A college degree may NOT protect against dementia as previously thought, study finds

• Higher education has been associated with lower dementia risk and slower decline
• But a new Rush University study found no link to support that

Having a higher level of education may not protect the brain against dementia as previously thought, a new study finds.

Plenty of research has found an active brain is a healthy brain - being bilingual, having a college degree, reading and even playing chess have all been associated with lower risk.

But a new paper by US scientists found that, after extending the time frame of these studies, there was no correlation at all.

They say it could be that people with higher education may have life experiences or biological factors that influence their risk.But based solely on letters after their name, there was little evidence of a link.

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People with a higher education did not necessarily have a slower cognitive decline than their peers, nor did it delay the age at which they were diagnosed - as previously suggested

'The strengths of this analysis include that it was based on more participants who were observed for a longer period of time than previous analyses,' said study author Robert S Wilson, PhD, of Rush University Medical Center in Chicago. 

'It's possible that the contribution of education to cognitive reserve depends on other factors, such as life experiences or biological factors, but these results did not show a relationship between a higher level of education and a slower rate of decline of thinking and memory skills or a later onset of the accelerated decline that happens as dementia starts.'

For the study, published today in Neurology, the medical journal of the American Academy of Neurology, used national and local data of 2,899 older adults. 

The local data came from the Rush Memory and Aging project, including older people in Chicago. 

The national data came from the Religious Orders Study, of older Catholic clergy members from across the United States. 

All of the people involved - who had an average age of 78 when they entered - agree to annual evaluations and a brain autopsy after death.

Over the eight years they were studied, 696 participants developed dementia. By the end, 752 died and had the brain autopsy, of whom 405 were diagnosed with dementia.

Analyzing the data, the researchers divided people into three education level groups - 12 years or fewer (up to a high school diploma), 13 to 16 years (from high school to bachelor's), and 17 or more years (higher than a bachelor's).

At the start of the study, those with higher education levels were sharper, with better memory skills and faster responses to questions. 

After that, the gap narrowed. 

People with a higher education did not necessarily have a slower cognitive decline than their peers, nor did it delay the age at which they were diagnosed - as previously suggested. 

The study also managed to dispel concerns that higher education could speed up decline once it started. There was no evidence of that. 

And the researchers found no evidence that highly educated people with high levels of Alzheimer's biomarkers declined slower than others.  

'This finding that education apparently contributes little to cognitive reserve is surprising given that education affects cognitive growth and changes in brain structure,' Dr Wilson said. 

'But formal education typically ends decades before old age begins, so late-life activities involving thinking and memory skills such as learning another language or other experiences such as social activities, cognitively demanding work and having a purpose in life may also play a role in cognitive reserve than may be more important than remote experiences such as schooling.'

There is one clear limitation of the study: many of the people involved had a fairly high level of education. 

The researchers concede that more work is needed on a broader spectrum of education levels to consolidate their findings.

But Dr Wilson said the study's finding that people with higher education levels were sharper at the start should not be dismissed lightly.  

'Of course, even if one declines at the same rate it is still better to start at a higher level of cognition,' Dr Wilson added.