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Current Understanding: |
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The tables below summarize results from a series of observational studies of cognitive activity in relation to Alzheimer's disease dementia (AD) risk. Overall, these data are consistent with an association between participation in cognitive activities and lower risk of both clinical AD and all-cause dementia. Confounding and reverse causation could have biased some of these results, meaning that they should be interpreted with caution. Nonetheless, our bias sensitivity analysis, shown in an expanded paper, suggests that confounding per se is unlikely to explain the entirety of the findings, although reverse causation remains a concern (Sajeev G, et al. Epidemiology. 2016). In addition, the lack of an agreed-upon definition of cognitive activity as a construct and of its relevant dimensions, along with differences in its operationalization across studies also complicate comparison and synthesis of results. Thus far, the only large randomized trials of cognitive training interventions have shown modest, typically transient benefits on targeted cognitive domains, and it is unclear to what extent these relate to long-term pursuit of personally selected leisure activities. Further, whereas recommendations to remain cognitively engaged (“use it or lose it!”) are unlikely to be harmful, little is known about dose-response relationships, and how issues such as type, duration, intensity and timing of activity influence AD risk. Overall, engaging in activities enjoyable for their own sake seems a safe approach while further information is gathered. For a review of the putative mechanisms by which cognitive activity may influence AD risk and detailed commentary on interpreting these findings in a broader context, please view the Discussion. An expanded review, which includes studies reporting only on all-cause dementia as well, and bias sensitivity analyses, see our published paper, Sajeev G, Weuve J, Jackson JW, VanderWeele TJ, Bennett DA, Grodstein F, Blacker D. Epidemiology. 2016 Sep;27(5):732-42. |
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