Association of Lifetime TBI and Military Employment with Late Life ADL Functioning: A Population-Based Prospective Cohort Study

Abstract: Objective: To determine associations of traumatic brain injury (TBI) and military employment with activities of daily living (ADL) in late life. Design: Population-based prospective cohort study with biennial follow-up and censoring at the time of dementia diagnosis. Participants: Participants (N=4953) were men (n=2066) and women (n=2887) aged ≥65 years who were dementia free. Results: TBI with loss of consciousness (LOC) before the age of 40 years was associated with slightly higher ADL difficulty at baseline for women (rate ratio [RR], 1.44; 95% confidence interval [CI], 1.08-1.93; P=.01). For men, TBI with LOC at any age was associated with greater ADL difficulty at baseline (age <40y: RR, 1.58; 95% CI, 1.20-2.08; P=.001; age ≥40y: RR, 2.14; 95% CI, 1.24-3.68; P=.006). TBI with LOC was not associated with the rate of accumulation of ADL difficulties over time in men or women. There was no evidence of an association between military employment and either outcome, nor of an interaction between military employment and TBI with LOC. Findings were consistent across a variety of sensitivity analyses.