Does physical activity prevent cognitive decline and dementia?: a systematic review and meta-analysis of longitudinal studies

Blondell, Sarah J. and Hammersley-Mather, Rachel and Veerman, J. Lennert (2014) Does physical activity prevent cognitive decline and dementia?: a systematic review and meta-analysis of longitudinal studies. BMC Public Health, 14 (1). pp. 510-521.

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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.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2014 Blondell et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.
Faculty / Department / School: Current - USQ Other
Date Deposited: 14 Jul 2014 02:27
Last Modified: 08 Mar 2017 05:22
Uncontrolled Keywords: alzheimer's disease; cognition; cognitive decline; cognitive impairment; dementia; exercise; physical activity
Fields of Research : 11 Medical and Health Sciences > 1106 Human Movement and Sports Science > 110602 Exercise Physiology
17 Psychology and Cognitive Sciences > 1701 Psychology > 170102 Developmental Psychology and Ageing
17 Psychology and Cognitive Sciences > 1701 Psychology > 170110 Psychological Methodology, Design and Analysis
Socio-Economic Objective: C Society > 92 Health > 9205 Specific Population Health (excl. Indigenous Health) > 920502 Health Related to Ageing
Identification Number or DOI: 10.1186/1471-2458-14-510

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