title: Parental age at delivery, birth order, birth weight and gestational age are associated with the risk of childhood Type 1 diabetes: a UK regional retrospective cohort study.
abstract: OBJECTIVE
  To investigate perinatal risk factors for childhood Type 1 diabetes in a UK population cohort.
  
  
  METHODS
  Perinatal data have been routinely recorded in Northern Ireland for all births in the period 1971-86 (n = 447 663). Diabetes status at the age of 15 years was ascertained in this cohort by identifying 991 children from 1079 registered with Type 1 diabetes diagnosed from 1971 to 2001 and date of birth in the period 1971-86.
  
  
  RESULTS
  Increased Type 1 diabetes risk was associated with higher maternal age, paternal age, birth weight and birth weight for gestational and lower gestational age. After adjustment for maternal age, the association between Type 1 diabetes and paternal age remained significant [relative risk (RR) = 1.52 (1.10, 2.09) comparing father's age 35 years or more to less than 25 years] but not vice versa [RR = 1.11 (0.80, 1.54) comparing mother's age 35 years or more to less than 25 years]. Increased birth order was associated with a significant decrease in the risk of Type 1 diabetes [adjusted RR = 0.75 (0.62, 0.90) comparing birth order three or more with firstborn], but this only became apparent when adjustment was made for maternal age. Furthermore this association with birth order was significant only for diabetes diagnosed under the age of 5 years.
  
  
  CONCLUSIONS
  Our analysis demonstrates, for the first time in a UK regional cohort setting, that maternal age and paternal age at delivery, birth order, birth weight and gestational age are significantly associated with Type 1 diabetes risk.
authors.affiliation: Department of Epidemiology & Public Health, The Queen's University of Belfast, Belfast, UK. c.cardwell@qub.ac.uk
authors.forename: C R
authors.initials: CR
authors.lastname: Cardwell
authors.forename: D J
authors.initials: DJ
authors.lastname: Carson
authors.forename: C C
authors.initials: CC
authors.lastname: Patterson
mesh_terms: D000293:Adolescent; D001722:Birth Order; D001724:Birth Weight; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003922:Diabetes Mellitus, Type 1 / Q000209:etiology*; D005865:Gestational Age; D006801:Humans; D015994:Incidence; D008423:Maternal Age; D010290:Parents; D012189:Retrospective Studies; D012307:Risk Factors; D006113:United Kingdom