John D. and Catherine T. MacArthur
Research Network on Socioeconomic Status and Health

NETWORK MISSION

Director: Nancy E. Adler, Ph.D.
University of California San Francisco
Established 1997

 Purpose and Origins

  Chronic disease, disability, and early death are destructive forces in individual lives and in whole communities. Their toll is high-- and they do not strike at random. A growing body of evidence indicates that socioeconomic status (SES) is a strong predictor of health. Better health is associated with having more income, more years of education, and a more prestigious job, as well as living in neighborhoods where a higher percentage of residents have higher incomes and more education.

  The mission of the Network on Socioeconomic Status and Health is to enhance our understanding of the mechanisms by which socioeconomic factors affect the health of individuals and their communities. The network’s research agenda is designed to inform both policy and practice: to stimulate additional research in diverse fields, to contribute data to discussions of economic and social policy, and to provide a basis for social and medical interventions that will foster better health among individuals and communities.

  Major Program Elements

  The network’s investigators are drawn from the fields of psychology, sociology, psychoimmunology, medicine, epidemiology, neuroscience, biostatistics and economics.

  The investigators have developed an integrated conceptual model of pathways from SES to health that incorporates seven facts about the SES and health association, and organizes their conceptual and empirical work.

1. There is a strong dynamic association between socioeconomic status & health; health affects SES & SES affects health. The Network focuses on the impact of the multiple components of SES on health, and the mechanisms and pathways by which the impact occurs. Besides traditional objective measures of education, income, occupational status and wealth, the Network has developed a subjective measure of perceived social status.

2. SES is related to a wide range of diseases; with a few exceptions disease is more prevalent and life expectancy shorter the lower one is in the SES hierarchy. The Network has examined the relationship of SES to a wide range of diseases and mortality, the effects of SES on cognitive and physical functioning as individuals age, and the role of SES in disease recovery.
   
   
3. SES gradients can be seen in preclinical indicators of disease (eg. blood pressure, cortisol levels and patterns, central adiposity, carotid atherosclerosis).  The Network hypothesizes that preclinical indicators of disease may reflect the differential wear and tear on the body of exposure to stressors and life-style factors associated with lower SES position and this may represent a common pathway to diverse health outcomes. Preliminary evidence has shown that summary scores of these preclinical indicators are more strongly predictive than conventional risk factors for a number of diseases, cognitive and physical functional decline, and mortality.
   
   
4. The association of SES & health begins at birth and extends through the lifespan but the strength and nature of the relationship varies at different stages of the life course. The Network hypothesizes that the effects of child and adult SES are not redundant but rather may have cumulative effects, underscoring the value of examining trajectories of SES along with trajectories of risk.
   
   
5. The association of SES & health is not due only to the effects of poverty and extreme adversity.  There is a graded relationship such that health improves with each step up the SES ladder.   The greatest individual burden of disease occurs among the most disadvantaged, but the greatest population effects of SES-related health disparities occur from adverse health effects in middle SES groups. The Network’s focus is on discovering the mechanisms underlying the graded relationship between SES and health.
   
   
6.   Socioeconomic status and race/ethnicity interact in their associations with health. The Network is examining this interaction by studying black/white differences in SES trajectories over the life course, material hardship differences by race, experiences of discrimination, and the impact of these differences on pre-clinical indicators of disease and disease states.
   
   
7. There are multiple pathways by which SES may affect health.  These include:
   a)      Access and quality of health care
   b)       Health behaviors (e.g. smoking, lack of physical activity, nutrition)
   c)        Psychosocial processes (e.g. stress, lack of personal control, hostility, depression)
   d)       Physical environment (e.g. pollution, exposure to toxins & crowding
   e)       Social environments (e.g. neighborhood, work and school environments, social capital, discrimination)

 Access and quality of health care explain only part of the association of SES with health. Health behaviors play a significant role in health outcomes; these are the result of the interaction of individual characteristics and psychosocial processes with environmental constraints and opportunities. The Network focuses on the downstream psychosocial processes, and upstream physical and social environmental determinants.  In each domain, we are interested in the balance between resources and demands or hazards, and in the capacity that higher socioeconomic status provides individuals to deal with these demands/hazards.

Progress and Plans

 The network has undertaken a variety of studies focusing on the social, psychological, and biological processes involved in "social gradients" in health and disease. Several of these involve collaborations with existing MacArthur initiatives and other ongoing research--for example, embedding in-depth studies in broader research projects or adding components to follow-up studies in longitudinal research projects.   

•   Added new measures to waves of data collection in the Whitehall Study of British Civil Servants, a longitudinal study that has shown a persistent influence of SES on health well into old age.

• Added new psychosocial measures to the 15-year follow-up wave of the CARDIA study, a multi-site, longitudinal project funded by the National Heart Lung and Blood Institute, and collaborated on in-depth “allostatic load” ancillary studies at the Oakland and Chicago sites. The network was also involved in the 20-year exam.
  
  
• Initiated a large study of work environment and health across 15 plants of a large industrial company using available administrative and physical status data supplemented with surveys to assess psychosocial and environmental factors affecting allostatic indicators and health.

  Data collected from these studies, and other studies designed to refine measures and test particular pathways, will enable the group to estimate and test for the first time the integrated model of the environmental and psychosocial pathways by which SES alters the performance of the body’s biological systems, thereby affecting risks of a variety of diseases, their progression, and ultimately, mortality.