The Nun Study: Unlocking the Secrets of Alzheimer’s

Precious little is known about this terrible illness, Alzheimer’s, which threatens to strike some 14 million Americans by 2050. Its precise cause is still largely mysterious, and effective treatments are still years away. But epidemiologists are beginning to get a handle on what kinds of people (1) are most seriously ravaged by Alzheimer’s—and, conversely, which people tend to escape relatively unscathed.

Much of this knowledge comes from a single, powerful piece of ongoing research: the aptly named Nun Study. Since 1986, University of Kentucky scientist David Snowdon has been studying 678 School Sisters—painstakingly researching their personal and medical histories, testing them for cognitive function (2) and even dissecting their brains after death. Over the years, as he explains in Aging with Grace, a moving, intensely personal account of his research, Snowdon and his colleagues have teased out a series of intriguing—and quite revealing—links between lifestyle and Alzheimer’s.

Scientists know that genes can predispose people to Alzheimer’s disease. But as described in nearly three dozen scientific papers, Snowdon’s study has shown, among other things, that a history of stroke and head trauma can boost your chances of coming down with debilitating symptoms of Alzheimer’s later in life; and that a college education and an active intellectual life, on the other hand, may actually protect you from the effects of the disease.

Perhaps the most surprising result of the Nun Study, though, is the discovery that the way we express ourselves in language, even at an early age, can foretell how long we’ll live and how vulnerable we’ll be to Alzheimer’s decades down the line. Indeed, Snowdon’s latest finding, scheduled to be announced this week, reinforces that notion. After analyzing short autobiographies of almost 200 nuns, written when they first took holy orders, he found that the sisters who had expressed the most positive emotions in their writing as girls ended up living longest, and that those on the road to Alzheimer’s expressed fewer and fewer positive emotions as their mental functions declined. These findings, like many of Snowdon’s earlier conclusions, will undoubtedly spark a lively debate (8).

Adapted from Time, May 14, 2001

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