title: The risk of Parkinson disease associated with urate in a community-based cohort of older adults.
abstract: OBJECTIVE
  Studies suggest an inverse association between urate concentration and the risk of Parkinson disease (PD). We investigated this in the Cardiovascular Health Study in an elderly community-based cohort of adults.
  
  
  METHODS
  The association of baseline urate (µmol/l) and incident PD over 14 years was assessed with locally weighted scatterplot smoothing (LOESS) regression from which categories of low (<300 µmol/l), middle (300-500 µmol/l), and high (>500 µmol/l) urate ranges were derived. Multivariate logistic regression models assessed the risk of PD for each urate range. Linear and quadratic terms were tested when modeling the association between urate and the risk of PD.
  
  
  RESULTS
  Women had significantly lower urate concentrations than did men [316.8 µmol/l (SD 88.0) vs. 367.4 µmol/l (SD 87.7), p < 0.0001] and in women no associations between urate and PD risk were observed. In men, LOESS curves suggested a U-shaped or threshold effect between urate and PD risk. With the middle range as reference, the risk of developing PD was significantly increased for urate <300 µmol/l (OR 1.69, 95% CI 1.03-2.78) but not for urate >500 µmol/l (OR 1.55, 95% CI 0.72-3.32) in men. A negative linear term was significant for urate <500 µmol/l, and across the entire range a convex quadratic term was significant.
  
  
  CONCLUSIONS
  Results suggest a more complex relationship than previously reported between urate levels and the risk of PD in men. Low urate concentrations were associated with a higher PD risk and high urate concentrations were not associated with a further decrease in PD risk.
authors.affiliation: Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15213-3232, USA. jains@upmc.edu
authors.forename: S
authors.initials: S
authors.lastname: Jain
authors.forename: T G
authors.initials: TG
authors.lastname: Ton
authors.forename: R M
authors.initials: RM
authors.lastname: Boudreau
authors.forename: M
authors.initials: M
authors.lastname: Yang
authors.forename: E L
authors.initials: EL
authors.lastname: Thacker
authors.forename: S
authors.initials: S
authors.lastname: Studenski
authors.forename: W T
authors.initials: WT
authors.lastname: Longstreth
authors.forename: E S
authors.initials: ES
authors.lastname: Strotmeyer
authors.forename: A B
authors.initials: AB
authors.lastname: Newman
mesh_terms: D000368:Aged; D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008396:Maryland / Q000453:epidemiology; D009657:North Carolina / Q000453:epidemiology; D010300:Parkinson Disease / Q000097:blood* / Q000453:epidemiology*; D010414:Pennsylvania / Q000453:epidemiology; D011446:Prospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D012737:Sex Factors; D014527:Uric Acid / Q000097:blood*
chemical_list: D014527:Uric Acid