title: Stroke is predicted by low visuospatial in relation to other intellectual abilities and coronary heart disease by low general intelligence.
abstract: BACKGROUND
  Low intellectual ability is associated with an increased risk of coronary heart disease and stroke. Most studies have used a general intelligence score. We studied whether three different subscores of intellectual ability predict these disorders.
  
  
  METHODS
  We studied 2,786 men, born between 1934 and 1944 in Helsinki, Finland, who as conscripts at age 20 underwent an intellectual ability test comprising verbal, visuospatial (analogous to Raven's progressive matrices) and arithmetic reasoning subtests. We ascertained the later occurrence of coronary heart disease and stroke from validated national hospital discharge and death registers.
  
  
  RESULTS
  281 men (10.1%) had experienced a coronary heart disease event and 131 (4.7%) a stroke event. Coronary heart disease was predicted by low scores in all subtests, hazard ratios for each standard deviation (SD) lower score ranging from 1.21 to 1.30 (confidence intervals 1.08 to 1.46). Stroke was predicted by a low visuospatial reasoning score, the corresponding hazard ratio being 1.23 (95% confidence interval 1.04 to 1.46), adjusted for year and age at testing. Adjusted in addition for the two other scores, the hazard ratio was 1.40 (1.10 to 1.79). This hazard ratio was little affected by adjustment for socioeconomic status in childhood and adult life, whereas the same adjustments attenuated the associations between intellectual ability and coronary heart disease. The associations with stroke were also unchanged when adjusted for systolic blood pressure at 20 years and reimbursement for adult antihypertensive medication.
  
  
  CONCLUSIONS
  Stroke is predicted by low visuospatial reasoning scores in relation to scores in the two other subtests. This association may be mediated by common underlying causes such as impaired brain development, rather than by mechanisms associated with risk factors shared by stroke and coronary heart disease, such as socio-economic status, hypertension and atherosclerosis.
authors.affiliation: National Institute for Health and Welfare, Helsinki, Finland. eero.kajantie@helsinki.fi
authors.forename: Eero
authors.initials: E
authors.lastname: Kajantie
authors.forename: Katri
authors.initials: K
authors.lastname: Räikkönen
authors.forename: Markus
authors.initials: M
authors.lastname: Henriksson
authors.forename: Jukka T
authors.initials: JT
authors.lastname: Leskinen
authors.forename: Tom
authors.initials: T
authors.lastname: Forsén
authors.forename: Kati
authors.initials: K
authors.lastname: Heinonen
authors.forename: Anu-Katriina
authors.initials: AK
authors.lastname: Pesonen
authors.forename: Clive
authors.initials: C
authors.lastname: Osmond
authors.forename: David J P
authors.initials: DJ
authors.lastname: Barker
authors.forename: Johan G
authors.initials: JG
authors.lastname: Eriksson
mesh_terms: D000328:Adult; D015331:Cohort Studies; D003327:Coronary Disease / Q000175:diagnosis / Q000453:epidemiology*; D005387:Finland / Q000453:epidemiology; D006801:Humans; D007360:Intelligence; D007361:Intelligence Tests; D008297:Male; D011379:Prognosis; D012307:Risk Factors; D012923:Social Class; D013028:Space Perception; D020521:Stroke / Q000175:diagnosis / Q000453:epidemiology*; D055815:Young Adult