Furthermore, when overweight was replaced by obesity, the observed associations of V with DNA methylation of NOS2A CpG+5099, IFNγ CpG−54, and IFNγ CpG−186 shown in Additional file 1: Table S5, remained strong (RR [95% CI]: 0.40 [0.26-0.63]; p = 0.03, 0.71 [0.54-0.92]; p = 0.001, 1.42 [1.02-1.97]; p = 0.039 for NOS2A CpG+5099, IFNγ CpG−54, and IFNγ CpG−186 respectively). Here, IFNG is linked to obesity due to melanocortin 4 receptor deficiency.