Factors Associated With All-Cause Mortality in a Western State Prison System, 1999-2020

Incarceration is linked to mortality, yet specific factors associated with death during imprisonment remain poorly understood, limiting efforts to identify vulnerable populations and develop effective prevention strategies in carceral settings.

Administrative records from 91,979 adults who served any portion of their sentence in a Western U.S. state prison system between 1999 and 2020 were analyzed. Complementary log-log regression was used to identify demographic, criminal history, institutional, and behavioral health-related factors associated with all-cause mortality in prison.

Of incarcerated individuals (mean age=35.83 years at admission; 86.3% male), 839 (0.91%) died in prison. Self-harm incidents (hazard ratio=15.19; 95% CI=10.50, 21.98) and sentences of ≥21 years (hazard ratio=16.84; 95% CI=10.49, 27.03 vs ≤1 year) were most strongly associated with mortality. The variety of correctional programs completed was a protective factor (hazard ratio=0.78; 95% CI=0.74, 0.82), and foreign-born status (hazard ratio=0.41; 95% CI=0.26, 0.65), Black race (hazard ratio=0.73; 95% CI=0.59, 0.91 vs White), and violent infractions (hazard ratio=0.91; 95% CI=0.88, 0.95) also had inverse associations with mortality. Mortality risk increased substantially with age, with individuals aged ≥55 years at admission having over 11 times the risk of death compared with those aged ≤24 years (hazard ratio=11.79; 95% CI=8.75, 15.88). Male sex, prior incarcerations, higher custody levels, drug infractions, mental health needs, academic needs, and criminogenic needs were additionally associated with mortality.

This study identified new risk factors for mortality during imprisonment. The findings highlight directions for future research and actionable intervention points for reducing mortality in incarcerated populations.