The large effect sizes of some CpGs for REI and minimum SpO2, such as MKNK2-cg03246954, PFDN2-cg00816397, ATF2-cg02622866, and ARSA-cg07453718, indicate strong associations with OSA, and potential applicability as disease biomarkers (Table S8-S9). Here, PFDN2 is linked to obstructive sleep apnea syndrome.