Similar environmental influences and general lifestyles among the participants make the nuns an ideal population to study, and although it is ongoing it has yielded several findings. At the University of Minnesota, Kelvin Lim and Laura Hemmy are developing a new Alzheimer's Disease study working with the School Sisters of Notre Dame.A few of the major findings from the nun study came from archived manuscripts Snowdon came across. Among these archives were several of the sister's autobiographies written just before they took their vows. After coding these archives several themes arose. Positivity was closely related to longevity, as well as idea density. Idea Density is an analysis which measures ideas in speech and writing. This research found the higher idea density scores, the higher chance of having sufficient mental capacity in late-life despite neurological evidence that shows the onset of Alzheimer's disease.In 1992, researchers at Rush University Medical Center Rush Alzheimer's Disease Center (RADC), building on the success of the Nun Study, proposed the Rush Religious Orders Study. The Religious Orders Study was funded by the National Institute on Aging in 1993, and is ongoing. Researchers at the University of Minnesota are collaborating with the Rush Alzheimer's Disease Center on the Religious Orders Study, as well as several other ongoing studies.
Origin and Procedure
During the examination process Snowdon was able to compare the collected cognitive test scores with the data received from examining the brains of the subject. These results assisted in giving new layers of understanding to the nature of Alzheimer’s Disease.
In 1992 a genetic component was found to be linked to the development of Alzheimer’s disease. A gene called Apolipoprotein E, responsible for carrying fat and cholesterol through the bloodstream had been correlated to the development of Alzheimer’s. Through his study Snowdon discovered that the gene present in an individual does not predict the presence or future presence of Alzheimer’s. Snowdon found that exercise was also correlated to the development of Alzheimer’s disease. Participants who engaged in some sort of daily exercise were more likely to retain their mental durability in their later years. Participants who started exercising later in life were still more likely to retain mental stability, even if they hadn’t exercised before. Comparisons between subject’s brains have also led to the theory that low weight or extreme weight loss could have a stronger negative effect on cognitive ability in Alzheimer’s patients.
One of the major findings by Snowdon was the existence of plaques and tangles in the brain. Plaques are abnormal clusters of dead brain cells that build up between nerves in the brain while Tangles are twisted strands of dead and dying protein. The original experiment helped to draw some connection between the location of the of neurofibrillary tangles and the type of impairment caused by the disease, though this connection is described by Snowdon himself as being somewhat inconsistent. Results did indicate that neurofibrillary tangles located in regions of the brain outside the neocortex and hippocampus have less of an effect than ones located within those areas. Another potential factor is brain weight, as subjects with brains weighing under 1000 grams were seen as higher risk than those in a higher weight class.
Overall, findings of the Nun Study have suggested multiple factors concerning expression of Alzheimer's traits. The data primarily states that age and disease do not always guarantee impaired cognitive ability and "that traits in early, mid, and late life have strong relationships with the risk of Alzheimer's disease, as well as the mental and cognitive disabilities of old age."The findings from this study have influenced many other scientific studies and discoveries. One of these studies includes the finding that if a person has a stroke, there is a smaller requirement of Alzheimer’s brain lesions necessary to diagnose a person with dementia. Another is that postmortem MRI scans of the hippocampus can help distinguish that some nondemented individuals fit the criteria or Alzheimer’s disease. Researchers have also used the autopsy data from this study to determine that there is a relationship between the number of teeth an individual has at death with how likely they were to have had dementia. Those with less teeth were more likely to have dementia while living. In another study researchers were able to confirm that neuronal hypertrophy is one of the first steps towards getting Alzheimer’s disease on the cellular level. This same study reaffirmed the findings of The Nun Study that state that higher idea density is connected with better cognition with age, even if the individual had brain lesions tied to Alzheimer’s disease.