title: Cognitive Reserve and the Risk of Postoperative Cognitive Dysfunction.
abstract: BACKGROUND
  Post-operative cognitive dysfunction (POCD) occurs in 10 to 54% of older patients during the first few weeks after surgery, but little is known about risk factors predisposing to POCD.
  
  
  METHODS
  Systematic literature review and meta-analysis of cognitive reserve indicators and POCD risk.
  
  
  RESULTS
  Fifteen studies on 5104 patients were included. Follow-up periods spanned 1 day to 6 months. Educational level was the most commonly assessed cognitive reserve indicator, and a longer time spent in education was associated with a reduced risk of POCD (relative risk [RR] per year increment 0.90; 95% confidence interval: [0.87; 0.94]), i.e. each year increase in education was associated with a 10% reduced risk. Similar findings were made for some analyses on education as a categorical predictor (high school versus further/higher education, RR 1.71, [1.30; 2.25]; lower than high school versus further/higher education, RR 1.69, [1.17; 2.44]) though risk was equivalent for patients with high school education and those with lower than high school education (RR 1.02; [0.78; 1.32]).
  
  
  CONCLUSIONS
  Patients with a relatively higher level of education are at reduced risk of POCD. Risk stratification of surgical patients according to educational level may prove useful.
authors.affiliation: Molecular Epidemiology Research Group, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin-Buch; Charité - Universitätsmedizin Berlin; MDC/BIH Biobank, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin-Buch and Berlin Institute of Health (BIH), Berlin.
authors.forename: Insa
authors.initials: I
authors.lastname: Feinkohl
authors.forename: Georg
authors.initials: G
authors.lastname: Winterer
authors.forename: Claudia D
authors.initials: CD
authors.lastname: Spies
authors.forename: Tobias
authors.initials: T
authors.lastname: Pischon
mesh_terms: D000328:Adult; D060825:Cognitive Dysfunction / Q000209:etiology*; D058245:Cognitive Reserve; D003693:Delirium; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D011183:Postoperative Complications