Abstract
OBJECTIVES: To evaluate whether indices of preinjury health and functioning are associated with risk of incident traumatic brain injury (TBI) with loss of consciousness (LOC) and to evaluate health-related factors associated with mortality in individuals with incident TBI. DESIGN: Prospective community cohort study. SETTING: Group Health, Seattle, Washington. PARTICIPANTS: Individuals aged 65 and older with no self-reported prior TBI with LOC (N = 3,363) were enrolled and followed every 2 years for an average of 7.5 years (range 0-18 years). MEASUREMENTS: Weibull survival models were used to evaluate baseline and time-varying predictors of incident TBI with LOC, including measures of depression, activities of daily living (ADLs), cerebrovascular disease, and disease comorbidity. RESULTS: In an adjusted multivariate model, baseline depression symptoms as measured according to Center for Epidemiologic Studies Depression Scale (CES-D) score (hazard ratio (HR) for 4 points = 1.23, 95% confidence interval (CI) = 1.02-1.49, P = .03) and baseline activity of daily living (ADL) impairment (HR = 2.37, 95% CI = 1.24-4.53, P = .009) were associated with incident TBI. In a model that included time-dependent covariates, cerebrovascular disease at the previous visit (HR = 2.28, 95% CI = 1.37-3.78, P < .001), CES-D score the previous visit (HR for 4 points = 1.23, 95% CI = 1.02-1.49, P < .04) and baseline ADL impairment (HR 2.14, 95% CI = 1.11-4.13, P = .02) predicted incident TBI. Of factors considered, cerebrovascular disease and ADL impairment were associated with earlier mortality in participants with incident TBI with LOC. CONCLUSION: Indices of health, mood, and functional status predict incident TBI with LOC in older adults. These findings may have implications for injury prevention and postinjury clinical management.