single pathway by which this occurs. Rather, resources associated with where people stand on the social ladder shape multiple aspects of their lives in ways that affect their health and well-being. Key findings are:

(1) The effects of socioeconomic status are substantial. They are not limited to the effects of poverty but occur at all levels. Premature death is more than twice as likely for middle income Americans as for those who are the best off, and more than three times as likely for those who live near or in poverty compared to the most privileged.

(2) Throughout life, from birth onward, our access to socioeconomic resources affects our chances for living a healthy life. The conditions we live in during childhood affect our health throughout our lives.

(3) Health care is important when we are ill but accounts for only a small portion of health disparities. More important are factors that determine if we fall ill in the first place.

(4) Each step up the social ladder provides greater access to social and physical environments that enable individuals to engage in health protective behaviors, (e.g., safe places to walk and access to healthier foods).

(5) Conditions at work can contribute to health and health disparities. Jobs held by those lower on the ladder are more likely to involve shift work and physical hazards, low control over how and when tasks are done, job insecurity, and conflicts between family obligations and work requirements.

(6) Exposure to extreme and prolonged stress,( “toxic stress”), is more common lower on the social ladder. Stressors that last a long time, like financial insecurity, interpersonal disputes, work-induced exhaustion, or chronic conflict are recorded in the body.

(7) The biological consequences of exposure to stress are not transitory; they are cumulative. The normal functioning of the cardiovascular, immune, metabolic and nervous systems is disrupted. This disruption is made worse by poor health habits molded by social and physical environments lacking health-promoting alternatives.

What can be done?

Two kinds of policies are required to reduce premature death and eliminate health disparities:
1. Policies that impact income and wealth distribution, educational attainment and occupational mobility, and 2. Policies that buffer individuals from the damaging conditions of living below the top rungs. Supporting educational attainment, assuring a living wage, reducing crime, increasing opportunities for control at work, banning sale of soft drinks and junk food in schools are just a few policies with health consequences. Economic, education, labor and zoning policies are all health policies.

The facts contained in this document support the case that policies to support healthy living conditions for all citizens are needed. The cost of implementing such policies would be offset by subsequent savings through increased productivity and lower health case costs. The initial investment would be money well spent. The one thing we cannot afford to do is nothing.

Reaching for a Healthier Life is available electronically, or write the network office to request a hardcopy at Russell.Heiman@ucsf.edu.

 

The Biology of Disadvantage: Socioeconomic Status and Health

Editors: Nancy E. Adler and Judith Stewart
A New York Academy of Sciences Annals publication (Wiley-Blackwell publisher)
Expected publication date: Early 2010 hardcopy and online access

Synopsis and chapter abstracts

A decade ago the MacArthur network examined possible mechanisms by which socioeconomic status “gets into the body” to affect health at a conference presented under the auspices of the New York Academy of Sciences. At that time, we considered those mechanisms for which there was at least some evidence linking them to socioeconomic status and/or to health. The 1999 NYAS volume “Socioeconomic Status in Industrialized Nations: Social, Psychological and Biological Pathways” has been cited extensively over the years since its publication. The conference and the volume contributed to the upsurge in research into the mediators of the gradient relationship between socioeconomic status and health.

In the intervening years the network has published numerous articles in academic journals and was influential in getting health disparities on the NIH agenda. In the final phase of the network, we are turning to the application of this knowledge for policy and practice. To this end, we produced Reaching for a Healthier Life, and group members served as experts for the influential PBS series Unnatural Causes: Is inequality making us sick? The compendium and the series bring the facts of socioeconomic status and health in the U.S. to a broader audience, and are tools for moving from research to policy and intervention.  

The volume Biology of Disadvantage: Socioeconomic Status and Health in the U.S. is a series of review articles examining the current scientific evidence for the facts of socioeconomic status and health in the U.S., explicating the pathways and mediators that explain “how SES gets into the body”. It is an in depth reference for those readers of “Reaching for a Healthier Life” or viewers of “Unnatural Causes” who want access to the scientific evidence upon which those works are based, and will capture the network’s view of where the field stands after ten years of intense investigation by us and many others into the mechanisms of health disparities. In addition it will illustrate the power of a multidisciplinary approach to complex social issues. It attempts to point the way towards applications of the accumulated knowledge for social interventions, and to raise pragmatic issues that are important when science is translated into policy and intervention.

 

Table of Contents

Preface--Nancy E. Adler and Judith Stewart

1. Health Disparities across the Lifespan: Meaning, Methods and Mechanisms

Nancy E. Adler and Judith Stewart

Concern about health disparities has increased markedly over the past two decades, fueled by exponential growth of empirical research. In this chapter we show the progression of research on SES and health through several eras. The first era reflected an implicit threshold model of the association of poverty and health. The second era produced evidence for a graded association between SES and health where each improvement in education, income, occupation, or wealth is associated with better health outcomes. Moving from description of the association to exploration of pathways, the third era focused on mechanisms linking SES and health, while the fourth era expanded on mechanisms to consider multi-level influences, and a fifth era added a focus on interactions among factors, not just their main effects or contributions as mediators. Questions from earlier eras remain active areas of research, while later eras add depth and complexity.

 

2. Health Disparities in International and Historical Context

William H. Dow and David Rehkopf

This chapter places current U.S. health disparities in a broader perspective through historical and international comparisons. Section 1 will present comparisons of health outcome levels in countries at different stages of development over time and space. Section 1A will focus on the historical changes in key health indicators within the United States over the course of the 20th century, for example, discussing trends in mortality, including recent evidence of declining life expectancy in sub-populations. Section 1b will present historical health trends in international comparison. This includes life expectancy trends in the United States compared to other OECD countries, and the life expectancy catch-up among less developed countries. This section will also highlight outlier countries that have achieved high levels of population health even at low levels of economic development, such as China and Costa Rica.

Section 2 will focus on SES gradients in health over time and space. Section 2A will discuss evidence of changing gradients in the U.S. over recent decades. Section 2B will discuss contemporaneous comparisons of U.S. gradients to those in other countries, for example, highlighting recent evidence comparing gradients in the U.S. to those in the U.K. The chapter will include discussion of the interpretation of international and historical comparative data, elucidating powerful lessons that might be drawn but also highlighting the inherent limitations of such comparisons. Barriers to further comparisons will be discussed (such as data problems), as will suggestions for future comparisons that would be of particular interest.

 

3. Childhood Socioeconomic Status and Adult Health

Sheldon Cohen, Denise Janicki-Deverts, Edith Chen and Karen Matthews

A large body of literature documents the association between socioeconomic status (SES) and disease (primarily cardiovascular) risk factors, morbidity, and mortality. SES is usually measured by educational attainment, occupational prestige, or family income in mid- or late life. Another largely separate literature suggests that childhood SES is associated with later morbidity and mortality. Most of the latter work has been conducted in European populations using retrospective recall of parental occupation during childhood. Furthermore, many studies did not statistically adjust for adult SES, raising the possibility that childhood SES is related to adulthood SES because of the high association between the two. More recently, a small but growing literature merging these two literatures addresses whether SES across childhood and adulthood is related to later health risks.

A number of models have been proposed to describe the role of SES in health over the life span.  Accumulation models suggest that the duration of exposure to low SES is critical, regardless of life stage, because the effects of low SES aggregate over time. Change models suggest that increasing or decreasing SES over the life span can have effects independent of the average SES exposure, because of costs of adaptation to varying life circumstances. Timing models suggest that the impact of SES depends on timing of the exposure, with some data suggesting most recent SES is more important, e.g. for triggering clinical events, whereas other work suggests that early SES is more critical. The latter is based on the notion that early life circumstances may program biological and behavioral responses that have life long effects on health. This chapter will address the evidence for each type of model with emphasis on studies that provide sufficient evidence to compare models and more recent research that has not been discussed in earlier reviews.

 

4. Money, Schooling, and Health: Causal Evidence and Mechanisms

Ichiro Kawachi, Nancy E. Adler and William Dow

An association between higher educational attainment and better health status has been repeatedly reported in the literature. Similarly, thousands of studies have found a relationship between higher income and better health. However, whether these repeated observations amount to causality remains a challenge, not least because of the practical limitations of randomizing people to receive different amounts of money or schooling. In this essay, we review the potential causal mechanisms linking schooling and income to health, and discuss the twin challenges to causal inference in observational studies, viz., reverse causation and omitted variable bias. We provide a survey of the empirical attempts to identify the causal effects of schooling and income on health, including natural experiments. There is evidence to suggest that schooling is causally related to improvements in health outcomes. Evidence also suggests that raising the incomes of the poor leads to improvement in their health outcomes. Much remains unknown beyond these crude findings, however; for example, what type of education matters for health, or whether there is a difference between the health impacts of temporary income shocks versus changes in long term income.

 

5. Socioeconomic Status and Racial/Ethnic Differences in Health: Patterns and Needed Research

David R. Williams, Jacinta Leavell, Chiquita Collins

This paper provides an overview of recent research on racial disparities in health and the complex ways in which race, ethnicity, and socioeconomic status (SES) combine to affect patterns of the distribution of disease. It begins by considering evidence of the magnitude of racial disparities in health and the striking pattern of earlier onset of illness and more severe disease for minorities compared to whites. It uses recent national data to illustrate the persistence of racial differences in SES and gives attention to the accumulating evidence that racial disparities in health persist at every level of SES. Migration history and status are important predictors of variation in health and the paper also explores the complex ways in which race, SES and immigration status combine to affect health. There has been polarizing discourse regarding the potential contribution of genetics and medical care to racial differences in disease. Both of these explanations are critically evaluated and the paper calls for a new generation of research that will move beyond either/or explanations. It argues that comprehensive approaches toward quantifying risks in the social environment are needed and research that will advance scientific understanding should seek to understand the ways in which risks and resources linked to race and SES cumulate over the life course and combine with innate and acquired biological factors to affect health.  

 

6. Work and its Role in Shaping the Social Gradient in Health

Jane E. Clougherty, Kerry Souza, Mark R. Cullen

Adults with better jobs enjoy better health: job title was, in fact, the social gradient metric first used to study the relationship between social class and chronic disease etiology, a core finding now replicated in most developed countries. What has been less well proved is whether this correlation is causal, and if so, through what mechanisms. During the past decade, much research has been directed at these issues. Best evidence in 2009 suggests that occupation does affect health. Most recent research on the relationship has been directed at disentangling the pathways through which lower status work leads to adverse health outcomes. This review focuses on five areas of recent progress: 1) the role of status in a hierarchical occupational system; 2) the roles of psychosocial job stressors; 3) effects of workplace physical and chemical hazard exposures; 4) evidence that work organization matters as a contextual factor; and 5) emerging evidence that women may be impacted differently by adverse working conditions, and possibly more strongly, than men.

 

7. Neighborhoods and Health

Ana V. Diez Roux and Christina Mair
          
Features of neighborhoods or residential environments may affect health and contribute to social and race/ethnic inequalities in health. The study of neighborhood health effects has grown exponentially over the last 15 years. This chapter summarizes key work in this area with a particular focus on chronic disease outcomes (specifically obesity and related risk factors) and mental health (specifically depression and depressive symptoms). Empirical work is classified into two main eras: studies that use census proxies and studies that directly measure neighborhood attributes using a variety of approaches. Key conceptual and methodological challenges in studying neighborhood health effects are reviewed. Existing gaps in knowledge and promising new directions in the field are highlighted.

 

8. Are Psychosocial Factors Mediators of SES and Health Connections? A Progress Report and Blueprint for the Future

Karen A. Matthews, Linda C. Gallo and Shelley E. Taylor

The association between socioeconomic status (SES) and physical health is robust. Yet, the psychosocial mediators of SES-health association have been studied in relatively few investigations. In this chapter, we summarize and critique the recent literature regarding negative emotions and cognitions, psychological stress, and resources as potential pathways connecting SES and physical health. We discuss the psychosocial origins of the SES-health links and outline how psychosocial factors may lead to persistently low SES. We conclude that psychosocial resources may play a critical mediating role, and the origins of the SES-health connection are apparent in childhood. We offer a blueprint for future research, which we hope contributes to a better understanding of how SES gets under the skin across the life span.

 

9. Multiple Risk Exposure as a Potential Explanatory Mechanism for the SES-Health Gradient

Gary W. Evans and Pilyoung Kim
The social patterning of disease and mortality provokes a search for explanation. One potential underlying explanation for SES gradients in health is exposure to multiple risk factors. Income and class tend to sort individuals into different settings that are often accompanied by systematic differences in environmental quality. Housing and neighborhood quality, pollutants and toxins, crowding and congestion, and noise exposure all vary with SES. Persons lower in SES also experience more adverse interpersonal relationships with family members, friends, supervisors, and community members. Furthermore, exposure to these multiple risk factors is associated with worse health outcomes. Thus, the convergence of exposure to multiple physical and psychosocial risk factors accompanying disadvantage may account for a portion of SES gradients in health in both childhood and adulthood.

 

10. Central Role of the Brain in Stress and Adaptation: Links to Socioeconomic Status, Health, and Disease

Bruce S. McEwen and Peter J. Gianaros

The brain is the key organ of stress reactivity, coping, and recovery processes. Within the brain, a distributed neural circuitry determines what is threatening and thus stressful to the individual. Instrumental brain systems of this circuitry include the hippocampus, amygdala, and areas of the prefrontal cortex. Together, these systems regulate physiological and behavioral stress processes, which can be adaptive in the short-term and maladaptive in the long-term. Importantly, such stress processes arise from bidirectional patterns of communication between the brain and the autonomic, cardiovascular, and immune systems via neural and endocrine mechanisms underpinning cognition, experience, and behavior. In one respect, these bidirectional stress mechanisms are protective in that they promote short-term adaptation (allostasis). In another respect, however, these stress mechanisms can lead to a long-term dysregulation of allostasis in that they promote maladaptive wear-and-tear on the body and brain under chronically stressful conditions (allostatic load), compromising stress resiliency and health. This review focuses specifically on the links between stress-related processes embedded within the social environment and embodied within the brain, which is viewed as the central mediator and target of allostasis and allostatic load.

 

11. Socio-economic Differentials in Peripheral Biology: Cumulative Allostatic Load

T. Seeman, E. Epel, T. Gruenewald, A. Karlamangla, and B. McEwen

Building on the chapter on SES differences in central (brain) aging and function, this chapter examines evidence regarding SES impacts on “downstream”, peripheral biology, documenting the further “brain-mediated” influences of SES on patterns of activity and “aging” of major “downstream” peripheral physiological regulatory systems, including the autonomic nervous system, cardiovascular, metabolic, and inflammatory processes. We present evidence for SES gradients in major parameters of each of these major systems as well as evidence that though the gradients for individual biological parameters are generally relatively modest, the cumulative differences in burden of biological risk by level of SES are highly significant with lower SES individuals showing evidence of more rapid “aging” of all major systems. Consistent with the hypothesis that lower SES is associated with greater “wear-and-tear” on physiological regulatory systems, SES related gradients are seen as early as 1-5 years of age, becoming more prominent in adulthood, and persist into older age. The contributions of other factors, including psychosocial and behavioral factors will also be examined, including evidence that such characteristics are themselves related to differences in cumulative burdens of biological aging and help to explain some of the observed SES gradient. Finally, evidence will be presented showing the role of these SES differentials in biological aging in observed patterns of disease, disability and mortality.

 

12. Policies and Interventions to Address SES Gradients in Health

William H. Dow, Robert F. Schoeni, Nancy Adler and Judith Stewart

This chapter discusses broad types of intervention/policy strategies that could be effective in reducing health disparities and improving population health. The types of policies/strategies discussed are similar to those in the MacArthur publication “Reaching for a Healthier Life”, but this chapter treats each in greater depth. Particular emphasis is placed on discussing the evidence regarding the potential efficacy and effect sizes of the suggested interventions/policies. The chapter concludes by discussing the many holes in the literature for supporting evidence-based policy, and describes what type of information might be needed for conducting convincing Health Impact Assessments of legislation in these areas. Future research opportunities that have particular promise are highlighted.

 

13. SES and Health Network History and Team Science

Nancy E. Adler and Judith Stewart

In this chapter the director and the administrator of the MacArthur Network on SES and Health reflect on the evolution of the network. Against the backdrop of the science of “team science”, they describe the history and process of the network including the forging of a group agenda, the development of a creative, productive group working style, and the outcomes arising from these processes.

 

 

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