A higher level of education is not related to better cognitive reserve — the ability of the adult brain to maintain normal cognitive function in the presence of neurodegeneration — in old age, a study suggests.
Higher education levels are widely associated with a higher cognitive reserve, lower risk of dementia, and delayed cognitive decline — the reduced storage capacity in the brain that usually occurs as a person ages. However, scientific evidence supporting these claims is controversial. Some studies suggest that this association is mostly due to the connection between education and a higher acquisition of knowledge rather than higher adaptability.
To assess the contribution of education to cognitive reserve in old age, researchers from Rush University in Chicago analyzed 2,899 participants (older than 50 years of age; average age of 77.8 years) who participated in two ongoing clinical studies: the Religious Orders Study, which began in 1994 and included older Catholic clergy members from across the U.S.; and the Memory and Aging Project, which began in 1997 and involved older laypeople from the Chicago metropolitan region.
At the time of enrollment, none of the participants had been diagnosed with dementia.
They were followed for an average of eight years; 2,143 (73.9%) were women, and 2,569 (88.6%) were white. All participants took cognitive tests once a year, and data were collected between 1994 and 2018.
Researchers evaluated two subgroups, the first one — the incident dementia subgroup — consisted of 696 participants who developed incident dementia during follow-up over a mean of 10.5 years. The second one — the incident dementia neuropathologically examined subgroup — included 405 individuals who died during follow-up and underwent an autopsy to assess if they had any neurodegenerative conditions.
Participants had a mean of 16.3 years of education, ranging from zero to 30. Higher education was associated with an initial higher rate of global cognition at a younger age but not with more significant cognitive change. This means that more educated people had a high storage capacity at the beginning of the study, but did not show greater cognitive adaptability.
There was a quicker decline in cognition in patients who developed dementia about 1.8 years before diagnosis. The level of education did not alter this decrease.
In the patients who had died, there was a faster cognition decline approximately 3.4 years before death. The level of education did not alter this decline, but researchers noted that in individuals with higher education, this decline started about 0.2 years earlier.
People with higher education were less likely to have areas of dead tissue in the brain. “There have been previous reports linking higher level of education with a lower risk of stroke consistent with the present findings,” according to the researchers. Higher education was not associated with any other neuropathology.
“The results suggest that the contribution of education to cognitive reserve is limited to its association with premorbid cognitive level and does not involve an association with cognitive aging trajectories,” the researchers wrote.
“That education apparently contributes little to cognitive reserve is surprising given its association with cognitive growth and changes in brain structure. However, formal education typically ends decades before old age begins … This implies that influences on cognitive reserve vary over time, with recent experiences more influential than remote experiences such as schooling,” they added.
The researchers noted that most individuals had some level of education, which might underestimate the effects on a non-educated group. Therefore, further studies that evaluate a higher sample of participants with less education would help them better understand the association between education and cognition.