Britain's 1972 school reform may have lowered dementia diagnoses half a century later

This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: A new study provides perhaps the strongest evidence yet that education can help mitigate long-term dementia risk. Led by researchers at the University of Wisconsin–Madison and the University of Southern California in Los Angeles, the analysis demonstrates that an education reform in the United Kingdom, which raised the minimum school-leaving age by a year, reduced dementia incidence up to 50 years later.

Study participants whose genetics placed them at higher risk of developing Alzheimer's disease (AD) and AD-related dementias (ADRD) benefited most from the reform. The research is published in the journal Proceedings of the National Academy of Sciences. "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 Richard Hodes, director of NIH's National Institute on Aging (NIA).

The link between higher levels of education and reductions in dementia risk is not a novel idea. In fact, the two have a long-documented correlation. However, scientists have struggled to determine whether this link is causal.

Doing so would require comparing an intervention with a control in a large population of students and following them for an extended period. Coincidentally, a law enacted in England, Wales and Scotland in 1972 afforded researchers this type of opportunity. A compulsory education reform in the U.K. raised the minimum age at which students could drop out of school from 15 to 16, affecting students who were born after Sept. 1, 1957.

The change led to a 14% increase in the number of students enrolled in school until they reached 16. To gauge the impact of this increase on long-term AD/ADRD incidence, the authors analyzed medical data from more than 100,000 participants in a large aging cohort, the UK Biobank. Diagnoses made before December 2022, when the oldest study participants turned 65, served as the primary point of comparison between groups who were affected or unaffected by the educational reform.

The researchers obtained diagnoses from multiple sources, including medical histories, hospital records and death registries, to limit the impact of survival and other biases that could skew the data toward individuals capable of obtaining diagnoses during life. The researchers found that the additional year of school reduced AD/ADRD incidence over the following 50 years by 0.88%—a large effect given that overall rates of dementia in the study population were low. This signal was strongest for high-risk participants carrying specific genetic variants known to increase AD/ADRD incidence.