Black Americans die younger than their white counterparts, with an estimated 1.63 million "excess" deaths having occurred between 1999 and 2020, according to research in the Journal of the American Medical Association. These excess deaths are predominantly attributable to chronic conditions such as heart disease and cancer.
In a new study published in JAMA Network Open, researchers at Washington University in St. Louis found that the elevated mortality risk among Black Americans is largely explained by greater stress exposure across the lifespan as well as inflammation in later life.
The research came from a unique longitudinal study, the St. Louis Personality and Aging Network (SPAN) Study, which has followed older adults for nearly 20 years. WashU graduate student Isaiah Spears said he "saw the stark difference between the rate in which our Black participants in the sample have been dying relative to the white participants" and wanted dig into the question of what might be contributing to such racial disparities.
Spears led this research, with support from his adviser, Ryan Bogdan, as well as other WashU co-authors. Bogdan, the William R. Stuckenberg Professor in Human Values and Moral Development, directs the BRAIN lab in the Department of Psychological and Brain Sciences in Arts & Sciences.
Bogdan noted that the SPAN data offered an opportunity to develop a "cumulative stress index" because it includes a longitudinal cohort with ample data from blood draws and surveys over almost 20 years as well as retrospective reports of experiences during childhood. Much racial disparity research has focused on overt experiences of discrimination (like being turned down for a loan). But such efforts may not capture the disadvantage associated with structural racism that generates elevated stress exposure, which may prematurely weather individuals to negatively impact health, he explained.
Spears wanted to take the "lifespan view" of stress exposure to test whether a heightened burden of chronic stress and its associations with inflammation may plausibly drive elevated mortality risk among Black Americans. To do that, the team looked at the extent of stress exposure across the lifespan and its association with inflammatory biological markers C-reactive protein and Interleukin-6 and how they are associated with racial differences in mortality risk.
They found that the elevated stress exposure experienced by Black Americans across their lifespan is associated with heightened inflammation and that these factors explained roughly half of the elevated mortality risk among Black relative to white Americans in their study.
Scientists think that stress shortens life via immune dysregulation and inflammation. The concept of allostatic load, or wear and tear on the body, means that chronic stress can dysregulate body systems and homeostasis, leading to dysregulated recovery and response as well as premature aging. "If stress becomes chronic, that could be incorporated into one's homeostasis; you may become less able to mount your biological systems to respond to acute stress challenges and you may be less able to return to a bodily state that promotes regeneration and restoration," Bogdan said.
"Over time, continued chronic exposure to stress leads to dysregulation and an earlier breakdown of some of the biological systems in the human body," said Spears, adding that too much stress leads to early aging and greater disease risk, problems seen in Black populations. The greater stress exposure we see in Black Americans likely has origins in societal structures that have cumulatively disadvantaged Black Americans across generations, he said.
While this study suggests policy efforts to prevent and reduce explicit and structural discrimination as well as stress exposure, Bogdan noted that the work also suggests it's important to research treatments to help those exposed - which could benefit all Americans.
"Addressing large-scale societal issues requires concerted efforts enacted over time," he said. "That needle can be extremely hard to move."
"Stress exposure will always be there, so we need to devote more efforts to understand the mechanisms through which stress contributes to adverse health outcomes so that factors could be targeted to minimize health risks among those exposed."
Spears ID, Gorelik AJ, Norton SA, Boudreaux MJ, Wolk MW, Siudzinski J, Paul SE, Cox MA, Rogers C, Oltmanns TF, Hill PL. Bogdan R. Cumulative Lifespan Stress and Inflammation are Associated with Black-White Racial Disparities in Mortality Among Americans. JAMA Network Open. Published Online: January 26, 2026;9;(1):e2554701 DOI: 10.1001/jamanetworkopen.2025.54701
This study was supported by R01 AG061162 (RB, TFO) and R01 AG045231 (TFO). Investigators were also supported by T32 AG000030 (IDS), NSF DGE-213989 (AJG), F31 AA029934 (SEP).
