Education amplifies brain atrophy effect on cognitive decline: Implications for cognitive reserve

Abstract Level of education is often regarded as a proxy for cognitive reservein older adults. This implies that brain degeneration has a smaller effect on cognitive declinein those with more education, but this has not been directly tested in previous research. We examined how education, quantitative magnetic resonance imaging–based measurement of brain degeneration, and their interaction affect cognitive declinein diverse older adults spanning the spectrum from normal cognitionto dementia. Gray matter atrophywas strongly related to cognitive decline. While education was not related to cognitive decline, brain atrophyhad a stronger effect on cognitive declinein those with more education. Importantly, high education was associated with slower declinein individuals with lesser atrophybut with faster declinein those with greater atrophy. This moderation effect was observed in Hispanics (who had high heterogeneity of education) but not in African-Americans or Caucasians. These results suggest that education is an indicator of cognitive reservein individuals with low levels of brain degeneration, but the protective effect of higher education is rapidly depleted as brain degeneration progresses.