Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Meta-Analysis
, 14, 510

Does Physical Activity Prevent Cognitive Decline and Dementia?: A Systematic Review and Meta-Analysis of Longitudinal Studies

Affiliations
Meta-Analysis

Does Physical Activity Prevent Cognitive Decline and Dementia?: A Systematic Review and Meta-Analysis of Longitudinal Studies

Sarah J Blondell et al. BMC Public Health.

Abstract

Background: By 2050, it has been estimated that approximately one-fifth of the population will be made up of older adults (aged ≥60 years). Old age often comes with cognitive decline and dementia. Physical activity may prevent cognitive decline and dementia.

Methods: We reviewed and synthesised prospective studies into physical activity and cognitive decline, and physical activity and dementia, published until January 2014. Forty-seven cohorts, derived from two previous systematic reviews and an updated database search, were used in the meta-analyses. Included participants were aged ≥40 years, in good health and/or randomly selected from the community. Studies were assessed for methodological quality.

Results: Twenty-one cohorts on physical activity and cognitive decline and twenty-six cohorts on physical activity and dementia were included. Meta-analysis, using the quality-effects model, suggests that participants with higher levels of physical activity, when compared to those with lower levels, are at reduced risk of cognitive decline, RR 0.65, 95% CI 0.55-0.76, and dementia, RR 0.86, 95% CI 0.76-0.97. Sensitivity analyses revealed a more conservative estimate of the impact of physical activity on cognitive decline and dementia for high quality studies, studies reporting effect sizes as ORs, greater number of adjustments (≥10), and longer follow-up time (≥10 years). When one heavily weighted study was excluded, physical activity was associated with an 18% reduction in the risk of dementia (RR 0.82; 0.73-0.91).

Conclusions: Longitudinal observational studies show an association between higher levels of physical activity and a reduced risk of cognitive decline and dementia. A case can be made for a causal interpretation. Future research should use objective measures of physical activity, adjust for the full range of confounders and have adequate follow-up length. Ideally, randomised controlled trials will be conducted. Regardless of any effect on cognition, physical activity should be encouraged, as it has been shown to be beneficial on numerous levels.

Figures

Figure 1
Figure 1
Flow diagram of search strategy. *Note – one paper [50] assesses both cognitive decline and dementia and is thus included in both analyses. **Three papers identified in the review for physical activity and dementia were excluded due to ‘outcome not of interest’.
Figure 2
Figure 2
The association between high physical activity and cognitive decline.
Figure 3
Figure 3
The association between high physical activity and dementia.
Figure 4
Figure 4
Funnel plot for studies on high physical activity and cognitive decline.
Figure 5
Figure 5
Funnel plot for studies on high physical activity and dementia.

Similar articles

See all similar articles

Cited by 98 articles

See all "Cited by" articles

References

    1. World Health Organization. Dementia: A Public Health Priority. 2012. whqlibdoc.who.int/publications/2012/9789241564458_eng.pdf.
    1. Mortazavi SS, Mohammad K, Ardebili HE, Beni RD, Mahmoodi M, Keshteli AH. Mental disorder prevention and physical activity in Iranian elderly. Int J Prev Med. 2012;3(Suppl 1):S64–S72. - PMC - PubMed
    1. Angevaren M, Aufdemkampe G, Verhaar HJJ, Aleman A, Vanhees L. Physical activity and enhanced fitness improve cognitive function in older people without known cognitive impairment, a Cochrane Systematic Review. Parkinsonism Relat Disord. 2008;14:S44.
    1. Miller DI, Taler V, Davidson PSR, Messier C. Measuring the impact of exercise on cognitive aging: methodological issues. Neurobiol Aging. 2012;33(3):622.e629–622.e643. - PubMed
    1. Ahlskog JE, Geda YE, Graff-Radford NR, Petersen RC. Physical exercise as a preventive or disease-modifying treatment of dementia and brain aging. Mayo Clin Proc. 2011;86(9):876–884. doi: 10.4065/mcp.2011.0252. - DOI - PMC - PubMed
Feedback