Participation in cognitively demanding activities reduces dementia

June 18, 2003

Wed, 18 Jun 2003 21:00:00

New York, NY - Participation in cognitively demanding leisure activities, such as reading, playing board games, playing musical instruments, and dancing, was associated with a lower risk of both Alzheimer's and vascular dementia in a new observational study.

The authors, from the Albert Einstein College of Medicine and Syracuse University, New York, note that the association remained after adjustment for baseline cognitive status and the exclusion of subjects with possible preclinical dementia. But they caution that these findings need to be confirmed in controlled trials.

In a paper in the June 19, 2003 issue of the New England Journal of Medicine, the researchers explain that an association between participation in leisure activities and a reduced risk of dementia in elderly people has previously been seen, but as there is often a long period of cognitive decline preceding diagnosis of dementia, reduced participation in activities during this preclinical phase of dementia may be the consequence and not the cause of cognitive decline.

Resolution of this issue requires a long period of observation before diagnosis to account for preclinical dementia and any other confounding factors such as baseline cognitive status, educational level, and depression, they note.

The Bronx Aging Study provided this opportunity. This was a community-based study that followed a cohort of 488 persons aged between 75 and 85 years who did not have dementia at baseline, with clinical and neuropsychological evaluations performed at regular intervals. In the current study, the relation between leisure activities and the risk of dementia in this cohort of patients was assessed.

Over a median follow-up period of 5.1 years, dementia developed in 124 subjects (Alzheimer's disease in 61 subjects, vascular dementia in 30, mixed dementia in 25, and other types of dementia in 8). Among leisure activities, reading, playing board games, playing musical instruments, and dancing were associated with a reduced risk of dementia. A one-point increment in the cognitive-activity score was significantly associated with a reduced risk of dementia, but a one-point increment in the physical-activity score was not. The association with the cognitive-activity score persisted after the exclusion of the subjects with possible preclinical dementia at baseline. Results were similar for Alzheimer's disease and vascular dementia.

The reduction in risk of dementia did seem to be related to the frequency with which activities were conducted. For example, elderly persons who did crossword puzzles four days a week had a risk of dementia that was 47% lower than that among subjects who did puzzles once a week.

No effect of physical activity?

In the current study, there was no association between physical activity and the risk of dementia. The researchers point out that cognitive and physical activities overlap, making it difficult to draw conclusions, but they add that although physical activities are clearly important in promoting overall health, their protective effect against dementia remains uncertain.

The authors cite other studies that have shown similar results. These include one in which knitting, doing odd jobs, gardening, and traveling was associated with a reduced risk of dementia, and another that showed reduced cognitive declines after cognitive training in elderly persons. They note that the role of individual leisure activities is not well known and that leisure activities studied in each trial reflect the interests of that particular cohort, so it is quite likely that other activities are also protective.

However, despite these observations, controlled trials are still necessary to confirm these findings, they say. "If confirmed, our results may support recommendations for participation in cognitive activities to lower the risk of dementia that parallel current recommendations for participation in physical activities to reduce the risk of cardiovascular diseases," they conclude.

"Use it or lose it"

In an accompanying editorial, entitled "Use it or lose it," Dr Joseph Coyle (Harvard Medical School, Boston, MA) tries to answer the question: "How can the molecular determinism of Alzheimer's disease be trumped by elderly people's card playing?"

He notes that one hypothesis put forward is that of "cognitive reserve"which subscribes to the view that having greater intellectual resources may buffer the underlying damage associated with the early stages of dementia, thereby delaying the onset of symptoms. But Coyle says this view does not give proper recognition to the use-dependent plasticity of the corticolimbic regions of the brain. He adds that effortful mental activity strengthens existing synaptic connections and generates new ones, "thus, persistent engagement by the elderly in effortful mental activities may promote plastic changes in the brain that circumvent the pathology underlying the symptoms of dementia."

"Determining the relative contributions of genes that confer risk and environmental factors such as effortful mental activity to the pathogenesis of dementia remains an important but unrealized goal in research on dementia. In the meantime, seniors should be encouraged to read, play board games, and go ballroom dancing, because these activities, at the very least, enhance their quality of life, and they just might do more than that," he adds.

Related links

1. [HeartWire > News; Oct 13, 2002]

2. [HeartWire > News; Jun 28, 2002]

3. [HeartWire > News; Apr 19, 2002]

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