A landmark study suggests that spending even one extra year in school could have lasting benefits for brain health, potentially reducing the risk of dementia decades later. The findings offer fresh evidence that education may help protect against cognitive decline, even among people genetically predisposed to the disease.

Researchers from the University of Southern California, the University of Wisconsin–Madison and the University of Michigan examined the long-term effects of a British education reform introduced in 1972. The legislation raised the compulsory school-leaving age from 15 to 16, providing a rare opportunity to investigate whether additional schooling directly influences dementia risk.

The reform applied to students born on or after September 1, 1957, while those born just days earlier could still leave school at 15. By comparing individuals on either side of this cutoff, researchers could examine the effects of additional education while minimising differences in family background and socioeconomic circumstances.

Using information from the UK Biobank, the team analysed medical histories, hospital records and death registrations for participants followed through age 65. They discovered that people required to remain in school longer were less likely to receive a dementia diagnosis decades later. The reform had increased the proportion staying in school until at least 16 by 14 percentage points.

The findings, published in the Proceedings of the National Academy of Sciences, provide unusually strong evidence that education itself can reduce dementia risk, rather than merely being associated with better health. Previous research had struggled to distinguish the benefits of schooling from advantages linked to wealth, upbringing and lifestyle.

Perhaps the most encouraging discovery involved participants with a high inherited susceptibility to Alzheimer’s disease and related dementias. Additional schooling appeared to reduce dementia incidence even among those facing the greatest genetic risk, suggesting that inherited vulnerability does not necessarily determine a person’s future health.

Lead researcher Silvia Barcellos, a health economist affiliated with USC and the University of Wisconsin–Madison, explained that the school reform helped researchers isolate education’s effects from other influences. The results strengthen the case that schooling can provide health benefits extending far beyond academic achievement or employment prospects.

Researchers also found that additional education was associated with higher household income and lower rates of stroke and heart attack. These improvements could help explain the connection with dementia, although the study could not establish precisely which factors were responsible for the protective effect.

Coauthor Leandro Carvalho, an economics professor at USC, said the findings offer hope to people concerned about inherited dementia risk. While genes influence susceptibility, experiences and circumstances throughout life may help determine whether that vulnerability eventually develops into disease.

The researchers cautioned that the precise size of the benefit remains uncertain because dementia was relatively uncommon among participants, who were followed only through age 65. Further monitoring will be needed as they grow older. Nevertheless, the study suggests that education policies introduced early in life could have unexpected public health benefits nearly half a century later.

More information: Silvia Barcellos et al, Education reduces dementia incidence and mitigates genetic risk, Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.2529506123

Journal information: Proceedings of the National Academy of Sciences Provided by University of Southern California