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Higher level of education may not protect against dementia

Although prior research has shown that having a higher level of education may protect the brain against dementia, new evidence published in Neurology showed that education was not associated with onset or rate of accelerated decline in older adults who developed dementia.

These findings indicated that the contribution of education to “cognitive reserve” may be limited to its link with level of cognitive function before old age, according to researchers.

“Level of education is widely used as an indicator of cognitive reserve. That higher level of education is associated with lower risk of dementia supports this idea,” Robert S. Wilson, PhD, of Rush University Medical Center, and colleagues wrote. “However, prospective studies suggest that this association is mostly attributable to the association of education with level of cognitive function rather than rate of cognitive change.”

To determine the role of education in cognitive reserve, the researchers analyzed data on older adults from two longitudinal clinical-pathologic cohort studies who had annual cognitive testing (n = 2,899) and subgroups that developed incident dementia, died and underwent neuropathologic examination.

The investigators also quantified 10 neurodegenerative and cerebrovascular pathologies from those who underwent neuropathologic exams. Participants were grouped into three education level groups: 12 years or fewer, 13 to 16 years, and 17 or more years.

Average years of education among participants was 16.3.

Although education was associated with initial level of global cognition in all participants, it was not associated with linear rate of cognitive change (estimate = –0.0004; P = .44), according to the results. These results remained after Wilson and colleagues repeated the analysis comparing the lowest education group with each of the other education groups.

In participants who developed dementia, the researchers found that the rate of global cognitive decline accelerated a mean of 1.8 years prior to diagnosis; however, education was tied to dementia onset or rate of accelerated decline.

In those who died, analysis revealed that the rate of global cognitive decline accelerated a mean of 3.4 years prior to death; however higher educational attainment was tied to earlier onset of accelerated decline and was not tied to rate of acceleration.

"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," Wilson said in a press release. "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."

In addition, education was not linked to global cognitive change not attributable to neuropathologic burden nor did education reduce the connection between higher neuropathologic burden and more rapid cognitive decline, the study revealed.

"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 ... may also play a role in cognitive reserve and may be more important than remote experiences such as schooling." – by Savannah Demko

Disclosure: Wilson reports grant support from NIH. Please see the study for all other authors’ relevant financial disclosures.