title: Modifiable lifestyle factors in dementia: a systematic review of longitudinal observational cohort studies.
abstract: BACKGROUND
  Numerous population-based longitudinal studies suggest an association between modifiable lifestyle factors and late-life dementia. A comprehensive description of these factors and their quantification criteria is an important preliminary step toward the elucidation of causes and mechanisms underlying the onset and progression of dementia.
  
  
  OBJECTIVE
  To present a systematic review of modifiable lifestyle factors associated with dementia risk in longitudinal observational cohort-studies.
  
  
  METHODS
  A systematic review of original articles, published in English until December 2013, listed in four electronic databases (including PubMed, MEDLINE, PsycINFO) was conducted.
  
  
  RESULTS
  75 papers from 33 epidemiologic studies met the inclusion criteria. Included papers focused on dietary habits (n = 26), leisure activities (social, physical, mental) (n = 23), beverages (juice, tea, coffee, alcohol) (n = 15), smoking (n = 13), social network (n = 6), and combined lifestyle factors (n = 2).
  
  
  CONCLUSIONS
  Broad consensus emerged on the protective role against dementia of leisure activities. Conflicting results were found for the association between dementia and putative risk factors (smoking) and protective factors (mild-to-moderate alcohol consumption, dietary antioxidants, Mediterranean diet, and living with others). However, studies varied largely in the quantification of lifestyle factors in terms of intensity, frequency and duration of exposure, and in the choice of confounders in statistical analyses. The need for standardized quantification criteria emerges, together with the current limitation in reliably tracking the past history of each patient, from childhood and young adulthood to midlife.
authors.affiliation: Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Department of Mechanical Engineering, University of Sheffield, Sheffield, UK.
authors.forename: Luigi Yuri
authors.initials: LY
authors.lastname: Di Marco
authors.affiliation: Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Department of Mechanical Engineering, University of Sheffield, Sheffield, UK.
authors.forename: Alberto
authors.initials: A
authors.lastname: Marzo
authors.affiliation: Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland and Kuopio University Hospital, Kuopio, Finland.
authors.forename: Miguel
authors.initials: M
authors.lastname: Muñoz-Ruiz
authors.affiliation: Departments of Epidemiology, Radiology, Neurology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: M Arfan
authors.initials: MA
authors.lastname: Ikram
authors.affiliation: Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland and Kuopio University Hospital, Kuopio, Finland.
authors.forename: Miia
authors.initials: M
authors.lastname: Kivipelto
authors.affiliation: Swiss Neuro Institute (SNI), Klinik Hirslanden, Zürich, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Ruefenacht
authors.affiliation: Department of Neuroscience, University of Sheffield, Sheffield, UK.
authors.forename: Annalena
authors.initials: A
authors.lastname: Venneri
authors.affiliation: Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland and Kuopio University Hospital, Kuopio, Finland.
authors.forename: Hilkka
authors.initials: H
authors.lastname: Soininen
authors.affiliation: Swiss Neuro Institute (SNI), Klinik Hirslanden, Zürich, Switzerland.
authors.forename: Isabel
authors.initials: I
authors.lastname: Wanke
authors.affiliation: Department of Mechanical Engineering, University College London, London, UK.
authors.forename: Yiannis A
authors.initials: YA
authors.lastname: Ventikos
authors.affiliation: Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Department of Mechanical Engineering, University of Sheffield, Sheffield, UK.
authors.forename: Alejandro F
authors.initials: AF
authors.lastname: Frangi
mesh_terms: D003704:Dementia / Q000453:epidemiology* / Q000628:therapy*; D004032:Diet; D006801:Humans; D008019:Life Style; D009043:Motor Activity; D064887:Observational Studies as Topic
keywords: Alzheimer's disease; dementia; longitudinal observational cohort studies; modifiable lifestyle factors