Impact of exposure to second-hand smoke during childhood on blood DNA methylation

Meta-analysis results for CpGs associated with household postnatal exposure to second hand smoke (SHS). Cohorts order are GenR, PIAMA, HELIX, BAMSE_Medall, BAMSE_EpiGene, and ALSPAC. Effect size represents the change in DNAm by number of household smokers (from 0 smokers to 2 smokers or more). Gene and CpG Island relative position are indicated (TSS200 is the region from Transcription start site (TSS) to − 200 nt upstream of TSS; TSS1500 covers − 200 to − 1500 nt upstream of TSS; S_Shore corresponds to the 2 kb regions immediately downstream of the CpG island; N_Shore corresponds to the 2 kb regions immediately upstream of the CpG island). Chr stands for Chromosome, SE stands for standard error, I2  stands for heterogeneity index, and FDR stands for False Discovery Rate. (DNA data obtained through Iluumina 450K array profiling)