“While previous research has linked discrimination with poor health outcomes, the biological pathways responsible for this association have been poorly understood. This study sheds some light on how and why it may happen,” said Tené Lewis, the study’s lead researcher and an assistant professor in the division of Chronic Disease Epidemiology.
The protein marker, C-reactive protein (CRP), is found in the blood and its levels increase in response to inflammation. In addition to heart problems, its presence has also been linked with several psychosocial processes such as mental stress and depression.
The researchers studied 296 older African-American adults and assessed their experiences with discrimination through a nine-item questionnaire that rated the frequency of various forms of mistreatment (ranging from subtle forms of disrespect to outright insults and harassment). Blood samples were taken from each participant and a significant correlation was identified between CRP levels and the degrees of discrimination experienced.
“People are often reluctant to believe that discriminatory treatment may have a negative impact on health,” said Lewis. “It is important to note that these types of experiences, in addition to making people feel bad, are also associated with actual physiological processes inside the body. These processes, in turn, may have long-term effects on health.”
The association between discrimination and CRP remained strong after adjusting for a range of existing health problems, including depressive symptoms, smoking, heart disease and hypertension.
Lewis said that future research will look at whether reports of discriminatory treatment are associated with changes in CRP levels over time, and whether there are any physical, psychological or social factors that might alter the effects of discrimination on CRP, in the hope of developing preventive interventions.
Researchers from the University of Michigan and Rush University Medical Center also participated in the study.