# Tobacco Smoke Exposure From Prenatal To Adolescent Periods Drives IBD Pathogenesis: Dynamic DNA Methylation Signatures Across Lifespan Stages

## TL;DR

Exposure to tobacco smoke from prenatal to adolescent periods increases IBD risk in offspring through DNA methylation changes.

## Contribution

This study identifies specific DNA methylation signatures linking maternal and adolescent smoking to IBD risk in offspring.

## Key findings

- Maternal smoking during pregnancy is associated with increased IBD, Crohn's disease, and ulcerative colitis risk in offspring.
- DNA methylation changes in genes like TNF/LTA, AHRR, and MYO1G persist across life stages and correlate with IBD risk.
- Adolescent smoking increases CD and IBD risk, suggesting DNA methylation as a key mechanistic pathway.

## Abstract

The association between early life exposure to smoking and the risk of inflammatory bowel disease (IBD) needs to be further verified, and the potential role of DNA methylation in the association is unclear. Through an integrated study design, this study demonstrates that maternal smoking during pregnancy (MSDP) is potentially associated with increased risk of IBD, Crohn's disease (CD), and ulcerative colitis (UC) in offspring. In addition, individuals who started smoking in adolescence have a higher risk of developing CD and IBD. Mechanistically, MSDP‐associated DNA methylation alterations in ADCY7 (newborn), AKAP8L (newborn), TIGD7 (newborn), and TNF/LTA (across life stages) are significantly correlated with increased risk of CD in offspring; MSDP‐induced DNA methylation changes in PRRT1 (newborn), AHRR (across life stages), and MYO1G (across life stages) show significant associations with UC risk in offspring. Notably, the alterations of DNA methylation status within AHRR, MYO1G, and TNF/LTA loci associated with smoking exposure are present throughout the life course. Collectively, MSDP may serve as an independent risk factor for IBD in offspring, and active smoking during adolescence may cause increased risk of developing CD and IBD. MSDP may contribute to IBD susceptibility by inducing persistent DNA methylation alterations at multiple developmental stages.

This study illustrates that maternal smoking during pregnancy (MSDP) is an independent risk factor for IBD in offspring, and DNA methylation serves as a key mechanistic pathway connecting early‐life smoking exposure with IBD risk in offspring. That highlights the urgent need for preventive interventions targeting prospective parents and minors to mitigate the rising global incidence of IBD.