title: Parkinson's disease and colorectal cancer risk-A nested case control study.
abstract: A pro-inflammatory gut microbiota was described in both Parkinson's disease and colorectal cancer (CRC) and recently α-synuclein was demonstrated in the enteric nervous system. We sought to evaluate the association between Parkinson's disease and CRC.
  
  
  
  We conducted a nested case-control study using a large primary-care database. Cases were defined as all individuals with CRC. Up to 4 controls were matched with each case based on age, sex, practice-site and duration of follow-up. The primary exposure of interest was diagnosis of Parkinson's disease prior to CRC as well as disease duration, and Parkinson's specific therapies. The primary analysis was a conditional logistic-regression to estimate odds ratios (ORs) and 95% confidence interval (95%CI).
  
  
  
  The study included 22,093 CRC cases and 85,833 matched controls. Past medical history of Parkinson's disease >1 year before index-date was associated with lower CRC risk (OR 0.74, 95%CI 0.59-0.94). The inverse association was more prominent among females compared to males (0.64, 95%CI 0.42-0.96 and 0.8, 95%CI 0.60-1.07, respectively). While patients who received no therapy or therapy with dopamine agonists had a non-significant decrease in cancer risk, patients who were treated with dopamine had a non-significant elevated cancer risk.
  
  
  
  Parkinson's disease is inversely associated with CRC risk.
authors.affiliation: Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA, USA; Tel-Aviv University, Tel-Aviv, Israel.
authors.forename: Ben
authors.initials: B
authors.lastname: Boursi
authors.affiliation: Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Ronac
authors.initials: R
authors.lastname: Mamtani
authors.affiliation: Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Haynes
authors.affiliation: Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA. Electronic address: yangy@mail.med.upenn.edu.
authors.forename: Yu-Xiao
authors.initials: YX
authors.lastname: Yang
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis* / Q000453:epidemiology; D012307:Risk Factors
keywords: Age; Colorectal cancer; Dopamine; Microbiota; Parkinson’s disease; Risk