June 19, 2003

Reading a novel, playing checkers or waltzing to Mozart may help you stay mentally sharp in your senior years. In other words, “use the brain or lose it,” concludes a rigorous long-term study that appeared in today’s New England Journal of Medicine.

Seniors who engaged in intellectually challenging activities had a lower risk of developing Alzheimer’s or other forms of dementia than those who rarely participated in such activities, the researchers found. But not all intellectual activities were equal. Reading books and newspapers; playing cards or board games such as backgammon, checkers or chess; or playing a musical instrument correlated with a lower risk. Writing for pleasure or participating in organized group discussions, on the other hand, did not afford protection.

What’s more, the more frequent the activity, the lower the risk. Those who did crossword puzzles four days a week, for example, had almost half the risk of those who did them once a week.

The scientists also assessed 11 physical activities, but dancing was the only one that reduced Alzheimer’s risks. Other physical activities, such as climbing stairs or bowling, did not appear to have an effect, although too few participated in pastimes such as tennis and golf to draw reliable conclusions.

Still, regular physical activity is good for the heart and blood vessels throughout the body, and other research has shown it may prevent strokes and possibly reduce your Alzheimer’s risk. Therefore, everyone should be encouraged to remain active, both physically and mentally.

Building “Brain Reserve”?

Earlier research had found that participating in leisure activities reduces the risk of Alzheimer’s. Population studies suggest, for example, that men and women who slack off on leisure-time activities in their midlife years are more likely to develop Alzheimer’s when they are old. Similarly, seniors who maintain a rich social network and remain active throughout old age are less likely to develop the illness than those who participate in fewer activities.

Still, scientists aren’t sure whether the activities themselves provide direct benefits, or whether people who forego participation are showing subtle, early symptoms of dementia. People with Alzheimer’s often give up on favorite hobbies like crossword puzzles, and such lack of interest and apathy may develop years before they are actually diagnosed with the disease.

Researchers in the current trial, the Einstein Aging Study, sought to take these factors in account by carefully assessing patients at the start of the study and following them for an extended period. They recruited 469 seniors, aged 75 and up, and assessed them regularly for as long as 21 years. None had Alzheimer’s or other forms of dementia when the study began. The investigators also excluded anyone who was diagnosed with dementia within seven years of the start of the study, since early disease may have caused them to be less active and engaged.

By the end of the study, 124 of the participants had developed Alzheimer’s or other forms of dementia. On average, Alzheimer’s tended to develop in those who were older, had lower levels of formal education, and participated in fewer cognitive activities. Alzheimer’s did not occur at a higher rate in those who were less physically active, however.

How might mental activity protect against Alzheimer’s?

One proposal is that people who remain active and engaged throughout their lives build up a so-called “brain reserve.” According to this theory, intellectual activities cause brain cells to establish rich and complex connections that may protect them from damage. It is also possible that mental stimulation causes new brain cells to grow. If some cells die, due to Alzheimer’s or another disease, enough other cells may remain to keep the person healthy and mentally alert, thereby delaying the onset of symptoms.

Still, the connection between mental exercise and Alzheimer’s remains unproven. Genes are proving to play an important role in same cases of Alzheimer’s, and other factors will no doubt emerge as significant contributors to the illness.

Seniors– and everyone else — should nevertheless be encouraged to read, play bridge, and hit the dance floor. “At the very least, [these activities] enhance their quality of life,” writes Dr. Joseph T. Coyle, M.D., of Harvard Medical School in an editorial that accompanied the study. “And they just might do more than that.”

By Toby Bilanow, Medical Writer for www.ALZinfo.org, The Alzheimer’s Information Site.

Reviewed by Samuel E. Gandy, M.D., Ph.D., Chairman of the Scientific Advisory Board, Fisher Center for Alzheimer’s Research Foundation.