Associations Between Smoking Characteristics and DNA Methylation in a Korean Population

The purpose of this study was to analyze the differences in DNA methylation levels between current, former, and never smokers and the differences in DNA methylation according to the smoking duration, age at smoking initiation, and pack-year of smoking.

A secondary data analysis was performed using the data from the National Biobank of Korea. The epigenome data included the DNA methylation information of 400 individuals who participated in the Korean Genome and Epidemiology Study (KoGES). Epigenome-wide DNA methylation analysis was performed using DNA extracted from peripheral blood and analyzed with the Illumina HumanMethylation450 BeadChip.

The study found global hypomethylation among smokers compared to never smokers. In particular, AHRR (cg05575921 and cg23576855) were hypomethylated in smokers compared to never smokers (delta beta > .20, p < .05). In addition, a longer smoking duration was associated with hypomethylation in AHRR (cg05575921, cg23576855, and cg21161138) and F2RL3 (cg03636183).

These findings suggest that prolonged smoking exposure is associated with altered DNA methylation patterns in smoking-related loci, including AHRR and F2RL3. The findings may help inform smokers about smoking-related alterations in DNA methylation and their potential significance, while also supporting the potential utility of epigenetic biomarkers in assessing smoking exposure.