Effects of Incarceration on Peripheral Inflammation: Evidence for Greater C-Reactive Protein and Interleukin-10 Concentrations In a U.S. Sample of Older Adults.

Objective: The United States has one of the highest incarceration rates globally, and individuals with incarceration histories experience elevated risks for adverse mental and physical health outcomes. The Conserved Transcriptional Response to Adversity (CTRA), founded in the field of social genomics, suggests that repeated stress exposure may lead to chronic inflammation through upregulation of immune processes. Prior research has linked incarceration history to higher C-reactive protein (CRP), a general marker of inflammation, but little is known about associations with specific inflammatory biomarkers or the role of incarceration duration. This study examines whether lifetime incarceration and duration of incarceration are associated with multiple inflammatory markers.

Method: Data were drawn from the Health and Retirement Study (N = 4,123). Two sets of linear regression models were estimated. The first set of models examined associations between lifetime incarceration history and the inflammatory biomarkers CRP, interleukin (IL)-1 receptor antagonist, IL-6, IL-10, and soluble tumor necrosis factor receptor-1. The second set of models examined associations between incarceration duration and the same inflammatory biomarkers. Both sets of models controlled for participant self-reported demographic characteristics (age, wealth, race, ethnicity, parental education), health behaviors (alcohol use, smoking, physical activity), and biological indicators (HDL cholesterol, LDL cholesterol, fasting glucose, triglycerides, body mass index). Missing data were estimated using random forest imputation with predictive mean matching.

Results: Participants had a mean age of 69.60 years (SD = 9.63); most identified as White (77%), non-Hispanic (88%), and female (60%). About 7% of participants reported a history of incarceration, with most incarcerated for less than one month. Multivariate models showed that individuals with a history of incarceration had higher presence of inflammatory biomarkers. For example, individuals with a history of incarceration showed higher IL-10 concentrations compared to those with no history (b = 0.097, SE = 0.025, p < 0.001). Longer incarceration duration was associated with a higher presence of inflammatory biomarkers. Individuals with a history of incarceration had higher presence of CRP (b = 0.084, SE = 0.017, p < 0.01) and IL-10 (b = 0.044, SE = 0.013, p < 0.001) compared to those with no history.

Conclusion: Incarceration is associated with both elevated CRP, a general inflammation marker, and elevated IL-10, an anti-inflammatory cytokine. Results may indicate that incarceration is associated with persistent immune system activation, potentially reflecting an inflammatory scarring process. These findings highlight the need for improved healthcare services within correctional settings and stronger reentry processes that address chronic stress and physiological dysregulation. Such efforts may be advanced through Medicaid expansion, strengthened correctional health standards, and increased investment in reentry health programs. Findings underscore incarceration as a critical social determinant of health and reinforces the role of social work in advancing equity-focused, systems-level responses to mitigate its lasting biological impacts.