nominally significantP < 0.05
To underpin this, we further checked the directions of effect of all nominally significant a-DMSs ( P < 0.05) and found that methylation changes tended to be negatively associated with maternal smoking between 0 and 4/5 years (Fig. 4b ) and, moreover, that 721/971 (74.2%) a-DMSs showed a stronger decrease in methylation levels from 0 to 4/5 years (Additional file 1 : Table S7).