Depressive symptoms and cognitive decline in nondemented elderly women - Aprospective study

Background: The association between depressive disorders and subsequent cog nitive decline is controversial. We tested the hypothesis that elderly wome n (aged 65 years and older) without dementia but with depressive symptoms h ave worse cognitive function and greater cognitive decline than women with few or no symptoms. Methods hs part of an ongoing prospective study, we evaluated 5781 elderly, mostly white, community-dwelling women. Women completed the Geriatric Depr ession Scale short form. Three cognitive tests-Trails B, Digit Symbol, and a modified Mini-Mental State Examination-were administered at baseline and approximately 4 years later. Baseline, follow-up, and change scores for the cognitive tests were analyzed by analysis of covariance and Kruskal-Wallis analysis; the odds of cognitive deterioration (greater than or equal to 3- point decline on the modified Mini-Mental State Examination) were determine d by logistic regression. Results: At baseline, 211 (3.6%) of the women had 6 or more depressive symp toms. Only 16 (7.6%) of these women were receiving antidepressant medicatio n. Increasing symptoms of depression were associated with worse performance at baseline and follow-up on all 3 tests of cognitive function (P<.001 for all comparisons). For example, the baseline Digit Symbol score (mean +/- S D) was 45.5 +/- 10.7 among women with 0 to 2 symptoms of depression, 40.3 /- 10.7 for women with 3 to 5 symptoms, and 39.0 +/- 11.3 for women with 6 or more symptoms. After adjusting for the baseline score, cognitive change scores were also inversely associated with the number of depressive symptom s (P<.001 for all comparisons). Odds ratios for cognitive deterioration usi ng 0 to 2 symptoms as the reference were 1.6 (95% confidence interval, 1.3- 2.1) for 3 to 5 symptoms and 2.3 (95% confidence interval, 1.6-3.3) for 6 o r more symptoms. Results were similar after being adjusted for education, a ge, health status, exercise, alcohol use, functional status, and clinic sit e. Conclusions: Depressive symptoms in older women are associated with both po or cognitive function and subsequent cognitive decline. Mechanisms underlyi ng the association between these 2 common conditions need further explorati on.