Socioeconomic Position Across the Life Course and Cognitive Ability Later in Life: The Importance of Considering Early Cognitive Ability.

Objective: Investigate direct and indirect associations between markers of socioeconomic position (SEP) across the life course and midlife cognitive ability while addressing methodological limitations in prior work. Method: Longitudinal data from the Danish Metropolit cohort of men born in 1953 (N = 2,479) who completed ability tests at age 12, 18, and 56-58 linked to register-based information on paternal occupational class, educational attainment, and occupational level. Associations were assessed using structural equation models, and different models were estimated to examine the importance of accounting for childhood ability and measurement error. Results: Associations between adult SEP measures and midlife ability decreased significantly when adjusting for childhood ability and measurement error. The association between childhood and midlife ability was by far the strongest. Discussion: The impact of adult SEP on later life ability may be exaggerated when not accounting for the stability of individual differences in cognitive ability and measurement error in test scores.