Within twin pairs, education–methylation associations persist but are attenuated, implicating shared environmental or genetic factors¶

Claim · All claims
Evidence · 1 study · associational r2 · q2
Currency · newest study 2018 · not yet checked against its sources · not reviewed by a person

Subclaims¶

q2 i? Within 1478 twins adjusted for smoking, education–methylation effect sizes correlated with population effect sizes (r = 0.83) and averaged 0.76 of population estimates; in monozygotic pairs they fell to 0.28 of population estimates. → Jenny van Dongen et al 2018

Evidence¶

Jenny van Dongen et al 2018¶

Jenny van Dongen et al. (2018). DNA methylation signatures of educational attainment. npj Science of Learning 3:7. https://doi.org/10.1038/s41539-018-0020-2

q2 · i? · associational · r2

Within-pair analysis in 1478 twins (492 monozygotic and 247 dizygotic pairs, mean age 37) regressing within-pair methylation differences on within-pair educational-attainment differences, adjusted for smoking, which controls shared prenatal/childhood environment and part of genetic variation.

"The effect sizes within twin pairs were on average 0.76 of the effect sizes in the entire population"

Discussion¶

Related Claims¶

• Education-associated methylation differences persist in never smokers, indicating sources beyond a person's own smoking behaviour — related
• Educational-attainment methylation sites overlap strongly with cigarette-smoke signatures, and associations remain after adjusting for smoking at 11 genome-wide significant CpGs — related
• A Classical Twin Design model of educational attainment in the TwinLife sample estimates shared environmental influence at 43% and additive genetic influence at 34% — related
• The best-fitting NTFD model estimates heritability of educational attainment at 51% and total shared environmental influence at 26%, disaggregated into twin-specific (16%) and sibling-shared (10%) components — related
• Twin-specific shared environments account for a substantial portion of CTD shared-environment estimates for educational attainment and cannot be interpreted as between-family environmental differences — related
• Adjusting published twin-study ACE estimates for assortative mating raises mean heritability by about 17 points and lowers shared environmental estimates by about 16 points — related
• A meta-analysis of four Dutch cohorts identifies 58 CpG sites whose blood DNA methylation is associated with educational attainment, mostly with higher methylation at higher education — related
• Genetic factors account for a substantial share of variation in educational outcomes and related behavioral traits — related