title: Depression as a risk factor for dementia and mild cognitive impairment: a meta-analysis of longitudinal studies.
abstract: BACKGROUND
  This study examined whether depression was a risk factor for onset of dementia including Alzheimer's disease (AD), vascular dementia (VD) and any dementia, and mild cognitive impairment (MCI) by using a quantitative meta-analysis of longitudinal studies.
  
  
  METHODS
  EMBASE and MEDLINE were searched for articles published up to February 2011. All studies that examined the relationship between depression and the onset of dementia or MCI were included. Pooled relative risk was calculated using fixed-effects models.
  
  
  RESULTS
  Twelve studies met our inclusion criteria for this meta-analysis. All subjects were without dementia or MCI at baseline. Four, two, five, and four studies compared the incidence of AD, VD, any dementia, and MCI between subjects with or without depression, respectively. After pooling all the studies, subjects with depression had higher incidence of AD (relative risk (RR):1.66, 95% confidence interval (CI): 1.29-2.14), VD (RR: 1.89, 95% CI: 1.19-3.01), any dementia (RR: 1.55, 95% CI: 1.31-2.83), and MCI (RR: 1.97, 95% CI: 1.53-2.54) than those without depression.
  
  
  CONCLUSIONS
  The quantitative meta-analysis showed that depression was a major risk factor for incidence of dementia (including AD, VD, and any dementia) and MCI.
authors: Department of Geriatrics, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China.
authors: Yuan
authors: Y
authors: Gao
authors: Changquan
authors: C
authors: Huang
authors: Kexiang
authors: K
authors: Zhao
authors: Louyan
authors: L
authors: Ma
authors: Xuan
authors: X
authors: Qiu
authors: Lei
authors: L
authors: Zhang
authors: Yun
authors: Y
authors: Xiu
authors: Lin
authors: L
authors: Chen
authors: Wei
authors: W
authors: Lu
authors: Chunxia
authors: C
authors: Huang
authors: Yong
authors: Y
authors: Tang
authors: Qian
authors: Q
authors: Xiao
mesh_terms: D060825:Cognitive Dysfunction / Q000523:psychology*; D003704:Dementia / Q000523:psychology*; D003866:Depressive Disorder / Q000150:complications* / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D012307:Risk Factors