Depressive Symptoms in Oldest-Old Women: Risk of Mild Cognitive Impairment and Dementia

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Increasing evidence suggests that depression is a risk factor for cognitive impairment, but it is unclear if this is true among the oldest old. We determined whether elevated depressive symptoms predicted 5-year incident mild cognitive impairment (MCI) or dementia, and neuropsychological test performance among oldest-old women. Prospective. Three study sites. 302 women ≥85 years (mean, 87 ± 2). Depressive symptoms were measured with the 15-item Geriatric Depression Scale (GDS); scores of 6 or more indicated elevated symptoms. Five years later, participants completed neuropsychological testing and clinical cognitive status was adjudicated. In analyses of MCI versus normal cognition, 70% of women with GDS score 6 or more at baseline developed MCI versus 37% with GDS score less than 6. After adjustment for age, education, alcohol, and benzodiazepine use, and study site, GDS score 6 or more remained independently associated with much greater likelihood of developing MCI (multivariable odds ratio [MOR] = 3.71, 95% confidence interval (CI): 1.30-10.59). In analyses of dementia versus normal cognition, 65% of women with GDS score 6 or more developed dementia compared with 37% of those with GDS score less than 6 (MOR = 3.15, 95% CI: 1.03-9.65). Only 19% of women with GDS score 6 or more had normal cognitive status 5 years later, compared with 46% of those with GDS score less than 6 (MOR = 0.28, 95% CI: 0.11-0.73). Women with elevated depressive symptoms had worse scores on tests of global cognition and working memory. Elevated depressive symptoms are an important risk factor for cognitive disorders and lower cognitive performance among women living to their ninth and tenth decades.