Military Service and Cognitive Decline after age 90: The LifeAfter90 Study

Abstract

AbstractBackgroundStudies have shown that military veterans are at higher risk of dementia. Less is known about cognitive aging and decline, especially among veterans who have survived past age 90. We investigated the association of military service with cognitive function and decline in the LifeAfter90 (LA90) cohort.MethodLA90 included Asian, Black, Latino, White, and multi‐racial individuals aged 90 years or more without a history of dementia diagnosis at recruitment. We assessed active US military service via self‐report at baseline. Due to the small number of women reporting military service (n = 5), analyses were restricted to men participants. Cognitive domains of executive function, verbal episodic memory, and semantic memory were assessed every six months using the Spanish and English Neuropsychological Assessment Scales (z‐standardized). Linear mixed models with random intercepts and slopes evaluated the association between military service with cognitive change over 3 visits (mean = 1.2 years), adjusting for years since baseline, baseline age, education, practice effects (indicator variables for visits 1 and 2), and interview mode (phone vs in‐person).ResultOf the 195 participants, 151 (77%) had served in the active military (Table 1). Those who served in the military had, on average, higher baseline executive function (β[95% CI] = 0.33[0.13, 0.54]) and semantic memory (β[95% CI] = 0.53[0.24, 0.82]) compared to those who did serve in the military; there was no difference in baseline verbal episodic memory (Table 2; Model 2). Those who served in the military had slower decline in verbal episodic memory (β[95% CI] = 0.35[0.07, 0.63]), compared to those who did not serve. Point estimates suggest slower decline in executive function and semantic memory for those who served in the military but were not significant.ConclusionAmong the oldest‐old men, military service was associated with higher baseline executive function and semantic memory, and slower decline in verbal episodic memory compared to not having served in the military. Future research may explore whether veteran benefits in educational or financial support, such as the GI Bill, help explain the apparent protective effects of veteran status.