Li H, Wu TT, Tang L, et al. - In order to clarify if there exists a link between DNA methylation and the development of postoperative cognitive dysfunction (POCD), researchers undertook this inquiry in 124 people older than 65 years-of-age undergoing hip replacement surgery. Through the reliable change index (RCI), an analysis of early POCD was done, and the presence of RCI <-1.96 was taken as the diagnosis of POCD. They isolated peripheral leukocyte DNA and measured DNA methylation via 5-methylcytosine (mC) using Elisa. The occurrence of early POCD was reported in 24 patients (19.4%). Patients who developed early POCD had significantly reduced 5-mC levels on day 7 postoperatively, but no such finding was obtained in non-POCD patients. POCD patients had significantly lower postoperative 5-mC levels vs non-POCD patients. An independent link between postoperative 5-mC level and early POCD was clearly revealed in bivariate logistic models adjusted for age, gender, BMI, duration of anesthesia and education level. Overall, a link between postoperative global hypomethylation of leukocyte DNA and the development of early POCD was evident in this study.