An extra year of education does not protect against brain aging, study finds

Thanks to a “natural experiment” involving 30,000 people, researchers at Radboud University Medical Center were able to pinpoint exactly how an extra year of schooling affects the brain in the long term. To their surprise, they found no effect on brain structure and no protective benefit of additional education against brain aging.

It is common knowledge that education has many positive effects. People who spend more time in school tend to be healthier, smarter, have better jobs and higher incomes than people with lower levels of education. However, until now it was unknown whether long-term education actually causes changes in brain structure in the long term and protects it from aging.

This is difficult to study because, in addition to education, brain structure is influenced by many other factors, such as the environment in which a person grows up, DNA patterns and environmental pollution. However, researchers Rogier Kievit (lead member of the Cognitive Lifespan Dynamics Laboratory) and Nicholas Judd from Radboudum and the Donders Institute found a unique opportunity to study the effects of an additional year of schooling very precisely.

Aging

In 1972, a change in law in the United Kingdom increased the number of compulsory school years from fifteen to sixteen, while all other circumstances remained unchanged. This created an interesting “natural experiment”, an event outside the researchers’ control that divides people into exposed and unexposed groups. Data is available on approximately 30,000 people who attended the school around that time, including MRI scans taken much later (46 years later). This dataset represents the world’s largest collection of brain imaging data.

Researchers examined MRI scans for the structure of different brain regions but found no differences between those who attended school longer and those who did not. “It surprised us,” Judd says. “We know that education is beneficial, and we expected that education would provide protection against brain aging. Aging is evident across all MRI measures: for example, we see decreases in total volume, surface area, cortical thickness, and decreased water diffusion in the brain. However, an additional year of study does not seem to have any effect here.”

Brain structure

It is possible that the brain looked different immediately after the extra year of training, but this was not measured. “Perhaps education temporarily increases brain size, but later it returns to normal. After all, it has to fit in your head,” explains Kievit. “It can be like sports: if you train hard for a year at age sixteen, you will see a positive effect on your muscles, but fifty years later that effect will disappear.” It is also possible that the extra mass causes only microscopic changes in the brain that are not visible with MRI.

Both this study and other smaller studies have found a link between higher levels of education and brain benefits. For example, people who receive more education have stronger cognitive abilities, better health, and a higher likelihood of being employed. However, this is not visible in brain structure using MRI. Kievit notes, “Our study suggests that one should be cautious in establishing causation when only correlation is observed. Although we also see a correlation between education and the brain, we do not see any evidence of this in brain structure.”