Education and cognitive reserve in old age

To assess the contribution of education to cognitive reserve.

Analyses are based on older participants in a longitudinal clinical-pathologic cohort study who had annual cognitive testing (n = 2,899) and subgroups that developed incident dementia (n = 696), died, and underwent a neuropathologic examination from which 10 neurodegenerative and cerebrovascular markers were derived (n = 752), or both (n = 405). Cognitive test scores were converted to a standard scale and averaged to yield composite measures of cognition.

Participants had a mean of 16.3 years of education (SD = 3.7, range 0-30). In all participants, education was associated with initial level of global cognition but not rate of cognitive change. In those who developed dementia, rate of global cognitive decline accelerated a mean of 1.8 years before the diagnosis, but education was not related to the onset or rate of accelerated decline. In the deceased, rate of global cognitive decline accelerated a mean of 3.4 years before death, but higher educational attainment was related to earlier (not later) onset of accelerated decline and unrelated to rate of acceleration. Higher education was associated with lower likelihood of gross and microscopic cerebral infarcts but not with other neuropathologic markers. Education was not related to global cognitive change not attributable to neuropathologic burden and did not decrease the association of higher neuropathologic burden with more rapid cognitive decline.

The results suggest that the contribution of education to cognitive reserve is limited to its association with level of cognitive function before old age.