title: Prelabor Cesarean Section and Risk of Childhood Type 1 Diabetes: A Nationwide Register-based Cohort Study.
abstract: Unfavorable conditions associated with cesarean section may influence the risk of type 1 diabetes in offspring, but results from studies are conflicting. We aimed to evaluate the association between prelabor cesarean section and risk of childhood type 1 diabetes.
  
  
  
  A Danish nationwide cohort study followed all singletons born during 1982-2010. Four national registers provided information on mode of delivery, outcome, and confounders. The risk of childhood type 1 diabetes with onset before the age of 15 years was assessed by Cox regression. A total of 1,760,336 singletons contributed 20,436,684 person-years, during which 4,400 were diagnosed with childhood type 1 diabetes.
  
  
  
  The hazard ratio (HR) for childhood type 1 diabetes was increased in children delivered by prelabor cesarean section compared with vaginal delivery when adjusted for year of birth, parity, sex, parental age, and education and paternal type 1 diabetes status at childbirth (HR = 1.2; 95% confidence interval [CI] = 1.0, 1.3), but not after additional adjustment for maternal type 1 diabetes status at childbirth (HR = 1.1; 95% CI = 0.95, 1.2). Delivery by intrapartum cesarean section was not associated with childhood type 1 diabetes. Paternal type 1 diabetes was a stronger risk factor for childhood type 1 (HR = 12; 95% CI = 10, 14) than maternal type 1 diabetes (HR = 6.5; 95% CI = 5.2, 8.0).
  
  
  
  Delivery by prelabor cesarean section was not associated with an increased risk of childhood type 1 diabetes in the offspring.
authors.affiliation: From the aDepartment of Gynecology and Obstetrics, Nordsjællands Hospital, University of Copenhagen, Hillerød, Denmark; bSection of Biostatistics, Department of Public Health, University of Copenhagen, Copenhagen, Denmark; and cDepartment of Microbiology, Hvidovre Hospital, Copenhagen, Denmark.
authors.forename: Tine Dalsgaard
authors.initials: TD
authors.lastname: Clausen
authors.forename: Thomas
authors.initials: T
authors.lastname: Bergholt
authors.forename: Frank
authors.initials: F
authors.lastname: Eriksson
authors.forename: Steen
authors.initials: S
authors.lastname: Rasmussen
authors.forename: Niels
authors.initials: N
authors.lastname: Keiding
authors.forename: Ellen C
authors.initials: EC
authors.lastname: Løkkegaard
mesh_terms: D000293:Adolescent; D000328:Adult; D002585:Cesarean Section / Q000706:statistics & numerical data*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000706:statistics & numerical data; D003718:Denmark / Q000453:epidemiology; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology*; D005220:Fathers / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007743:Labor, Obstetric; D008137:Longitudinal Studies; D008297:Male; D009035:Mothers / Q000706:statistics & numerical data; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000453:epidemiology; D016016:Proportional Hazards Models; D012042:Registries; D012307:Risk Factors; D055815:Young Adult