Fig. 3

Differentially methylated positions after the intervention with folic acid and vitamin B₁₂. Volcano plots show the statistical significance versus the changes in DNA methylation after the intervention with (a) the placebo or (b) folic acid and vitamin B₁₂. Dashed lines represent 2 % methylation changes and a p value of 1.0E-05. Features of the positions (n = 162) that were differentially methylated after the intervention with folic acid and vitamin B₁₂ are presented in (c) percentages of positions expressed per relationship to CpG islands for the differentially methylated positions (n = 162) as well as for all considered positions on the Infinium HumanMethylation450 Beadchip (n = 431,312), and (d) percentage of positions expressed per relationship to the nearest gene(s). e Number of positions according to the presented categories for absolute changes in DNA methylation for the 162 positions that were differentially methylated after the intervention with folic acid and vitamin B₁₂. f Individual changes in DNA methylation for probe cg06191076 located within DIRAS3. Horizontal lines represent median ± interquartile ranges of DNA methylation, which is expressed as a beta value (0–100 %). Abbreviations: TSS200 200 base pairs around the transcription start site, TSS1500 1500 base pairs around the transcription start site, 3′UTR 3′ untranslated region, 5′UTR 5′ untranslated region, IGR intergenic region