title: Risk of dementia after anaesthesia and surgery.
abstract: BACKGROUND
  The potential relationship between anaesthesia, surgery and onset of dementia remains elusive.
  
  
  OBJECTIVE
  To determine whether the risk of dementia increases after surgery with anaesthesia, and to evaluate possible associations among age, mode of anaesthesia, type of surgery and risk of dementia.
  
  
  METHODS
  The study cohort comprised patients aged 50 years and older who were anaesthetised for the first time since 1995 between 1 January 2004 and 31 December 2007, and a control group of randomly selected patients matched for age and gender. Patients were followed until 31 December 2010 to identify the emergence of dementia.
  
  
  RESULTS
  Relative to the control group, patients who underwent anaesthesia and surgery exhibited an increased risk of dementia (hazard ratio = 1.99) and a reduced mean interval to dementia diagnosis. The risk of dementia increased in patients who received intravenous or intramuscular anaesthesia, regional anaesthesia and general anaesthesia.
  
  
  CONCLUSIONS
  The results of our nationwide, population-based study suggest that patients who undergo anaesthesia and surgery may be at increased risk of dementia.
authors.affiliation: Pin-Liang Chen, MS, Department of Computer Science and Information Engineering, National Taiwan University, Taipei; Chih-Wen Yang, MD, Department of Neurology, Taipei Veterans General Hospital, Su-Ao and Yuanshan Branch, and National Yang-Ming University School of Medicine, Taipei; Yi-Kuan Tseng, PhD, Graduate Institute of Statistics, National Central University, Jhongli; Wei-Zen Sun, MD, PhD, Department of Anaesthesiology, National Taiwan University Hospital, Taipei, Taiwan; Jane-Ling Wang, PhD, Department of Statistics, University of California, Davis, California, USA; Shuu-Jiun Wang, MD, National Yang-Ming University School of Medicine, and Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei; Yen-Jen Oyang, PhD, Department of Computer Science and Information Engineering, National Taiwan University, and Graduate Institutes of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei; Jong-Ling Fuh, MD, Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, and National Yang-Ming University School of Medicine, Taipei, Taiwan.
authors.forename: Pin-Liang
authors.initials: PL
authors.lastname: Chen
authors.forename: Chih-Wen
authors.initials: CW
authors.lastname: Yang
authors.forename: Yi-Kuan
authors.initials: YK
authors.lastname: Tseng
authors.forename: Wei-Zen
authors.initials: WZ
authors.lastname: Sun
authors.forename: Jane-Ling
authors.initials: JL
authors.lastname: Wang
authors.forename: Shuu-Jiun
authors.initials: SJ
authors.lastname: Wang
authors.forename: Yen-Jen
authors.initials: YJ
authors.lastname: Oyang
authors.forename: Jong-Ling
authors.initials: JL
authors.lastname: Fuh
mesh_terms: D000368:Aged; D000758:Anesthesia / Q000009:adverse effects* / Q000706:statistics & numerical data; D016022:Case-Control Studies; D003704:Dementia / Q000139:chemically induced / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013514:Surgical Procedures, Operative / Q000009:adverse effects* / Q000706:statistics & numerical data; D013624:Taiwan / Q000453:epidemiology