Depression subtypes and 5-year risk of dementia and Alzheimer disease in patients aged 70 years

Objective The objective of this study was to estimate several subtypes of depressive disorders as risk factors for dementia and Alzheimer disease (AD) specifically. Methods This is a population-based cohort study using a sample of 451 non-demented older people. Adjusted Cox proportional hazard models were calculated to determine the association of depression with dementia or AD development after 5years. Baseline evaluation included the Cambridge Mental Disorders of the Elderly Examination (CAMDEX). Depressive disorders (major episode [MD] and minor depressive disorders [MDDIS]) were assessed following DSM-IV criteria and further classified according to the age at onset (early versus late onset). In turn, all late-onset depressions were grouped as with or without depression-executive dysfunction syndrome (DEDS). Dementia (and dementia subtypes) diagnoses were made using the CAMDEX. When the patients were deceased, the Retrospective Collateral Dementia Interview was used. Results Late-onset depressions (both MD and MDDIS) were associated with increased dementia (hazard ratio [HR]=2.635; 95% CI=1.1536.023; and HR=2.517; 95% CI=1.2005.280, respectively), and AD (HR=6.262; 95% CI=2.01719.446; and HR=4.208; 95% CI=1.8289.685, respectively) after adjustment by age, gender, marital status, education, cognitive impairment, executive function and stroke history. A second model revealed that only late-onset depressions with DEDS increased the risk for both dementia (late-onset MD with DEDS: HR=6.262; 95% CI=2.01719.446; late-onset MDDIS with DEDS: HR=4.208; 95% CI=1.8289.685) and AD (late-onset MD with DEDS: HR=7.807; 95% CI=1.56738.894; late-onset MDDIS with DEDS: HR=6.099; 95% CI=2.12317.524). Conclusions Late-onset depressive episodes with DEDS are risk factors for dementia and AD development, regardless of the severity of the depression. Copyright (c) 2012 John Wiley & Sons, Ltd.