title: Paternal age and general cognitive ability-a cross sectional study of Danish male conscripts.
abstract: OBJECTIVE
  Offspring of older men have impaired cognitive ability as children, but it is unclear if this impairment persists into adulthood. The main objective of this study was to explore the association between paternal age at offspring birth and general cognitive ability as young adults.
  
  
  METHODS
  Population-based cross-sectional study with prospectively collected data on obstetric factors and parental education.
  
  
  METHODS
  Nationwide Danish sample.
  
  
  METHODS
  Male conscripts (n = 169,009).
  
  
  METHODS
  General cognitive ability as assessed by the Børge Priens test score, an intelligence test with components related to logical, verbal, numerical and spatial reasoning.
  
  
  RESULTS
  We observed an inverse U-shaped association between paternal age and general cognitive ability (slightly lower test scores in the offspring of fathers aged less than 25 years and older than 40 years, compared with fathers aged 25 to 29 years). However, after adjustment for maternal age, parental education and birth order the shape of the association changed. Offspring of fathers younger than 20 still showed slightly lower cognitive ability (-1.11 (95% CI -1.68 to -0.54)), but no significant impairments were identified in the men whose fathers were older than 29 years at the time of their birth (e.g. the mean difference in test score in the offspring of fathers aged 40 to 44 years were -0.03 [95% CI (-0.27 to 0.20)] compared with fathers aged 25 to 29 years).
  
  
  CONCLUSIONS
  We did not find that the offspring of older fathers had impaired cognitive ability as young adults. Whereas, we found a tendency that the offspring of teen fathers have lower cognitive ability. Thus, our results suggest that any potentially deleterious effects of older fathers on general cognitive ability as young adults may be counter-balanced by other potentially beneficial factors.
authors.affiliation: Queensland Brain Institute, The University of Queensland, St. Lucia, Australia ; Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Richlands, Australia.
authors.forename: John
authors.initials: J
authors.lastname: McGrath
authors.forename: Preben Bo
authors.initials: PB
authors.lastname: Mortensen
authors.forename: Carsten Bøcker
authors.initials: CB
authors.lastname: Pedersen
authors.forename: Vera
authors.initials: V
authors.lastname: Ehrenstein
authors.forename: Liselotte
authors.initials: L
authors.lastname: Petersen
mesh_terms: D000328:Adult; D002648:Child; D003071:Cognition / Q000502:physiology*; D003430:Cross-Sectional Studies; D004522:Educational Status; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D008423:Maternal Age; D010331:Paternal Age; D055815:Young Adult