Gynaecology An exhaustive epidemiological study by F. Gagnon based on 3,280 Canadian nuns, which found no cancers of the uterine cervix, confirming Rigoni-Stern’s 1842 observation that cervical cancer is linked to sexual activity.
Neurology A study in which linguistic ability in early life and cognitive function and Alzheimer’s disease in late life were compared in a religious order—the School Sisters of Notre Dame
Lon White, MD, MPH, a neuroepidemiologist, and his team from the University of Hawaii and the Veterans Affairs-affiliated Pacific Health Research and Education Institute analyzed studies involving more than 1,100 people who had participated in the Nun Study or the Honolulu-Asia Aging Study.
Snowdon's 2001 book, Aging With Grace: What the Nun Study Teaches Us About Leading Longer, Healthier, and More Meaningful Lives, was based on that research and drew immense attention to Alzheimer's disease.
A particularly powerful study along those lines is called either the Nun study or the Religious Orders study, in which individuals have been in a known and relatively controlled environment their entire lives.
We suggest that the contrary findings of the nun study reflect the operation of factors that determined the nuns' youthful and subsequent levels of ability before they wrote their autobiographical notes on induction to their order.
They found in their subjects from the Honolulu Aging Study and the Nun Study (average age 88 and 90 years, respectively) that an individual's dementia is the result of multiple pathologies, including Alzheimer's, vascular disease, Lewy body disease, and hippocampal sclerosis, rather than a single cause.