Education-associated methylation differences persist in never smokers, indicating sources beyond a person's own smoking behaviour¶

Claim · All claims
Evidence · 1 study · associational r3 · q2
Currency · newest study 2018 · not yet checked against its sources · not reviewed by a person

Subclaims¶

q2 i? In never smokers (N=2001), effect sizes across the 58 CpGs were on average 60% smaller than in the full sample but strongly correlated with them (r = 0.83), with 27 sites at least nominally significant. → 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 · r3

Restricted analysis excluding all current and former smokers (52% of the sample; new N = 2001). Effect sizes at cg05575921 (AHRR) were 86% smaller in never smokers; CpGs in PCDH9, SPATA5 and SNORD93 showed the strongest evidence of association beyond own smoking, with small smoking-mediated proportions.

"effect sizes in never-smokers were strongly correlated with effect sizes in the entire population (r = 0.83), were in the same direction at 57 sites, and were at least nominally significant in never-smokers (p < 0.05) at 27 sites"

Discussion¶

Related Claims¶

• Education methylation signatures correlate with maternal smoking signatures and show small positive correlations with maternal folate and air pollution signatures, but not alcohol — 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 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 — a broader claim this one bears on
• Within twin pairs, education–methylation associations persist but are attenuated, implicating shared environmental or genetic factors — related