title: Caffeine and progression of Parkinson disease.
abstract: OBJECTIVE
  Caffeine use is negatively associated with the risk of developing Parkinson disease (PD) and is protective in animal models of PD, but the relationship between caffeine intake and rate of progression of PD is unknown. We assessed this relationship using data from 2 recent clinical trials of PD.
  
  
  METHODS
  Data were ascertained from 2 recent 1-year clinical trials that together included 413 early PD subjects who did not require symptomatic therapy at the time of study entry. Exploratory analyses compared caffeine intake with rate of progression of PD, as measured by either the likelihood of progression to the point of requiring symptomatic therapy or by change in the total Unified Parkinson Disease Rating Scale score.
  
  
  RESULTS
  Rate of progression of PD did not differ significantly between those in the highest and lowest quartiles for caffeine use for either of the primary measures or for secondary analyses of changes in scores on the motor or activities of daily living subsections of the Unified Parkinson Disease Rating Scale. Other secondary analyses yielded variable results.
  
  
  CONCLUSIONS
  These data do not reveal a consistent relationship between caffeine intake and rate of progression of PD by these measures, although a larger study is required for sufficient power to more fully assess this relationship.
authors.affiliation: Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02115, USA. dsimon1@bidmc.harvard.edu
authors.forename: David K
authors.initials: DK
authors.lastname: Simon
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Swearingen
authors.forename: Robert A
authors.initials: RA
authors.lastname: Hauser
authors.forename: Joel M
authors.initials: JM
authors.lastname: Trugman
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Aminoff
authors.forename: Carlos
authors.initials: C
authors.lastname: Singer
authors.forename: Daniel
authors.initials: D
authors.lastname: Truong
authors.forename: Barbara C
authors.initials: BC
authors.lastname: Tilley
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001628:Beverages; D002110:Caffeine / Q000008:administration & dosage*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage*; D003401:Creatine / Q000627:therapeutic use; D018450:Disease Progression; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008911:Minocycline / Q000627:therapeutic use; D010300:Parkinson Disease / Q000503:physiopathology*; D016032:Randomized Controlled Trials as Topic; D011795:Surveys and Questionnaires
chemical_list: D000900:Anti-Bacterial Agents; D000697:Central Nervous System Stimulants; D002110:Caffeine; D008911:Minocycline; D003401:Creatine