USING THE CONTENTS OF THE COBB RESEARCH LABORATORY TO UNDERSTAND TODAY’S HEALTH DISPARITIES

Marisela B. Gomez, M.S., Ph.D., M.D., M.P.H. (mb-gomez@hotmail.com)


Abstract

The investigation of the Cobb Collection and New York African Burial Ground Collection for patterns of stress-mediated changes in biomedical markers may offer some insight into the existence of health disparities today. Specifically, genetic analysis of the extent of DNA methylation of key genes which code for biological mediators, increased or decreased by stress, would help in understanding potential trans-generational epigenetic phenomena increasing the risk for diminished health outcomes in Afro-descendant people living in the U.S. today. Analysis for epigenetic changes or consistency of genes affecting the physiological pathway of stress in past and present Afro-descendants would help to understand risk factors for current health disparities. 


The New York African Burial Ground Collection contains the remains of enslaved Afro-descendant people living in colonial New York City in the 17th and 18th century. Previous investigation of those buried in the New York African Burial Ground Collection offers some indication that African and African Americans (forward referred to as Afro-descendants) had poor health. This conclusion was arrived at secondary to analysis of skeletons for stature, biomechanical stressors, and craniosynostosis, nutrition, biomechanics, and infection relationships (1). These data suggest that Afro-descendant people living at that time did not reach their full growth potential (1). In addition, mortality rates for Afro-descendant people during the 18th century in Philadelphia, indicative of other colonies in the U.S. show an increased rate relative to whites (2). The living and working conditions for Afro-descendant people living in urban areas were also more squalid and violent than those for whites and therefore increased the risk of diseases and death during these times. This is indicated by the high mortality rate for males and females assessed from the remains of the New York African Burial Ground population-15.8 % in 30-34 age group (3).

The Cobb Collection contains the human skeletal remains of primarily Afro-descendant peoples living in 19th and 20th century Washington DC. It has largely been understudied but what research has been done suggests that the Afro-descendants had poor health (13, 14).

Current health inequities in the Afro-descendant population include differences in rates of death from stroke, coronary heart disease, infant mortality, and homicide; occurrences of pre-term birth, diabetes, periodontitis and life expectancy relative to whites (4). Populations today living in poverty also exhibit health inequities including asthma attacks, obesity, preventable hospitalizations, periodontitis, and diabetes (4). Because a greater percent of Afro-descendant people continue to live below the poverty line, attend college, and are employed when compared to their white counterparts this presents a double set of risk factors for health disparities in Afro-descendant people, not unlike the conditions faced by Afro-descendants of previous centuries. Research shows that when adequate emotional and environmental support are not in place, chronic stress can have an adverse effect on cardiovascular health, metabolism, waist circumference, autonomic and sympathetic nervous system (ANS, SNS), hypothalamic-pituatary axis (HPA), and inflammation (5). While some stress is normal and can be protective, prolonged stress results in a shift in the physiological homeostasis of the mind and body mediated through these systems or the allostatic load. Chronic stress results in an allostatic load or greater burden to be balanced and accommodated through greater demand of energy- referred to as allostasis (5) (figure 1). In chronic stress mediated through challenging environmental conditions the body and brain continuously attempts to maintain this allostasis or balance thereby placing greater demand on the physiological functions of the body and mind. Such chronic states of accommodation places the body at risk for illnesses otherwise managed or minimized when the body is not in such chronically active states. Recent research shows that the allostatic load is greater in African Americans adult and adolescents, neighborhoods of poverty, and social conflict with lower allostatic loads in people with social support and higher education (6, 7, 8, 9, 10). Such data support previous studies on increased blood pressure in African Americans attributed to racial discrimination and other minority groups facing stress of exclusion (11, 12).

 Assessing the possible epigenetic effects from stress in colonial times of Afro-descendant people may help to elucidate causal pathways to current health disparities in Afro-descendants today. Many of the health outcomes in this population today are affected by various systems of the allostatic load mediated through stress. Previous research hint at differential effects on health outcomes on Afro-descendant people in Africa and the United States suggesting variation in causal pathways affected by environmental conditions, such as slavery. The continued environmental stressors faced throughout slavery and subsequently provide a psychosocial causal pathway worthy of investigating in an effort to understand and address health inequities today.***

Figure 1. Social environment and health: the role of the brain. The stress response and development of allostatic load are illustrated. Perception of stress is influenced by one's experiences, genetics, and behavior. When the brain perceives an experience as stressful, physiologic and behavioral responses are initiated leading to allostasis and adaptation. Over time, allostatic load can accumulate, and the overexposure to neural, endocrine, and immune stress mediators can have adverse effects on various organ systems, leading to disease. Reprinted from McEwen 1998, with permission.  

Figure 1. Social environment and health: the role of the brain. The stress response and development of allostatic load are illustrated. Perception of stress is influenced by one's experiences, genetics, and behavior. When the brain perceives an experience as stressful, physiologic and behavioral responses are initiated leading to allostasis and adaptation. Over time, allostatic load can accumulate, and the overexposure to neural, endocrine, and immune stress mediators can have adverse effects on various organ systems, leading to disease. Reprinted from McEwen 1998, with permission.

 


References

1.  S. K. Goode-Null, K. J. Shujaa, and L. M. Rankin-Hill Chapter 12. Subadult growth and development, pg 250. In Volume 1, Part 1. The Skeletal Biology of the New York African Burial Ground. Ed. Blakey Ml, Rankin-Hill LM. Howard University Press, 2009.

2.  Chapter 13 . The Political Economy of Forced Migration. pg 261. In Volume 1, Part 1. The Skeletal Biology of the New York African Burial Ground. Ed.  Blakey Ml, Rankin-Hill LM. Howard University Press, 2009.

3.  Chapter 13 . The Political Economy of Forced Migration. pg 262. In Volume 1, Part 1. The Skeletal Biology of the New York African Burial Ground. Ed.  Blakey Ml, Rankin-Hill LM. Howard University Press, 2009.

4.  CDC health disparities and inequalities report: U.S. 2013 http://www.cdc.gov/disparitiesanalytics/Docs/CHDIR13_factsheet_nov_20_2013_final_508.pdf

5.  McEwan BS. 1998. Protective and damaging effects of stress mediators. N Engl JMed. 15:338

6.  Merkin SS, Karlamangia A, Roux AV, Seeman, T. 2014 Life course socioeconomic status and longitudinal accumulation of allostatic load in adulthood: multi-ethnic study of atherosclerosis. AJPH. 104:e48.

7.  Chyu L, Upchurch DM. 2011. Racial and ethnic patterns of allostatic load among adult women in the United States: Findings from the National Health and Nutrition Examination Survey 1999-2004. J Womens Health. 20:575

8.  Rainisch BK, Upchurch DM. 2013. Sociodemographic correlates of allostatic load among a national sample of adolescents: findings from the National Health and Nutrition Examination Survey, 1999-2008. Adolesc Health. 53:506.

9.  Beckie TM. 2012. A systematic review of allostatic load, health, and health disparities. Biol Res Nurs.14:311.

10. Needham BL, Carroll JE, Diez Roux AV, Fitzpatrick AL, Moore K, Seeman TE. 2014. Neighborhood characteristics and leukocyte telomere length: the Multi-Ethnic Study of Atherosclerosis. Health Place. 28:167.

11. Kreiger N, Sidney S. 1996. Racial discrimination and blood pressure: The CARDIA study of young Black and White adults. AJPH. 86: 1370.

12.Blakey, M.1994. Psychophysiological Stress and Disorders of Industrial Society: A Critical Theoretical Formulation for Biocultural Research. In S. Forman, Diagnosing America: Anthropology and Public Engagement. Ann Arbor: University of Michigan Press: 149–192.

© W. Montague Cobb Research Laboratory

Download the PDF of this Article!