Research Paper Volume 8, Issue 5 pp 1034—1044

Figure 1. Epigenetic aging model for blood needs to be adjusted for buccal swabs. (A) Illustration of sample collection with a buccal swab. (B) Epigenetic age predictions of 55 mouth swab samples using an age predictor that was trained on blood samples as described before [4]. (C) For comparison, we demonstrate the predictions for 151 whole blood samples of our previous work [4]. (D) The multivariate model for age predictions was then retrained on pyrosequencing results of 55 mouth swab samples and validated on 55 independent additional samples that were analyzed in a different lab. (E-G) Correlation of β-values of age-associated CpG sites with chronological age. To this end, we used publically available datasets of blood (GSE41037), saliva (GSE28746), and mouth swabs (GSE50586). The CpG site cg17861230 corresponds to the neighboring CpG site in PDE4C that was used in the pyrosequencing models (because, the latter is not represented by Illumina Bead Chips). (H) β-values of the CpG site in the PDE4C gene in swab samples were determined by pyrosequencing and correlated with chronological age. (I) Age predictions based on DNAm levels at the CpG site in PDE4C. The linear regression model is depicted in (H). MAD = mean absolute deviation.