Education and cognitive change over 15 years: The atherosclerosis risk in communities study

Objectives To evaluate whether education level is associated with change in cognitive performance. Design Prospective cohort study. Setting The Atherosclerosis Risk in Communities (ARIC) Study, a community-based cohort. Participants Nine thousand two hundred sixty-eight ARIC participants who underwent cognitive evaluation at least twice over a 15-year period. Measurements Education was evaluated as a predictor of change in word recall, the Digit Symbol Substitution Test (DSST), and word fluency. A random-effects linear regression model, and a time by educational level interaction was used. Results Educational level was highly associated with cognitive performance. The effect on performance of a less than high school education (vs more than high school) was equivalent to the effect of as much as 22 years of cognitive aging, but educational level was not associated with change in cognitive performance in whites or blacks, with the exception of the DSST for whites, in whom those with lower levels of education had less decline in scores. Conclusion Educational level was not associated with change in cognitive performance, although the higher baseline cognitive performance of individuals with more education might explain lower rates of dementia in more-educated individuals, because more decline would have to take place between baseline higher performance and time at which dementia was diagnosed in more-educated individuals.