Apathy and risk of probable incident dementia among community-dwelling older adults

OBJECTIVETo evaluate the association between baseline apathy and probable incident dementia in a population-based sample of community-dwelling older adults. METHODSWe studied 2,018 white and black community-dwelling older adults from the Health, Aging, and Body Composition (Health ABC) study. We measured apathy at year 6 (our study baseline) with the modified Apathy Evaluation Scale and divided participants into tertiles based on low, moderate, or severe apathy symptoms. Incident dementia was ascertained over 9 years by dementia medication use, hospital records, or clinically relevant cognitive decline on global cognition. We examined the association between apathy and probable incident dementia using a Cox proportional hazards model adjusting for demographics, cardiovascular risk factors, APOE-4 status, and depressed mood. We also evaluated the association between the apathy group and cognitive change (as measured by the Modified Mini Mental State Examination and Digit Symbol Substitution Test over 5 years) using linear mixed effects models. RESULTSOver 9 years of follow-up, 381 participants developed probable dementia. Severe apathy was associated with an increased risk of dementia compared to low apathy (25% vs 14%) in unadjusted (HR 1.9, 95% CI 1.5–2.5) and adjusted models (HR 1.7, 95% CI 1.3–2.2). Greater apathy was associated with worse cognitive score at baseline, but not rate of change over time. CONCLUSIONIn a diverse cohort of community-dwelling adults, apathy was associated with increased risk of developing probable dementia. This study provides novel evidence for apathy as a prodrome of dementia.