title: Frequency of bowel movements and the future risk of Parkinson's disease.
abstract: BACKGROUND
  Constipation is frequent in PD, although its onset in relation to clinical PD has not been well described. Demonstration that constipation can precede clinical PD could provide important clues to understanding disease progression and etiology. The purpose of this report is to examine the association between the frequency of bowel movements and the future risk of PD.
  
  
  METHODS
  Information on the frequency of bowel movements was collected from 1971 to 1974 in 6790 men aged 51 to 75 years without PD in the Honolulu Heart Program. Follow-up for incident PD occurred over a 24-year period.
  
  
  RESULTS
  Ninety-six men developed PD an average of 12 years into follow-up. Age-adjusted incidence declined consistently from 18.9/10,000 person-years in men with <1 bowel movement/day to 3.8/10,000 person-years in those with >2/day (p = 0.005). After adjustment for age, pack-years of cigarette smoking, coffee consumption, laxative use, jogging, and the intake of fruits, vegetables, and grains, men with <1 bowel movement/day had a 2.7-fold excess risk of PD versus men with 1/day (95% CI: 1.3, 5.5; p = 0.007). The risk of PD in men with <1 bowel movement/day increased to a 4.1-fold excess when compared with men with 2/day (95% CI: 1.7, 9.6; p = 0.001) and to a 4.5-fold excess versus men with >2/day (95% CI: 1.2, 16.9; p = 0.025).
  
  
  CONCLUSIONS
  Findings indicate that infrequent bowel movements are associated with an elevated risk of future PD. Further study is needed to determine whether constipation is part of early PD processes or is a marker of susceptibility or environmental factors that may cause PD.
authors.affiliation: Division of Biostatistics and Epidemiology, University of Virginia School of Medicine, Charlottesville, USA. rda3e@virginia.edu
authors.forename: R D
authors.initials: RD
authors.lastname: Abbott
authors.forename: H
authors.initials: H
authors.lastname: Petrovitch
authors.forename: L R
authors.initials: LR
authors.lastname: White
authors.forename: K H
authors.initials: KH
authors.lastname: Masaki
authors.forename: C M
authors.initials: CM
authors.lastname: Tanner
authors.forename: J D
authors.initials: JD
authors.lastname: Curb
authors.forename: A
authors.initials: A
authors.lastname: Grandinetti
authors.forename: P L
authors.initials: PL
authors.lastname: Blanchette
authors.forename: J S
authors.initials: JS
authors.lastname: Popper
authors.forename: G W
authors.initials: GW
authors.lastname: Ross
mesh_terms: D000367:Age Factors; D000368:Aged; D003248:Constipation / Q000453:epidemiology / Q000503:physiopathology*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000209:etiology*; D012307:Risk Factors