Lifetime discrimination, global sleep quality, and inflammation burden in a multiethnic sample of middle-aged adults

Despite considerable evidence that greater exposure to discrimination over the life course increases risk for systemic inflammation, little is known about the mechanisms responsible for this association. Here we examine the role of global sleep quality as a potential pathway by which self-reported experiences of discrimination contribute to inflammatory dysfunction in a multiethnic sample of middle-aged adults.

Participants were 300 adults (36-85 years; 65% women) from Milwaukee, Wisconsin, a subset of the Midlife in the United States Study 2 (2004-2006). Racial/ethnic representation included African American (77.7%), Hispanic (12.7%), Asian/Pacific Islander (5.6%), and Native American (4.0%). Global sleep quality and perceptions of lifetime and daily discrimination were measured by questionnaire. A composite score of inflammation burden was computed as the sum of five markers including C-reactive protein (CRP), interleukin-6 (IL-6), fibrinogen, E-selectin, and intracellular adhesion molecule-1 (ICAM-1).

Greater lifetime exposure to discrimination was associated with higher inflammation burden. This relationship remained significant after adjustments for potential confounding factors, including demographics, medication use, health behaviors, psychological distress, and daily discrimination. Mediation analyses suggested that poor global sleep quality was a key mechanism underlying the link between lifetime discrimination and inflammation burden.

These results add to a growing literature on the effects of bias and unfair treatment experienced by people of color and other marginalized groups by demonstrating how such experiences may be particularly consequential for sleep and physiological functioning in midlife. (PsycINFO Database Record (c) 2019 APA, all rights reserved).