Education May Not Protect Against Dementia as Previously Thought

CHICAGO – Previous studies have suggested that attaining a higher level of education may protect a person against dementia to some extent by providing a “cognitive reserve” that buffers against the disease.

However, a study led by researchers from Rush University Medical Center has found that education does not play a role in when the disease starts or how fast it progresses.

The study’s results were published today in the online issue of Neurology, the medical journal of the American Academy of Neurology.

“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 lead study author Robert S. Wilson, PhD, a neuropsychologist with the Rush Alzheimer’s Disease Center, or RADC.

“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,” Wilson said.

Study compared nearly 3,000 participants grouped by education levels

For the study, researchers analyzed information from two long-term studies conducted by the RADC — the Religious Orders Study, which involves older Catholic clergy members from across the United States, and the Rush Memory and Aging Project, which involves older adults from the Chicago metropolitan area. Participants in both studies take part in annual evaluations and agree to donate their brains for research upon death.

The 2,899 participants whose information was included in the study Wilson led were 78 years old on average at the start of the study and had received an average of 16.3 years of education. Participants were followed for an average of eight years. A total of 696 participants developed dementia during the study and 752 died over the course of the study, including 405 who had developed dementia. The researchers autopsied the brains of all the participants who died.

Researchers divided participants into three education level groups, 12 years or fewer, 13 to 16 years, and 17 or more years. To assess whether education provided protection against dementia, they compared the onset and progress of dementia in these groups, as shown in the annual evaluations and the development of dementia pathology found in examinations of the deceased participants’ brains.

Mental activity later in life may be more important to preventing dementia than early schooling

The researchers did find an association between having a higher level of education and having higher thinking and memory skills at the start of the study, decades after formal education had ended. However, they did not find an association between higher education and slower cognitive decline. Education level also was not related to how old people were when the disease started.

On the other hand, the researchers also did not see the results found in earlier studies that showed that once cognitive decline started in more educated people, it accelerated faster than in people with less education. They also did not replicate earlier findings that people with high levels of Alzheimer’s disease markers in their brains who had high levels of education did not decline as rapidly as people the same levels of disease markers in the brain who had lower levels of education.

“This finding that education apparently contributes little to cognitive reserve is surprising, given that education affects cognitive growth and changes in brain structure,” 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.”

“A limitation of the study is that participants had a relatively high level of education, so it is possible that effects previously seen on cognitive reserve due to education may have been primarily driven by variations at the lower end of the education level spectrum,” said Wilson.

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

The study was supported by the National Institutes of Health and the Illinois Department of Public Health.