Depression and the Risk of Alzheimer Disease

Department of Psychiatry, Odense University Hospital, DK-5000 Odense C, Denmark.
Epidemiology (Impact Factor: 6.18). 02/2005; 16(2):233-238. DOI: 10.1097/01.ede.0000152116.32580.24

ABSTRACT Background: Several epidemiologic studies have examined depression as a risk factor for Alzheimer disease with conflicting results. Most studies relied on self-reported depression, but the agreement between self-reported depression and clinical diagnosis has been reported to be weak, thereby diluting the association.
Methods: A population-based cohort in Odense, Denmark, of 3346 persons age 65-84 years was examined at baseline (1992-1994) and after 2 years (1994-1996) and 5 years (1997-1999). History of depression was collected at baseline as self-report. We used logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (CIs).
Results: Persons with a history of depression had an increased risk of Alzheimer disease both at baseline (OR = 1.7; CI = 1.0-2.7) and at follow up (at 2 years, 1.9 [1.0-3.3] and at 5 years, 1.6 [0.9-2.7]).
Conclusions: Depression was associated with an increased risk of Alzheimer disease. The odds ratios were lower than generally reported from follow-up studies and are similar to cross-sectional studies.

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