The Nun Study

Sunday, May. 06, 2001 By MICHAEL D. LEMONICK AND ALICE PARK/MANKATO

Article Tools

It's the day after Easter, and the first crocus shoots have ventured tentatively above the ground at the convent on Good Counsel Hill. This is Minnesota, however; the temperature is 23[degrees]F and the wind chill makes it feel far colder. Yet even though she's wearing only a skirt and sweater, Sister Ada, 91, wants to go outside. She wants to feed the pigs.

But the pigs she and the other nuns once cared for have been gone for 30 years. Sister Ada simply can't keep that straight. In recent years, her brain, like a time machine gone awry, has been wrenching her back and forth between the present and the past, depositing her without warning into the days when she taught primary schoolchildren in Minnesota or to the years when she was a college student in St. Paul. Or to the times when she and the sisters had to feed the pigs several times a day.

Like some 4 million Americans, Sister Ada (not her real name) is suffering from Alzheimer's disease; as the years go by, she'll gradually lose her memory, her personality and finally all cognitive function. But advanced age does not automatically lead to senility. Ada's fellow nun, Sister Rosella, 89, continues to be mentally sharp and totally alert, eagerly anticipating the celebration of her 70th anniversary as a sister without the slightest sign of dementia. In a very real sense, this pair of retired schoolteachers haven't finished their teaching careers. Along with hundreds of other nuns in their order, the School Sisters of Notre Dame, they have joined a long-term study of Alzheimer's disease that could teach the rest of us how to escape the worst ravages of this heartbreaking illness.

The groundbreaking research they are helping conduct probably won't lead directly to any new drugs, and it's unlikely to uncover a genetic or biochemical cause of Alzheimer's. Doctors know, however, that preventing disease can be a lot easier and cheaper than trying to cure it. It was by studying the differences between people who get sick and people who don't--the branch of medical science known as epidemiology--that doctors discovered the link between smoking and lung cancer, between cholesterol and heart disease, between salt and high blood pressure. Epidemiology also led to the understanding that cooked tomatoes may help protect against prostate cancer, and that fruits and vegetables tend to stave off cancers of all sorts.

Now it's Alzheimer's turn. Precious little is known about this terrible illness, 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 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, of which Sisters Ada and Rosella are part. 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 and even dissecting their brains after death. Over the years, as he explains in Aging with Grace (Bantam; $24.95), a moving, intensely personal account of his research that arrives in bookstores this week, 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. As laboratory scientists and clinicians are quick to point out, cause and effect are notoriously difficult to tease out of population studies like this one, and exactly what the emotion-Alzheimer's link means has yet to be established. But even hard-nosed lab scientists admit that the Nun Study has helped sharpen the focus of their research. The study has impressed the National Institutes of Health enough that it has provided $5 million in funding over the past decade and a half. "It is," says Dr. Richard Suzman, director of the National Institute on Aging, "a very innovative, pioneering study."