Insufficient evidence for physical activity in preventing late-life dementia

1. Physical activity interventions to prevent late-life dementia included aerobic exercise, resistance training, Tai Chi, and multidomain interventions.

2. There is insufficient evidence to draw conclusions as to the efficacy of physical activity with respect to preventing cognitive decline and dementia.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Dementia is defined as a decline in cognitive function that results in functional impairment. There is currently a growing body of research assessing the different factors necessary to reduce the development of dementia in adults with previously normal cognitive function. The authors of this study conducted a systematic review to assess the efficacy of such activities in delaying cognitive decline. This study has several limitations related to the studies retrieved in this systematic review. First, many of the trials were small and did not assess long-term outcomes. As well, there was significant variability in terms of primary study outcomes and factors being assessed. The authors also observed several challenges within the study methodologies, such as not correcting for using various instruments to measure cognitive outcomes or poor definitions of how adult sedentary status was defined. Overall, the results of this systematic review highlight that there is currently insufficient evidence to determine the efficacy of physical activity on reducing the development of dementia.

Click to read the study in the Annals of Internal Medicine

Relevant Reading: Cognitive Reserve and the Prevention of Dementia: the Role of Physical and Cognitive Activities

In-Depth [systematic review]: The authors of this study compared 16 trials that assessed the impact of a physical activity intervention versus an inactive control on the development of dementia in persons with previously normal cognition. Of the studies included in this review, with 6 trials specifically addressing aerobic activity, 1 trial evaluating Tai Chi, and 3 trials assessing resistance training. Data extracted and confirmed by 2 independent reviewers. In general, the authors found insufficient evidence to draw conclusions related to the efficacy of physical activity in preventing the development of dementia. Specifically, no improvement in cognitive function was observed for multicomponent physical activity (low-strength evidence). Low-strength evidence did suggest that a multidomain intervention, including physical activity, diet, and cognitive training, might help delay cognitive decline and improve cognitive outcomes.

Image: PD

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