By Stephen Beech via SWNS

An extra year of education does not protect against brain aging after all, suggests a new study.

Researchers were surprised to find no effect on brain structure and no protective benefits as a result of an extra 12 months of schooling.

Scientists at Radboud University Medical Centre in The Netherlands were able to determine very precisely what an extra year of education does to the brain in the long term thanks to a "natural experiment" involving 30,000 British people.

Previous research has shown that education has many positive effects.

People who spend more time in school are generally healthier, and smarter, and have better jobs and higher incomes than those with less education.

But whether prolonged education actually causes changes in brain structure over the long term and protects against brain aging is still unknown.

Many other factors influence brain structure - such as the conditions in which someone grows up, DNA traits, and environmental pollution - so it is difficult to study the influence of education.

But Raboud researchers Professor Rogier Kievit and Doctor Nicholas Judd discovered a "unique" opportunity to very precisely examine the effects of an extra year of education.

In 1972, a change in the law in the UK raised the minimum school leaving age from 15 to 16, while all other circumstances remained constant.

The researchers say that they created an interesting 'natural experiment', an event not under their control that divides people into an exposed and unexposed group.

Data from around 30,000 people who attended school around that time - including MRI scans taken 46 years later - was available for the new study, published in the journal eLife, making it the world's largest collection of brain imaging data.

The research team examined the MRI scans for the structure of various brain regions, but they found no differences between those who attended school longer and those who didn't.

Dr Judd said: "This surprised us.

"We know that education is beneficial, and we had expected education to provide protection against brain aging.

"Ageing shows up in all of our MRI measures, for instance, we see a decline in total volume, surface area, cortical thickness, and worse water diffusion in the brain. However, the extra year of education appears to have no effect here."

The researchers say it's possible that the brain looked different immediately after the extra year of education, but that wasn't measured.

Kievit said: "Maybe education temporarily increases brain size, but it returns to normal later. After all, it has to fit in your head.

"It could be like sports: if you train hard for a year at 16, you'll see a positive effect on your muscles, but 50 years later, that effect is gone."

The team said it's also possible that extra education only produces microscopic changes in the brain, which are not visible with MRI.

Both in the new research and in other, smaller studies, links have been found between more education and brain benefits.

For example, people who receive more education have stronger cognitive abilities, better health, and a higher likelihood of employment.

But Kievit says that is not visible in brain structure via MRI.

He added: "Our study shows that one should be cautious about assigning causation when only a correlation is observed.

"Although we also see correlations between education and the brain, we see no evidence of this in brain structure."

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