title: A 9-year prospective population-based study on the association between the APOE*E4 allele and late-life depression in Sweden.
abstract: BACKGROUND
  It is well established that there is an association between the apolipoprotein E (APOE) ε4 allele (APOE*E4) and Alzheimer's disease. It is less clear whether there is also an association with geriatric depression. We examined the relationship between APOE*E4 and 5-year incidence of depression in a Swedish population-based sample of older adults without dementia and excluding older adults who developed dementia within 4 years after the diagnosis of depression.
  
  
  METHODS
  In 2000-2001, 839 women and men (age range, 70-92 years; mean age, 73.8 years) free from dementia and depression underwent neuropsychiatric and neuropsychological examinations and genotyping of the APOE*E4 allele. Follow-up evaluations were conducted in 2005 and 2009.The association between APOE*E4 allele and 5-year incidence of depression was examined, while avoiding possible confounding effects of clinical or preclinical dementia by excluding participants who had dementia at study entry, subsequently developed dementia during the 9-year follow-up period, or had a decline in Mini-Mental State Examination score of ≥5 points.
  
  
  RESULTS
  Among subjects without depression at study entry and without dementia or significant cognitive decline during the subsequent 9 years, APOE*E4 was prospectively associated with more severe depressive symptoms (b = 1.56, p = .007), incident minor depression (odds ratio = 1.99 [confidence interval = 1.11-3.55], p = .020), and any depression (odds ratio = 1.75 [confidence interval = 1.01-3.03], p = .048).
  
  
  CONCLUSIONS
  The presence of the APOE*E4 allele predicted future depression in this Swedish population study, even after excluding depressed individuals who later developed dementia, suggesting that the APOE*E4 allele could potentially identify people at high risk for clinically significant depression.
authors.affiliation: Neuropsychiatric Epidemiology Unit.
authors.forename: Ingmar
authors.initials: I
authors.lastname: Skoog
authors.affiliation: Neuropsychiatric Epidemiology Unit.
authors.forename: Margda
authors.initials: M
authors.lastname: Waern
authors.affiliation: Departments of Psychiatry and Family Medicine, University of Rochester Medical Center, Rochester, New York.
authors.forename: Paul
authors.initials: P
authors.lastname: Duberstein
authors.affiliation: Clinical Neurochemistry Laboratory, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Kaj
authors.initials: K
authors.lastname: Blennow
authors.affiliation: Clinical Neurochemistry Laboratory, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden; UCL Institute of Neurology, London, United Kingdom.
authors.forename: Henrik
authors.initials: H
authors.lastname: Zetterberg
authors.affiliation: Neuropsychiatric Epidemiology Unit.
authors.forename: Anne
authors.initials: A
authors.lastname: Börjesson-Hanson
authors.affiliation: Neuropsychiatric Epidemiology Unit.
authors.forename: Svante
authors.initials: S
authors.lastname: Östling
authors.affiliation: Neuropsychiatric Epidemiology Unit.
authors.forename: Xinxin
authors.initials: X
authors.lastname: Guo
authors.affiliation: Neuropsychiatric Epidemiology Unit.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Kern
authors.affiliation: Neuropsychiatric Epidemiology Unit.
authors.forename: Deborah
authors.initials: D
authors.lastname: Gustafson
authors.affiliation: Neuropsychiatric Epidemiology Unit.
authors.forename: Pia
authors.initials: P
authors.lastname: Gudmundsson
authors.affiliation: Neuropsychiatric Epidemiology Unit.
authors.forename: Thomas
authors.initials: T
authors.lastname: Marlow
authors.affiliation: Neuropsychiatric Epidemiology Unit; Clinical Neurochemistry Laboratory, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden. Electronic address: silke.kern@neuro.gu.se.
authors.forename: Silke
authors.initials: S
authors.lastname: Kern
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D053327:Apolipoprotein E4 / Q000235:genetics*; D003866:Depressive Disorder / Q000453:epidemiology* / Q000235:genetics*; D003865:Major Depressive Disorder / Q000453:epidemiology / Q000235:genetics; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D000067562:Late Onset Disorders / Q000453:epidemiology / Q000235:genetics; D008297:Male; D011446:Prospective Studies; D013548:Sweden / Q000453:epidemiology
chemical_list: D053327:Apolipoprotein E4
keywords: Apolipoprotein E ε4 (APOE*E4) allele; Dementia; Depression; Older adults; Population-based study; Prospective