By midlife, many African-Americans have experienced enough day-to-day forms of mistreatment – being followed around stores or stopped without cause by police – to make them sick: clinically, chronically and even fatally sick.

Now a research team is linking what psychology and sociology researchers call “everyday unfair treatment” with higher incidence of diabetes, cardiovascular disease, hypertension, obesity and other life-limiting conditions in African-Americans.

“Chronic experiences of discrimination and mistreatment can affect health in the most insidious of ways, both because such experiences can undercut rights and opportunities that may be of vital importance to stigmatized groups and because they have the potential to negate the significance of personal agency and identity in the lives of marginalized individuals,” said Anthony D. Ong, associate professor of human development in Cornell’s College of Human Ecology. He is the lead author of the report, “Everyday Unfair Treatment and Multisystem Biological Dysregulation in African-American Adults,” in press at the journal Cultural Diversity and Ethnic Minority Psychology.

Other authors of the paper are David R. Williams at the Harvard University T.H. Chan School of Public Health; Ujuonu Nwizu ’17, at Cornell’s Africana Studies and Research Center; and Tara Gruenewald, at the University of Southern California’s Davis School of Gerontology.

The authors believe their findings – among middle-aged African-Americans in Milwaukee – shed light on the biological underpinnings of chronic exposure to unfair treatment. The study, they say, “is among the first to consider the cumulative effects of unfair treatment across a comprehensive, 22-biomarker measure of multisystem biological dysregulation.”

The biomarkers for elevated disease risk were found in laboratory samples (blood, urine, saliva) and medical examinations of 233 African-American adults, who also responded to interviews and questionnaires about their life experiences. The researchers analyzed the frequency of what they call “interpersonal unfair treatment in their daily lives.”

How often, the study asked, are you treated with less courtesy or respect than others? Receive poorer service than others at restaurants or stores? Called names, insulted, threatened or harassed? Do people act afraid of you because of your color? Have people ever acted like you’re dishonest, not smart or not as good as they are?

The majority (81.1 percent) of African-Americans in the study said “race” was the basis for at least one of the unfair treatment events they experienced.

The research tested an emerging theory: That coping with chronic, everyday mistreatment triggers a cascade of psychological responses that over time may place demands on the body’s ability to effectively respond to challenges. “We were searching for the biological footprint of everyday discrimination,” Ong said.

The researchers sought to differentiate everyday hassles from experiencing what they termed lifetime unfair treatment – being denied a promotion, a loan or a lease in certain neighborhoods, for example. Everyday incidents of discrimination correlated best with the medical indicator called allostatic load (AL).

For the Milwaukee study, AL was the sum of seven physiological system risk indices: cardiovascular regulation, lipid, glucose, inflammation, sympathetic nervous system, parasympathetic nervous system, and the hypothalamic-pituitary-adrenal axis.

If individuals with heavy allostatic loads weren’t already suffering related medical conditions at mid-life, they were at markedly higher risk in the future. (AL has been shown in other studies, the researchers noted, to predict incident cardiovascular disease, decline in cognitive and physical functioning and all-cause mortality.)

Inviting further examination of the issue, the researchers said their study “points to the significance of chronic everyday discrimination in the lives of African-Americans … by illustrating how social conditions external to the individual ‘get under the skin’ to affect later health and disease outcomes.”

The study was funded by the National Institute on Aging, based on the Milwaukee study, which was funded by the John D. and Catherine T. MacArthur Foundation.

H. Roger Segelken is a freelance writer.