In 1986, Snowdon began what would become known as the Nun Study. With the cooperation of the 678 School Sisters of Notre Dame, who lived in convents in seven states, Snowdon and colleagues began examining every aspect of the nuns’ lives. By studying a group with so much in common, the scientists hoped to eliminate many of the extraneous variables that might otherwise confound their research. The nuns had similar diets, health care and living conditions; consumed little or no alcohol; and did not smoke, use drugs or have children.
Each year, the researchers administered medical and cognitive tests to the nuns. They analyzed the women’s genes and measured their balance and strength. They tested how many words the sisters could remember after reading them on flashcards, how many animals they could name in a minute and whether they could count coins correctly. The scientists parsed the autobiographical essays the women wrote when they first joined the order. And as the nuns have died—fewer than 100 remain—their brains have been removed and shipped to a laboratory where they are, of course, analyzed.
The study has yielded a treasure trove of information about how the brain ages. For example, it has shown that small, barely perceptible strokes may trigger some dementia. That folic acid may help stave off Alzheimer’s disease. And that the nuns who packed the most ideas into their early autobiographies were less likely to develop Alzheimer’s a half-century later.
As the findings emerged, the medical research community recognized the power of the Nun Study. So in 1993, Dr. David Bennett launched a follow-up effort. This research, dubbed the Religious Orders Study, expanded its rolls to include more than 1,100 nuns, priests and brothers in 32 Catholic orders in 13 states. Led by Rush University Medical Center in Chicago, researchers would study their subjects’ cognitive abilities during life and, upon their deaths, their brains. Everything the scientists did would be keyed to understanding the transition from normal brain function to Alzheimer’s disease.
Among the researchers they tapped to assist them was OMRF’s Dr. Kenneth Hensley. A biochemist by training, Hensley studies inflammation that occurs in the brain when it is struck by neurodegenerative diseases such as Alzheimer’s.
For Hensley, the Religious Orders Study represented something of a full career circle: As an undergraduate and later a doctoral candidate at the University of Kentucky, he’d studied with Snowdon. He’d learned much about the Nun Study, and he felt lucky to participate in a project that not only stands the chance to make important contributions to science but also one that is driven by such charity.
“The nuns, the priests, the brothers—they surrender their lives to service. And when they die, they literally give themselves to us,” says Hensley. “I can’t think of a more sacred gift.”