A study of Black Americans is among the first to show how the internalization of negative messages about dark skin tones could be linked to harms to health.
Researchers found that Black Americans who are, or perceive themselves to be, dark skinned show clear markers of cellular aging associated with immune-system damage and also score lower on a measurement of self-worth. Cellular aging and low self-worth are both associated with relatively poor health outcomes.
"These findings provide evidence that colourism-related pressures are associated with biological and psychological differences in well-being among Black Americans," said lead author Alexis C. Dennis, an assistant professor in McGill's Department of Sociology.
Dennis conducted the study along with colleagues in the United States. It was published in the Journal of Health and Social Behavior.
Colourism's legacy and health impact
Colourism, a legacy of colonial and historical practices, gives preference to lighter skin tones within racial groups, leading to social and economic inequities. While previous research has shown that darker-skinned Black Americans often face worse health outcomes than lighter-skinned Black Americans, the biological and psychological mechanisms that could help explain this disparity have been unclear.
"Experiences of discrimination and structural inequality reinforce the message that 'whiteness' is preferred," said Dennis. "This may damage an individual's sense of themselves and trigger social pain, a form of emotional distress that activates chronic inflammation. Over time, this can accelerate cellular aging and increase the risk of various diseases."
Methodology
The team analyzed data from 627 Black American adults who participated in the Nashville Stress and Health Study between 2011 and 2014. Black Americans were defined as the descendants of slaves; other Afro-descended people in the United States were not included. Those with darker skin tones, whether actual or self-rated, had shorter leukocyte telomere length and a diminished "sense of mattering" compared to lighter-skinned participants. These patterns held regardless of age, sex or socioeconomic status.
Telomeres are protective caps found at the ends of chromosomes in the white blood cells. Shorter leukocyte telomere length is associated with accelerated cellular degradation, chronic inflammation and immune system damage, which in turn increases the risks of various diseases, including heart disease and cancer.
Implications for health equity
The researchers said that the findings highlight biological and psychological mechanisms through which colourism-related stress may "get under the skin" to produce health inequities.
"Our interest in colourism and health inequity is a matter of equity and justice," Dennis added. "It is not fair for some people in society to experience better health than others based on their complexions, as we can't choose the skin that we are born in."
The researchers suggested that future studies focused on other Black populations use biomarkers other than telomere length, which they said is no longer the best measure of epigenetic aging; and consider other physical traits in addition to skin tone.
About the study
"Colorism and Health Inequities among Black Americans: A Biopsychosocial Perspective" by Alexis C. Dennis et al was published in the Journal of Health and Social Behavior
DOI: 10.1177/00221465251364373
Funding
Duke Aging Center, Carolina Population Center at the University of North Carolina at Chapel Hill, Eunice Kennedy Shriver National Institute of Child Health and Human Development
