Poverty and Social Exclusion at a Cellular Level
The key to understanding the health effects of poverty and marginalization may lie in adding cellular research to detailed sociological data. A recent study lead by two-time CASBS Fellow Arline Geronimus, shows that weathering the stresses of poverty can be observed in differences in blood samples and that poverty leads to lives more prone to illness and early aging across races in a distressed urban setting. In fact, it also shows that poor whites suffer the molecular impacts of aging at a greater rate than other impoverished racial groups in this specific setting.
Press Release: May 4, 2015
Poverty and Social Exclusion at a Cellular Level.
The key to understanding the health effects of poverty and marginalization may lie in adding cellular research to detailed sociological data. A recent study shows that weathering the stresses of poverty can be observed in differences in blood samples and that poverty leads to lives more prone to illness and early aging across races in a distressed urban setting. In fact, it also shows that poor whites suffer the molecular impacts of aging at a greater rate than other impoverished racial groups in this specific setting.
Are the daily stresses of living in some of the poorest neighborhoods in America: struggling to cope with chronic ill health, to stay safe, to feed hungry kids, written on the body?
Two time CASBS Fellow Arline Geronimus (2007-08, 2014-15) investigated that question as the lead researcher in a team including a Nobel prize-winning UCSF biochemist, public health policy experts, and the Healthy Environments Partnership, a community-based participatory research partnership in Detroit. The collaboration married science with detailed local insight. It allowed researchers to gather an unprecedented set of data from a group of 239 adults in three, impoverished neighborhoods.
Central to the study is the understanding that the everyday challenges of living in poverty and in under-resourced urban areas trigger repeated physiological stress responses that accumulate, cause ill health and ultimately shorten life. Geronimus’ team were interested in whether the impact of those stress responses could be measured at a cellular level and compared across populations to assess the effects of weathering lives lived at the socioeconomic margins.
Detroit leads the nation in a set of socio-economic statistics no other city wants to compete with. Sixty percent of children born there live below the poverty threshold. As manufacturing jobs have disappeared the population has shrunk from a high in 1950 of 1.8 million to just 706,585 in 2011. The city’s compounding fiscal problems reached a peak in 2013 when Detroit was forced to file for bankruptcy – the largest municipal filing in U.S history. According to Geronimus, because of these disadvantages, the city offers an important opportunity to examine the relationship between health and urban disinvestment, race-based residential segregation, and additional stressors characteristic of resource-poor settings.
“We believe that the key to understanding racial, ethnic and socioeconomic health inequalities lies in studying the connections between social conditions and biological mechanisms,” Geronimus explained.
Geronimus has spent the past two decades researching the human costs of weathering poverty and marginalization. A current CASBS Fellow she is also Professor of Health Behavior and Health Education, School of Public Health and Research Professor, Population Studies Center, Institute for Social Research an the University of Michigan.
“The weathering hypothesis suggests that the cumulative biological impact of being chronically exposed to, and having to cope with, socially structured stressors can increase health vulnerability and accelerate aging in marginalized populations.” (Geronimus 1992; Geronimus et al. 2006, 2010)
This time Geronimus and her co-authors * added a new element to the study. They took blood samples.
“Because of the participation of the community organizations we had respondents who agreed to provide blood samples and from these we were able to compare telomere lengths,” said Geronimus.
A growing body of research has focused on using telomere length as a measure of biological rather than chronological age. Telomeres are a subset of leukocytes that function as stabilizing caps on chromosomes, protecting them from deterioration. Telomeres shorten with cell division to a point at which the chromosomes are functionally impaired. Studies have noted that telomere length differs in sets of twins over the life course, suggesting that each person’s life experience impacts the rate at which they age. Shorter telomere length has also been studied as a signal of higher risk of infection and chronic disease.
Geronimus’ and her co-authors on “Race-Ethnicity, Poverty, Urban Stressors, and Telomere Length in a Detroit Community-based Sample”, published by the American Sociological Association in the Journal of Health and Social Behavior (May 5, 2015), consider the evidence presented by blood samples compared across a range of detailed social, psychological, and locational data provided by the respondents. Importantly, they were also able to measure the effects of weathering across a diverse racial sample that included African American, white and Mexican respondents.
Geronimus cautions that an important implication of the study is that researchers who interpret racial disparities in telomere length or health outcomes as having a genetic basis are on shaky ground. “ This study shows that telomere lengths of racial-ethnic groups in Detroit are not consistently ranked and vary depending on context and experiences not accounted for in other research.”
“There is nothing biologically essential about race or ethnicity; as humans we are all working with the same basic biological canvas ,” explains Geronimus. “Race or ethnicity can become expressed as physiological difference as social inequalities privilege some groups and marginalize others, in ways that can affect their health, by placing members of different groups in different social and environmental contexts.”
The researchers wanted to investigate whether strong social ties and networks, among groups that were otherwise seriously disadvantaged, may work to mitigate the lifelong stresses of poverty. When they measured the lengths of the telomere samples against socioeconomic, psychosocial, neighborhood and behavioral stressors the findings were perhaps, surprising.
In the three Detroit neighborhoods studied, living below the poverty level was associated with much shorter telomeres for whites and an insignificant but also negative effect for blacks. For Mexican residents of Detroit, living below the poverty line was associated with longer telomeres , the more positive outcome, compared to Mexican Detroiters who were not poor.
“African Americans have worse outcomes generally because they are more likely to have experienced adversity. They live with a long history of adversity: poverty, discrimination, toxic environments. When all races are subject to the same level of deep impoverishment and adversity it seems as if whites are worse off because the black population in this case, may have developed some social methods to protect themselves. We think that because the white population in this case does not have such a long history of social disadvantage, they may not have developed social methods of coping.” For the Mexican group, those in poverty were more likely to be immigrants or maintain ties to their Mexican heritage, such as speaking Spanish at home. This may be health protective for them.
Geronimus stressed that if some groups have developed strengths to cope better with marginalization than others, this does not mean they are not adversely affected by marginalization.
The findings suggest it could be wrong to assume that the effect of poverty on the health of particular racial groups is consistent across different locations. Just as importantly, the findings suggest that social identity can play an important role in defending against the weathering impact of poverty.
Jay A. Pearson, Duke University;?Erin Linnenbringer, University of Michigan, Washington University, St. Louis; Amy J. Schulz, University of Michigan; Angela G. Reyes Detroit Hispanic Development Corporation; Elissa S. Epel, University of California, San Francisco; Jue Lin University of California, San Francisco; and Elizabeth H. Blackburn University of California, San Francisco.
CONTACT:
Arline Geronimus, CASBS Fellow 2014-15, arline@umich.edu http://www.psc.isr.umich.edu/people/profile/35/Arline_T_Geronimus
Janet Gibson, CASBS Communications, (650) 521 2573
Research results: Race-Ethnicity, Poverty, Urban Stressors, and Telomere Length in a Detroit Community-based Sample (Journal of Health and Social Behavior)
http://hsb.sagepub.com/content/early/2015/04/30/0022146515582100.full
Coverage of the study in HuffPost:Scientists Find Alarming Deterioration In DNA Of The Urban Poor