Depressive symptoms predict incident cognitive impairment in cognitive healthy older women

Objective: There is an increasing evidence that depressive symptoms are associated with the development of cognitive impairment and dementia in late life. The authors sought to examine whether depression increased the risk of incident cognitive impairment in a longitudinal study of older women. Methods: Observational study, up to six examinations spanning up to 9 years. Setting: University-based Division of Geriatric Medicine. Participants: Community-based sample of 436 older, nondemented women. Measurements: Participants were followed up with regular medical and neuropsychiatric evaluations. Cognitive assessment included episodic immediate and delayed memory, psychomotor speed, and executive functioning. Participants were characterized as having incident impairment on a cognitive test when scores fell below the 10th percentile on age-adjusted norms. Baseline depressive symptoms were measured using the Geriatric Depression Scale (GDS) (30-item). Discrete-time Cox proportional hazards regression with generalized linear models were used to determine whether baseline risk factors predicted incident impairment on each cognitive test, defined as performance below the tenth percentile on age-adjusted norms. Results: Baseline GDS was highly associated with incident impairment on all cognitive tests (p <0.03). These associations were unaffected by vascular conditions except diabetes, which was associated with incident impairment in delayed recall and psychomotor speed. Conclusion: These data suggest that depression may be the risk factors for cognitive decline, and thus a potential target for diagnostic and therapeutic interventions.