A 1972 UK school reform provided evidence that an extra year of education reduced dementia diagnoses decades later, with stronger effects among those with higher genetic risk, according to a study published in PNAS.
In 1972, the UK raised the school-leaving age from 15 to 16, creating a natural experiment to study education’s long-term health impacts. Researchers analyzed data from UK Biobank, comparing individuals born just before and after the September 1, 1957, cutoff. Those required to stay in school longer were 14 percentage points more likely to remain in education until age 16, and by 2022, they showed significantly lower dementia rates. The study, published in the Proceedings of the National Academy of Sciences, used UK Biobank data, following participants through age 65 via hospital records, death registries, and self-reported medical histories.
Education’s Protective Effect Against Dementia
The study found that additional schooling reduced dementia diagnoses even among individuals with high genetic risk. Among those born after the cutoff, the gap in dementia rates between high- and low-genetic-risk groups fell from 0.18 to 0.02 percentage points. Genes help shape disease risk, but they do not necessarily determine the outcome,
said Leandro Carvalho, a study co-author and associate professor of economics at CESR and the USC Dornsife College of Letters, Arts and Sciences. For people who know they have a higher genetic risk of dementia, this is a hopeful finding,
Participants who stayed in school longer were 2.3 percentage points more likely to have a household income of at least £31,000 and 0.64 points less likely to have had a stroke or heart attack. However, the exact mechanisms remain unclear. Barcellos led the study, which included coauthors from USC, the University of Wisconsin–Madison and the University of Michigan.
The analysis compared individuals born just before and after the 1957 cutoff, leveraging the 1972 reform’s strict date to isolate the effect of schooling. The team studied up to 107,200 people born within four years of the cutoff. Those born after the cutoff faced a 14 percentage point increase in the likelihood of staying in school until 16, though the average additional schooling was just over two months, as some students would have remained in education regardless. The study’s design, as noted in the Proceedings of the National Academy of Sciences, is the first to demonstrate a causal link between education and reduced dementia incidence.
Among participants with genetic variants linked to elevated dementia risk, such as the APOE4 gene, the protective effect of additional schooling was more pronounced. In the higher-risk group, 58% carried at least one APOE4 copy, compared to 0.02% in the lower-risk group. Despite this, the study could not definitively establish whether education directly reduces risk or if factors like income, health behaviors, or social networks mediated the effect. The difference between the halves was too small to rule out an equal benefit for both,
the researchers noted, which keeps a bigger benefit for high-risk people a possibility rather than a finding.
Researchers Note Effects May Not Persist As Cohort Ages
The study’s findings are based on participants aged 65 or younger in 2022, when dementia is still relatively rare. Researchers caution that the observed effects may not persist as the cohort ages. The effects of staying in school for one year longer reduced ADRD cumulative incidence in the cohort by approximately 0.88 percentage points,
the team noted, – an effect that the team acknowledges is implausibly large, given that the prevalence of ADRD in the sample was lower than 1 percent overall.
The researchers attributed this anomaly to potential statistical factors, acknowledging the need for further investigation. Dementia diagnoses were assessed through December 2022, when the oldest participants were 65 years old. As dementia becomes more common with age, the relatively low incidence in this cohort limits the precision of the estimates.
Additional year of education was also associated with higher income and lower stroke and heart attack rates, but the study could not determine which mechanisms accounted for the observed effect. Extra schooling could have opened doors to more mentally demanding jobs, raised income, or surrounded students with healthier peers,
the researchers suggested. However, these possibilities remain unproven.
The research team included Dr. Yaakov Stern, professor of neuropsychology at Columbia University in New York City, who highlighted the complexity of linking education to brain health. Low education could be a proxy for all of those,
Stern said, referring to socioeconomic and health factors. The team urged caution in interpreting the results, stressing the need for replication in other contexts.
Published on October 23, 2026, the study’s open-access article in the Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.2529506123) was supported by grants from the National Institutes of Health and the Russell Sage Foundation. The research team included Patrick Turley and Sneha Nimmagadda from USC Dornsife, Kenneth Langa from the University of Michigan, and Silvia Barcellos from the University of Wisconsin–Madison. The study’s findings underscore the potential for educational policies to influence long-term brain health, though further research is needed to clarify the pathways and generalize the results.