(55 monozygotic (MZ) individuals (one co-twin from each MZ pair), 80 dizygotic (DZ) individuals from 40 full DZ pairs and additional 76 DZ individuals (one co-twin from each DZ pair)) with cotinine above 10ng/ml and 1000Genomes imputed genome-wide genotype data available were included in the NMR GWAS analyses. Genome-wide Infinium 450k Methylation BeadChip data (from whole blood DNA) were available on 157 of the NMR GWAS subjects.
