Q: Can staying in school longer really protect against dementia?
That is what a major new study suggests — and it may be the strongest evidence yet. Researchers funded by the US National Institutes of Health (NIH) report that a single extra year of secondary school reduced dementia diagnoses decades later, with the biggest benefit going to people at the highest genetic risk. The findings were released on Friday, October 23.
Q: How could researchers possibly prove that? You can’t run a 50-year experiment on children.
You can’t — but Britain accidentally ran one. In 1972, the United Kingdom raised the minimum school-leaving age from 15 to 16 in England, Wales and Scotland. The rule applied to everyone born after September 1, 1957, which created a natural experiment: children born just before the cutoff could leave at 15, while those born just after had to stay another year. School enrollment to age 16 jumped 14 percent.
A team led by researchers at the University of Wisconsin–Madison and the University of Southern California then followed the health records of more than 100,000 participants in the UK Biobank — a giant long-term health study — for up to half a century, pulling dementia diagnoses from medical histories, hospital records and death registries.
Q: And the extra year made a difference?
Yes — a modest but real one. The group that stayed in school the extra year developed Alzheimer’s disease and related dementias at lower rates over the following decades. The researchers describe the effect as “considerably large” given how few people in the study developed dementia at all, and the NIH calls it “perhaps the strongest evidence yet that education can help mitigate long-term dementia risk.”
The most striking finding: the protection was strongest in people whose genes put them at elevated risk of Alzheimer’s. Schooling, it seems, can blunt even an unlucky genetic hand.
Q: What do the scientists say?
“These findings reinforce the understanding that dementia risk is determined by factors beyond one’s genetic makeup and that changes such as additional schooling can offset inherited vulnerability,” said Dr Richard Hodes, director of the NIH’s National Institute on Aging, which funded the work.
Lead author Silvia Barcellos, a health economist at UW–Madison, framed it as a rare piece of good news in a field with almost none: “There are few preventative options out there so even one could make a world of difference.”
Q: Why does this matter? We already knew educated people get less dementia.
We knew they were correlated — educated people also tend to be wealthier, healthier and better nourished, so nobody could say the schooling itself caused the difference. This study’s design gets around that, because the 1972 reform assigned the extra year by birth date, not by family background. The researchers believe it is the first study to document a causal relationship between education and diagnosed dementia.
Q: So should everyone stay in school an extra year?
Not so fast. The authors urge caution: the oldest participants were only 65 when the data was cut off in December 2022, and the gap between the groups could grow or shrink as they age into the decades when dementia is most common. A separate line of research using brain scans has found no protective effect of education on brain structure itself — a reminder that the mechanism here is still a mystery. Nobody knows whether the extra year builds some kind of cognitive reserve, or simply steers people toward healthier lives.
Still, in a field where prevention options are vanishingly scarce, one more year of school looking like a genuine shield — especially for those who need it most — is the kind of result worth paying attention to.
The study, “Education Reduces Dementia Incidence and Mitigates Genetic Risk,” was published October 23, 2026, in the Proceedings of the National Academy of Sciences (PNAS).
