title: Parkinson disease male-to-female ratios increase with age: French nationwide study and meta-analysis.
abstract: BACKGROUND
  Parkinson's disease (PD) is 1.5 times more frequent in men than women. Whether age modifies this ratio is unclear. We examined whether male-to-female (M-F) ratios change with age through a French nationwide prevalence/incidence study (2010) and a meta-analysis of incidence studies.
  
  
  METHODS
  We used French national drug claims databases to identify PD cases using a validated algorithm. We computed M-F prevalence/incidence ratios overall and by age using Poisson regression. Ratios were regressed on age to estimate their annual change. We identified all PD incidence studies with age/sex-specific data, and performed a meta-analysis of M-F ratios.
  
  
  RESULTS
  On the basis of 149 672 prevalent (50% women) and 25 438 incident (49% women) cases, age-standardised rates were higher in men (prevalence=2.865/1000; incidence=0.490/1000 person-years) than women (prevalence=1.934/1000; incidence=0.328/1000 person-years). The overall M-F ratio was 1.48 for prevalence and 1.49 for incidence. Prevalence and incidence M-F ratios increased by 0.05 and 0.14, respectively, per 10 years of age. Incidence was similar in men and women under 50 years (M-F ratio <1.2, p>0.20), and over 1.6 (p<0.001) times higher in men than women above 80 years (p trend <0.001). A meta-analysis of 22 incidence studies (14 126 cases, 46% women) confirmed that M- F ratios increased with age (0.26 per 10 years, p trend=0.005).
  
  
  CONCLUSIONS
  Age-increasing M-F ratios suggest that PD aetiology changes with age. Sex-related risk/protective factors may play a different role across the continuum of age at onset. This finding may inform aetiological PD research.
authors.affiliation: Département santé travail, Institut de veille sanitaire (InVS), Saint-Maurice, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Moisan
authors.affiliation: Département santé travail, Institut de veille sanitaire (InVS), Saint-Maurice, France Department of Epidemiology of ageing and age related diseases, INSERM, Centre for Research in Epidemiology and Population Health, U1018, Villejuif, France University Paris-Sud, UMRS 1018, Villejuif, France.
authors.forename: Sofiane
authors.initials: S
authors.lastname: Kab
authors.affiliation: Department of Epidemiology of ageing and age related diseases, INSERM, Centre for Research in Epidemiology and Population Health, U1018, Villejuif, France University Paris-Sud, UMRS 1018, Villejuif, France.
authors.forename: Fatima
authors.initials: F
authors.lastname: Mohamed
authors.affiliation: Department of Epidemiology of ageing and age related diseases, INSERM, Centre for Research in Epidemiology and Population Health, U1018, Villejuif, France University Paris-Sud, UMRS 1018, Villejuif, France.
authors.forename: Marianne
authors.initials: M
authors.lastname: Canonico
authors.affiliation: Département santé travail, Institut de veille sanitaire (InVS), Saint-Maurice, France.
authors.forename: Morgane
authors.initials: M
authors.lastname: Le Guern
authors.affiliation: Département des maladies chroniques et des traumatismes, Institut de veille sanitaire (InVS), Saint-Maurice, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Quintin
authors.affiliation: Département des maladies chroniques et des traumatismes, Institut de veille sanitaire (InVS), Saint-Maurice, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Carcaillon
authors.affiliation: Institut de veille sanitaire (InVS), Direction scientifique et de la qualité, Saint-Maurice, France.
authors.forename: Javier
authors.initials: J
authors.lastname: Nicolau
authors.affiliation: Département des maladies chroniques et des traumatismes, Institut de veille sanitaire (InVS), Saint-Maurice, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Duport
authors.affiliation: Department of Epidemiology of ageing and age related diseases, INSERM, Centre for Research in Epidemiology and Population Health, U1018, Villejuif, France University Paris-Sud, UMRS 1018, Villejuif, France.
authors.forename: Archana
authors.initials: A
authors.lastname: Singh-Manoux
authors.affiliation: Institut de veille sanitaire (InVS), Direction scientifique et de la qualité, Saint-Maurice, France.
authors.forename: Marjorie
authors.initials: M
authors.lastname: Boussac-Zarebska
authors.affiliation: Département santé travail, Institut de veille sanitaire (InVS), Saint-Maurice, France Department of Epidemiology of ageing and age related diseases, INSERM, Centre for Research in Epidemiology and Population Health, U1018, Villejuif, France University Paris-Sud, UMRS 1018, Villejuif, France.
authors.forename: Alexis
authors.initials: A
authors.lastname: Elbaz
mesh_terms: D000328:Adult; D000465:Algorithms; D000978:Antiparkinson Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000188:drug therapy* / Q000453:epidemiology*; D015995:Prevalence; D012306:Risk; D017678:Sex Distribution
chemical_list: D000978:Antiparkinson Agents
keywords: EPIDEMIOLOGY; PARKINSON'S DISEASE; STATISTICS