%0 Journal Article
%T Cumulative Effect of Depression on Dementia Risk
%A J. Olazar¨¢n
%A R. Trincado
%A F. Bermejo-Pareja
%J International Journal of Alzheimer's Disease
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/457175
%X Objective. To analyze a potential cumulative effect of life-time depression on dementia and Alzheimer¡¯s disease (AD), with control of vascular factors (VFs). Methods. This study was a subanalysis of the Neurological Disorders in Central Spain (NEDICES) study. Past and present depression, VFs, dementia status, and dementia due to AD were documented at study inception. Dementia status was also documented after three years. Four groups were created according to baseline data: never depression (nD), past depression (pD), present depression (prD), and present and past depression (prpD). Logistic regression was used. Results. Data of 1,807 subjects were investigated at baseline (mean age 74.3, 59.3% women), and 1,376 (81.6%) subjects were evaluated after three years. The prevalence of dementia at baseline was 6.7%, and dementia incidence was 6.3%. An effect of depression was observed on dementia prevalence (OR [CI 95%] 1.84 [1.01¨C3.35] for prD and 2.73 [1.08¨C6.87] for prpD), and on dementia due to AD (OR 1.98 [0.98¨C3.99] for prD and OR 3.98 [1.48¨C10.71] for prpD) (fully adjusted models, nD as reference). Depression did not influence dementia incidence. Conclusions. Present depression and, particularly, present and past depression are associated with dementia at old age. Multiple mechanisms, including toxic effect of depression on hippocampal neurons, plausibly explain these associations. 1. Introduction Depression has been associated with an increased risk of dementia in old age, but the mechanisms underlying this association are not well understood. Several hypothetical, not mutually exclusive, mechanisms can be proposed: (1) depression is a prodrome of dementia, (2) depression reduces the threshold for dementia manifestation, and (3) depression leads to damage to neural systems, particularly the hippocampus, thus contributing to the development of dementia [1]. In addition, depression can be regarded as a potential reaction to early cognitive deficits. In fact, one epidemiological study reported depressive symptoms following the onset of dementia, rather than preceding it [2]. Under any of the above-mentioned mechanisms, depression at any time during life should be associated with an increased risk of dementia in unselected old population. An important role of vascular factors (VFs) in the association between depression and dementia is also possible. Indeed, previous studies demonstrated that cerebrovascular disease (CVD), hypertension, diabetes, and other VFs may cause both cognitive impairment [3, 4] and depression [5]. Depression could also influence
%U http://www.hindawi.com/journals/ijad/2013/457175/