title: Female gender but not cigarette smoking delays the onset of Parkinson's disease.
abstract: OBJECTIVE
  Cigarette smoking has been proposed as a protective factor against Parkinson's disease (PD); however it is not known whether smoking also delays its onset.
  
  
  METHODS
  We conducted a long-term study of 247 patients with idiopathic PD to determine whether smoking and other factors influence its onset and development.
  
  
  RESULTS
  The mean age at disease onset was 57+/-9 years. In smokers, the intensity and age at which exposure occurred did not modify the beginning of symptoms. Only female gender (p=0.005) and low educational level (p=0.03) showed a statistical association in the multivariate analysis with a delayed onset of symptoms.
  
  
  CONCLUSIONS
  Our results suggest that females have a delayed onset of symptoms, possibly related to the gonadotropin profile of our population upon the nigrostriatal dopaminergic system. The effect of low educational level may be related to a delayed diagnosis, rather than a true delay of disease onset. This report suggests an influence of gender on the onset of Parkinson's disease.
authors.affiliation: Neuroimmunology Unit, Instituto Nacional de Neurología y Neurocirugía, Col. La Fama, Tlalpan 14269, Mexico City, Mexico.
authors.forename: Abelardo
authors.initials: A
authors.lastname: Martínez-Rumayor
authors.forename: Oscar
authors.initials: O
authors.lastname: Arrieta
authors.forename: Julio
authors.initials: J
authors.lastname: Sotelo
authors.forename: Esperanza
authors.initials: E
authors.lastname: García
mesh_terms: D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D004493:Education; D005260:Female; D006801:Humans; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D010300:Parkinson Disease / Q000453:epidemiology*; D018570:Risk Assessment; D012424:Rural Population; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology*; D014505:Urban Population