MacArthur Research Network on Socioeconomic Status and Health
Director: Nancy E. Adler, Ph.D.
University of California San Francisco
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 large 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 Network on Socioeconomic Status and Health has enhanced understanding of the mechanisms by which socioeconomic factors affect the health of individuals and their communities. The Network’s research agenda established in 1997 has stimulated additional research in diverse fields, has contributed data to discussions of economic and social policy, and has provided a basis for social and medical interventions to foster better health among individuals and communities.
The network’s investigators are drawn from the fields of psychology, sociology, psychoneuroimmunology, medicine, epidemiology, neuroscience, biostatistics, and economics. Their research is organized around an integrated conceptual model of the environmental and psychosocial pathways by which SES alters the performance of biological systems, thereby affecting disease risk, disease progression, and ultimately mortality.
The model addresses several fundamental facts:
There is a strong, two-directional association between socioeconomic status and health. The Network focuses on the multiple components of SES, their impact on health, and the mechanisms and pathways by which the impact occurs. Besides the objective measures of education, income, occupational status and wealth, the Network has developed a subjective measure of perceived social status.
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, and the effects of SES on cognitive and physical functioning as people age.
The effects of poverty and extreme adversity alone do not explain the association of SES and health. Health improves with each step up the SES ladder. While the greatest individual burden of disease occurs among the most disadvantaged, the greatest population effects are seen in the middle SES groups. The Network’s focus is on discovering the mechanisms underlying the graded relationship between SES and health.
The association of SES and health begins at birth and extends throughout life, but the strength and nature of the relationship can vary at different stages of life. The effects of SES in childhood and later appear to be cumulative, underscoring the value of examining trajectories of SES along with trajectories of risk.
There are multiple pathways by which SES may affect health, including access and quality of health care, health-related behaviors, individual psychosocial processes, and physical and social environments. The Network focuses on the downstream psychosocial processes and the upstream physical and social environmental determinants. In each domain, it is interested in the balance between resources and demands, and in the capacity provided by higher SES to deal with these demands.
Socioeconomic status and race/ethnicity interact in their associations with health. The Network examines this interaction by studying racial differences in SES trajectories, material hardship, and experiences of discrimination, and the impact of these differences on pre-clinical indicators of disease and disease states.
SES gradients can be seen in pre-disease indicators such as blood pressure, cortisol patterns, central adiposity, and carotid atherosclerosis. This may reflect the wear and tear on the body of exposure to stressors and lifestyle factors associated with lower SES. Network research indicates that summary scores of these indicators appear to be better predicators of certain diseases, cognitive and physical decline, and mortality than are conventional risk factors.
The network publication Reaching for a Healthier Life expands on these essential facts of SES and health in the U.S. A new volume, Biology of Disadvantage: Socioeconomic Status and Health which provides more detailed support for the findings presented in Reaching for a Healthier Life, is in preparation and will be published by Blackwell publishing on behalf of the New York Academy of Sciences in late 2009.
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. For example in our integrative studies, the Network added measures to the Whitehall Study of British Civil Servants, to CARDIA, a multi-site longitudinal project funded by the National Heart Lung and Blood Institute, and to a project sited in a large U.S. industrial company. In addition the Network has collaborated on a variety of smaller collaborative projects which address specific aspects of the model. This work has resulted in a rich and diverse cumulative set of publications.
Examples of important findings include:
- The MacArthur Subjective Social Status Scales. The SES ladder has been used in a number of studies with populations that range from British civil servants, to pregnant women from four different US ethnic groups, to adolescents in the US Midwest, to elderly residents of Taiwan, to residents of small towns in three provinces in China, to low-income rural Mexicans, to older retired residents of Britain, and representative samples of individuals in the United States and Hungary. The results have shown that subjective status is related to a range of health indicators, including poor self-rated health, higher mortality, depression, cardiovascular risk, diabetes and respiratory illness. In several of the studies subjective status showed a stronger relationship with the health indicators than did objective status and remained significant when objective indicators of SES were entered simultaneously into analytic models.
- New-markers of Allostatic Load--Caregiver Study and Telomerase length: Telomeres appear to provide a good summative measure of aging and have allowed the Network to test the hypothesis that lower SES contributes to accelerated aging through greater stress exposure. Telomeres are repetitive sequences at the ends of chromosomes which protect the ends of the chromosome from damage. It has been established in the literature that telomeres tend to shorten with age, with exposure to oxidative stress, and with low levels of the reparative enzyme, telomerase. In the Network study of healthy women, some of whom were caregiving for a seriously ill child, measures indicating greater chronic stress (greater perceived stress, lower levels of education, and greater excretion of urinary stress hormones) were related to shorter telomeres and/or lowered telomerase levels. In the same sample, low telomerase activity (a precursor to telomere shortening), but not telomere length, was related to cardiovascular disease (CVD) risk factors, including greater abdominal adiposity, higher lipids, and higher fasting glucose.
As the Network draws to a close, the group is focused on exploring how to translate our research and knowledge about health disparities into interventions and policies on the local, regional, and national level.
Individual to whom inquiries should be directed:
Name: Judith Stewart, Ph.D. MPH
Title: Network Administrator
Address: 3333 California St. Suite 465
City, State, ZIP: San Francisco, CA 94143-0848
Phone Number: 415-476-7680
E-mail Address: email@example.com