Fig. 2.

To determine reliability of OXTR methylation values obtained from saliva at CpG site -924, a tissue comparison study was performed in which 206 healthy adults provided both passive drool and intravenous blood for assessment of methylation derived from peripheral blood mononuclear cells (PBMCs) (N = 142), and/or assessment of whole blood methylation (N = 181). Saliva-derived methylation levels are highly correlated with PBMC-derived methylation (r(140) = 0.74, p <  0.0001) and whole blood-derived methylation (r(179) = 0.77, p <  0.0001).