Associations between cognitive reserve, traumatic events, post-traumatic stress symptoms, and mid- to late-life cognitive performance.

Exposure to potentially traumatic events is common across the lifespan, yet individual differences in cognitive outcomes following trauma exposure in older adults remain poorly understood. Cognitive reserve (CR) may protect against trauma-related cognitive deficits, but CR's moderating role in relationships between trauma exposure, post-traumatic stress symptoms (PTSS), and cognition is unclear. We examined 745 community-dwelling middle-aged to older adults (50-86 years, mean age = 64.5, 69.1% female) who completed assessments of traumatic event exposure (Life Events Checklist for DSM-5), post-traumatic stress symptoms (PCL-5), cognitive performance, and CR proxies (Cognitive Reserve Index Questionnaire and verbal IQ). Higher CR was associated with weaker relationships between traumatic events and cognition (β = 0.03, 95% CI [0.01, 0.06], p = .02), between PTSS and cognition (β = 0.005, 95% CI [3.21 ∗ 10-5, 0.010], p = .04), and between traumatic events and PTSS (β = -0.41, 95% CI [-0.74, -0.09], p = .01). Moderated mediation analyses further revealed that the indirect association between traumatic events and cognition via PTSS weakened as CR increased and was non-significant at higher CR (95% CI [-0.02, 0.01], p = .28), with this pattern consistent across both human-caused and natural/accidental trauma types. These findings suggest that CR may buffer the cognitive and psychological impact of traumatic experiences in mid-to-late life, and that modifiable CR components warrant investigation as potential intervention targets in trauma-exposed older adults.