CO-TWIN CONTROL MODELS INDICATE GENETIC CONFOUNDING BETWEEN EDUCATION AND LONGITUDINAL CHANGES IN COGNITIVE AGING

Sep 29, 2026

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Education is examined as a key early-life protective factor against cognitive decline, with competing explanations including direct causation, indirect effects via advantageous environments, or genetic confounding. Using twin studies and longitudinal latent growth curve models, pair means and within-pair differences were analyzed across intercepts and age-based quadratic slopes. Results from IGEMS (N=23,269; up to 27 years) showed task-specific patterns, with MZ within-pair education effects more attenuated than DZ, supporting genetic confounding. Sex differences likely reflect cohort-specific access to education.

LanguageEnglish

CategoryResearch & Report

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Abstract

Study design and model approach

Sample and measures across cognitive domains

Covariates and model comparisons (MZ vs DZ)

Key findings and interpretation

Innovation in Aging, 2025, Vol. 9, No. S2 463 Abstract citation ID: igaf122.1583 CO-TWIN CONTROL MODELS INDICATE GENETIC CONFOUNDING BETWEEN EDUCATION AND LONGITUDINAL CHANGES IN COGNITIVE AGING Deborah Finkel1, Malin Ericsson2, Ida Karlsson2, Miriam Mosing2, Marianne Nygaard3, Chandra Reynolds4, Margaret Gatz1, and Brian Finch1, 1. University of Southern California, Los Angeles, California, United States, 2. Karolinska Institutet, Solna, Stockholms Lan, Sweden, 3. University of Southern Denmark, Odense M, Syddanmark, Denmark, 4. University of Colorado Boulder, Boulder, Colorado, United States Education is perhaps the most widely examined early life protective factor for cognitive decline. Potential mechanisms for the relationship include direct causation, indirect causation (education may reflect a more advantaged early life environment), or genetic confounding (genes associated with educational attainment may also impact cognitive aging) . Twin studies offer a method for testing causal hypotheses by incorporating within and between twin pair differences in longitudinal latent growth curve models (LGCM) of cognitive aging on both level of functioning and rate of change with age. Nine longitudinal twin studies of aging from the IGEMS consortium (N = 23,269) included up to 27 years of follow-up on measures of cognitive function in the domains of memory, perceptual speed, verbal ability, and semantic fluency. Pair means (between family effect) and within pair differences (within family effect) were included as covariatesof both intercept and slopes in age-based quadratic LGCM (centered at age 65) . LGCM results were compared across full sample, monozygotic twins, and dizygotic twins. Results differed across cognitive tasks, but generally MZ within pair effects of education were strongly attenuated compared with DZ within pair effects, indicating some genetic confounding. Some sex differences in the results were identified, likely a result of the differential access to education among the birth cohorts represented in the sample (birthyears 1900-1948) . Thus, results suggest shared genetic factors explain some of the association between education and longitudinal change in cognitive function. In other words, genes that impact educational achievement also influence cognitive aging.

FAQs

Why is education considered in cognitive decline research?

Education is widely studied as an early-life protective factor for cognitive decline, and the document outlines multiple possible mechanisms linking education to later cognitive outcomes.

How do the twin models test causal hypotheses in this study?

The study uses within- and between-twin-pair differences in longitudinal latent growth curve models to compare level of functioning and rate of change with age.

What do the results suggest about genetic confounding?

MZ within-pair effects of education were strongly attenuated compared with DZ within-pair effects, indicating that shared genetic factors partly explain the association between education and longitudinal cognitive change.

Sep 29, 2026

Upload by nayy☆