title: Body mass index and cognitive function: birth cohort effects in young men.
abstract: OBJECTIVE
  Body mass index (BMI) and intelligence quotient (IQ) are associated. We examined whether this association varied by birth cohort.
  
  
  METHODS
  Among 37,414 Danish conscripts, the association between BMI and IQ overall and by birth cohort was examined. IQ was measured by the Børge Prien's Prøve (BPP) group intelligence test score.
  
  
  RESULTS
  Compared with men of normal BMI, mean differences (95% CI [confidence interval]) in BPP score were -0.6 (-1.1;-0.1) for underweight men; -0.8 (-1.1;-0.5) for overweight men; and -2.0 (-2.4;-1.5) for men with obesity. Crude prevalence ratios (95% CI) for low cognitive scores associated with obesity were, respectively, 1.52 (1.24; 1.85), 1.64 (1.32; 2.04), 1.56 (1.38; 1.76), and 1.35 (1.18; 1.54) among men born in 1955, 1965-1969, 1970-1979, and 1980-1984. Confounding by familial BMI or IQ could not be controlled.
  
  
  CONCLUSIONS
  The association between BMI and IQ is subject to secular trends.
authors: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
authors: Vera
authors: V
authors: Ehrenstein
authors: Anna-Marie Bloch
authors: AM
authors: Münster
authors: Arnold
authors: A
authors: Milstein
authors: Nancy E
authors: NE
authors: Adler
authors: Henrik Toft
authors: HT
authors: Sørensen
mesh_terms: D000328:Adult; D000367:Age Factors; D015992:Body Mass Index; D003071:Cognition / Q000502:physiology*; D015988:Cohort Effect; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003718:Denmark; D006801:Humans; D007360:Intelligence / Q000502:physiology*; D007361:Intelligence Tests; D008297:Male; D009765:Obesity / Q000453:epidemiology* / Q000503:physiopathology; D050177:Overweight / Q000453:epidemiology* / Q000503:physiopathology; D015995:Prevalence; D013851:Thinness / Q000453:epidemiology* / Q000503:physiopathology; D055815:Young Adult