Studies consistently link more education and more mentally stimulating activity with a lower risk of dementia, but these are observational findings and some records argue that the link may partly run the other way. A 2012 meta-analysis of 437,477 subjects found pooled odds ratios of 2.61 (prevalence) and 1.88 (incidence) for low education, while a 2019 study found that after accounting for cognitive ability at about age 20, additional education accounted for less than 1% of the variance in late-midlife cognition.
What the studies found
A 2012 systematic review in PLoS One, using education as a proxy for cognitive reserve, covered 133 articles and 437,477 subjects. Prevalence and incidence studies with pooled ORs of 2.61 (95% CI 2.21-3.07) and 1.88 (95% CI 1.51-2.34) respectively showed that low education increased the risk of dementia.
A 2022 coordinated analysis in the Journal of Alzheimer's Disease used 10,195 participants from 9 international datasets across 6 countries (median baseline age 74.1). 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, and there was evidence of threshold effects: high school completion or above, compared with middle school completion or below.
- Study
- Education, Occupational Complexity, and Incident Dementia: A COSMIC Collaborative Cohort Study
Mentally stimulating activity has also been studied. In a 2003 New England Journal of Medicine cohort of 469 community residents older than 75, dementia developed in 124 subjects over a median of 5.1 years; reading, playing board games, playing musical instruments and dancing were associated with a reduced risk, and a one-point increment in the cognitive-activity score was associated with a hazard ratio of 0.93 (95% CI 0.90 to 0.97), while a one-point increment in the physical-activity score was not (hazard ratio 1.00).
In a 2002 JAMA cohort of 801 older Catholic nuns, priests and brothers without dementia at enrollment, 111 persons developed Alzheimer's during an average of 4.5 years. After controlling for age, sex and education, a 1-point increase in cognitive activity score was associated with a 33% reduction in risk of Alzheimer's (hazard ratio 0.67; 95% CI 0.49-0.92).
On bilingualism, a 2020 meta-analysis found a moderate effect size for the protective effect on the age of onset of Alzheimer's symptoms (Cohen's d = 0.32) and weaker evidence that bilingualism prevents the occurrence of the disease itself (Cohen's d = 0.10). The authors say their results cannot be explained by socioeconomic status, education or publication bias, and describe the idea as remaining controversial.
How the link might run the other way
A 2019 study in PNAS of men aged 56-66 (n = 1009) found that, after accounting for general cognitive ability at an average age of 20, additional education, occupational complexity and engagement in cognitive-intellectual activities each accounted for less than 1% of the variance in late-midlife cognitive outcomes, whereas age-20 ability accounted for 40% of the variance in the same measure. The authors say the effect of the other factors likely reflects reverse causation, and that longitudinal studies with multiple assessments before education is completed would be needed to confirm their explanation.
A 2020 review in Psychological Science in the Public Interest found that years of formal education are positively correlated with cognitive function throughout adulthood and predict lower risk of dementia late in life. It also found evidence that cognitive abilities are associated with selection into longer education, and that common factors such as parental socioeconomic resources affect both educational attainment and cognitive development.
What remains uncertain
Most of the studies above are observational, so they show association rather than cause. The 2003 authors state that it is unclear whether more leisure activity lowers the risk of dementia or whether participation declines during the preclinical phase of dementia, and the 2022 record lists that its cohorts differ in education systems and in how dementia was identified.
- Studies
- Leisure activities and the risk of dementia in the elderly
- Education, Occupational Complexity, and Incident Dementia: A COSMIC Collaborative Cohort Study
The records do not agree on mechanism. One reads education as a marker of early-adult cognitive ability, another as an influence on late-life cognition, and the bilingualism authors note that the field is still disputed. None of the records above tests a change in education or activity as an intervention in adults. A clinician who knows the person can say what these findings mean for them.
- Studies
- Influence of young adult cognitive ability and additional education on later-life cognition
- Education and Cognitive Functioning Across the Life Span
- Does bilingualism protect against dementia? A meta-analysis
This page describes what published studies in alzhub's library report. It is not medical advice and does not apply to any one person. Where a decision would follow, a clinician who knows the person is the one who can say what a result or a choice means for them.
Questions
- Does a higher level of education lower the risk of dementia?
- Observational studies link it with lower risk: a meta-analysis of 437,477 subjects found pooled ORs of 2.61 for prevalence and 1.88 for incidence with low education. Whether education itself is the cause is debated.
- Do reading and puzzles protect the brain?
- In a cohort of 469 people older than 75, reading, board games, musical instruments and dancing were associated with a reduced risk of dementia, and in a cohort of 801 nuns, priests and brothers more cognitive activity was associated with a 33% lower risk of Alzheimer's. Both are observational.
- Could the link between education and dementia run the other way?
- A 2019 study found that after accounting for general cognitive ability at about age 20, additional education accounted for less than 1% of the variance in late-midlife cognition, and the authors say the effect likely reflects reverse causation.
Read on
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