UC Irvine

BACKGROUND:: There is increasing evidence that depressive symptoms are associated with increased risk of cognitive impairment and dementia in older adults. In current study, we aimed to investigate the effect of depressive symptoms on incident Alzheimer disease and all-cause dementia in a community sample of older adults. METHODS:: Participants were 1219 older adults from the Einstein Aging Study, a longitudinal cohort study of community-dwelling older adults in Bronx County, New York. The Geriatric Depression Scale (GDS, 15-item) was used as a measure of depressive symptoms. The primary outcome was incident dementia diagnosed using the Diagnostic and Statistical Manual, Fourth Edition, criteria. Cox proportional hazard models were used to estimate the risk of incident dementia as a function of GDS score for the whole population and also for 2 different time intervals, <3 years and ≥3 years after baseline assessment. RESULTS:: Among participants, 132 individuals developed dementia over an average 4.5 years (standard deviation [SD] = 3.5) of follow-up. Participants had an average age of 78.3 (SD = 5.4) at baseline, and 62% were women. Among all participants, after controlling for demographic variables and medical comorbidities, a 1-point increase in GDS was associated with higher incidence of dementia (hazard ratio [HR] = 1.11, P = .007). After up to 3 years of follow-up, depressive symptoms were not significantly associated with dementia incidence (HR = 1.09; P = .070). However, after more than 3 years, GDS score was a significant predictor of incident dementia (HR = 1.13, P = .028). CONCLUSIONS:: Our results suggest that depressive symptoms are associated with an increased risk of incident dementia in older adults.