Sixty years ago when two young women studying to be nuns were about to take their final vows, they were required to write an autobiography.
“Sister A” wrote: “I was born in Eau Claire, Wis., on May 24, 1913, and was baptized in St. James Church.”
“Sister B” wrote: “The happiest day of my life so far was my First Communion Day which was in June nineteen hundred and twenty when I was but eight years of age, and four years later in the same month I was confirmed by Bishop D.D. McGavick.”
Decades later, Sister A died of Alzheimer’s disease. Sister B is alive and remains mentally sharp.
Researchers who analyzed the autobiographies of Sisters A and B and about 100 other nuns from the School Sisters of Notre Dame’s Milwaukee convent believe that the writings of their youth signal their likelihood of developing Alzheimer’s in old age.
“Sisters with low linguistic ability in early life (like Sister A) had a very high risk of Alzheimer’s disease in late life and abundant Alzheimer’s disease lesions in their brains,” said David Snowdon, a University of Kentucky researcher who reports on the findings in today’s Journal of the American Medical Association.
Nuns whose writings were rich with ideas and grammatical complexity - such as Sister B - were more likely to stay mentally healthy.
While Snowdon and his research team can’t explain the link, they postulate that weak linguistic ability in youth may be a sign that the mental deterioration of Alzheimer’s disease has already begun.
“This strongly suggests that Alzheimer’s disease may be a lifelong disease process just like atherosclerosis,” or hardening of the arteries, Snowdon said.
While later Alzheimer’s disease is marked by memory loss, confusion and ultimately a total loss of function, Snowdon said the nuns’ autobiographies suggest that subtle changes may be occurring decades before.
Neil Buckholtz, a scientist at the National Institute on Aging, which funded the study, said there was enough evidence to support the theory that Alzheimer’s disease begins its course of destruction early.
It could be, Buckholtz and Snowdon agree, that a person with sophisticated linguistic skills simply has a healthy, well-functioning brain that is somehow resistant to Alzheimer’s.
The research published today is part of an unusual study, launched in 1986, in which Snowdon and a research team are tracking nearly 700 nuns, all 75 years of age or older, who belong to the School Sisters of Notre Dame. The nuns agreed to have their mental and physical health evaluated periodically and then, upon death, to have their brains studied.
The nuns are ideal to study because as adults they all had similar lifestyles. They didn’t smoke, drink much or have children. They had access to good medical care and had similar nutrition, all eating from the same convent kitchens.
He was particularly intrigued by their autobiographies, which he thought would give some insight into their mental capacity in youth.
Just before taking their final vows to join the order, usually around the age of 22, the nuns were asked to write a short account of their lives.
Snowdon’s team analyzed autobiographies of women taking their vows in Milwaukee between 1931 and 1939. The team scored them for “idea density,” defined as the average number of ideas for each 10 written words, and grammatical complexity.
The association between linguistic skills and Alzheimer’s was particularly striking when the researchers looked at the writings of 25 nuns who had died and whose brains had been checked for the telltale protein lesions and nerve tangles that are characteristic of Alzheimer’s.
Of the 10 nuns who had Alzheimer’s confirmed by autopsy, nine of them - 90 percent - had shown low linguistic ability in early writings.
By comparison, of the nuns who died without Alzheimer’s, only 13 percent had scored low in their autobiographies.
While other studies have shown that people with more education are at lower risk for Alzheimer’s, Snowdon said the differences in linguistic ability among the nuns was not necessarily a reflection of their formal education. Sister A, in fact, had a master’s degree.