title: Appendectomy in mid and later life and risk of Parkinson's disease: A population-based study.
abstract: Pathogenic movement of alpha-synuclein from the gut to the brain in PD has been proposed. The appendix has a relatively high density of alpha-synuclein deposition in neurologically healthy individuals. We investigated the incidence of PD after appendectomy.
  
  
  
  Using cause-specific hazards regression models, we compared persons over 35 years of age who had undergone appendectomy with two groups of age- and sex-matched individuals having had: (1) a cholecystectomy and (2) neither procedure. Subsequent diagnoses of PD were identified.
  
  
  
  Among 42,999 individuals undergoing appendectomy, no difference in risk of PD was identified compared to cholecystectomy (hazard ratio = 1.004; 95% confidence interval: 0.740-1.364). Compared with no procedure, individuals with appendectomy had a higher incidence of PD within 5 years, but no significant difference in risk thereafter.
  
  
  
  In our study, appendectomy in mid or late life does not appear to be associated with a reduced risk of PD. © 2016 International Parkinson and Movement Disorder Society.
authors.affiliation: Morton and Gloria Shulman Movement Disorders Center, Toronto Western Hospital and The Edmond J. Safra Program in PD, Toronto, Ontario, Canada, University of Toronto, Toronto, Ontario, Canada.|Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Connie
authors.initials: C
authors.lastname: Marras
authors.affiliation: Morton and Gloria Shulman Movement Disorders Center, Toronto Western Hospital and The Edmond J. Safra Program in PD, Toronto, Ontario, Canada, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Anthony E
authors.initials: AE
authors.lastname: Lang
authors.affiliation: The Institute for Clinical Evaluative Sciences and the University of Toronto, Toronto, Ontario, Canada.|Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Austin
authors.affiliation: The Institute for Clinical Evaluative Sciences and the University of Toronto, Toronto, Ontario, Canada.
authors.forename: Cindy
authors.initials: C
authors.lastname: Lau
authors.affiliation: The Institute for Clinical Evaluative Sciences and the University of Toronto, Toronto, Ontario, Canada.|Toronto General Research Institute, University Health Network, Department of Surgery, Toronto, Ontario, Canada.|Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada.
authors.forename: David R
authors.initials: DR
authors.lastname: Urbach
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001062:Appendectomy / Q000706:statistics & numerical data*; D002763:Cholecystectomy / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D010300:Parkinson Disease / Q000453:epidemiology*; D012306:Risk; D013997:Time Factors
keywords: Parkinson's disease; appendectomy; etiology