Education and occupational experiences occur during early life and adulthood respectively, and dementia prevention efforts could thus be made at different stages of the life course, according to new research led by Albert Einstein College of Medicine.
Dementia currently affects more than 50 million people worldwide and although age is the strongest risk factor for developing dementia, dementia is not an inevitable consequence of aging.
Estimates suggest that 40% to 50% of dementia cases may be preventable through intervention of modifiable risk factors.
Education and occupational complexity are main sources of mental engagement during early life and adulthood respectively, but previous research findings were not conclusive regarding protective effects of these factors against late-life dementia.
Dr. Jinshil Hyun, a researcher at Albert Einstein College of Medicine and a member of the Cohort Studies of Memory in an International Consortium (COSMIC), and colleagues aimed to examine the unique contributions of education and occupational complexity to incident dementia, and to assess the mediating effects of occupational complexity on the association between education and dementia across diverse cohorts.
The researchers analyzed data from 10,195 participants (median baseline age: 74.1 years, range: 58-103 years), representing nine international datasets from six countries over four continents.
Their results indicated that both education and occupational complexity were independently associated with increased dementia-free survival time, with 28% of the effect of education mediated by occupational complexity.
There was evidence of threshold effects for education, with increased dementia-free survival time associated with ‘high school completion’ or ‘above high school’ compared to ‘middle school completion or below.’
“The findings were fairly consistent across the different countries investigated, though more so for occupational complexity than for education,” Dr. Hyun said.
“Interestingly, it seemed that ‘high school completion’ was enough to prevent developing dementia, which suggested a threshold effect.”
“There was no significant difference in dementia rates between ‘high school completion’ and ‘above high school completion’.”
“Around one quarter of the association between education and dementia was due to occupational complexity, consistent with higher levels of education often leading to more complex occupations.”
“This research emphasises the significance of complex mental activity throughout life for reducing the risk of dementia,” said Professor Perminder Sachdev, co-director of the Centre for Healthy Brain Ageing (CHeBA) at the University of New South Wales.
The findings were publihsed in the Journal of Alzheimer’s Disease.
Jinshil Hyun et al. Education, Occupational Complexity, and Incident Dementia: A COSMIC Collaborative Cohort Study. Journal of Alzheimer’s Disease, published online November 11, 2021; doi: 10.3233/JAD-210627
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