General cognitive ability in high school, attained education, occupational complexity, and dementia risk

We address the extent to which adolescent cognition predicts dementia risk in later life, mediated by educational attainment and occupational complexity.

Using data from Project Talent Aging Study (PTAS), we fitted two structural equation models to test whether adolescent cognition predicts cognitive impairment (CI) and Ascertain Dementia 8 (AD8) status simultaneously (N_{Cognitive Assessment} = 2477) and AD8 alone (N_{Questionnaire} = 6491) 60 years later, mediated by education and occupational complexity. Co-twin control analysis examined 82 discordant pairs for CI/AD8.

Education partially mediated the effect of adolescent cognition on CI in the cognitive assessment aample and AD8 in the questionnaire sample (Ps < 0.001). Within twin pairs, differences in adolescent cognition were small, but intrapair differences in education predicted CI status.

Adolescent cognition predicted dementia risk 60 years later, partially mediated through education. Educational attainment, but not occupational complexity, contributes to CI risk beyond its role as a mediator of adolescent cognition, further supported by the co-twin analyses.

Project Talent Aging Study follows enrollees from high school for nearly 60 years. General cognitive ability in high school predicts later-life cognitive impairment. Low education is a risk partially due to its association with cognitive ability.