title: Physical activity and the risk of Parkinson disease.
abstract: OBJECTIVE
  To investigate whether greater physical activity is associated with a lower risk of Parkinson disease (PD).
  
  
  METHODS
  The authors prospectively followed 48,574 men and 77,254 women who provided information on physical activity in 1986 or in early adulthood. During the follow-up, a total of 252 (male) and 135 (female) incident PD cases were identified.
  
  
  RESULTS
  In men, greater baseline physical activity was associated with a lower PD risk; compared with the lowest quintile, the multivariate relative risk (RR) of PD for the highest quintile was 0.7 (95% CI 0.5 to 1.1; p value, test for trend = 0.007), and the inverse association was still present after excluding the first 10 years of follow-up (RR = 0.5; p value, test for trend = 0.02). Further, strenuous exercise in early adult life was also inversely related to PD risk in men: compared with men who regularly exercised < or =2 months/year, those with > or =10 months of strenuous exercise had a 60% lower PD risk (RR = 0.4; p value, test for trend = 0.005). In women, physical activity assessed at baseline was not related to PD risk, whereas strenuous exercise in early adulthood tended to be inversely related to PD risk later in life (highest vs lowest categories, RR = 0.5, 95% CI 0.2 to 1.4; p value, test for trend = 0.06).
  
  
  CONCLUSIONS
  This study suggests either that higher levels of physical activity may lower the risk of Parkinson disease (PD) in men or that men predisposed to PD tend to avoid strenuous physical activity in their early adult years.
authors.affiliation: Department of Nutrition, Harvard School of Public Health, 665 Huntington Ave., Boston, MA 02115, USA. hchen@hsph.harvard.edu
authors.forename: H
authors.initials: H
authors.lastname: Chen
authors.forename: S M
authors.initials: SM
authors.lastname: Zhang
authors.forename: M A
authors.initials: MA
authors.lastname: Schwarzschild
authors.forename: M A
authors.initials: MA
authors.lastname: Hernán
authors.forename: A
authors.initials: A
authors.lastname: Ascherio
mesh_terms: D000328:Adult; D000368:Aged; D001900:Boston / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D010300:Parkinson Disease / Q000453:epidemiology*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012306:Risk; D012907:Smoking / Q000453:epidemiology; D013177:Sports / Q000706:statistics & numerical data; D011795:Surveys and Questionnaires