title: The association between switching hand preference and the declining prevalence of left-handedness with age.
abstract: OBJECTIVE
  This study determined the prevalence of left-handedness and of switching hand preference among innately left-handed subjects.
  
  
  METHODS
  Subjects of Swiss nationality (n = 1692), participating in a population-based survey in Geneva, Switzerland, completed a questionnaire on innate hand preference and current hand preference for writing.
  
  
  RESULTS
  From 35 to 44 years of age to 65 to 74 years of age, the prevalence of innate left-handedness declined from 11.9% to 6.2% (trend P = .007). In these same age groups, the proportion of innately left-handed subjects who switched to the right hand for writing increased from 26.6% to 88.9% (trend P = .0001).
  
  
  CONCLUSIONS
  Across generations, we found an increase in the prevalence of switching hand preference among innately left-handed subjects. This phenomenon could be explained by social and parental pressure to use the right hand.
authors.affiliation: Division of Clinical Epidemiology, University Hospital of Geneva, Switzerland. bruna.galobardes@hcuge.ch
authors.forename: B
authors.initials: B
authors.lastname: Galobardes
authors.forename: M S
authors.initials: MS
authors.lastname: Bernstein
authors.forename: A
authors.initials: A
authors.lastname: Morabia
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D005260:Female; D007839:Functional Laterality; D006184:Habits; D006801:Humans; D008297:Male; D008875:Middle Aged; D012925:Social Conformity; D013557:Switzerland