This investigation further demonstrated that (i) for each 1% decrease in CpG methylation at this site, the OR of being included in the T2D group increases by 6.1% and (ii) based on the receiver-operating characteristic area under the curve (ROC AUC) comparison, the CpG site methylation at the FTO gene is more effective in detecting T2D risk (ROC AUC = 0.638) than either the identification of rs7901695 at the TCF7L2 gene (ROC AUC = 0.55) or that of the combination of the 18 best established genetic variants (ROC AUC = 0.6) [97]. Here, TCF7L2 is linked to type 2 diabetes mellitus.