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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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.


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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 (http://creativecommons.org/licenses/by/4.0), 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
URI: http://eprints.usq.edu.au/id/eprint/25476

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