title: Impact of Physical Activity on Cognitive Decline, Dementia, and Its Subtypes: Meta-Analysis of Prospective Studies.
abstract: The association of physical activity with dementia and its subtypes has remained controversial in the literature and has continued to be a subject of debate among researchers. A systematic review and meta-analysis of longitudinal studies on the relationship between physical activity and the risk of cognitive decline, all-cause dementia, Alzheimer's disease, and vascular dementia among nondemented subjects are considered. A comprehensive literature search in all available databases was conducted up until April 2016. Well-defined inclusion and exclusion criteria were developed with focus on prospective studies ≥ 12 months. The overall sample from all studies is 117410 with the highest follow-up of 28 years. The analyses are performed with both Bayesian parametric and nonparametric models. Our analysis reveals a protective effect for high physical activity on all-cause dementia, odds ratio of 0.79, 95% CI (0.69, 0.88), a higher and better protective effect for Alzheimer's disease, odds ratio of 0.62, 95% CI (0.49, 0.75), cognitive decline odds ratio of 0.67, 95% CI (0.55, 0.78), and a nonprotective effect for vascular dementia of 0.92, 95% CI (0.62, 1.30). Our findings suggest that physical activity is more protective against Alzheimer's disease than it is for all-cause dementia, vascular dementia, and cognitive decline.
authors.affiliation: Department of Biostatistics, School of Public Health, University of Ghana, Legon, Accra, Ghana; Department of Mathematics, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia.
authors.forename: Chris B
authors.identifier: 0000-0001-6595-9587
authors.initials: CB
authors.lastname: Guure
authors.affiliation: Department of Mathematics, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; Institute for Mathematical Research, Universiti Putra Malaysia, Serdang, Selangor, Malaysia.
authors.forename: Noor A
authors.initials: NA
authors.lastname: Ibrahim
authors.affiliation: Institute for Mathematical Research, Universiti Putra Malaysia, Serdang, Selangor, Malaysia.
authors.forename: Mohd B
authors.initials: MB
authors.lastname: Adam
authors.affiliation: Department of Community Health, Faculty of Medicine & Health Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia.
authors.forename: Salmiah Md
authors.initials: SM
authors.lastname: Said
mesh_terms: D000544:Alzheimer Disease / Q000503:physiopathology; D060825:Cognitive Dysfunction / Q000503:physiopathology*; D003704:Dementia / Q000145:classification* / Q000503:physiopathology*; D015444:Exercise; D006801:Humans; D016017:Odds Ratio; D011336:Probability; D011446:Prospective Studies; D017594:Publication Bias