title: Neonatal non-hemolytic hyperbilirubinemia: a prevalence study of adult neuropsychiatric disability and cognitive function in 463 male Danish conscripts.
abstract: OBJECTIVE
  To examine whether neonatal non-hemolytic hyperbilirubinemia is associated with adult neuropsychiatric disability and cognitive function.
  
  
  METHODS
  The study included all men born as singletons > or =35 gestational weeks in two Danish counties from 1 January 1977 to 31 December 1983 that registered at conscription in a Danish region. Their infant levels of hyperbilirubinemia was ascertained from hospital records. At conscription, the prevalence of neurologic conditions and performance on a standard group intelligence test (Boerge Prien test) was compared between men with and without neonatal non-hemolytic hyperbilirubinemia.
  
  
  RESULTS
  The study group consisted of 463 conscripts exposed to neonatal non-hemolytic hyperbilirubinemia and 12 718 unexposed conscripts. The median value of maximum serum bilirubin concentration was 256 micromol/l (range 105-482). Among the exposed, 5.6% were deemed unfit for military service due to a neurologic or a psychiatric condition, compared with 4.8% among the unexposed (prevalence ratio 1.18, 95% CI 0.81 to 1.73). Among men with Boerge Prien measurement, mean Boerge Prien test score among 391 exposed men was 42.4 points compared with 43.4 points among 11 248 unexposed men (mean difference 1.0 points, 95% CI 0.0 to 1.9). There was no association between level of hyperbilirubinemia and cognitive score. Adjusted prevalence ratio of obtaining a Boerge Prien test score in the lowest quartile was 1.04 (95% CI 0.87 to 1.23).
  
  
  CONCLUSIONS
  The study found no evidence of an association between neonatal non-hemolytic hyperbilirubinemia and adult neurodevelopment and cognitive performance in male conscripts. Since cognitive performance was not associated with the severity of hyperbilirubinemia we ascribe the slightly lower cognitive scores among exposed to uncontrolled confounding.
authors.affiliation: Department of Pediatrics, Aalborg Hospital, Aarhus University Hospital, Aalborg, Denmark. fe@rn.dk
authors.forename: Finn
authors.initials: F
authors.lastname: Ebbesen
authors.forename: Vera
authors.initials: V
authors.lastname: Ehrenstein
authors.forename: Mette
authors.initials: M
authors.lastname: Traeger
authors.forename: Gunnar Lauge
authors.initials: GL
authors.lastname: Nielsen
mesh_terms: D000293:Adolescent; D003072:Cognition Disorders / Q000453:epidemiology / Q000209:etiology; D003718:Denmark / Q000453:epidemiology; D006801:Humans; D051556:Hyperbilirubinemia, Neonatal / Q000453:epidemiology / Q000523:psychology*; D007231:Infant, Newborn; D007360:Intelligence; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology / Q000209:etiology*; D008889:Military Personnel; D009422:Nervous System Diseases / Q000453:epidemiology / Q000209:etiology*; D015995:Prevalence; D011379:Prognosis; D055815:Young Adult