Modifiable Lifestyle Factors in Dementia: A Systematic Review of Longitudinal Observational Cohort Studies

Article type: Research Article

Authors: Di Marco, Luigi Yuri^{a; *} | Marzo, Alberto^a | Muñoz-Ruiz, Miguel^b | Ikram, M. Arfan^c | Kivipelto, Miia^b | Ruefenacht, Daniel^d | Venneri, Annalena^e | Soininen, Hilkka^b | Wanke, Isabel^d | Ventikos, Yiannis A.^f | Frangi, Alejandro F.^a

Affiliations: [a] Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Department of Mechanical Engineering, University of Sheffield, Sheffield, UK | [b] Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland and Kuopio University Hospital, Kuopio, Finland | [c] Departments of Epidemiology, Radiology, Neurology, Erasmus Medical Center, Rotterdam, The Netherlands | [d] Swiss Neuro Institute (SNI), Klinik Hirslanden, Zürich, Switzerland | [e] Department of Neuroscience, University of Sheffield, Sheffield, UK | [f] Department of Mechanical Engineering, University College London, London, UK

Correspondence: [*] Correspondence to: Luigi Yuri Di Marco, Center for Computational Imaging & Simulation Technologies in Biomedicine (CISTIB), Department of Mechanical Engineering, The University of Sheffield, Sheffield S1 3JD, UK. Tel.: +44 114 2226074; E-mail: l.dimarco@sheffield.ac.uk.

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.

Keywords: Alzheimer's disease, dementia, longitudinal observational cohort studies, modifiable lifestyle factors

DOI: 10.3233/JAD-132225

Journal: Journal of Alzheimer's Disease, vol. 42, no. 1, pp. 119-135, 2014