Evaluation of scores in independent validation sets. Independent dataset comprising 304 matched blood and buccal samples (n = 152 each) and 442 cervical samples was used to validate the findings. A–C, Mean beta values (uncorrected) in each of the four sets of CpGs in buccal (A), blood (B), and cervical (C) samples of never smokers, ex-smokers, and current smokers versus immune cell proportion (A and C) or lymphoid proportion (B). D–F, AUC of corrected values in each of the four sets of CpG comparing never smokers with current or former smokers in buccal (D), blood (E), and cervical (F) samples. Mean methylation scores in this figure only include sites present on the 450K array for comparability between datasets.